Star Raiders source code by Lorenz Wiest#

Lorenz Wiest did a tremendous must see job with a complete commented Star Raiders source code at the highest level possible! Highly recommended!!!
Every assembly source code should look like this. The reader can take his work as a template on how to do it the right way!

Source Code in TXT-Format#

  • StarRaiders.source.txt(info) ; size: 840 KB ; incredible source code listing with assembled hex bytes!!! A must see!!!
  • StarRaiders.source.asm.txt(info) ; size: 644 KB ; incredible source code listing without assembled hex bytes, ready to use in an assembler!!! A must see!!!

Read Me from Lorenz Wiest#

Reverse engineered and fully documented STAR RAIDERS source code

STAR RAIDERS is a seminal computer game, published by Atari Inc. in 1979 as one of the first titles for the original Atari 8-bit Home Computer System (Atari 400 and 800).

During the last years, as a hobby afterhours project, I reverse engineered a complete, extensively documented assembly language source code of STAR RAIDERS. I reverse engineered the source code directly from the binary file of the ROM cartridge, finishing it in September 2015.

This repo contains both the reverse enginered assembly source code input StarRaiders.source.asm.txt(info) and output StarRaiders.source.txt(info).

You may find this useful if you are curious about the internals of STAR RAIDERS or if you are planning to make your own, modified version.

After very positive reader feedback on the initial release of my reverse engineered source code I reviewed it again, resulting in a minor update.

Enjoy -- Lorenz

P.S. I was absolutely thrilled to learn that in October 2015 scans of the original STAR RAIDERS source code re-surfaced.

To my delight, inspection of the original source code confirmed the findings of my reverse engineered version and caused only a few trivial corrections.

Even more, the documentation of my reverse engineered version adds a substantial amount of information - from overall theory of operation down to some tricky details - to the understanding of the often sparsely commented original (quite expected for source code never meant for publication). So, if you are interested in learning how STAR RAIDERS works, my reverse engineered source code could be of help to you.

Extras#

Genome Sequence#

The picture below shows the 'genome sequence' of the reverse engineered STAR RAIDERS 8 KB ROM (which I prepared for a publication. I stacked the 8192 bytes vertically, with each byte represented by a tiny, solid horizontal line of 8 pixels. Then, I split the stack into strips of 192 bytes, arranged side-by-side. The segments of the stack are color-coded:
  • Code (main game loop and subroutines) is in alternating shades of blue.
  • Data (lookup tables, texts, etc.) is in alternating shades of green.
  • Bitmap data (Player-Missile shapes and character set) is in alternating shades of purple and the solid line of a byte is replaced by its actual bit pattern.


STAR RAIDERS 8KB ROM Genome Sequence ; thank you so much Lorenz, that is totally incredible! :-)

ColorSheets#

DisplayListSheets#

References#

Source Code Listing#

              00001 ;*******************************************************************************
              00002 ;*                                                                             *
              00003 ;*                           S T A R   R A I D E R S                           *
              00004 ;*                                                                             *
              00005 ;*                  for the Atari 8-bit Home Computer System                   *
              00006 ;*                                                                             *
              00007 ;*       Reverse engineered and documented assembly language source code       *
              00008 ;*                                                                             *
              00009 ;*                                     by                                      *
              00010 ;*                                                                             *
              00011 ;*                                Lorenz Wiest                                 *
              00012 ;*                                                                             *
              00013 ;*                            (lo.wiest(at)web.de)                             *
              00014 ;*                                                                             *
              00015 ;*                                First Release                                *
              00016 ;*                                 22-SEP-2015                                 *
              00017 ;*                                                                             *
              00018 ;*                                 Last Update                                 *
              00019 ;*                                 10-DEC-2016                                 *
              00020 ;*                                                                             *
              00021 ;*                STAR RAIDERS was created by Douglas Neubauer                 *
              00022 ;*                  STAR RAIDERS was published by Atari Inc.                   *
              00023 ;*                                                                             *
              00024 ;*******************************************************************************
              00025
              00026 ; I wrote this document out of my own curiosity. When STAR RAIDERS was released
              00027 ; in 1979 it became the killer app for the Atari 8-bit Home Computer System.
              00028 ; Since then I have always been wondering what made it tick and how its (at that
              00029 ; time) spectacular 3D graphics worked, especially the rotating star field.
              00030 ; Impressed by "The Atari BASIC Source Book" I decided to reverse engineer the
              00031 ; STAR RAIDERS 8KB ROM cartridge to recreate a fully documented assembly
              00032 ; language source code file. I had no access to the original source code, so the
              00033 ; only way to succeed was a combination of educated guesses, trial-and-error,
              00034 ; and patience. Eventually, I made it.
              00035 ;
              00036 ; Essential in preparing this document were three programs I wrote:
              00037 ;
              00038 ; (1) A 6502-cross-assembler based on the syntax of the MAC/65 assembler for the
              00039 ;     Atari 8-bit Home Computer System to create the binary file that I verified
              00040 ;     against the binary of the original ROM cartridge.
              00041 ;
              00042 ; (2) A text formatter to layout the source code file with its copious comment
              00043 ;     sections. This was a big time saver, because as the documentation grew the
              00044 ;     source code had to be reformatted over and over again.
              00045 ;
              00046 ; (3) A symbol checker to verify that the ubiquitous symbol-value pairs in the
              00047 ;     documentation match the corresponding symbol values produced by the
              00048 ;     assembler.
              00049 ;
              00050 ; This assembly language source code file is compatible with the MAC/65
              00051 ; assembler for the Atari 8-bit Home Computer System. I was able to assemble it
              00052 ; on an emulated Atari running MAC/65, producing the identical binary of the ROM
              00053 ; cartridge. 
              00054 ;
              00055 ; Your feedback is welcome! Send feedback to lo.wiest(at)web.de.
              00056 ;
              00057 ; Enjoy! -- Lorenz
              00058
              00059 ;*******************************************************************************
              00060 ;*                                                                             *
              00061 ;*                               N O T A T I O N                               *
              00062 ;*                                                                             *
              00063 ;*******************************************************************************
              00064
              00065 ; BITS AND BYTES
              00066 ;
              00067 ; o   A "byte" consists of 8 bits. They are numbered B7..0. Bit B0 is the least
              00068 ;     significant bit.
              00069 ;
              00070 ; o   A "word" consists of 16 bits. They are numbered B15..B0. Bit B0 is the
              00071 ;     least significant bit. A word is stored in low-order then high-order byte
              00072 ;     order.
              00073 ;
              00074 ; o   The high-order byte ("high byte") of a word consists of bits B15..8 of the
              00075 ;     word.
              00076 ;
              00077 ; o   The low-order byte ("low byte") of a word consists of bits B7..0 of the
              00078 ;     word.
              00079 ;
              00080 ; NUMBERS
              00081 ;
              00082 ; o   The dollar sign ($) prefixes hexadecimal numbers.
              00083 ;     Example: $101 is the decimal number 257.
              00084 ;
              00085 ; o   The percent sign (%) prefixes binary numbers.
              00086 ;     Example: %101 is the decimal number 5.
              00087 ;
              00088 ; o   The asterisk (*) is a wildcard character for a single hexadecimal or
              00089 ;     binary digit.
              00090 ;     Example: $0*00 is a placeholder for the numbers $0000, $0100, ..., $0F00.
              00091 ;
              00092 ; o   The lowercase R (r) is a wildcard character for a single random
              00093 ;     hexadecimal or binary digit. The random digit r is chosen by a random
              00094 ;     number generator.
              00095 ;     Example: %00r0 is a placeholder for the numbers %0000 or %0010.
              00096 ;
              00097 ; OPERATORS
              00098 ;
              00099 ; o   The exclamation mark (!) is the binary OR operator.
              00100 ;     Example: $01!$02 is $03.
              00101 ;
              00102 ; o   The less-than sign (<) indicates bits B7..0 of a word.
              00103 ;     Example: <$1234 is $34.
              00104 ;
              00105 ; o   The greater-than sign (>) indicates bits B15..8 of a word.
              00106 ;     Example: >$1234 is $12.
              00107 ;
              00108 ; o   A pair of brackets ([]) groups mathematical expressions.
              00109 ;     Example: [3-1]*4 is 8.
              00110 ;
              00111 ; ASSEMBLY LANGUAGE
              00112 ;
              00113 ; o   The uppercase A (A) indicates the accumulator register of the 6502 CPU.
              00114 ;
              00115 ; o   The uppercase X (X) indicates the X register of the 6502 CPU.
              00116 ;
              00117 ; o   The uppercase Y (Y) indicates the Y register of the 6502 CPU.
              00118 ;
              00119 ; o   The prefix uppercase L and dot (L.) indicates a local variable, a memory
              00120 ;     location used temporarily in a subroutine.
              00121 ;
              00122 ; PSEUDO-FUNCTIONS
              00123 ;
              00124 ; o   The function ABS(<num>) returns the absolute value of <num>.
              00125 ;     Example: ABS(3) returns 3.
              00126 ;     Example: ABS(-3) returns 3.
              00127 ;
              00128 ; o   The function RND(<num1>..<num2>) returns a random integer in
              00129 ;     <num1>..<num2>.
              00130 ;     Example: RND(3..5) returns a random number out of 3, 4, or 5.
              00131 ;
              00132 ; o   The function MAX(<num1>,<num2>) returns the larger number of <num1> and
              00133 ;     <num2>.
              00134 ;     Example: MAX(2,4) returns 4.
              00135 ;
              00136 ; VECTORS
              00137 ;
              00138 ; o   The lowercase X (x) indicates the x-axis of the 3D coordinate system.
              00139 ;
              00140 ; o   The lowercase Y (y) indicates the y-axis of the 3D coordinate system.
              00141 ;
              00142 ; o   The lowercase Z (z) indicates the z-axis of the 3D coordinate system.
              00143 ;
              00144 ; o   Components of a position vector (called "coordinates") have the arbitrary
              00145 ;     unit <KM> ("kilometers").
              00146 ;
              00147 ; o   Components of a velocity vector have the arbitrary unit <KM/H>
              00148 ;     ("kilometers per hour").
              00149 ;
              00150 ; o   A positive component of a position vector (coordinate) in hexadecimal
              00151 ;     notation is written in the form +$<hexNum> <KM>. <hexNum> is an unsigned
              00152 ;     integer value.
              00153 ;     Example: The starbase is +$1000 (or 4096) <KM> ahead of our starship.
              00154 ;
              00155 ; o   A negative component of a position vector (coordinate) in hexadecimal
              00156 ;     notation is written in the form -($<hexNum>) <KM>. <hexNum> is an unsigned
              00157 ;     integer value. To calculate the actual bit pattern of this coordinate
              00158 ;     value compute the two's-complement of <hexNum>. See also "ON POSITION
              00159 ;     VECTORS".
              00160 ;     Example: The starbase is -($1000) (or -4096) <KM> behind our starship.
              00161 ;
              00162 ; o   An absolute component of a position vector (coordinate) in hexadecimal
              00163 ;     notation is written in the form $<hexNum> <KM>. <hexNum> is an unsigned
              00164 ;     integer value.
              00165 ;     Example: The Zylon fighter fires when it is closer than $1000 (or 4096)
              00166 ;              <KM>. 
              00167 ;
              00168 ; DISPLAY LIST
              00169 ;
              00170 ; o   The following notation is used for Display List instructions:
              00171 ;
              00172 ;     BLK<n>           = Display <n> blank video lines (<n> in 1..8)
              00173 ;     GR1              = Display one GRAPHICS 1 row of 20 text characters
              00174 ;     GR2              = Display one GRAPHICS 2 row of 20 text characters
              00175 ;     GR7              = Display one GRAPHICS 7 row of 160 pixels
              00176 ;     DLI              = Trigger a Display List Interrupt
              00177 ;     ... @ <addr>     = Point to screen memory at address <addr>
              00178 ;     JMP @ <addr>     = Jump to next Display List instruction at address <addr>
              00179 ;     WAITJMP @ <addr> = Wait for vertical blank phase, then jump to next
              00180 ;                        Display List instruction at address <addr>
              00181 ;
              00182 ; MISCELLANEOUS
              00183 ;
              00184 ; o   Probabilities are written in the form <percentage>% (<number of values out
              00185 ;     of the possible values>:<number of possible values>).
              00186 ;     Example: The probability to throw the number 3 with a die is 16% (1:6).
              00187 ;
              00188 ; o   A "game loop iteration" (or "game loop") is a single execution of the game
              00189 ;     loop, the main program of the game.
              00190 ;
              00191 ; o   A "TICK" is the time span it takes to update the TV screen (1/60 s on an
              00192 ;     NTSC TV system, 1/50 s on a PAL TV system).
              00193 ;
              00194 ; o   A pair of braces ({}) encloses color names.
              00195 ;     Example: {BLACK}
              00196 ;
              00197 ; o   A pair of parentheses enclosing a question mark ((?)) indicates code that
              00198 ;     is not well understood.
              00199 ;
              00200 ; o   A pair of parentheses enclosing an exclamation mark ((!)) indicates a
              00201 ;     potential bug.
              00202
              00203 ;*******************************************************************************
              00204 ;*                                                                             *
              00205 ;*                               O V E R V I E W                               *
              00206 ;*                                                                             *
              00207 ;*******************************************************************************
              00208
              00209 ; ON POSITION VECTORS
              00210 ;
              00211 ; The game uses a 3D coordinate system with the position of our starship at the
              00212 ; center of the coordinate system and the following coordinate axes:
              00213 ;
              00214 ; o   The x-axis points to the right.
              00215 ; o   The y-axis points up.
              00216 ; o   The z-axis points in flight direction.
              00217 ;
              00218 ; By the way, this is called a "left-handed" coordinate system.
              00219 ;
              00220 ; The locations of all space objects (Zylon ships, meteors, photon torpedoes,
              00221 ; starbase, transfer vessel, Hyperwarp Target Marker, stars, and explosion
              00222 ; fragments) are described by a "position vector".
              00223 ;
              00224 ; A "position vector" is composed of an x, y, and z component. The values of the
              00225 ; position vector components are called the x, y, and z "coordinates". They have
              00226 ; the arbitrary unit <KM>.
              00227 ;
              00228 ; Each coordinate is a signed 17-bit integer number, which fits into 3 bytes:
              00229 ;
              00230 ;     Sign     Mantissa
              00231 ;          B16 B15...B8 B7....B0
              00232 ;            | |      | |      |
              00233 ;     0000000* ******** ********
              00234 ;
              00235 ; o   B16 contains the sign bit. Used values are:
              00236 ;       1 -> Positive sign
              00237 ;       0 -> Negative sign
              00238 ; o   B15..0 contain the coordinate value (or "mantissa") as a two's-complement
              00239 ;     integer number.
              00240 ;
              00241 ; The range of a position vector component is -65536..+65535 <KM>.
              00242 ;
              00243 ; Examples:
              00244 ;
              00245 ;     00000001 11111111 11111111 = +65535 <KM>
              00246 ;     00000001 00010000 00000000 =  +4096 <KM>
              00247 ;     00000001 00001111 11111111 =  +4095 <KM>
              00248 ;     00000001 00000001 00000000 =   +256 <KM>
              00249 ;     00000001 00000000 11111111 =   +255 <KM>
              00250 ;     00000001 00000000 00010000 =    +16 <KM>
              00251 ;     00000001 00000000 00001111 =    +15 <KM>
              00252 ;     00000001 00000000 00000001 =     +1 <KM>
              00253 ;     00000001 00000000 00000000 =     +0 <KM>
              00254 ;
              00255 ;     00000000 11111111 11111111 =     -1 <KM>
              00256 ;     00000000 11111111 11111110 =     -2 <KM>
              00257 ;     00000000 11111111 11110001 =    -15 <KM>
              00258 ;     00000000 11111111 11110000 =    -16 <KM>
              00259 ;     00000000 11111111 00000001 =   -255 <KM>
              00260 ;     00000000 11111111 00000000 =   -256 <KM>
              00261 ;     00000000 11110000 00000001 =  -4095 <KM>
              00262 ;     00000000 11110000 00000000 =  -4096 <KM>
              00263 ;     00000000 00000000 00000000 = -65536 <KM>
              00264 ;
              00265 ; The position vector for each space object is stored in 9 tables:
              00266 ;
              00267 ; o   XPOSSIGN ($09DE..$0A0E), XPOSHI ($0A71..$0AA1), and XPOSLO ($0B04..$0B34)
              00268 ; o   YPOSSIGN ($0A0F..$0A3F), YPOSHI ($0AA2..$0AD2), and YPOSLO ($0B35..$0B65)
              00269 ; o   ZPOSSIGN ($09AD..$09DD), ZPOSHI ($0A40..$0A70), and ZPOSLO ($0AD3..$0B03)
              00270 ;
              00271 ; There are up to 49 space objects used in the game simultaneously, thus each
              00272 ; table is 49 bytes long.
              00273 ;
              00274 ; o   Position vectors 0..4 belong to space objects represented by PLAYERs
              00275 ;     (Zylon ships, meteors, photon torpedoes, starbase, transfer vessel, and
              00276 ;     Hyperwarp Target Marker).
              00277 ; o   Position vectors 5..48 belong to space objects represented by PLAYFIELD
              00278 ;     pixels. Position vectors 5..16 (stars, explosion fragments) are used for
              00279 ;     stars, position vectors 17..48 are used for explosion fragments and star
              00280 ;     trails.
              00281 ;
              00282 ; INFO: The x and y coordinates of space objects are converted and displayed by
              00283 ; the THETA and PHI readouts of the Control Panel Display in "gradons". The
              00284 ; z-coordinate is converted and displayed by the RANGE readout in "centrons".
              00285 ; The conversion takes place in subroutine SHOWDIGITS ($B8CD) where the high
              00286 ; byte of a coordinate (with values $00..$FF) is transformed with lookup table
              00287 ; MAPTOBCD99 ($0EE9) into a BCD value of 00..99 in "gradons" or "centrons".
              00288 ;
              00289 ;
              00290 ; ON VELOCITY VECTORS
              00291 ;
              00292 ; The velocities of all space objects are described by a "velocity vector". The
              00293 ; velocity vector is relative to our starship.
              00294 ;
              00295 ; A "velocity vector" is composed of an x, y, and z component. The values of the
              00296 ; velocity vector components are called the x, y, and z "velocities". They have
              00297 ; the arbitrary unit <KM/H>.
              00298 ;
              00299 ; Each velocity vector component is an 8-bit integer number, which fits into 1
              00300 ; byte:
              00301 ;
              00302 ;     B7 Sign
              00303 ;     |
              00304 ;     |B6...B0 Mantissa
              00305 ;     ||     |
              00306 ;     ********
              00307 ;
              00308 ; o   B7 contains the sign bit. Used values are:
              00309 ;     0 -> Positive sign, movement along the positive coordinate axis
              00310 ;          (x-velocity: right, y-velocity: up, z-velocity: in flight direction)
              00311 ;     1 -> Negative sign, movement along the negative coordinate axis
              00312 ;          (x-velocity: left, y-velocity: down, z-velocity: in reverse flight
              00313 ;          direction)
              00314 ; o   B6..B0 contain the velocity value (or "mantissa"). It is an unsigned
              00315 ;     number.
              00316 ;
              00317 ; The range of a velocity vector component is -127..+127 <KM/H>.
              00318 ;
              00319 ; Examples:
              00320 ;
              00321 ;     01111111 = +127 <KM/H>
              00322 ;     00010000 =  +16 <KM/H>
              00323 ;     00001111 =  +15 <KM/H>
              00324 ;     00000001 =   +1 <KM/H>
              00325 ;     00000000 =   +0 <KM/H>
              00326 ;
              00327 ;     10000000 =   -0 <KM/H>
              00328 ;     10000001 =   -1 <KM/H>
              00329 ;     10001111 =  +15 <KM/H>
              00330 ;     10010000 =  +16 <KM/H>
              00331 ;     11111111 = -127 <KM/H>
              00332 ;
              00333 ; The velocity vector for each space object stored in 3 tables:
              00334 ;
              00335 ; o   XVEL ($0B97..$0BC7)
              00336 ; o   YVEL ($0BC8..$0BF8)
              00337 ; o   ZVEL ($0B66..$0B96)
              00338 ;
              00339 ; There are up to 49 space objects used in the game simultaneously, thus each
              00340 ; table is 49 bytes long.
              00341 ;
              00342 ; o   Velocity vectors 0..4 belong to space objects represented by PLAYERs
              00343 ;     (Zylon ships, meteors, photon torpedoes, starbase, transfer vessel, and
              00344 ;     Hyperwarp Target Marker).
              00345 ; o   Velocity vectors 5..48 belong to space objects represented by PLAYFIELD
              00346 ;     pixels. Velocity vectors 5..16 are used for stars, velocity vectors 17..48
              00347 ;     are used for explosion fragments and star trails.
              00348 ;
              00349 ; INFO: The velocity of our starship is converted and displayed by the VELOCITY
              00350 ; readout of the Control Panel Display in "metrons per second" units. The
              00351 ; conversion takes place in subroutine SHOWDIGITS ($B8CD) where our starship's
              00352 ; velocity VELOCITYL ($70) (with values $00..$FF) is transformed with lookup
              00353 ; table MAPTOBCD99 ($0EE9) into a BCD value of 00..99 in "metrons per second".  
              00354
              00355 ;*******************************************************************************
              00356 ;*                                                                             *
              00357 ;*                             M E M O R Y   M A P                             *
              00358 ;*                                                                             *
              00359 ;*******************************************************************************
              00360 ;
              00361 ; The following variables are not changed by a SYSTEM RESET:
              00362 ;
              00363 ; $62      MISSIONLEVEL
              00364 ;
              00365 ;          Mission level. Used values are:
              00366 ;            $00 -> NOVICE mission
              00367 ;            $01 -> PILOT mission
              00368 ;            $02 -> WARRIOR mission
              00369 ;            $03 -> COMMANDER mission
              00370 ;
              00371 ; $63      FKEYCODE
              00372 ;
              00373 ;          Function key code. Used values are:
              00374 ;            $00 -> No function key pressed
              00375 ;            $01 -> START function key pressed
              00376 ;            $02 -> SELECT function key pressed
              00377 ;
              00378 ; $64      ISDEMOMODE
              00379 ;
              00380 ;          Indicates whether the game is in game or in demo mode. Used values
              00381 ;          are:
              00382 ;            $00 -> Game mode
              00383 ;            $FF -> Demo mode
              00384 ;
              00385 ; $65      NEWTITLEPHR
              00386 ;
              00387 ;          New title phrase offset for the text in the title line. The new title
              00388 ;          phrase is not immediately displayed in the title line but only after
              00389 ;          the display time of the currently displayed title phrase has expired.
              00390 ;          Thus, setting a value to NEWTITLEPHR ($65) "enqueues" the display of
              00391 ;          new title phrase. Used values are:
              00392 ;            $00..$7B -> Title phrase offset into PHRASETAB ($BBAA)
              00393 ;            $FF      -> Hide title line
              00394 ;
              00395 ;          See also TITLEPHR ($D1).
              00396 ;
              00397 ; $66      IDLECNTHI
              00398 ;
              00399 ;          Idle counter (high byte). Forms a 16-bit counter together with
              00400 ;          IDLECNTLO ($77), which is incremented during the execution of the
              00401 ;          Vertical Blank Interrupt handler VBIHNDLR ($A6D1). IDLECNTHI ($66) is
              00402 ;          reset to 0 when the joystick trigger or a keyboard key has been
              00403 ;          pressed, or to 1..3 when a function key has been pressed. When
              00404 ;          IDLECNTHI ($66) reaches a value of 128 (after about 10 min idle time)
              00405 ;          the game enters demo mode.
              00406 ;
              00407 ; The following variables are set to 0 after a SYSTEM RESET:
              00408 ;
              00409 ; $67      ISVBISYNC
              00410 ;
              00411 ;          Indicates whether the Vertical Blank Interrupt handler VBIHNDLR
              00412 ;          ($A6D1) is executed. Used to synchronize the execution of a new game
              00413 ;          loop iteration in GAMELOOP ($A1F3) with the vertical blank phase.
              00414 ;          Used values are:
              00415 ;            $00 -> Halt execution at start of game loop and wait for VBI
              00416 ;            $FF -> Continue execution of game loop
              00417 ;
              00418 ; $68..$69 MEMPTR
              00419 ;
              00420 ;          A 16-bit memory pointer.
              00421 ;
              00422 ;          Also used as a local variable.
              00423 ;
              00424 ; $6A..$6B DIVIDEND
              00425 ;
              00426 ;          A 16-bit dividend value passed in GAMELOOP ($A1F3) to subroutine
              00427 ;          PROJECTION ($AA21) to calculate a division.
              00428 ;
              00429 ;          Also used as a local variable.
              00430 ;
              00431 ; $6C      Used as a local variable.
              00432 ;
              00433 ; $6D      JOYSTICKDELTA
              00434 ;
              00435 ;          Used to pass joystick directions from GAMELOOP ($A1F3) to subroutine
              00436 ;          ROTATE ($B69B). Used values are:
              00437 ;            $01 -> Joystick pressed right or up
              00438 ;            $00 -> Joystick centered
              00439 ;            $FF -> Joystick pressed left or down
              00440 ;
              00441 ;          Also used as a local variable.
              00442 ;
              00443 ; $6E      Used as a local variable.
              00444 ;
              00445 ; $70      VELOCITYLO
              00446 ;
              00447 ;          Our starship's current velocity (low byte) in <KM/H>. Forms a 16-bit
              00448 ;          value together with VELOCITYHI ($C1). In subroutine UPDPANEL ($B804),
              00449 ;          VELOCITYLO ($70) is mapped to a BCD-value in 00..99 and displayed by
              00450 ;          the VELOCITY readout of the Control Panel Display. See also
              00451 ;          NEWVELOCITY ($71).
              00452 ;
              00453 ; $71      NEWVELOCITY
              00454 ;
              00455 ;          Our starship's new velocity (low byte) in <KM/H>. It is set by
              00456 ;          pressing one of the speed keys '0'..'9'. A pressed speed key is
              00457 ;          mapped to the new velocity value with VELOCITYTAB ($BAB4).
              00458 ;
              00459 ; $72      COUNT8
              00460 ;
              00461 ;          Wrap-around counter. Counts from 0..7, then starts over at 0. It is
              00462 ;          incremented every game loop iteration. It is used to change the
              00463 ;          brightness of stars and explosion fragments more randomly in GAMELOOP
              00464 ;          ($A1F3) and to slow down the movement of the hyperwarp markers of the
              00465 ;          Galactic Chart in subroutine SELECTWARP ($B162).
              00466 ;
              00467 ; $73      EXPLLIFE
              00468 ;
              00469 ;          Explosion lifetime. It is decremented every game loop iteration. Used
              00470 ;          values are:
              00471 ;              $00 -> Explosion is over
              00472 ;            < $18 -> Number of explosion fragment space objects is decremented
              00473 ;            < $70 -> HITBADNESS ($8A) is reset
              00474 ;              $80 -> Initial value at start of explosion
              00475 ;
              00476 ; $74      CLOCKTIM
              00477 ;
              00478 ;          Star date clock delay timer. Counts down from 40 to 0. It is
              00479 ;          decremented every game loop iteration. When the timer falls below 0
              00480 ;          the last digit of the star date of the Galactic Chart Panel Display
              00481 ;          is increased and the timer is reset to a value of 40. 
              00482 ;
              00483 ; $75      DOCKSTATE
              00484 ;
              00485 ;          State of docking operation. Used values are:
              00486 ;            $00 -> NOT DOCKED
              00487 ;            $01 -> TRANSFER COMPLETE
              00488 ;            $81 -> RETURN TRANSFER VESSEL
              00489 ;            $FF -> ORBIT ESTABLISHED
              00490 ;
              00491 ; $76      COUNT256
              00492 ;
              00493 ;          Wrap-around counter. Counts from 0..255, then starts over at 0. It is
              00494 ;          incremented every game loop iteration. It is used to make the
              00495 ;          starbase pulsate in brightness in GAMELOOP ($A1F3) and to decide on
              00496 ;          the creation of a meteor in subroutine MANEUVER ($AA79).
              00497 ;
              00498 ; $77      IDLECNTLO
              00499 ;
              00500 ;          Idle counter (low byte). Forms a 16-bit counter together with
              00501 ;          IDLECNTHI ($66), which is incremented during the execution of the
              00502 ;          Vertical Blank Interrupt handler VBIHNDLR ($A6D1).
              00503 ;
              00504 ;          NOTE: This variable is never properly initialized except at initial
              00505 ;          cartridge startup (cold start).
              00506 ;
              00507 ; $78      ZYLONUNITTIM
              00508 ;
              00509 ;          Zylon unit movement timer. This delay timer triggers movement of
              00510 ;          Zylon units on the Galactic Chart. At the start of the game, the
              00511 ;          timer is initialized to a value of 100. It is decremented every 40
              00512 ;          game loop iterations. When the timer falls below 0 the Zylon units
              00513 ;          move on the Galactic Chart and the timer value is reset to 49. If a
              00514 ;          starbase is surrounded the timer is reset to 99 to buy you some extra
              00515 ;          time to destroy one of the surrounding Zylon units.
              00516 ;
              00517 ; $79      MAXSPCOBJIND
              00518 ;
              00519 ;          Maximum index of used space objects in the current game loop
              00520 ;          iteration. Frequently used values are:
              00521 ;            $10 -> During regular cruise (5 PLAYER space objects + 12 PLAYFIELD
              00522 ;                   space objects (stars), counted $00..$10)
              00523 ;            $30 -> During explosion or hyperwarp (5 PLAYER space objects + 12
              00524 ;                   PLAYFIELD space objects (stars) + 32 PLAYFIELD space objects
              00525 ;                   (explosion fragments or stars of star trails), counted
              00526 ;                   $00..$30)
              00527 ;
              00528 ; $7A      OLDMAXSPCOBJIND
              00529 ;
              00530 ;          Maximum index of used space objects in the previous game loop
              00531 ;          iteration. Frequently used values are:
              00532 ;            $10 -> During regular cruise (5 PLAYER space objects + 12 PLAYFIELD
              00533 ;                   space objects (stars), counted $00..$10)
              00534 ;            $30 -> During explosion or hyperwarp (5 PLAYER space objects + 12
              00535 ;                   PLAYFIELD space objects (stars) + 32 PLAYFIELD space objects
              00536 ;                   (explosion fragments or stars of star trails), counted
              00537 ;                   $00..$30)
              00538 ;
              00539 ; $7B      ISSTARBASESECT
              00540 ;
              00541 ;          Indicates whether a starbase is in this sector. Used values are:
              00542 ;            $00 -> Sector contains no starbase
              00543 ;            $FF -> Sector contains starbase
              00544 ;
              00545 ; $7C      ISTRACKCOMPON
              00546 ;
              00547 ;          Indicates whether the Tracking Computer is on or off. Used values
              00548 ;          are:
              00549 ;            $00 -> Tracking Computer is off
              00550 ;            $FF -> Tracking Computer is on
              00551 ;
              00552 ; $7D      DRAINSHIELDS
              00553 ;
              00554 ;          Energy drain rate of the Shields per game loop iteration in energy
              00555 ;          subunits. See also subroutine UPDPANEL ($B804). Used values are:
              00556 ;            $00 -> Shields are off
              00557 ;            $08 -> Shields are on
              00558 ;
              00559 ; $7E      DRAINATTCOMP
              00560 ;
              00561 ;          Energy drain rate of the Attack Computer per game loop iteration in
              00562 ;          energy subunits. See also subroutine UPDPANEL ($B804). Used values
              00563 ;          are:
              00564 ;            $00 -> Attack Computer off
              00565 ;            $02 -> Attack Computer on
              00566 ;
              00567 ; $7F      ENERGYCNT
              00568 ;
              00569 ;          Running counter of consumed energy subunits (256 energy subunits = 1
              00570 ;          energy unit displayed by the 4-digit ENERGY readout of the Control
              00571 ;          Panel Display). Forms an invisible fractional or "decimals" part of
              00572 ;          the 4-digit ENERGY readout of the Control Panel Display. See also
              00573 ;          subroutine UPDPANEL ($B804).
              00574 ;
              00575 ; $80      DRAINENGINES
              00576 ;
              00577 ;          Energy drain rate of our starship's Engines per game loop iteration
              00578 ;          in energy subunits (256 energy subunits = 1 energy unit displayed by
              00579 ;          the 4-digit ENERGY readout of the Control Panel Display). Values are
              00580 ;          picked from table DRAINRATETAB ($BAD3). See also subroutine UPDPANEL
              00581 ;          ($B804).
              00582 ;
              00583 ; $81      SHIELDSCOLOR
              00584 ;
              00585 ;          Shields color. Used values are: 
              00586 ;            $00 -> {BLACK} (Shields are off)
              00587 ;            $A0 -> {DARK GREEN} (Shields are on)
              00588 ;
              00589 ; $82      PL3HIT
              00590 ;
              00591 ;          Collision register of PLAYER3 (usually our starship's photon torpedo
              00592 ;          0) with other PLAYERs. Used values are:
              00593 ;              $00 -> No collision
              00594 ;            > $00 -> PLAYER3 has collided with another PLAYER space object. See
              00595 ;                     subroutine COLLISION ($AF3D) for details which PLAYER has
              00596 ;                     been hit by PLAYER3.
              00597 ;
              00598 ; $83      PL4HIT
              00599 ;
              00600 ;          Collision register of PLAYER4 (usually our starship's photon torpedo
              00601 ;          1) with other PLAYERs. Used values are:
              00602 ;              $00 -> No collision
              00603 ;            > $00 -> PLAYER4 has collided with another PLAYER space object. See
              00604 ;                     subroutine COLLISION ($AF3D) for details which PLAYER has
              00605 ;                     been hit by PLAYER4.
              00606 ;
              00607 ; $84      OLDTRIG0
              00608 ;
              00609 ;          Joystick trigger state. Used values are:
              00610 ;            $00 -> Joystick trigger was pressed
              00611 ;            $01 -> Joystick trigger was not pressed
              00612 ;            $AA -> Joystick trigger was "virtually" pressed (will launch
              00613 ;                   another of our starship's photon torpedoes, see subroutine
              00614 ;                   TRIGGER ($AE29).
              00615 ;
              00616 ; $86      ISTRACKING
              00617 ;
              00618 ;          Indicates whether one of our starship's photon torpedoes is currently
              00619 ;          tracking (homing in on) the target space object. Used values are:
              00620 ;              $00 -> No target space object tracked. Our starship's photon
              00621 ;                     torpedoes will fly just straight ahead.
              00622 ;            > $00 -> Tracking a target space object. Our starship's photon
              00623 ;                     torpedoes will home in on the tracked space object.
              00624 ;
              00625 ; $87      BARRELNR
              00626 ;
              00627 ;          Barrel from which our starship's next photon torpedo will be
              00628 ;          launched. Used values are:
              00629 ;            $00 -> Left barrel
              00630 ;            $01 -> Right barrel
              00631 ;
              00632 ; $88      LOCKONLIFE
              00633 ;
              00634 ;          Lifetime of target lock-on. A target remains in lock-on while
              00635 ;          LOCKONLIFE ($88) counts down from 12 to 0. It is decremented every
              00636 ;          game loop iteration.
              00637 ;
              00638 ; $89      PLTRACKED
              00639 ;
              00640 ;          Index of currently tracked PLAYER. It is copied in subroutine TRIGGER
              00641 ;          ($AE29) from TRACKDIGIT ($095C). Used values are:
              00642 ;            $00 -> Track Zylon ship 0
              00643 ;            $01 -> Track Zylon ship 1
              00644 ;            $02 -> Track starbase during docking operations
              00645 ;            $03 -> Track Hyperwarp Target Marker during hyperwarp
              00646 ;
              00647 ; $8A      HITBADNESS
              00648 ;
              00649 ;          Severity of a Zylon photon torpedo hit. Used values are:
              00650 ;            $00 -> NO HIT
              00651 ;            $7F -> SHIELDS HIT
              00652 ;            $FF -> STARSHIP DESTROYED
              00653 ;
              00654 ; $8B      REDALERTLIFE
              00655 ;
              00656 ;          Lifetime of red alert. It decreases from 255 to 0. It is decremented
              00657 ;          every game loop iteration.
              00658 ;
              00659 ; $8C      WARPDEPRROW
              00660 ;
              00661 ;          Departure hyperwarp marker row number on the Galactic Chart. It is
              00662 ;          given in Player/Missile pixels relative to the top Galactic Chart
              00663 ;          border. It is initialized to a value of $47 (vertical center of
              00664 ;          Galactic Chart). Divide this value by 16 to get the departure sector
              00665 ;          row number. Used values are: $00..$7F.
              00666 ;
              00667 ; $8D      WARPDEPRCOLUMN
              00668 ;
              00669 ;          Departure hyperwarp marker column number on the Galactic Chart. It is
              00670 ;          given in Player/Missile pixels relative to the left Galactic Chart
              00671 ;          border and initialized to a value of $43 (horizontal center of
              00672 ;          Galactic Chart). Divide this value by 8 to get the departure sector
              00673 ;          column number. Used values are: $00..$7F.
              00674 ;
              00675 ; $8E      WARPARRVROW
              00676 ;
              00677 ;          Arrival hyperwarp marker row number on the Galactic Chart in
              00678 ;          Player/Missile pixels relative to top Galactic Chart border. It is
              00679 ;          initialized to a value of $47 (vertical center of Galactic Chart).
              00680 ;          Divide this value by 16 to get the arrival sector row number. Used
              00681 ;          values are: $00..$7F. 
              00682 ;
              00683 ; $8F      WARPARRVCOLUMN
              00684 ;
              00685 ;          Arrival hyperwarp marker column number on the Galactic Chart in
              00686 ;          Player/Missile pixels relative to left Galactic Chart border. It is
              00687 ;          initialized to a value of $43 (horizontal center of Galactic Chart).
              00688 ;          Divide this value by 8 to get the arrival sector column number. Used
              00689 ;          values are: $00..$7F. 
              00690 ;
              00691 ; $90      CURRSECTOR
              00692 ;
              00693 ;          Galactic Chart sector of the current location of our starship. At the
              00694 ;          start of the game it is initialized to a value of $48. Used values
              00695 ;          are: $00..$7F with, for example,
              00696 ;            $00 -> NORTHWEST corner sector
              00697 ;            $0F -> NORTHEAST corner sector
              00698 ;            $70 -> SOUTHWEST corner sector
              00699 ;            $7F -> SOUTHWEST corner sector
              00700 ;
              00701 ;          See also ARRVSECTOR ($92). 
              00702 ;
              00703 ; $91      WARPENERGY
              00704 ;
              00705 ;          Energy required to hyperwarp between the departure and arrival
              00706 ;          hyperwarp marker locations on the Galactic Chart divided by 10.
              00707 ;          Values are picked from table WARPENERGYTAB ($BADD). Multiply this
              00708 ;          value by 10 to get the actual value in energy units displayed by the
              00709 ;          Galactic Chart Panel Display.
              00710 ;
              00711 ; $92      ARRVSECTOR
              00712 ;
              00713 ;          Galactic Chart arrival sector of our starship after hyperwarp. Used
              00714 ;          values are: $00..$7F with, for example,
              00715 ;            $00 -> NORTHWEST corner sector
              00716 ;            $0F -> NORTHEAST corner sector
              00717 ;            $70 -> SOUTHWEST corner sector
              00718 ;            $7F -> SOUTHWEST corner sector
              00719 ;
              00720 ;          See also CURRSECTOR ($90). 
              00721 ;
              00722 ; $93      HUNTSECTOR
              00723 ;
              00724 ;          Galactic Chart sector of the starbase toward which the Zylon units
              00725 ;          are currently moving. Used values are: $00..$7F with, for example,
              00726 ;            $00 -> NORTHWEST corner sector
              00727 ;            $0F -> NORTHEAST corner sector
              00728 ;            $70 -> SOUTHWEST corner sector
              00729 ;            $7F -> SOUTHWEST corner sector
              00730 ;
              00731 ; $94      HUNTSECTCOLUMN
              00732 ;
              00733 ;          Galactic Chart sector column number of the starbase toward which the
              00734 ;          Zylon units are currently moving. Used values are: 0..15.
              00735 ;
              00736 ; $95      HUNTSECTROW
              00737 ;
              00738 ;          Galactic Chart sector row number of the starbase toward which the
              00739 ;          Zylon units are currently moving. Used values are: 0..7.
              00740 ;
              00741 ; $96..$9E NEWZYLONDIST
              00742 ;
              00743 ;          Table of distances between a Zylon unit and the hunted starbase when
              00744 ;          the Zylon unit is tentatively moved in one of the 9 possible
              00745 ;          directions NORTH, NORTHWEST, WEST, SOUTHWEST, SOUTH, SOUTHEAST, EAST,
              00746 ;          NORTHEAST, CENTER. Used to decide into which sector the Zylon unit
              00747 ;          should move.
              00748 ;
              00749 ; $9E      OLDZYLONDIST
              00750 ;
              00751 ;          Current distance between the Zylon unit and the hunted starbase.
              00752 ;
              00753 ; $9F      HUNTTIM
              00754 ;
              00755 ;          Delay timer for Zylon units to decide on which starbase to hunt. It
              00756 ;          counts down from 7. It is decremented every game loop iteration. When
              00757 ;          the timer falls below 0 the Zylon units re-decide toward which
              00758 ;          starbase to move.
              00759 ;
              00760 ; $A0      BLIPCOLUMN
              00761 ;
              00762 ;          Top-left screen pixel column number of blip shape displayed in the
              00763 ;          Attack Computer Display. Used in subroutine UPDATTCOMP ($A7BF). Used
              00764 ;          values are: 120..142.
              00765 ;
              00766 ; $A1      BLIPROW
              00767 ;
              00768 ;          Top-left screen pixel row number of blip shape displayed in the
              00769 ;          Attack Computer Display. Used in subroutine UPDATTCOMP ($A7BF). Used
              00770 ;          values are: 71..81.
              00771 ;
              00772 ; $A2      BLIPCYCLECNT
              00773 ;
              00774 ;          Blip cycle counter. It controls drawing the blip shape in the Attack
              00775 ;          Computer Display. Its value is incremented every game loop iteration.
              00776 ;          Used in subroutine UPDATTCOMP ($A7BF). Used values are:
              00777 ;            $00..$04 -> Draw 0..4th row of blip shape
              00778 ;            $05..$09 -> Do not draw blip shape (delay)
              00779 ;            $0A      -> Recalculate blip shape position, erase Attack Computer
              00780 ;                        Display
              00781 ;
              00782 ; $A3      ISINLOCKON
              00783 ;
              00784 ;          Indicates whether the tracked space object is currently in full
              00785 ;          lock-on (horizontally and vertically centered as well as in range) in
              00786 ;          the Attack Computer Display. If so, all lock-on markers show up on
              00787 ;          the Attack Computer Display and our starship's launched photon
              00788 ;          torpedoes will home in on the tracked space object. Used values are:
              00789 ;            $00 -> Not in lock-on
              00790 ;            $A0 -> In lock-on
              00791 ;
              00792 ; $A4      DIRLEN
              00793 ;
              00794 ;          Used to pass the direction and length of a single line to be drawn in
              00795 ;          the PLAYFIELD. Used in subroutines DRAWLINES ($A76F), DRAWLINE
              00796 ;          ($A782), and UPDATTCOMP ($A7BF). Used values are:
              00797 ;            Bit B7 = 0 -> Draw right
              00798 ;            Bit B7 = 1 -> Draw down
              00799 ;            Bits B6..0 -> Length of line in pixels.
              00800 ;
              00801 ;          See also PENROW ($A5) and PENCOLUMN ($A6).
              00802 ;
              00803 ; $A5      PENROW
              00804 ;
              00805 ;          Used to pass the start screen pixel row number of the line to be
              00806 ;          drawn in the PLAYFIELD. Used in subroutines DRAWLINES ($A76F),
              00807 ;          DRAWLINE ($A782), and UPDATTCOMP ($A7BF).
              00808 ;
              00809 ; $A6      PENCOLUMN
              00810 ;
              00811 ;          Used to pass the start screen pixel column number of the line to be
              00812 ;          drawn in the PLAYFIELD. Used in subroutines DRAWLINES ($A76F),
              00813 ;          DRAWLINE ($A782), and UPDATTCOMP ($A7BF).
              00814 ;
              00815 ; $A7      CTRLDZYLON
              00816 ;
              00817 ;          Index of Zylon ship currently controlled by the game. Used in
              00818 ;          subroutine MANEUVER ($AA79). The value is toggled every other game
              00819 ;          loop iteration. Used values are:
              00820 ;            $00 -> Control Zylon ship 0.
              00821 ;            $01 -> Control Zylon ship 1.
              00822 ;
              00823 ; $A8      ZYLONFLPAT0
              00824 ;
              00825 ;          Flight pattern of Zylon ship 0. Used in subroutine MANEUVER ($AA79).
              00826 ;          Used values are:
              00827 ;            $00 -> Attack flight pattern "0"
              00828 ;            $01 -> Flight pattern "1"
              00829 ;            $04 -> Flight pattern "4"
              00830 ;
              00831 ; $A9      ZYLONFLPAT1
              00832 ;
              00833 ;          Flight pattern of Zylon ship 1. Compare ZYLONFLPAT0 ($A8).
              00834 ;
              00835 ; $AA      MILESTTIM0
              00836 ;
              00837 ;          Delay timer of the milestone velocity indices of Zylon ship 0. Used
              00838 ;          in subroutine MANEUVER ($AA79).
              00839 ;
              00840 ;          When Zylon ship 0 is active, this value is decremented every game
              00841 ;          loop iteration. If it falls below 0 then the milestone velocity
              00842 ;          indices of Zylon ship 0 are recalculated. When Zylon ship 0 is
              00843 ;          controlled by the computer for the first time, the timer is set to an
              00844 ;          initial value of 1, later to an initial value of 120.
              00845 ;
              00846 ; $AB      MILESTTIM1
              00847 ;
              00848 ;          Delay timer of the milestone velocity index vector of Zylon ship 1.
              00849 ;          Compare MILESTTIM0 ($AA).
              00850 ;
              00851 ; $AC      MILESTVELINDZ0
              00852 ;
              00853 ;          Milestone z-velocity index of Zylon ship 0. Used in subroutine
              00854 ;          MANEUVER ($AA79). The current z-velocity index of Zylon ship 0
              00855 ;          ZYLONVELINDZ0 ($B2) is compared with this index and gradually
              00856 ;          adjusted to it. Used values are: 0..15.
              00857 ;
              00858 ; $AD      MILESTVELINDZ1
              00859 ;
              00860 ;          Milestone z-velocity index of Zylon ship 1. Compare MILESTVELINDZ0
              00861 ;          ($AC).
              00862 ;
              00863 ; $AE      MILESTVELINDX0
              00864 ;
              00865 ;          Milestone x-velocity index of Zylon ship 0. Used in subroutine
              00866 ;          MANEUVER ($AA79). The current x-velocity index of Zylon ship 0
              00867 ;          ZYLONVELINDX0 ($B4) is compared with this index and gradually
              00868 ;          adjusted to it. Used values are: 0..15.
              00869 ;
              00870 ; $AF      MILESTVELINDX1
              00871 ;
              00872 ;          Milestone x-velocity index of Zylon ship 1. Compare MILESTVELINDX0
              00873 ;          ($AE).
              00874 ;
              00875 ; $B0      MILESTVELINDY0
              00876 ;
              00877 ;          Milestone y-velocity index of Zylon ship 0. Used in subroutine
              00878 ;          MANEUVER ($AA79). The current y-velocity index of Zylon ship 0
              00879 ;          ZYLONVELINDY0 ($B6) is compared with this index and gradually
              00880 ;          adjusted to it. Used values are: 0..15.
              00881 ;
              00882 ; $B1      MILESTVELINDY1
              00883 ;
              00884 ;          Milestone y-velocity index of Zylon ship 1. Compare MILESTVELINDY0
              00885 ;          ($B0).
              00886 ;
              00887 ; $B2      ZYLONVELINDZ0
              00888 ;
              00889 ;          Current z-velocity index of Zylon ship 0. Used in subroutine MANEUVER
              00890 ;          ($AA79). It indexes velocity values in ZYLONVELTAB ($BF99). Used
              00891 ;          values are: 0..15.
              00892 ;
              00893 ; $B3      ZYLONVELINDZ1
              00894 ;
              00895 ;          Current z-velocity index of Zylon ship 1. Compare ZYLONVELINDZ0
              00896 ;          ($B2).
              00897 ;
              00898 ; $B4      ZYLONVELINDX0
              00899 ;
              00900 ;          Current x-velocity index of Zylon ship 0. Compare ZYLONVELINDZ0
              00901 ;          ($B2).
              00902 ;
              00903 ; $B5      ZYLONVELINDX1
              00904 ;
              00905 ;          Current x-velocity index of Zylon ship 1. Compare ZYLONVELINDZ0
              00906 ;          ($B2).
              00907 ;
              00908 ; $B6      ZYLONVELINDY0
              00909 ;
              00910 ;          Current y-velocity index of Zylon ship 0. Compare ZYLONVELINDZ0
              00911 ;          ($B2).
              00912 ;
              00913 ; $B7      ZYLONVELINDY1
              00914 ;
              00915 ;          Current y-velocity index of Zylon ship 1. Compare ZYLONVELINDZ0
              00916 ;          ($B2).
              00917 ;
              00918 ; $B8      ISBACKATTACK0
              00919 ;
              00920 ;          Indicates whether Zylon ship 0 will attack our starship from the
              00921 ;          back. Used in subroutine MANEUVER ($AA79). Used values are:
              00922 ;            $00 -> Zylon ship 0 attacks from the front of our starship
              00923 ;            $01 -> Zylon ship 0 attacks from the front and back of our starship
              00924 ;
              00925 ; $B9      ISBACKATTACK1
              00926 ;
              00927 ;          Indicates whether Zylon ship 1 will attack our starship from the
              00928 ;          back. Compare ISBACKATTACK0 ($B8).
              00929 ;
              00930 ; $BA      ZYLONTIMX0
              00931 ;
              00932 ;          Delay timer of the x-velocity index of Zylon ship 0. Used in
              00933 ;          subroutine MANEUVER ($AA79). It is decremented every game loop
              00934 ;          iteration. When the timer value falls below 0 the current velocity
              00935 ;          index ZYLONVELINDX0 ($B4) is adjusted depending on the current
              00936 ;          joystick position. The new timer value is set depending on the
              00937 ;          resulting new x-velocity index. Used values are: 0, 2, 4, ..., 14.
              00938 ;
              00939 ; $BB      ZYLONTIMX1
              00940 ;
              00941 ;          Delay timer of x-velocity index of Zylon ship 1. Compare ZYLONTIMX0
              00942 ;          ($BA).
              00943 ;
              00944 ; $BC      ZYLONTIMY0
              00945 ;
              00946 ;          Delay timer of y-velocity index of Zylon ship 0. Compare ZYLONTIMX0
              00947 ;          ($BA).
              00948 ;
              00949 ; $BD      ZYLONTIMY1
              00950 ;
              00951 ;          Delay timer of y-velocity index of Zylon ship 1. Compare ZYLONTIMX0
              00952 ;          ($BA).
              00953 ;
              00954 ; $BE      TORPEDODELAY
              00955 ;
              00956 ;          After a Zylon photon torpedo has hit our starship this delay timer is
              00957 ;          initialized to a value of 2. It is decremented every game loop
              00958 ;          iteration and so delays the launch of the next Zylon photon torpedo
              00959 ;          for 2 game loop iterations.
              00960 ;
              00961 ; $BF      ZYLONATTACKER
              00962 ;
              00963 ;          Index of the Zylon ship that launched the Zylon photon torpedo. It is
              00964 ;          used in GAMELOOP ($A1F3) to override the current tracking computer
              00965 ;          settings in order to track this Zylon ship first. Used values are:
              00966 ;            $00 -> Zylon photon torpedo was launched by Zylon ship 0
              00967 ;            $01 -> Zylon photon torpedo was launched by Zylon ship 1
              00968 ;
              00969 ; $C0      WARPSTATE
              00970 ;
              00971 ;          Hyperwarp state. Used values are:
              00972 ;            $00 -> Hyperwarp not engaged
              00973 ;            $7F -> Hyperwarp engaged
              00974 ;            $FF -> In hyperspace
              00975 ;
              00976 ; $C1      VELOCITYHI
              00977 ;
              00978 ;          Our starship's velocity (high byte) in <KM/H>. Used values are:
              00979 ;            $00 -> Not in hyperspace (regular cruise or accelerating to
              00980 ;                   hyperspace velocity)
              00981 ;            $01 -> Hyperspace velocity
              00982 ;
              00983 ;          See also VELOCITYLO ($70). 
              00984 ;
              00985 ; $C2      TRAILDELAY
              00986 ;
              00987 ;          Delay timer to create the next star trail. Its value is decremented
              00988 ;          from 3 to 0 every game loop iteration during the hyperwarp STAR TRAIL
              00989 ;          PHASE in subroutine INITTRAIL ($A9B4).
              00990 ;
              00991 ; $C3      TRAILIND
              00992 ;
              00993 ;          Position vector index of the star trail's first star. Used in
              00994 ;          subroutine INITTRAIL ($A9B4) to initialize a star trail, which is
              00995 ;          then displayed during the hyperwarp STAR TRAIL PHASE. Used values
              00996 ;          are: 17..48 in wrap-around fashion.
              00997 ;
              00998 ; $C4      WARPTEMPCOLUMN
              00999 ;
              01000 ;          Temporary arrival column number of our starship on the Galactic Chart
              01001 ;          at the beginning of hyperspace. It is given in Player/Missile pixels
              01002 ;          relative to the left Galactic Chart border. Divide this value by 8 to
              01003 ;          get the sector column number. Used values are: $00..$7F. See also
              01004 ;          WARPARRVCOLUMN ($8F).
              01005 ;
              01006 ; $C5      WARPTEMPROW
              01007 ;
              01008 ;          Temporary arrival row number of our starship on the Galactic Chart at
              01009 ;          the beginning of hyperspace. It is given in Player/Missile pixels
              01010 ;          relative to top Galactic Chart border. Divide this value by 16 to get
              01011 ;          the sector row number.  Used values are: $00..$7F. See also
              01012 ;          WARPARRVROW ($8E).
              01013 ;
              01014 ; $C6      VEERMASK
              01015 ;
              01016 ;          Limits the veer-off velocity of the Hyperwarp Target Marker during
              01017 ;          the hyperwarp ACCELERATION PHASE in subroutine HYPERWARP ($A89B).
              01018 ;          Values are picked from table VEERMASKTAB ($BED7).
              01019 ;
              01020 ;          Also used as a local variable.
              01021 ;
              01022 ; $C7      VICINITYMASK
              01023 ;
              01024 ;          Mask to confine space objects' position vector components
              01025 ;          (coordinates) in a sector into a certain interval around our starship
              01026 ;          after its arrival from hyperspace. Values are picked from table
              01027 ;          VICINITYMASKTAB ($BFB3).
              01028 ;
              01029 ; $C8      JOYSTICKX
              01030 ;
              01031 ;          Horizontal joystick direction. Values are picked from table
              01032 ;          STICKINCTAB ($BAF5). Used values are:
              01033 ;            $01 -> Right
              01034 ;            $00 -> Centered
              01035 ;            $FF -> Left
              01036 ;
              01037 ; $C9      JOYSTICKY
              01038 ;
              01039 ;          Vertical joystick direction. Values are picked from table STICKINCTAB
              01040 ;          ($BAF5). Used values are:
              01041 ;            $01 -> Up
              01042 ;            $00 -> Centered 
              01043 ;            $FF -> Down
              01044 ;
              01045 ; $CA      KEYCODE
              01046 ;
              01047 ;          Hardware keyboard code of the pressed key on the keyboard. Shift and
              01048 ;          Control key bits B7..6 are always set.
              01049 ;
              01050 ; $CB..$CC SCORE
              01051 ;
              01052 ;          Internal 16-bit score of the game in low byte-high byte order
              01053 ;
              01054 ; $CD      SCOREDRANKIND
              01055 ;
              01056 ;          Scored Rank Index. It is translated with table RANKTAB ($BEE9) to a
              01057 ;          title phrase offset pointing to the rank string. Used values are: 
              01058 ;            $00 -> GALACTIC COOK
              01059 ;            $01 -> GARBAGE SCOW CAPTAIN
              01060 ;            $02 -> GARBAGE SCOW CAPTAIN
              01061 ;            $03 -> ROOKIE
              01062 ;            $04 -> ROOKIE
              01063 ;            $05 -> NOVICE
              01064 ;            $06 -> NOVICE
              01065 ;            $07 -> ENSIGN
              01066 ;            $08 -> ENSIGN
              01067 ;            $09 -> PILOT
              01068 ;            $0A -> PILOT
              01069 ;            $0B -> ACE
              01070 ;            $0C -> LIEUTENANT
              01071 ;            $0D -> WARRIOR
              01072 ;            $0E -> CAPTAIN
              01073 ;            $0F -> COMMANDER
              01074 ;            $10 -> COMMANDER
              01075 ;            $11 -> STAR COMMANDER
              01076 ;            $12 -> STAR COMMANDER
              01077 ;
              01078 ; $CE      SCOREDCLASSIND
              01079 ;
              01080 ;          Scored Class Index. It is translated into a class number with table
              01081 ;          CLASSTAB ($BEFC). Used values are:
              01082 ;            $00 -> Class 5
              01083 ;            $01 -> Class 5
              01084 ;            $02 -> Class 5
              01085 ;            $03 -> Class 4
              01086 ;            $04 -> Class 4
              01087 ;            $05 -> Class 4
              01088 ;            $06 -> Class 4
              01089 ;            $07 -> Class 3
              01090 ;            $08 -> Class 3
              01091 ;            $09 -> Class 3
              01092 ;            $0A -> Class 2
              01093 ;            $0B -> Class 2
              01094 ;            $0C -> Class 2
              01095 ;            $0D -> Class 1
              01096 ;            $0E -> Class 1
              01097 ;            $0F -> Class 1
              01098 ;
              01099 ; $CF      TITLELIFE
              01100 ;
              01101 ;          Lifetime of title line. It is decremented every game loop iteration.
              01102 ;          Used initial values are:
              01103 ;            $3C -> When displaying regular title phrases
              01104 ;            $FE -> When displaying "STARBASE SURROUNDED", "STARBASE DESTOYED",
              01105 ;                   and "RED ALERT" messages
              01106 ;            $FF -> Hide title line
              01107 ;
              01108 ; $D0      SHIPVIEW
              01109 ;
              01110 ;          Current view of our starship. Values are picked from table
              01111 ;          VIEWMODETAB ($BE22). Used values are:
              01112 ;            $00 -> Front view
              01113 ;            $01 -> Aft view
              01114 ;            $40 -> Long-Range Scan view
              01115 ;            $80 -> Galactic Chart view
              01116 ;
              01117 ; $D1      TITLEPHR
              01118 ;
              01119 ;          Title phrase offset for text phrase in title line. Used values are:
              01120 ;            $00..$7B -> Title phrase offset into PHRASETAB ($BBAA)
              01121 ;            $FF      -> Hide title line
              01122 ;
              01123 ;          See also NEWTITLEPHR ($65). 
              01124 ;
              01125 ; $D2      BEEPFRQIND
              01126 ;
              01127 ;          Beeper sound pattern: Running index into frequency table BEEPFRQTAB
              01128 ;          ($BF5C). See also BEEPFRQSTART ($D7). See also subroutines BEEP
              01129 ;          ($B3A6) and SOUND ($B2AB).
              01130 ;
              01131 ; $D3      BEEPREPEAT
              01132 ;
              01133 ;          Beeper sound pattern: Number of times the beeper sound pattern is
              01134 ;          repeated - 1. See also subroutines BEEP ($B3A6) and SOUND ($B2AB).
              01135 ;
              01136 ; $D4      BEEPTONELIFE
              01137 ;
              01138 ;          Beeper sound pattern: Lifetime of tone in TICKs - 1. See also
              01139 ;          subroutines BEEP ($B3A6) and SOUND ($B2AB).
              01140 ;
              01141 ; $D5      BEEPPAUSELIFE
              01142 ;
              01143 ;          Beeper sound pattern: Lifetime of pause in TICKs - 1. Used values
              01144 ;          are: 
              01145 ;            < $FF -> Number of TICKs - 1 to play
              01146 ;              $FF -> Skip playing pause
              01147 ;
              01148 ;          See also subroutines BEEP ($B3A6) and SOUND ($B2AB).
              01149 ;
              01150 ; $D6      BEEPPRIORITY
              01151 ;
              01152 ;          Beeper sound pattern: Pattern priority. Each beeper sound pattern has
              01153 ;          a priority. When a pattern of higher priority is about to be played
              01154 ;          the pattern that is currently playing is stopped. Used values are:
              01155 ;              $00 -> No pattern playing at the moment
              01156 ;            > $00 -> Pattern priority
              01157 ;
              01158 ;          See also subroutines BEEP ($B3A6) and SOUND ($B2AB).
              01159 ;
              01160 ; $D7      BEEPFRQSTART
              01161 ;
              01162 ;          Beeper sound pattern: Index to first byte of the pattern frequency in
              01163 ;          table BEEPFRQTAB ($BF5C). See also BEEPFRQIND ($D2). See also
              01164 ;          subroutines BEEP ($B3A6) and SOUND ($B2AB).
              01165 ;
              01166 ; $D8      BEEPLIFE
              01167 ;
              01168 ;          Beeper sound pattern: Lifetime of the current tone or pause in TICKs.
              01169 ;          It is decremented every TICK. See also subroutines BEEP ($B3A6) and
              01170 ;          SOUND ($B2AB). 
              01171 ;
              01172 ; $D9      BEEPTOGGLE
              01173 ;
              01174 ;          Beeper sound pattern: Indicates that either a tone or a pause is
              01175 ;          currently played. Used values are:
              01176 ;            $00 -> Tone
              01177 ;            $01 -> Pause
              01178 ;
              01179 ;          See also subroutines BEEP ($B3A6) and SOUND ($B2AB).    
              01180 ;
              01181 ; $DA      NOISETORPTIM
              01182 ;
              01183 ;          Noise sound pattern: Delay timer for PHOTON TORPEDO LAUNCHED noise
              01184 ;          sound pattern. It is decremented every TICK. See also subroutines
              01185 ;          NOISE ($AEA8) and SOUND ($B2AB).
              01186 ;
              01187 ; $DB      NOISEEXPLTIM
              01188 ;
              01189 ;          Noise sound pattern: Delay timer for SHIELD EXPLOSION and ZYLON
              01190 ;          EXPLOSION noise sound pattern. It is decremented every TICK. See also
              01191 ;          subroutines NOISE ($AEA8) and SOUND ($B2AB).
              01192 ;
              01193 ; $DC      NOISEAUDC2
              01194 ;
              01195 ;          Noise sound pattern: Audio channel 1/2 control shadow register. See
              01196 ;          also subroutines NOISE ($AEA8) and SOUND ($B2AB).
              01197 ;
              01198 ; $DD      NOISEAUDC3
              01199 ;
              01200 ;          Noise sound pattern: Audio channel 3 control shadow register. See
              01201 ;          also subroutines NOISE ($AEA8) and SOUND ($B2AB).
              01202 ;
              01203 ; $DE      NOISEAUDF1
              01204 ;
              01205 ;          Noise sound pattern: Audio channel 1 frequency shadow register. See
              01206 ;          also subroutines NOISE ($AEA8) and SOUND ($B2AB).
              01207 ;
              01208 ; $DF      NOISEAUDF2
              01209 ;
              01210 ;          Noise sound pattern: Audio channel 2 frequency shadow register. See
              01211 ;          also subroutines NOISE ($AEA8) and SOUND ($B2AB).
              01212 ;
              01213 ; $E0      NOISEFRQINC
              01214 ;
              01215 ;          Noise sound pattern: Audio channel 1/2 frequency increment. See also
              01216 ;          subroutines NOISE ($AEA8) and SOUND ($B2AB).
              01217 ;
              01218 ; $E1      NOISELIFE
              01219 ;
              01220 ;          Noise sound pattern: Noise sound pattern lifetime. It is decremented
              01221 ;          every TICK. See also subroutines NOISE ($AEA8) and SOUND ($B2AB).
              01222 ;
              01223 ; $E2      NOISEZYLONTIM
              01224 ;
              01225 ;          Delay timer to trigger the ZYLON EXPLOSION noise sound pattern. It is
              01226 ;          set in subroutine COLLISION ($AF3D) when an impact of one of our
              01227 ;          starship's photon torpedoes into a target is imminent. The timer is
              01228 ;          decremented every TICK during the execution of the Vertical Blank
              01229 ;          Interrupt handler VBIHNDLR ($A6D1). When the timer value reaches 0
              01230 ;          the ZYLON EXPLOSION noise sound pattern is played in subroutine SOUND
              01231 ;          ($B2AB). 
              01232 ;
              01233 ; $E3      NOISEHITLIFE
              01234 ;
              01235 ;          Lifetime of STARSHIP EXPLOSION noise when our starship was destroyed
              01236 ;          by a Zylon photon torpedo. It is set in routine GAMELOOP ($A1F3) to a
              01237 ;          value of 64 TICKs. It is decremented every TICK during the execution
              01238 ;          of the Vertical Blank Interrupt handler VBIHNDLR ($A6D1).
              01239 ;
              01240 ; $E4      PL0SHAPOFF
              01241 ;
              01242 ;          PLAYER0 offset into shape table PLSHAP2TAB ($B9B1)
              01243 ;
              01244 ; $E5      PL1SHAPOFF
              01245 ;
              01246 ;          PLAYER1 offset into shape table PLSHAP2TAB ($B9B1)
              01247 ;
              01248 ; $E6      PL2SHAPOFF
              01249 ;
              01250 ;          PLAYER2 offset into shape table PLSHAP1TAB ($B8E4)
              01251 ;
              01252 ; $E7      PL3SHAPOFF
              01253 ;
              01254 ;          PLAYER3 offset into shape table PLSHAP1TAB ($B8E4)
              01255 ;
              01256 ; $E8      PL4SHAPOFF
              01257 ;
              01258 ;          PLAYER4 offset into shape table PLSHAP1TAB ($B8E4)
              01259 ;
              01260 ; $E9      PL0LIFE
              01261 ;
              01262 ;          Lifetime of the space object represented by PLAYER0 (usually Zylon
              01263 ;          ship 0). Any value other than $FF is decremented with every game loop
              01264 ;          iteration. Used values are:
              01265 ;            $00      -> Space object not alive (= not in use)
              01266 ;            $01..$FE -> Values during lifetime countdown
              01267 ;            $FF      -> Infinite lifetime (not counted down)
              01268 ;
              01269 ; $EA      PL1LIFE
              01270 ;
              01271 ;          Lifetime of a space object represented by PLAYER1 (usually Zylon ship
              01272 ;          1). Compare PL0LIFE ($E9).
              01273 ;
              01274 ; $EB      PL2LIFE
              01275 ;
              01276 ;          Lifetime of a space object represented by PLAYER2 (usually the Zylon
              01277 ;          photon torpedo). Compare PL0LIFE ($E9).
              01278 ;
              01279 ;          If this PLAYER represents a photon torpedo, its lifetime is
              01280 ;          decremented from an initial value of $FF.
              01281 ;
              01282 ; $EC      PL3LIFE
              01283 ;
              01284 ;          Lifetime of a space object represented by PLAYER3 (usually our
              01285 ;          starship's photon torpedo 0). Compare PL2LIFE ($EB).
              01286 ;
              01287 ;          If this PLAYER represents a photon torpedo, its lifetime is
              01288 ;          decremented from an initial value of $FF.
              01289 ;
              01290 ; $ED      PL4LIFE
              01291 ;
              01292 ;          Lifetime of a space object represented by PLAYER4 (usually our
              01293 ;          starship's photon torpedo 1). Compare PL2LIFE ($EB).
              01294 ;
              01295 ;          If this PLAYER represents a photon torpedo, its lifetime is
              01296 ;          decremented from an initial value of $FF.
              01297 ;
              01298 ; $EE      PL0COLOR
              01299 ;
              01300 ;          Color of PLAYER0
              01301 ;
              01302 ; $EF      PL1COLOR
              01303 ;
              01304 ;          Color of PLAYER1
              01305 ;
              01306 ; $F0      PL2COLOR
              01307 ;
              01308 ;          Color of PLAYER2
              01309 ;
              01310 ; $F1      PL3COLOR
              01311 ;
              01312 ;          Color of PLAYER3
              01313 ;
              01314 ; $F2      PF0COLOR
              01315 ;
              01316 ;          Color of PLAYFIELD0
              01317 ;
              01318 ; $F3      PF1COLOR
              01319 ;
              01320 ;          Color of PLAYFIELD1
              01321 ;
              01322 ; $F4      PF2COLOR
              01323 ;
              01324 ;          Color of PLAYFIELD2
              01325 ;
              01326 ; $F5      PF3COLOR
              01327 ;
              01328 ;          Color of PLAYFIELD3
              01329 ;
              01330 ; $F6      BGRCOLOR
              01331 ;
              01332 ;          Color of BACKGROUND
              01333 ;
              01334 ; $F7      PF0COLORDLI
              01335 ;
              01336 ;          Color of PLAYFIELD0 after DLI
              01337 ;
              01338 ; $F8      PF1COLORDLI
              01339 ;
              01340 ;          Color of PLAYFIELD1 after DLI
              01341 ;
              01342 ; $F9      PF2COLORDLI
              01343 ;
              01344 ;          Color of PLAYFIELD2 after DLI
              01345 ;
              01346 ; $FA      PF3COLORDLI
              01347 ;
              01348 ;          Color of PLAYFIELD3 after DLI
              01349 ;
              01350 ; $FB      BGRCOLORDLI
              01351 ;
              01352 ;          Color of BACKGROUND after DLI
              01353 ;
              01354 ; $0280..$02E9 DSPLST
              01355 ;
              01356 ;              Display List
              01357 ;
              01358 ; $0300..$03FF PL4DATA
              01359 ;
              01360 ;              PLAYER4 data area
              01361 ;
              01362 ; $0400..$04FF PL0DATA
              01363 ;
              01364 ;              PLAYER0 data area
              01365 ;
              01366 ; $0500..$05FF PL1DATA
              01367 ;
              01368 ;              PLAYER1 data area
              01369 ;
              01370 ; $0600..$06FF PL2DATA
              01371 ;
              01372 ;              PLAYER2 data area
              01373 ;
              01374 ; $0700..$07FF PL3DATA
              01375 ;
              01376 ;              PLAYER3 data area
              01377 ;
              01378 ; $0800..$0863 PFMEMROWLO
              01379 ;
              01380 ;              Lookup table of start addresses (low byte) for each row of
              01381 ;              PLAYFIELD memory, which is located at PFMEM ($1000). The table
              01382 ;              contains 100 bytes for 100 rows (of which only 99 are shown by
              01383 ;              the Display List, the PLAYFIELD is 160 x 99 pixels). The
              01384 ;              addresses grow in increments of 40 (40 bytes = 160 pixels in
              01385 ;              GRAPHICS7 mode = 1 PLAYFIELD row of pixels). See also PFMEMROWHI
              01386 ;              ($0864).
              01387 ;
              01388 ; $0864..$08C7 PFMEMROWHI
              01389 ;
              01390 ;              Lookup table of start addresses (high byte) of each row of
              01391 ;              PLAYFIELD memory. See also PFMEMROWLO ($0800).
              01392 ;
              01393 ; $08C9..$0948 GCMEMMAP
              01394 ;
              01395 ;              Galactic Chart memory map (16 columns x 8 rows = 128 bytes)
              01396 ;
              01397 ; $0949..$0970 PANELTXT
              01398 ;
              01399 ;              Memory of Control Panel Display (bottom text window) in Front
              01400 ;              view, Aft view, and Long-Range Scan view (20 characters x 2 rows
              01401 ;              = 40 bytes).
              01402 ;
              01403 ; $094A        VELOCD1
              01404 ;
              01405 ;              First digit (of 2) of the VELOCITY readout in Control Panel
              01406 ;              Display memory.
              01407 ;
              01408 ; $0950        KILLCNTD1
              01409 ;
              01410 ;              First digit (of 2) of the KILL COUNTER readout in Control Panel
              01411 ;              Display memory.
              01412 ;
              01413 ; $0955        ENERGYD1
              01414 ;
              01415 ;              First digit (of 4) of the ENERGY readout in Control Panel Display
              01416 ;              memory.
              01417 ;
              01418 ; $095A        TRACKC1
              01419 ;
              01420 ;              Character of the TRACKING readout 'T' or 'C' in Control Panel
              01421 ;              Display memory.
              01422 ;
              01423 ; $095C        TRACKDIGIT
              01424 ;
              01425 ;              Digit of the TRACKING readout in Control Panel Display memory. It
              01426 ;              is used to store the index of the currently tracked space object.
              01427 ;              Used values are:
              01428 ;                $00 -> Track Zylon ship 0
              01429 ;                $01 -> Track Zylon ship 1
              01430 ;                $02 -> Track starbase
              01431 ;                $03 -> Track Hyperwarp Target Marker
              01432 ;
              01433 ; $0960        THETAC1
              01434 ;
              01435 ;              First character of the THETA readout in Control Panel Display
              01436 ;              memory.
              01437 ;
              01438 ; $0966        PHIC1
              01439 ;
              01440 ;              First character of the PHI readout in Control Panel Display
              01441 ;              memory.
              01442 ;
              01443 ; $096C        RANGEC1
              01444 ;
              01445 ;              First character of the RANGE readout in Control Panel Display
              01446 ;              memory.
              01447 ;
              01448 ; $0971..$09AC GCTXT
              01449 ;
              01450 ;              Memory of Galactic Chart Panel Display (bottom text window) of
              01451 ;              Galactic Chart view (20 characters x 3 rows = 60 bytes).
              01452 ;
              01453 ; $097D        GCWARPD1
              01454 ;
              01455 ;              First digit (of 4) of the HYPERWARP ENERGY readout in Galactic
              01456 ;              Chart Panel Display memory.
              01457 ;
              01458 ; $098D        GCTRGCNT
              01459 ;
              01460 ;              First target counter digit (of 2) in Galactic Chart Panel Display
              01461 ;              memory.
              01462 ;
              01463 ; $0992        GCSTATPHO
              01464 ;
              01465 ;              Photon Torpedo status letter in Galactic Chart Panel Display
              01466 ;              memory. Used values are:
              01467 ;                %00****** -> OK
              01468 ;                %10****** -> Destroyed
              01469 ;                %11****** -> Damaged
              01470 ;
              01471 ; $0993        GCSTATENG
              01472 ;
              01473 ;              Engines status letter in Galactic Chart Panel Display memory.
              01474 ;              Used values are:
              01475 ;                %00****** -> OK
              01476 ;                %10****** -> Destroyed
              01477 ;                %11****** -> Damaged
              01478 ;
              01479 ; $0994        GCSTATSHL
              01480 ;
              01481 ;              Shields status letter in Galactic Chart Panel Display memory.
              01482 ;              Used values are:
              01483 ;                %00****** -> OK
              01484 ;                %10****** -> Destroyed
              01485 ;                %11****** -> Damaged
              01486 ;
              01487 ; $0995        GCSTATCOM
              01488 ;
              01489 ;              Attack Computer status letter in Galactic Chart Panel Display
              01490 ;              memory. Used values are:
              01491 ;                %00****** -> OK
              01492 ;                %10****** -> Destroyed
              01493 ;                %11****** -> Damaged
              01494 ;
              01495 ; $0996        GCSTATLRS
              01496 ;
              01497 ;              Long-Range Scan status letter in Galactic Chart Panel Display
              01498 ;              memory. Used values are:
              01499 ;                %00****** -> OK
              01500 ;                %10****** -> Destroyed
              01501 ;                %11****** -> Damaged
              01502 ;
              01503 ; $0997        GCSTATRAD
              01504 ;
              01505 ;              Subspace Radio status letter in Galactic Chart Panel Display
              01506 ;              memory. Used values are:
              01507 ;                %00****** -> OK
              01508 ;                %10****** -> Destroyed
              01509 ;                %11****** -> Damaged
              01510 ;
              01511 ; $09A3        GCSTARDAT
              01512 ;
              01513 ;              First (of 5) digits of the star date clock in the Galactic Chart
              01514 ;              Panel Display memory.
              01515 ;
              01516 ; $09AD..$09DD ZPOSSIGN
              01517 ;
              01518 ;              Table containing the sign bit (B16) of position vector
              01519 ;              z-components (z-coordinate) (49 bytes). Bytes 0..4 belong to
              01520 ;              position vectors of PLAYER space objects (Zylon ships, photon
              01521 ;              torpedoes, etc.). Bytes 5..48 belong to position vectors of
              01522 ;              PLAYFIELD space objects (stars, explosion fragments). Used values
              01523 ;              are:
              01524 ;                $00 -> Negative sign (behind our starship)
              01525 ;                $01 -> Positive sign (in front of our starship)
              01526 ;
              01527 ;              See also "ON POSITION VECTORS".
              01528 ;
              01529 ; $09AD        PL0ZPOSSIGN
              01530 ;
              01531 ;              Sign bit (B16) of position vector z-component (z-coordinate) of
              01532 ;              PLAYER0. Compare ZPOSSIGN ($09AD). See also "ON POSITION
              01533 ;              VECTORS".
              01534 ;
              01535 ; $09AE        PL1ZPOSSIGN
              01536 ;
              01537 ;              Sign bit (B16) of position vector z-component (z-coordinate) of
              01538 ;              PLAYER1. Compare ZPOSSIGN ($09AD). See also "ON POSITION
              01539 ;              VECTORS".
              01540 ;
              01541 ; $09AF        PL2ZPOSSIGN
              01542 ;
              01543 ;              Sign bit (B16) of position vector z-component (z-coordinate) of
              01544 ;              PLAYER2. Compare ZPOSSIGN ($09AD). See also "ON POSITION
              01545 ;              VECTORS".
              01546 ;
              01547 ; $09B0        PL3ZPOSSIGN
              01548 ;
              01549 ;              Sign bit (B16) of position vector z-component (z-coordinate) of
              01550 ;              PLAYER3. Compare ZPOSSIGN ($09AD). See also "ON POSITION
              01551 ;              VECTORS".
              01552 ;
              01553 ; $09B1        PL4ZPOSSIGN
              01554 ;
              01555 ;              Sign bit (B16) of position vector z-component (z-coordinate) of
              01556 ;              PLAYER4. Compare ZPOSSIGN ($09AD). See also "ON POSITION
              01557 ;              VECTORS".
              01558 ;
              01559 ; $09DE..$0A0E XPOSSIGN
              01560 ;
              01561 ;              Table containing the sign bit (B16) of position vector
              01562 ;              x-components (x-coordinate) (49 bytes). Bytes 0..4 belong to
              01563 ;              position vectors of PLAYER space objects (Zylon ships, photon
              01564 ;              torpedoes, etc.). Bytes 5..48 belong to position vectors of
              01565 ;              PLAYFIELD space objects (stars, explosion fragments). Used values
              01566 ;              are:
              01567 ;                $00 -> Negative sign (left)
              01568 ;                $01 -> Positive sign (right)
              01569 ;
              01570 ;              See also "ON POSITION VECTORS".
              01571 ;
              01572 ; $09DE        PL0XPOSSIGN
              01573 ;
              01574 ;              Sign bit (B16) of position vector x-component (x-coordinate) of
              01575 ;              PLAYER0. Compare XPOSSIGN ($09DE). See also "ON POSITION
              01576 ;              VECTORS".
              01577 ;
              01578 ; $09DF        PL1XPOSSIGN
              01579 ;
              01580 ;              Sign bit (B16) of position vector x-component (x-coordinate) of
              01581 ;              PLAYER1. Compare XPOSSIGN ($09DE). See also "ON POSITION
              01582 ;              VECTORS".
              01583 ;
              01584 ; $09E0        PL2XPOSSIGN
              01585 ;
              01586 ;              Sign bit (B16) of position vector x-component (x-coordinate) of
              01587 ;              PLAYER2. Compare XPOSSIGN ($09DE). See also "ON POSITION
              01588 ;              VECTORS".
              01589 ;
              01590 ; $09E1        PL3XPOSSIGN
              01591 ;
              01592 ;              Sign bit (B16) of position vector x-component (x-coordinate) of
              01593 ;              PLAYER3. Compare XPOSSIGN ($09DE). See also "ON POSITION
              01594 ;              VECTORS".
              01595 ;
              01596 ; $09E2        PL4XPOSSIGN
              01597 ;
              01598 ;              Sign bit (B16) of position vector x-component (x-coordinate) of
              01599 ;              PLAYER4. Compare XPOSSIGN ($09DE). See also "ON POSITION
              01600 ;              VECTORS".
              01601 ;
              01602 ; $0A0F..$0A3F YPOSSIGN
              01603 ;
              01604 ;              Table containing the sign bit (B16) of position vector
              01605 ;              y-components (y-coordinate) (49 bytes). Bytes 0..4 belong to
              01606 ;              position vectors of PLAYER space objects (Zylon ships, photon
              01607 ;              torpedoes, etc.). Bytes 5..48 belong to position vectors of
              01608 ;              PLAYFIELD space objects (stars, explosion fragments). Used values
              01609 ;              are:
              01610 ;                $00 -> Negative sign (down)
              01611 ;                $01 -> Positive sign (up)
              01612 ;
              01613 ;              See also "ON POSITION VECTORS".
              01614 ;
              01615 ; $0A0F        PL0YPOSSIGN
              01616 ;
              01617 ;              Sign bit (B16) of position vector y-component (y-coordinate) of
              01618 ;              PLAYER0. Compare YPOSSIGN ($0A0F). See also "ON POSITION
              01619 ;              VECTORS".
              01620 ;
              01621 ; $0A10        PL1YPOSSIGN
              01622 ;
              01623 ;              Sign bit (B16) of position vector y-component (y-coordinate) of
              01624 ;              PLAYER1. Compare YPOSSIGN ($0A0F). See also "ON POSITION
              01625 ;              VECTORS".
              01626 ;
              01627 ; $0A11        PL2YPOSSIGN
              01628 ;
              01629 ;              Sign bit (B16) of position vector y-component (y-coordinate) of
              01630 ;              PLAYER2. Compare YPOSSIGN ($0A0F). See also "ON POSITION
              01631 ;              VECTORS".
              01632 ;
              01633 ; $0A12        PL3YPOSSIGN
              01634 ;
              01635 ;              Sign bit (B16) of position vector y-component (y-coordinate) of
              01636 ;              PLAYER3. Compare YPOSSIGN ($0A0F). See also "ON POSITION
              01637 ;              VECTORS".
              01638 ;
              01639 ; $0A13        PL4YPOSSIGN
              01640 ;
              01641 ;              Sign bit (B16) of position vector y-component (y-coordinate) of
              01642 ;              PLAYER4. Compare YPOSSIGN ($0A0F). See also "ON POSITION
              01643 ;              VECTORS".
              01644 ;
              01645 ; $0A40..$0A70 ZPOSHI
              01646 ;
              01647 ;              Table containing the high byte (B15..8) of position vector
              01648 ;              y-components (y-coordinate) (49 bytes). Bytes 0..4 belong to
              01649 ;              position vectors of PLAYER space objects (Zylon ships, photon
              01650 ;              torpedoes, etc.). Bytes 5..48 belong to position vectors of
              01651 ;              PLAYFIELD space objects (stars, explosion fragments). See also
              01652 ;              "ON POSITION VECTORS".
              01653 ;
              01654 ; $0A40        PL0ZPOSHI
              01655 ;
              01656 ;              High byte (B15..8) of position vector z-component (z-coordinate)
              01657 ;              of PLAYER0. Compare ZPOSHI ($0A40). See also "ON POSITION
              01658 ;              VECTORS".
              01659 ;
              01660 ; $0A41        PL1ZPOSHI
              01661 ;
              01662 ;              High byte (B15..8) of position vector z-component (z-coordinate)
              01663 ;              of PLAYER1. Compare ZPOSHI ($0A40). See also "ON POSITION
              01664 ;              VECTORS".
              01665 ;
              01666 ; $0A42        PL2ZPOSHI
              01667 ;
              01668 ;              High byte (B15..8) of position vector z-component (z-coordinate)
              01669 ;              of PLAYER2. Compare ZPOSHI ($0A40). See also "ON POSITION
              01670 ;              VECTORS".
              01671 ;
              01672 ; $0A43        PL3ZPOSHI
              01673 ;
              01674 ;              High byte (B15..8) of position vector z-component (z-coordinate)
              01675 ;              of PLAYER3. Compare ZPOSHI ($0A40). See also "ON POSITION
              01676 ;              VECTORS".
              01677 ;
              01678 ; $0A44        PL4ZPOSHI
              01679 ;
              01680 ;              High byte (B15..8) of position vector z-component (z-coordinate)
              01681 ;              of PLAYER4. Compare ZPOSHI ($0A40). See also "ON POSITION
              01682 ;              VECTORS".
              01683 ;
              01684 ; $0A71..$0AA1 XPOSHI
              01685 ;
              01686 ;              Table containing the high byte (B15..8) of position vector
              01687 ;              x-components (x-coordinate) (49 bytes). Bytes 0..4 belong to
              01688 ;              position vectors of PLAYER space objects (Zylon ships, photon
              01689 ;              torpedoes, etc.). Bytes 5..48 belong to position vectors of
              01690 ;              PLAYFIELD space objects (stars, explosion fragments). See also
              01691 ;              "ON POSITION VECTORS".
              01692 ;
              01693 ; $0A71        PL0XPOSHI
              01694 ;
              01695 ;              High byte (B15..8) of position vector x-component (x-coordinate)
              01696 ;              of PLAYER0. Compare XPOSHI ($0A71). See also "ON POSITION
              01697 ;              VECTORS".
              01698 ;
              01699 ; $0A72        PL1XPOSHI
              01700 ;
              01701 ;              High byte (B15..8) of position vector x-component (x-coordinate)
              01702 ;              of PLAYER1. Compare XPOSHI ($0A71). See also "ON POSITION
              01703 ;              VECTORS".
              01704 ;
              01705 ; $0A73        PL2XPOSHI
              01706 ;
              01707 ;              High byte (B15..8) of position vector x-component (x-coordinate)
              01708 ;              of PLAYER2. Compare XPOSHI ($0A71). See also "ON POSITION
              01709 ;              VECTORS".
              01710 ;
              01711 ; $0A74        PL3XPOSHI
              01712 ;
              01713 ;              High byte (B15..8) of position vector x-component (x-coordinate)
              01714 ;              of PLAYER3. Compare XPOSHI ($0A71). See also "ON POSITION
              01715 ;              VECTORS".
              01716 ;
              01717 ; $0A75        PL4XPOSHI
              01718 ;
              01719 ;              High byte (B15..8) of position vector x-component (x-coordinate)
              01720 ;              of PLAYER4. Compare XPOSHI ($0A71). See also "ON POSITION
              01721 ;              VECTORS".
              01722 ;
              01723 ; $0AA2..$0AD2 YPOSHI
              01724 ;
              01725 ;              Table containing the high byte (B15..8) of position vector
              01726 ;              y-components (y-coordinate) (49 bytes). Bytes 0..4 belong to
              01727 ;              position vectors of PLAYER space objects (Zylon ships, photon
              01728 ;              torpedoes, etc.). Bytes 5..48 belong to position vectors of
              01729 ;              PLAYFIELD space objects (stars, explosion fragments). See also
              01730 ;              "ON POSITION VECTORS".
              01731 ;
              01732 ; $0AA2        PL0YPOSHI
              01733 ;
              01734 ;              High byte (B15..8) of position vector y-component (y-coordinate)
              01735 ;              of PLAYER0. Compare YPOSHI ($0AA2). See also "ON POSITION
              01736 ;              VECTORS".
              01737 ;
              01738 ; $0AA3        PL1YPOSHI
              01739 ;
              01740 ;              High byte (B15..8) of position vector y-component (y-coordinate)
              01741 ;              of PLAYER1. Compare YPOSHI ($0AA2). See also "ON POSITION
              01742 ;              VECTORS".
              01743 ;
              01744 ; $0AA4        PL2YPOSHI
              01745 ;
              01746 ;              High byte (B15..8) of position vector y-component (y-coordinate)
              01747 ;              of PLAYER2. Compare YPOSHI ($0AA2). See also "ON POSITION
              01748 ;              VECTORS".
              01749 ;
              01750 ; $0AA5        PL3YPOSHI
              01751 ;
              01752 ;              High byte (B15..8) of position vector y-component (y-coordinate)
              01753 ;              of PLAYER3. Compare YPOSHI ($0AA2). See also "ON POSITION
              01754 ;              VECTORS".
              01755 ;
              01756 ; $0AA6        PL4YPOSHI
              01757 ;
              01758 ;              High byte (B15..8) of position vector y-component (y-coordinate)
              01759 ;              of PLAYER4. Compare YPOSHI ($0AA2). See also "ON POSITION
              01760 ;              VECTORS".
              01761 ;
              01762 ; $0AD3..$0B03 ZPOSLO
              01763 ;
              01764 ;              Table containing the low byte (B7..0) of position vector
              01765 ;              z-components (z-coordinate) (49 bytes). Bytes 0..4 belong to
              01766 ;              position vectors of PLAYER space objects (Zylon ships, photon
              01767 ;              torpedoes, etc.). Bytes 5..48 belong to position vectors of
              01768 ;              PLAYFIELD space objects (stars, explosion fragments). See also
              01769 ;              "ON POSITION VECTORS".
              01770 ;
              01771 ; $0AD3        PL0ZPOSLO
              01772 ;
              01773 ;              Low byte (B7..0) of position vector z-component (z-coordinate) of
              01774 ;              PLAYER0. Compare ZPOSLO ($0AD3). See also "ON POSITION VECTORS".
              01775 ;
              01776 ; $0AD4        PL1ZPOSLO
              01777 ;
              01778 ;              Low byte (B7..0) of position vector z-component (z-coordinate) of
              01779 ;              PLAYER1. Compare ZPOSLO ($0AD3). See also "ON POSITION VECTORS".
              01780 ;
              01781 ; $0AD5        PL2ZPOSLO
              01782 ;
              01783 ;              Low byte (B7..0) of position vector z-component (z-coordinate) of
              01784 ;              PLAYER2. Compare ZPOSLO ($0AD3). See also "ON POSITION VECTORS".
              01785 ;
              01786 ; $0AD6        PL3ZPOSLO
              01787 ;
              01788 ;              Low byte (B7..0) of position vector z-component (z-coordinate) of
              01789 ;              PLAYER3. Compare ZPOSLO ($0AD3). See also "ON POSITION VECTORS".
              01790 ;
              01791 ; $0AD7        PL4ZPOSLO
              01792 ;
              01793 ;              Low byte (B7..0) of position vector z-component (z-coordinate) of
              01794 ;              PLAYER4. Compare ZPOSLO ($0AD3). See also "ON POSITION VECTORS".
              01795 ;
              01796 ; $0B04..$0B34 XPOSLO
              01797 ;
              01798 ;              Table containing the low byte (B7..0) of position vector
              01799 ;              x-components (x-coordinate) (49 bytes). Bytes 0..4 belong to
              01800 ;              position vectors of PLAYER space objects (Zylon ships, photon
              01801 ;              torpedoes, etc.). Bytes 5..48 belong to position vectors of
              01802 ;              PLAYFIELD space objects (stars, explosion fragments). See also
              01803 ;              "ON POSITION VECTORS".
              01804 ;
              01805 ; $0B04        PL0XPOSLO
              01806 ;
              01807 ;              Low byte (B7..0) of position vector x-component (x-coordinate) of
              01808 ;              PLAYER0. Compare XPOSLO ($0B04). See also "ON POSITION VECTORS".
              01809 ;
              01810 ; $0B05        PL1XPOSLO
              01811 ;
              01812 ;              Low byte (B7..0) of position vector x-component (x-coordinate) of
              01813 ;              PLAYER1. Compare XPOSLO ($0B04). See also "ON POSITION VECTORS".
              01814 ;
              01815 ; $0B06        PL2XPOSLO
              01816 ;
              01817 ;              Low byte (B7..0) of position vector x-component (x-coordinate) of
              01818 ;              PLAYER2. Compare XPOSLO ($0B04). See also "ON POSITION VECTORS".
              01819 ;
              01820 ; $0B07        PL3XPOSLO
              01821 ;
              01822 ;              Low byte (B7..0) of position vector x-component (x-coordinate) of
              01823 ;              PLAYER3. Compare XPOSLO ($0B04). See also "ON POSITION VECTORS".
              01824 ;
              01825 ; $0B08        PL4XPOSLO
              01826 ;
              01827 ;              Low byte (B7..0) of position vector x-component (x-coordinate) of
              01828 ;              PLAYER4. Compare XPOSLO ($0B04). See also "ON POSITION VECTORS".
              01829 ;
              01830 ; $0B35..$0B65 YPOSLO
              01831 ;
              01832 ;              Table containing the low byte (B7..0) of position vector
              01833 ;              y-components (y-coordinate) (49 bytes). Bytes 0..4 belong to
              01834 ;              position vectors of PLAYER space objects (Zylon ships, photon
              01835 ;              torpedoes, etc.). Bytes 5..48 belong to position vectors of
              01836 ;              PLAYFIELD space objects (stars, explosion fragments). See also
              01837 ;              "ON POSITION VECTORS".
              01838 ;
              01839 ; $0B35        PL0YPOSLO
              01840 ;
              01841 ;              Low byte (B7..0) of position vector y-component (y-coordinate) of
              01842 ;              PLAYER0. Compare YPOSLO ($0B35). See also "ON POSITION VECTORS". 
              01843 ;
              01844 ; $0B36        PL1YPOSLO
              01845 ;
              01846 ;              Low byte (B7..0) of position vector y-component (y-coordinate) of
              01847 ;              PLAYER1. Compare YPOSLO ($0B35). See also "ON POSITION VECTORS".
              01848 ;
              01849 ; $0B37        PL2YPOSLO
              01850 ;
              01851 ;              Low byte (B7..0) of position vector y-component (y-coordinate) of
              01852 ;              PLAYER2. Compare YPOSLO ($0B35). See also "ON POSITION VECTORS".
              01853 ;
              01854 ; $0B38        PL3YPOSLO
              01855 ;
              01856 ;              Low byte (B7..0) of position vector y-component (y-coordinate) of
              01857 ;              PLAYER3. Compare YPOSLO ($0B35). See also "ON POSITION VECTORS".
              01858 ;
              01859 ; $0B39        PL4YPOSLO
              01860 ;
              01861 ;              Low byte (B7..0) of position vector y-component (y-coordinate) of
              01862 ;              PLAYER4. Compare YPOSLO ($0B35). See also "ON POSITION VECTORS".
              01863 ;
              01864 ; $0B66..$0B96 ZVEL
              01865 ;
              01866 ;              Table containing velocity vector z-components (z-velocities) (49
              01867 ;              bytes). Bytes 0..4 belong to velocity vectors of PLAYER space
              01868 ;              objects (Zylon ships, photon torpedoes, etc.). Bytes 5..48 belong
              01869 ;              to velocity vectors of PLAYFIELD space objects (stars, explosion
              01870 ;              fragments). Each z-velocity is stored in the binary format
              01871 ;              %sxxxxxxx where
              01872 ;                %s = 0   -> Positive sign (moving in flight direction)
              01873 ;                %s = 1   -> Negative sign (moving in reverse flight direction)
              01874 ;                %xxxxxxx -> Unsigned 7-bit velocity value in <KM/H>
              01875 ;
              01876 ;              See also "ON VELOCITY VECTORS".
              01877 ;
              01878 ; $0B66        PL0ZVEL
              01879 ;
              01880 ;              Velocity vector z-component (z-velocity) of PLAYER0. Compare ZVEL
              01881 ;              ($0B66). See also "ON VELOCITY VECTORS".
              01882 ;
              01883 ; $0B67        PL1ZVEL
              01884 ;
              01885 ;              Velocity vector z-component (z-velocity) of PLAYER1. Compare ZVEL
              01886 ;              ($0B66). See also "ON VELOCITY VECTORS".
              01887 ;
              01888 ; $0B68        PL2ZVEL
              01889 ;
              01890 ;              Velocity vector z-component (z-velocity) of PLAYER2. Compare ZVEL
              01891 ;              ($0B66). See also "ON VELOCITY VECTORS".
              01892 ;
              01893 ; $0B69        PL3ZVEL
              01894 ;
              01895 ;              Velocity vector z-component (z-velocity) of PLAYER3. Compare ZVEL
              01896 ;              ($0B66). See also "ON VELOCITY VECTORS".
              01897 ;
              01898 ; $0B6A        PL4ZVEL
              01899 ;
              01900 ;              Velocity vector z-component (z-velocity) of PLAYER4. Compare ZVEL
              01901 ;              ($0B66). See also "ON VELOCITY VECTORS".
              01902 ;
              01903 ; $0B97..$0BC7 XVEL
              01904 ;
              01905 ;              Table containing velocity vector x-components (x-velocities) (49
              01906 ;              bytes). Bytes 0..4 belong to velocity vectors of PLAYER space
              01907 ;              objects (Zylon ships, photon torpedoes, etc.). Bytes 5..48 belong
              01908 ;              to velocity vectors of PLAYFIELD space objects (stars, explosion
              01909 ;              fragments). Each x-velocity is stored in the binary format
              01910 ;              %sxxxxxxx where
              01911 ;                %s = 0   -> Positive sign (moving to the right)
              01912 ;                %s = 1   -> Negative sign (moving to the left)
              01913 ;                %xxxxxxx -> Unsigned 7-bit velocity value in <KM/H>
              01914 ;
              01915 ;              See also "ON VELOCITY VECTORS".
              01916 ;
              01917 ; $0B97        PL0XVEL
              01918 ;
              01919 ;              Velocity vector x-component (x-velocity) of PLAYER0. Compare XVEL
              01920 ;              ($0B97). See also "ON VELOCITY VECTORS". 
              01921 ;
              01922 ; $0B98        PL1XVEL
              01923 ;
              01924 ;              Velocity vector x-component (x-velocity) of PLAYER1. Compare XVEL
              01925 ;              ($0B97). See also "ON VELOCITY VECTORS".
              01926 ;
              01927 ; $0B99        PL2XVEL
              01928 ;
              01929 ;              Velocity vector x-component (x-velocity) of PLAYER2. Compare XVEL
              01930 ;              ($0B97). See also "ON VELOCITY VECTORS".
              01931 ;
              01932 ; $0B9A        PL3XVEL
              01933 ;
              01934 ;              Velocity vector x-component (x-velocity) of PLAYER3. Compare XVEL
              01935 ;              ($0B97). See also "ON VELOCITY VECTORS".
              01936 ;
              01937 ; $0B9B        PL4XVEL
              01938 ;
              01939 ;              Velocity vector x-component (x-velocity) of PLAYER4. Compare XVEL
              01940 ;              ($0B97). See also "ON VELOCITY VECTORS".
              01941 ;
              01942 ; $0BC8..$0BF8 YVEL
              01943 ;
              01944 ;              Table containing velocity vector y-components (y-velocities) (49
              01945 ;              bytes). Bytes 0..4 belong to velocity vectors of PLAYER space
              01946 ;              objects (Zylon ships, photon torpedoes, etc.). Bytes 5..48 belong
              01947 ;              to velocity vectors of PLAYFIELD space objects (stars, explosion
              01948 ;              fragments). Each y-velocity is stored in the binary format
              01949 ;              %sxxxxxxx where
              01950 ;                %s = 0   -> Positive sign (moving up)
              01951 ;                %s = 1   -> Negative sign (moving down)
              01952 ;                %xxxxxxx -> Unsigned 7-bit velocity value in <KM/H>
              01953 ;
              01954 ;              See also "ON VELOCITY VECTORS".
              01955 ;
              01956 ; $0BC8        PL0YVEL
              01957 ;
              01958 ;              Velocity vector y-component (y-velocity) of PLAYER0. Compare YVEL
              01959 ;              ($0BC8). See also "ON VELOCITY VECTORS". 
              01960 ;
              01961 ; $0BC9        PL1YVEL
              01962 ;
              01963 ;              Velocity vector y-component (y-velocity) of PLAYER1. Compare YVEL
              01964 ;              ($0BC8). See also "ON VELOCITY VECTORS".
              01965 ;
              01966 ; $0BCA        PL2YVEL
              01967 ;
              01968 ;              Velocity vector y-component (y-velocity) of PLAYER2. Compare YVEL
              01969 ;              ($0BC8). See also "ON VELOCITY VECTORS".
              01970 ;
              01971 ; $0BCB        PL3YVEL
              01972 ;
              01973 ;              Velocity vector y-component (y-velocity) of PLAYER3. Compare YVEL
              01974 ;              ($0BC8). See also "ON VELOCITY VECTORS".
              01975 ;
              01976 ; $0BCC        PL4YVEL
              01977 ;
              01978 ;              Velocity vector y-component (y-velocity) of PLAYER4. Compare YVEL
              01979 ;              ($0BC8). See also "ON VELOCITY VECTORS".
              01980 ;
              01981 ; $0BF9..$0C29 PIXELROWNEW
              01982 ;
              01983 ;              Table containing the new pixel row number of space objects (49
              01984 ;              bytes). Bytes 0..4 belong to PLAYER space objects and contain
              01985 ;              Player/Missile (PM) pixel row numbers. They are counted from
              01986 ;              vertical PM position 0, which is offscreen. Bytes 5..48 belong to
              01987 ;              PLAYFIELD space objects (stars, explosion fragments) and contain
              01988 ;              PLAYFIELD pixel row numbers. They are counted from the top border
              01989 ;              of the PLAYFIELD and have values of 0..99. See also PIXELROW
              01990 ;              ($0C5B).
              01991 ;
              01992 ; $0BF9        PL0ROWNEW
              01993 ;
              01994 ;              New pixel row number of PLAYER0 in Player/Missile pixels. See
              01995 ;              also PIXELROWNEW ($0BF9).
              01996 ;
              01997 ; $0BFA        PL1ROWNEW
              01998 ;
              01999 ;              New pixel row number of PLAYER1 in Player/Missile pixels. See
              02000 ;              also PIXELROWNEW ($0BF9).
              02001 ;
              02002 ; $0BFB        PL2ROWNEW
              02003 ;
              02004 ;              New pixel row number of PLAYER2 in Player/Missile pixels. See
              02005 ;              also PIXELROWNEW ($0BF9).
              02006 ;
              02007 ; $0BFC        PL3ROWNEW
              02008 ;
              02009 ;              New pixel row number of PLAYER3 in Player/Missile pixels. See
              02010 ;              also PIXELROWNEW ($0BF9).
              02011 ;
              02012 ; $0BFD        PL4ROWNEW
              02013 ;
              02014 ;              New pixel row number of PLAYER4 in Player/Missile pixels. See
              02015 ;              also PIXELROWNEW ($0BF9).
              02016 ;
              02017 ; $0C2A..$0C5A PIXELCOLUMN
              02018 ;
              02019 ;              Table containing the pixel column number of space objects (49
              02020 ;              bytes). Bytes 0..4 belong to PLAYER space objects and contain
              02021 ;              Player/Missile (PM) pixel column numbers. They are counted from
              02022 ;              horizontal PM position 0, which is offscreen. Bytes 5..48 belong
              02023 ;              to PLAYFIELD space objects (stars, explosion fragments) and
              02024 ;              contain PLAYFIELD pixel column numbers. They are counted from the
              02025 ;              left border of the PLAYFIELD and have values of 0..159.
              02026 ;
              02027 ; $0C2A        PL0COLUMN
              02028 ;
              02029 ;              Pixel column number of PLAYER0 in Player/Missile pixels. See also
              02030 ;              PIXELCOLUMN ($0C2A).
              02031 ;
              02032 ; $0C2B        PL1COLUMN
              02033 ;
              02034 ;              Pixel column number of PLAYER1 in Player/Missile pixels. See also
              02035 ;              PIXELCOLUMN ($0C2A).
              02036 ;
              02037 ; $0C2C        PL2COLUMN
              02038 ;
              02039 ;              Pixel column number of PLAYER2 in Player/Missile pixels. See also
              02040 ;              PIXELCOLUMN ($0C2A).
              02041 ;
              02042 ; $0C2D        PL3COLUMN
              02043 ;
              02044 ;              Pixel column number of PLAYER3 in Player/Missile pixels. See also
              02045 ;              PIXELCOLUMN ($0C2A).
              02046 ;
              02047 ; $0C2E        PL4COLUMN
              02048 ;
              02049 ;              Pixel column number of PLAYER4 in Player/Missile pixels. See also
              02050 ;              PIXELCOLUMN ($0C2A).
              02051 ;
              02052 ; $0C5B..$0C8B PIXELROW
              02053 ;
              02054 ;              Table containing the pixel row number of space objects (49
              02055 ;              bytes). Bytes 0..4 belong to PLAYER space objects and contain
              02056 ;              Player/Missile (PM) pixel row numbers. They are counted from
              02057 ;              vertical PM position 0, which is offscreen. Bytes 5..48 belong to
              02058 ;              PLAYFIELD space objects (stars, explosion fragments) and contain
              02059 ;              PLAYFIELD pixel row numbers. They are counted from the top border
              02060 ;              of the PLAYFIELD and have values of 0..99. See also PIXELROWNEW
              02061 ;              ($0BF9).
              02062 ;
              02063 ; $0C5B        PL0ROW
              02064 ;
              02065 ;              Pixel row number of PLAYER0 in Player/Missile pixels. See also
              02066 ;              PIXELROW ($0C5B).
              02067 ;
              02068 ; $0C5C        PL1ROW
              02069 ;
              02070 ;              Pixel row number of PLAYER1 in Player/Missile pixels. See also
              02071 ;              PIXELROW ($0C5B).
              02072 ;
              02073 ; $0C5D        PL2ROW
              02074 ;
              02075 ;              Pixel row number of PLAYER2 in Player/Missile pixels. See also
              02076 ;              PIXELROW ($0C5B).
              02077 ;
              02078 ; $0C5E        PL3ROW
              02079 ;
              02080 ;              Pixel row number of PLAYER3 in Player/Missile pixels. See also
              02081 ;              PIXELROW ($0C5B).
              02082 ;
              02083 ; $0C5F        PL4ROW
              02084 ;
              02085 ;              Pixel row number of PLAYER4 in Player/Missile pixels. See also
              02086 ;              PIXELROW ($0C5B).
              02087 ;
              02088 ; $0C8C..$0CBC PIXELBYTEOFF
              02089 ;
              02090 ;              Table containing a byte offset into PLAYFIELD memory for each
              02091 ;              PLAYFIELD space object (stars, explosion fragments) (49 bytes):
              02092 ;              the number of bytes from the start of the PLAYFIELD row to the
              02093 ;              byte containing the space object pixel in the same PLAYFIELD row.
              02094 ;              In other words, the pixel column modulo 4 (1 byte = 4 GRAPHICS7
              02095 ;              pixels).
              02096 ;
              02097 ;              NOTE: Only bytes 5..48 are used for PLAYFIELD space objects in
              02098 ;              this way. Bytes 0..4 are used differently. See PL0SHAPTYPE
              02099 ;              ($0C8C)..PL4SHAPTYPE ($0C90).
              02100 ;
              02101 ; $0C8C        PL0SHAPTYPE
              02102 ;
              02103 ;              Shape type of PLAYER0. Used to index the PLAYER's set of shape
              02104 ;              cells in tables PLSHAPOFFTAB ($BE2F) and PLSHAPHEIGHTTAB ($BE7F).
              02105 ;              Used values are:
              02106 ;                $00 -> PHOTON TORPEDO
              02107 ;                $10 -> ZYLON FIGHTER
              02108 ;                $20 -> STARBASE RIGHT
              02109 ;                $30 -> STARBASE CENTER
              02110 ;                $40 -> STARBASE LEFT
              02111 ;                $50 -> TRANSFER VESSEL
              02112 ;                $60 -> METEOR
              02113 ;                $70 -> ZYLON CRUISER
              02114 ;                $80 -> ZYLON BASESTAR
              02115 ;                $90 -> HYPERWARP TARGET MARKER
              02116 ;
              02117 ; $0C8D        PL1SHAPTYPE
              02118 ;
              02119 ;              Shape type of PLAYER1. Compare PL0SHAPTYPE ($0C8C).
              02120 ;
              02121 ; $0C8E        PL2SHAPTYPE
              02122 ;
              02123 ;              Shape type of PLAYER2. Compare PL0SHAPTYPE ($0C8C).
              02124 ;
              02125 ; $0C8F        PL3SHAPTYPE
              02126 ;
              02127 ;              Shape type of PLAYER3. Compare PL0SHAPTYPE ($0C8C).
              02128 ;
              02129 ; $0C90        PL4SHAPTYPE
              02130 ;
              02131 ;              Shape type of PLAYER4. Compare PL0SHAPTYPE ($0C8C).
              02132 ;
              02133 ; $0CBD..$0CED PIXELSAVE
              02134 ;
              02135 ;              Table containing the byte of PLAYFIELD memory before drawing the
              02136 ;              PLAYFIELD space object pixel into it (star, explosion fragments),
              02137 ;              for each PLAYFIELD space object (49 bytes). 
              02138 ;
              02139 ;              NOTE: Only bytes 5..48 are used for PLAYFIELD space objects in
              02140 ;              this way. Bytes 0..4 are used differently. See PL0HEIGHT
              02141 ;              ($0CBD)..PL4HEIGHT ($0CC1).
              02142 ;
              02143 ; $0CBD        PL0HEIGHT
              02144 ;
              02145 ;              Shape height of PLAYER0
              02146 ;
              02147 ; $0CBE        PL1HEIGHT
              02148 ;
              02149 ;              Shape height of PLAYER1
              02150 ;
              02151 ; $0CBF        PL2HEIGHT
              02152 ;
              02153 ;              Shape height of PLAYER2
              02154 ;
              02155 ; $0CC0        PL3HEIGHT
              02156 ;
              02157 ;              Shape height of PLAYER3
              02158 ;
              02159 ; $0CC1        PL4HEIGHT
              02160 ;
              02161 ;              Shape height of PLAYER4
              02162 ;
              02163 ; $0CEE..$0D1E PIXELBYTE
              02164 ;
              02165 ;              Table containing a 1-byte bit pattern for 4 pixels in the color
              02166 ;              of the space object's pixel, for each PLAYFIELD space object (49
              02167 ;              bytes). 
              02168 ;
              02169 ;              NOTE: Only bytes 5..48 are used for PLAYFIELD space objects in
              02170 ;              this way. Bytes 0..4 are used differently. See PL0HEIGHTNEW
              02171 ;              ($0CEE)..PL4HEIGHTNEW ($0CF2).
              02172 ;
              02173 ; $0CEE        PL0HEIGHTNEW
              02174 ;
              02175 ;              New shape height of PLAYER0
              02176 ;
              02177 ; $0CEF        PL1HEIGHTNEW
              02178 ;
              02179 ;              New shape height of PLAYER1
              02180 ;
              02181 ; $0CF0        PL2HEIGHTNEW
              02182 ;
              02183 ;              New shape height of PLAYER2
              02184 ;
              02185 ; $0CF1        PL3HEIGHTNEW
              02186 ;
              02187 ;              New shape height of PLAYER3
              02188 ;
              02189 ; $0CF2        PL4HEIGHTNEW
              02190 ;
              02191 ;              New shape height of PLAYER4
              02192 ;
              02193 ; $0D1F..$0D32 TITLETXT
              02194 ;
              02195 ;              Title text line, contains ATASCII-coded characters (20 bytes)
              02196 ;
              02197 ; $0D35..$0DE8 GCPFMEM
              02198 ;
              02199 ;              Galactic Chart PLAYFIELD memory (20 characters x 9 rows = 180
              02200 ;              bytes)
              02201 ;
              02202 ; $0DE9..$0EE8 MAPTO80
              02203 ;
              02204 ;              Lookup table to convert values in $00..$FF to values of 0..80
              02205 ;              (255 bytes). Used to map position vector components (coordinates)
              02206 ;              to pixel row or column numbers relative to the PLAYFIELD center. 
              02207 ;
              02208 ; $0EE9..$0FE8 MAPTOBCD99
              02209 ;
              02210 ;              Lookup table to convert values in $00..$FF to BCD-values of
              02211 ;              00..99 (255 bytes). Used in subroutines UPDPANEL ($B804) and
              02212 ;              SHOWDIGITS ($B8CD) to convert values to a 2-digit decimal readout
              02213 ;              value of the Control Panel Display.
              02214 ;
              02215 ; $1000..$1F77 PFMEM
              02216 ;
              02217 ;              PLAYFIELD graphics memory (40 bytes x 100 rows = 4000 bytes, 1
              02218 ;              byte stores 4 pixels, 40 bytes = 160 pixels in GRAPHICS7 mode = 1
              02219 ;              PLAYFIELD row of pixels).
              02220 ;
              02221 ;              NOTE: The Display List displays only PLAYFIELD rows 0..98.
              02222
              02223 ;*******************************************************************************
              02224 ;*                                                                             *
              02225 ;*                         S Y S T E M   S Y M B O L S                         *
              02226 ;*                                                                             *
              02227 ;*******************************************************************************
              02228
    =0200     02229 VDSLST          = $0200                           ; Display List Interrupt (DLI) vector
    =0216     02230 VIMIRQ          = $0216                           ; Interrupt request (IRQ) immediate vector
    =0222     02231 VVBLKI          = $0222                           ; Vertical blank immediate vector
    =D000     02232 HPOSP0          = $D000                           ; Horizontal position of PLAYER0
    =D001     02233 HPOSP1          = $D001                           ; Horizontal position of PLAYER1
    =D002     02234 HPOSP2          = $D002                           ; Horizontal position of PLAYER2
    =D003     02235 HPOSP3          = $D003                           ; Horizontal position of PLAYER3
    =D004     02236 HPOSM0          = $D004                           ; Horizontal position of MISSILE0
    =D005     02237 HPOSM1          = $D005                           ; Horizontal position of MISSILE1
    =D006     02238 HPOSM2          = $D006                           ; Horizontal position of MISSILE2
    =D007     02239 HPOSM3          = $D007                           ; Horizontal position of MISSILE3
    =D008     02240 M0PL            = $D008                           ; MISSILE0 to PLAYER collisions
    =D009     02241 M1PL            = $D009                           ; MISSILE1 to PLAYER collisions
    =D00A     02242 M2PL            = $D00A                           ; MISSILE2 to PLAYER collisions
    =D00B     02243 M3PL            = $D00B                           ; MISSILE3 to PLAYER collisions
    =D00F     02244 P3PL            = $D00F                           ; PLAYER3 to PLAYER collisions
    =D010     02245 TRIG0           = $D010                           ; Joystick 0 trigger
    =D012     02246 COLPM0          = $D012                           ; Color and brightness of PLAYER0
    =D016     02247 COLPF0          = $D016                           ; Color and brightness of PLAYFIELD0
    =D01B     02248 PRIOR           = $D01B                           ; Priority selection register
    =D01D     02249 GRACTL          = $D01D                           ; Graphics control register
    =D01E     02250 HITCLR          = $D01E                           ; Clear collision register
    =D01F     02251 CONSOL          = $D01F                           ; Function keys register
    =D200     02252 AUDF1           = $D200                           ; Audio channel 1 frequency
    =D202     02253 AUDF2           = $D202                           ; Audio channel 2 frequency
    =D203     02254 AUDC2           = $D203                           ; Audio channel 2 control
    =D204     02255 AUDF3           = $D204                           ; Audio channel 3 frequency
    =D205     02256 AUDC3           = $D205                           ; Audio channel 3 control
    =D206     02257 AUDF4           = $D206                           ; Audio channel 4 frequency
    =D207     02258 AUDC4           = $D207                           ; Audio channel 4 control
    =D208     02259 AUDCTL          = $D208                           ; Audio control
    =D209     02260 KBCODE          = $D209                           ; Keyboard code
    =D209     02261 STIMER          = $D209                           ; Start POKEY timers
    =D20A     02262 RANDOM          = $D20A                           ; Random number generator
    =D20E     02263 IRQEN           = $D20E                           ; Interrupt request (IRQ) enable
    =D20F     02264 SKCTL           = $D20F                           ; Serial port control
    =D300     02265 PORTA           = $D300                           ; Port A
    =D302     02266 PACTL           = $D302                           ; Port A control
    =D400     02267 DMACTL          = $D400                           ; Direct Memory Access (DMA) control
    =D402     02268 DLIST           = $D402                           ; Display List pointer
    =D407     02269 PMBASE          = $D407                           ; Player/Missile base address (high byte)
    =D409     02270 CHBASE          = $D409                           ; Character set base address (high byte)
    =D40A     02271 WSYNC           = $D40A                           ; Wait for horizontal synchronization
    =D40B     02272 VCOUNT          = $D40B                           ; Vertical line counter
    =D40E     02273 NMIEN           = $D40E                           ; Non-maskable interrupt (NMI) enable
    =E000     02274 ROMCHARSET      = $E000                           ; ROM character set
              02275
              02276 ;*******************************************************************************
              02277 ;*                                                                             *
              02278 ;*                           G A M E   S Y M B O L S                           *
              02279 ;*                                                                             *
              02280 ;*******************************************************************************
              02281
    =0062     02282 MISSIONLEVEL    = $62
    =0063     02283 FKEYCODE        = $63
    =0064     02284 ISDEMOMODE      = $64
    =0065     02285 NEWTITLEPHR     = $65
    =0066     02286 IDLECNTHI       = $66
    =0067     02287 ISVBISYNC       = $67
    =0068     02288 MEMPTR          = $68
              02289
    =006A     02290 DIVIDEND        = $6A
    =006D     02291 JOYSTICKDELTA   = $6D
              02292
              02293
    =0070     02294 VELOCITYLO      = $70
    =0071     02295 NEWVELOCITY     = $71
    =0072     02296 COUNT8          = $72
    =0073     02297 EXPLLIFE        = $73
    =0074     02298 CLOCKTIM        = $74
    =0075     02299 DOCKSTATE       = $75
    =0076     02300 COUNT256        = $76
    =0077     02301 IDLECNTLO       = $77
    =0078     02302 ZYLONUNITTIM    = $78
    =0079     02303 MAXSPCOBJIND    = $79
    =007A     02304 OLDMAXSPCOBJIND = $7A
    =007B     02305 ISSTARBASESECT  = $7B
    =007C     02306 ISTRACKCOMPON   = $7C
    =007D     02307 DRAINSHIELDS    = $7D
    =007E     02308 DRAINATTCOMP    = $7E
    =007F     02309 ENERGYCNT       = $7F
    =0080     02310 DRAINENGINES    = $80
    =0081     02311 SHIELDSCOLOR    = $81
    =0082     02312 PL3HIT          = $82
    =0083     02313 PL4HIT          = $83
    =0084     02314 OLDTRIG0        = $84
              02315
    =0086     02316 ISTRACKING      = $86
    =0087     02317 BARRELNR        = $87
    =0088     02318 LOCKONLIFE      = $88
    =0089     02319 PLTRACKED       = $89
    =008A     02320 HITBADNESS      = $8A
    =008B     02321 REDALERTLIFE    = $8B
    =008C     02322 WARPDEPRROW     = $8C
    =008D     02323 WARPDEPRCOLUMN  = $8D
    =008E     02324 WARPARRVROW     = $8E
    =008F     02325 WARPARRVCOLUMN  = $8F
    =0090     02326 CURRSECTOR      = $90
    =0091     02327 WARPENERGY      = $91
    =0092     02328 ARRVSECTOR      = $92
    =0093     02329 HUNTSECTOR      = $93
    =0094     02330 HUNTSECTCOLUMN  = $94
    =0095     02331 HUNTSECTROW     = $95
    =0096     02332 NEWZYLONDIST    = $96
    =009E     02333 OLDZYLONDIST    = $9E
    =009F     02334 HUNTTIM         = $9F
    =00A0     02335 BLIPCOLUMN      = $A0
    =00A1     02336 BLIPROW         = $A1
    =00A2     02337 BLIPCYCLECNT    = $A2
    =00A3     02338 ISINLOCKON      = $A3
    =00A4     02339 DIRLEN          = $A4
    =00A5     02340 PENROW          = $A5
    =00A6     02341 PENCOLUMN       = $A6
    =00A7     02342 CTRLDZYLON      = $A7
    =00A8     02343 ZYLONFLPAT0     = $A8
    =00A9     02344 ZYLONFLPAT1     = $A9
    =00AA     02345 MILESTTIM0      = $AA
    =00AB     02346 MILESTTIM1      = $AB
    =00AC     02347 MILESTVELINDZ0  = $AC
    =00AD     02348 MILESTVELINDZ1  = $AD
    =00AE     02349 MILESTVELINDX0  = $AE
    =00AF     02350 MILESTVELINDX1  = $AF
    =00B0     02351 MILESTVELINDY0  = $B0
    =00B1     02352 MILESTVELINDY1  = $B1
    =00B2     02353 ZYLONVELINDZ0   = $B2
    =00B3     02354 ZYLONVELINDZ1   = $B3
    =00B4     02355 ZYLONVELINDX0   = $B4
    =00B5     02356 ZYLONVELINDX1   = $B5
    =00B6     02357 ZYLONVELINDY0   = $B6
    =00B7     02358 ZYLONVELINDY1   = $B7
    =00B8     02359 ISBACKATTACK0   = $B8
    =00B9     02360 ISBACKATTACK1   = $B9
    =00BA     02361 ZYLONTIMX0      = $BA
    =00BB     02362 ZYLONTIMX1      = $BB
    =00BC     02363 ZYLONTIMY0      = $BC
    =00BD     02364 ZYLONTIMY1      = $BD
    =00BE     02365 TORPEDODELAY    = $BE
    =00BF     02366 ZYLONATTACKER   = $BF
    =00C0     02367 WARPSTATE       = $C0
    =00C1     02368 VELOCITYHI      = $C1
    =00C2     02369 TRAILDELAY      = $C2
    =00C3     02370 TRAILIND        = $C3
    =00C4     02371 WARPTEMPCOLUMN  = $C4
    =00C5     02372 WARPTEMPROW     = $C5
    =00C6     02373 VEERMASK        = $C6
    =00C7     02374 VICINITYMASK    = $C7
    =00C8     02375 JOYSTICKX       = $C8
    =00C9     02376 JOYSTICKY       = $C9
    =00CA     02377 KEYCODE         = $CA
    =00CB     02378 SCORE           = $CB
    =00CD     02379 SCOREDRANKIND   = $CD
    =00CE     02380 SCOREDCLASSIND  = $CE
    =00CF     02381 TITLELIFE       = $CF
    =00D0     02382 SHIPVIEW        = $D0
    =00D1     02383 TITLEPHR        = $D1
    =00D2     02384 BEEPFRQIND      = $D2
    =00D3     02385 BEEPREPEAT      = $D3
    =00D4     02386 BEEPTONELIFE    = $D4
    =00D5     02387 BEEPPAUSELIFE   = $D5
    =00D6     02388 BEEPPRIORITY    = $D6
    =00D7     02389 BEEPFRQSTART    = $D7
    =00D8     02390 BEEPLIFE        = $D8
    =00D9     02391 BEEPTOGGLE      = $D9
    =00DA     02392 NOISETORPTIM    = $DA
    =00DB     02393 NOISEEXPLTIM    = $DB
    =00DC     02394 NOISEAUDC2      = $DC
    =00DD     02395 NOISEAUDC3      = $DD
    =00DE     02396 NOISEAUDF1      = $DE
    =00DF     02397 NOISEAUDF2      = $DF
    =00E0     02398 NOISEFRQINC     = $E0
    =00E1     02399 NOISELIFE       = $E1
    =00E2     02400 NOISEZYLONTIM   = $E2
    =00E3     02401 NOISEHITLIFE    = $E3
    =00E4     02402 PL0SHAPOFF      = $E4
    =00E5     02403 PL1SHAPOFF      = $E5
    =00E6     02404 PL2SHAPOFF      = $E6
    =00E7     02405 PL3SHAPOFF      = $E7
    =00E8     02406 PL4SHAPOFF      = $E8
    =00E9     02407 PL0LIFE         = $E9
    =00EA     02408 PL1LIFE         = $EA
    =00EB     02409 PL2LIFE         = $EB
    =00EC     02410 PL3LIFE         = $EC
    =00ED     02411 PL4LIFE         = $ED
    =00EE     02412 PL0COLOR        = $EE
    =00EF     02413 PL1COLOR        = $EF
    =00F0     02414 PL2COLOR        = $F0
    =00F1     02415 PL3COLOR        = $F1
    =00F2     02416 PF0COLOR        = $F2
    =00F3     02417 PF1COLOR        = $F3
    =00F4     02418 PF2COLOR        = $F4
    =00F5     02419 PF3COLOR        = $F5
    =00F6     02420 BGRCOLOR        = $F6
    =00F7     02421 PF0COLORDLI     = $F7
    =00F8     02422 PF1COLORDLI     = $F8
    =00F9     02423 PF2COLORDLI     = $F9
    =00FA     02424 PF3COLORDLI     = $FA
    =00FB     02425 BGRCOLORDLI     = $FB
    =0280     02426 DSPLST          = $0280
    =0300     02427 PL4DATA         = $0300
    =0400     02428 PL0DATA         = $0400
    =0500     02429 PL1DATA         = $0500
    =0600     02430 PL2DATA         = $0600
    =0700     02431 PL3DATA         = $0700
    =0800     02432 PFMEMROWLO      = $0800
    =0864     02433 PFMEMROWHI      = $0864
    =08C9     02434 GCMEMMAP        = $08C9
    =0949     02435 PANELTXT        = $0949
    =094B     02436 VELOCD1         = $094B
    =0950     02437 KILLCNTD1       = $0950
    =0955     02438 ENERGYD1        = $0955
    =095A     02439 TRACKC1         = $095A
    =095C     02440 TRACKDIGIT      = $095C
    =0960     02441 THETAC1         = $0960
    =0966     02442 PHIC1           = $0966
    =096C     02443 RANGEC1         = $096C
    =0971     02444 GCTXT           = $0971
    =097D     02445 GCWARPD1        = $097D
    =098D     02446 GCTRGCNT        = $098D
    =0992     02447 GCSTATPHO       = $0992
    =0993     02448 GCSTATENG       = $0993
    =0994     02449 GCSTATSHL       = $0994
    =0995     02450 GCSTATCOM       = $0995
    =0996     02451 GCSTATLRS       = $0996
    =0997     02452 GCSTATRAD       = $0997
    =09A3     02453 GCSTARDAT       = $09A3
    =09AD     02454 ZPOSSIGN        = $09AD
    =09AF     02455 PL2ZPOSSIGN     = $09AF
    =09B0     02456 PL3ZPOSSIGN     = $09B0
    =09B1     02457 PL4ZPOSSIGN     = $09B1
    =09DE     02458 XPOSSIGN        = $09DE
    =09E0     02459 PL2XPOSSIGN     = $09E0
    =09E1     02460 PL3XPOSSIGN     = $09E1
    =09E2     02461 PL4XPOSSIGN     = $09E2
    =0A0F     02462 YPOSSIGN        = $0A0F
    =0A11     02463 PL2YPOSSIGN     = $0A11
    =0A12     02464 PL3YPOSSIGN     = $0A12
    =0A13     02465 PL4YPOSSIGN     = $0A13
    =0A40     02466 ZPOSHI          = $0A40
    =0A40     02467 PL0ZPOSHI       = $0A40
    =0A42     02468 PL2ZPOSHI       = $0A42
    =0A43     02469 PL3ZPOSHI       = $0A43
    =0A44     02470 PL4ZPOSHI       = $0A44
    =0A71     02471 XPOSHI          = $0A71
    =0A73     02472 PL2XPOSHI       = $0A73
    =0A74     02473 PL3XPOSHI       = $0A74
    =0A75     02474 PL4XPOSHI       = $0A75
    =0AA2     02475 YPOSHI          = $0AA2
    =0AA4     02476 PL2YPOSHI       = $0AA4
    =0AA5     02477 PL3YPOSHI       = $0AA5
    =0AA6     02478 PL4YPOSHI       = $0AA6
    =0AD3     02479 ZPOSLO          = $0AD3
    =0AD5     02480 PL2ZPOSLO       = $0AD5
    =0AD6     02481 PL3ZPOSLO       = $0AD6
    =0AD7     02482 PL4ZPOSLO       = $0AD7
    =0B04     02483 XPOSLO          = $0B04
    =0B06     02484 PL2XPOSLO       = $0B06
    =0B07     02485 PL3XPOSLO       = $0B07
    =0B08     02486 PL4XPOSLO       = $0B08
    =0B35     02487 YPOSLO          = $0B35
    =0B37     02488 PL2YPOSLO       = $0B37
    =0B38     02489 PL3YPOSLO       = $0B38
    =0B39     02490 PL4YPOSLO       = $0B39
    =0B66     02491 ZVEL            = $0B66
    =0B66     02492 PL0ZVEL         = $0B66
    =0B67     02493 PL1ZVEL         = $0B67
    =0B68     02494 PL2ZVEL         = $0B68
    =0B69     02495 PL3ZVEL         = $0B69
    =0B6A     02496 PL4ZVEL         = $0B6A
    =0B97     02497 XVEL            = $0B97
    =0B97     02498 PL0XVEL         = $0B97
    =0B98     02499 PL1XVEL         = $0B98
    =0B99     02500 PL2XVEL         = $0B99
    =0B9A     02501 PL3XVEL         = $0B9A
    =0B9B     02502 PL4XVEL         = $0B9B
    =0BC8     02503 YVEL            = $0BC8
    =0BC8     02504 PL0YVEL         = $0BC8
    =0BC9     02505 PL1YVEL         = $0BC9
    =0BCA     02506 PL2YVEL         = $0BCA
    =0BCB     02507 PL3YVEL         = $0BCB
    =0BCC     02508 PL4YVEL         = $0BCC
    =0BF9     02509 PIXELROWNEW     = $0BF9
    =0BF9     02510 PL0ROWNEW       = $0BF9
    =0BFA     02511 PL1ROWNEW       = $0BFA
    =0BFB     02512 PL2ROWNEW       = $0BFB
    =0BFC     02513 PL3ROWNEW       = $0BFC
    =0BFD     02514 PL4ROWNEW       = $0BFD
    =0C2A     02515 PIXELCOLUMN     = $0C2A
    =0C2A     02516 PL0COLUMN       = $0C2A
    =0C2B     02517 PL1COLUMN       = $0C2B
    =0C2C     02518 PL2COLUMN       = $0C2C
    =0C2D     02519 PL3COLUMN       = $0C2D
    =0C2E     02520 PL4COLUMN       = $0C2E
    =0C5B     02521 PIXELROW        = $0C5B
    =0C5B     02522 PL0ROW          = $0C5B
    =0C5C     02523 PL1ROW          = $0C5C
    =0C5D     02524 PL2ROW          = $0C5D
    =0C5E     02525 PL3ROW          = $0C5E
    =0C5F     02526 PL4ROW          = $0C5F
    =0C8C     02527 PIXELBYTEOFF    = $0C8C
    =0C8C     02528 PL0SHAPTYPE     = $0C8C
    =0C8D     02529 PL1SHAPTYPE     = $0C8D
    =0C8E     02530 PL2SHAPTYPE     = $0C8E
    =0C8F     02531 PL3SHAPTYPE     = $0C8F
    =0C90     02532 PL4SHAPTYPE     = $0C90
    =0CBD     02533 PIXELSAVE       = $0CBD
    =0CBD     02534 PL0HEIGHT       = $0CBD
    =0CBE     02535 PL1HEIGHT       = $0CBE
    =0CBF     02536 PL2HEIGHT       = $0CBF
    =0CC0     02537 PL3HEIGHT       = $0CC0
    =0CC1     02538 PL4HEIGHT       = $0CC1
    =0CEE     02539 PIXELBYTE       = $0CEE
    =0CEE     02540 PL0HEIGHTNEW    = $0CEE
    =0CEF     02541 PL1HEIGHTNEW    = $0CEF
    =0CF0     02542 PL2HEIGHTNEW    = $0CF0
    =0CF1     02543 PL3HEIGHTNEW    = $0CF1
    =0CF2     02544 PL4HEIGHTNEW    = $0CF2
    =0D1F     02545 TITLETXT        = $0D1F
    =0D35     02546 GCPFMEM         = $0D35
    =0DE9     02547 MAPTO80         = $0DE9
    =0EE9     02548 MAPTOBCD99      = $0EE9
    =1000     02549 PFMEM           = $1000
              02550
              02551                 *= $A000
              02552
              02553 ;*******************************************************************************
              02554 ;*                                                                             *
              02555 ;*                G A M E   D A T A   ( P A R T   1   O F   2 )                *
              02556 ;*                                                                             *
              02557 ;*******************************************************************************
              02558
              02559 ;*** Number of space objects ***************************************************
              02560
    =0005     02561 NUMSPCOBJ.PL    = 5                               ; Number of PLAYER space objects
    =000C     02562 NUMSPCOBJ.STARS = 12                              ; Number of PLAYFIELD space objects (stars)
    =0011     02563 NUMSPCOBJ.NORM  = NUMSPCOBJ.PL+NUMSPCOBJ.STARS    ; Normal number of space objects
    =0031     02564 NUMSPCOBJ.ALL   = 49                              ; Maximum number of space objects
              02565
              02566 ;*** PLAYER shape data offsets *************************************************
              02567
    =0000     02568 SHAP.TORPEDO    = $00                             ; Photon torpedo
    =0010     02569 SHAP.ZFIGHTER   = $10                             ; Zylon fighter
    =0020     02570 SHAP.STARBASEL  = $20                             ; Starbase (left part)
    =0030     02571 SHAP.STARBASEC  = $30                             ; Starbase (center part)
    =0040     02572 SHAP.STARBASER  = $40                             ; Starbase (right part)
    =0050     02573 SHAP.TRANSVSSL  = $50                             ; Transfer vessel
    =0060     02574 SHAP.METEOR     = $60                             ; Meteor
    =0070     02575 SHAP.ZCRUISER   = $70                             ; Zylon cruiser
    =0080     02576 SHAP.ZBASESTAR  = $80                             ; Zylon basestar
    =0090     02577 SHAP.HYPERWARP  = $90                             ; Hyperwarp Target Marker
              02578
              02579 ;*** ROM character set constants ***********************************************
    =0000     02580 ROM.SPC         = $00                             ; ROM character ' '
    =000E     02581 ROM.DOT         = $0E                             ; ROM character '.'
    =0010     02582 ROM.0           = $10                             ; ROM character '0'
    =0011     02583 ROM.1           = $11                             ; ROM character '1'
    =0012     02584 ROM.2           = $12                             ; ROM character '2'
    =0013     02585 ROM.3           = $13                             ; ROM character '3'
    =0014     02586 ROM.4           = $14                             ; ROM character '4'
    =0015     02587 ROM.5           = $15                             ; ROM character '5'
    =0019     02588 ROM.9           = $19                             ; ROM character '9'
    =001A     02589 ROM.COLON       = $1A                             ; ROM character ':'
    =0021     02590 ROM.A           = $21                             ; ROM character 'A'
    =0023     02591 ROM.C           = $23                             ; ROM character 'C'
    =0024     02592 ROM.D           = $24                             ; ROM character 'D'
    =0025     02593 ROM.E           = $25                             ; ROM character 'E'
    =0027     02594 ROM.G           = $27                             ; ROM character 'G'
    =002C     02595 ROM.L           = $2C                             ; ROM character 'L'
    =002E     02596 ROM.N           = $2E                             ; ROM character 'N'
    =0030     02597 ROM.P           = $30                             ; ROM character 'P'
    =0032     02598 ROM.R           = $32                             ; ROM character 'R'
    =0033     02599 ROM.S           = $33                             ; ROM character 'S'
    =0034     02600 ROM.T           = $34                             ; ROM character 'T'
    =0037     02601 ROM.W           = $37                             ; ROM character 'W'
    =0039     02602 ROM.Y           = $39                             ; ROM character 'Y'
              02603
              02604 ;*** Custom character set constants ********************************************
    =0040     02605 CCS.COL1        = $40                             ; COLOR1 bits for text in GR1/2 text mode
    =0080     02606 CCS.COL2        = $80                             ; COLOR2 bits for text in GR1/2 text mode
    =00C0     02607 CCS.COL3        = $C0                             ; COLOR3 bits for text in GR1/2 text mode
              02608
    =0000     02609 CCS.0           = 0                               ; Custom character '0'
    =0001     02610 CCS.1           = 1                               ; Custom character '1'
    =0002     02611 CCS.2           = 2                               ; Custom character '2'
    =0003     02612 CCS.3           = 3                               ; Custom character '3'
    =0004     02613 CCS.4           = 4                               ; Custom character '4'
    =0005     02614 CCS.5           = 5                               ; Custom character '5'
    =0006     02615 CCS.6           = 6                               ; Custom character '6'
    =0007     02616 CCS.7           = 7                               ; Custom character '7'
    =0008     02617 CCS.8           = 8                               ; Custom character '8'
    =0009     02618 CCS.9           = 9                               ; Custom character '9'
    =000A     02619 CCS.SPC         = 10                              ; Custom character ' '
    =000B     02620 CCS.COLON       = 11                              ; Custom character ':'
    =000C     02621 CCS.BORDERSW    = 12                              ; Custom character 'BORDER SOUTHWEST'
    =000D     02622 CCS.E           = 13                              ; Custom character 'E'
    =000E     02623 CCS.INF         = 14                              ; Custom character 'INFINITY'
    =000F     02624 CCS.MINUS       = 15                              ; Custom character '-'
    =0010     02625 CCS.PLUS        = 16                              ; Custom character '+'
    =0011     02626 CCS.PHI         = 17                              ; Custom character 'PHI'
    =0012     02627 CCS.V           = 18                              ; Custom character 'V'
    =0013     02628 CCS.R           = 19                              ; Custom character 'R'
    =0014     02629 CCS.THETA       = 20                              ; Custom character 'THETA'
    =0015     02630 CCS.K           = 21                              ; Custom character 'K'
    =0016     02631 CCS.T           = 22                              ; Custom character 'T'
    =0017     02632 CCS.C           = 23                              ; Custom character 'C'
    =0018     02633 CCS.BORDERS     = 24                              ; Custom character 'BORDER SOUTH'
    =0019     02634 CCS.BORDERW     = 25                              ; Custom character 'BORDER WEST'
    =001A     02635 CCS.CORNERSW    = 26                              ; Custom character 'CORNER SOUTHWEST'
    =001B     02636 CCS.STARBASE    = 27                              ; Custom character 'STARBASE SECTOR'
    =001C     02637 CCS.4ZYLONS     = 28                              ; Custom character '4-ZYLON SECTOR'
    =001D     02638 CCS.3ZYLONS     = 29                              ; Custom character '3-ZYLON SECTOR'
    =001E     02639 CCS.2ZYLONS     = 30                              ; Custom character '2-ZYLON SECTOR'
              02640
              02641 ;*** Custom character set ******************************************************
              02642 ;
              02643 ; 0        1        2        3        4        5        6        7
              02644 ; ........ ........ ........ ........ ........ ........ ........ ........
              02645 ; .####### ..##.... .####... .####... .##..... .####... .####... .#####..
              02646 ; .#...### ...#.... ....#... ....#... .##..... .#...... .#..#... .#...#..
              02647 ; .#...### ...#.... ....#... ....#... .##..... .#...... .#...... .....#..
              02648 ; .#...### ...#.... .####... .#####.. .##.##.. .####... .#...... ...###..
              02649 ; .#...### ..###... .#...... ....##.. .#####.. ....#... .######. ...#....
              02650 ; .#...### ..###... .#...... ....##.. ....##.. ....#... .#....#. ...#....
              02651 ; .####### ..###... .####... .#####.. ....##.. .####... .######. ...#....
              02652 ;
              02653 ; 8        9        10       11       12       13       14       15
              02654 ; ........ ........ ........ ..###... #....... ........ ........ ........
              02655 ; ..###... .#####.. ........ ..###... #....... ..####.. .##..##. ........
              02656 ; ..#.#... .#...#.. ........ ..###... #....... ..#..... #..##..# ........
              02657 ; ..#.#... .#...#.. ........ ........ #....... ..#..... #..##..# .######.
              02658 ; .#####.. .#####.. ........ ........ #....... .####... #..##..# ........
              02659 ; .##.##.. ....##.. ........ ..###... #....... .##..... .##..##. ........
              02660 ; .##.##.. ....##.. ........ ..###... #....... .##..... ........ ........
              02661 ; .#####.. ....##.. ........ ..###... ######## .#####.. ........ ........
              02662 ;
              02663 ; 16       17       18       19       20       21       22       23
              02664 ; ........ ........ .##..##. ........ ........ ........ #######. ######..
              02665 ; ...##... ...##... .##..##. .#####.. ...###.. .#...##. #..#..#. #...##..
              02666 ; ...##... .######. .##..##. .#...#.. ..#####. .#...##. ...#.... #...##..
              02667 ; ...##... ##.##.## .##..##. .#...#.. .##...## .#...#.. ...##... #.......
              02668 ; .######. #..##..# .##..##. .#####.. .#.###.# .#####.. ...##... #.......
              02669 ; ...##... ##.##.## ..#.##.. .##.#... .##...## .##..#.. ...##... #.......
              02670 ; ...##... .######. ..###... .##.##.. ..#####. .##..##. ...##... #....#..
              02671 ; ...##... ...##... ..##.... .##.##.. ...###.. .##..##. ...##... ######..
              02672 ;
              02673 ; 24       25       26       27       28       29       30
              02674 ; ........ #....... ........ #....... #....... #....... #.......
              02675 ; ........ #....... ........ #.#.#.#. #..##... #...###. #.##....
              02676 ; ........ #....... ........ #..###.. #....... #....... #..##...
              02677 ; ........ #....... ........ #.#####. #.##.##. #.###... #.#####.
              02678 ; ........ #....... ........ #..###.. #....... #....... #..##...
              02679 ; ........ #....... ........ #.#.#.#. #...##.. #..###.. #.##....
              02680 ; ........ #....... ........ #....... #....... #....... #.......
              02681 ; ######## #....... #....... ######## ######## ######## ########
              02682
A000 007F4747 02683 CHARSET         .BYTE $00,$7F,$47,$47,$47,$47,$47,$7F ; Custom character '0'
A004 4747477F
A008 00301010 02684                 .BYTE $00,$30,$10,$10,$10,$38,$38,$38 ; Custom character '1'
A00C 10383838
A010 00780808 02685                 .BYTE $00,$78,$08,$08,$78,$40,$40,$78 ; Custom character '2'
A014 78404078
A018 00780808 02686                 .BYTE $00,$78,$08,$08,$7C,$0C,$0C,$7C ; Custom character '3'
A01C 7C0C0C7C
A020 00606060 02687                 .BYTE $00,$60,$60,$60,$6C,$7C,$0C,$0C ; Custom character '4'
A024 6C7C0C0C
A028 00784040 02688                 .BYTE $00,$78,$40,$40,$78,$08,$08,$78 ; Custom character '5'
A02C 78080878
A030 00784840 02689                 .BYTE $00,$78,$48,$40,$40,$7E,$42,$7E ; Custom character '6'
A034 407E427E
A038 007C4404 02690                 .BYTE $00,$7C,$44,$04,$1C,$10,$10,$10 ; Custom character '7'
A03C 1C101010
A040 00382828 02691                 .BYTE $00,$38,$28,$28,$7C,$6C,$6C,$7C ; Custom character '8'
A044 7C6C6C7C
A048 007C4444 02692                 .BYTE $00,$7C,$44,$44,$7C,$0C,$0C,$0C ; Custom character '9'
A04C 7C0C0C0C
A050 00000000 02693                 .BYTE $00,$00,$00,$00,$00,$00,$00,$00 ; Custom character ' '
A054 00000000
A058 38383800 02694                 .BYTE $38,$38,$38,$00,$00,$38,$38,$38 ; Custom character ':'
A05C 00383838
A060 80808080 02695                 .BYTE $80,$80,$80,$80,$80,$80,$80,$FF ; Custom character 'BORDER SOUTHWEST'
A064 808080FF
A068 003C2020 02696                 .BYTE $00,$3C,$20,$20,$78,$60,$60,$7C ; Custom character 'E'
A06C 7860607C
A070 00669999 02697                 .BYTE $00,$66,$99,$99,$99,$66,$00,$00 ; Custom character 'INFINITY'
A074 99660000
A078 0000007E 02698                 .BYTE $00,$00,$00,$7E,$00,$00,$00,$00 ; Custom character '-'
A07C 00000000
A080 00181818 02699                 .BYTE $00,$18,$18,$18,$7E,$18,$18,$18 ; Custom character '+'
A084 7E181818
A088 00187EDB 02700                 .BYTE $00,$18,$7E,$DB,$99,$DB,$7E,$18 ; Custom character 'PHI'
A08C 99DB7E18
A090 66666666 02701                 .BYTE $66,$66,$66,$66,$66,$2C,$38,$30 ; Custom character 'V'
A094 662C3830
A098 007C4444 02702                 .BYTE $00,$7C,$44,$44,$7C,$68,$6C,$6C ; Custom character 'R'
A09C 7C686C6C
A0A0 001C3E63 02703                 .BYTE $00,$1C,$3E,$63,$5D,$63,$3E,$1C ; Custom character 'THETA'
A0A4 5D633E1C
A0A8 00464644 02704                 .BYTE $00,$46,$46,$44,$7C,$64,$66,$66 ; Custom character 'K'
A0AC 7C646666
A0B0 FE921018 02705                 .BYTE $FE,$92,$10,$18,$18,$18,$18,$18 ; Custom character 'T'
A0B4 18181818
A0B8 FC8C8C80 02706                 .BYTE $FC,$8C,$8C,$80,$80,$80,$84,$FC ; Custom character 'C'
A0BC 808084FC
A0C0 00000000 02707                 .BYTE $00,$00,$00,$00,$00,$00,$00,$FF ; Custom character 'BORDER SOUTH'
A0C4 000000FF
A0C8 80808080 02708                 .BYTE $80,$80,$80,$80,$80,$80,$80,$80 ; Custom character 'BORDER WEST'
A0CC 80808080
A0D0 00000000 02709                 .BYTE $00,$00,$00,$00,$00,$00,$00,$80 ; Custom character 'CORNER SOUTHWEST'
A0D4 00000080
A0D8 80AA9CBE 02710                 .BYTE $80,$AA,$9C,$BE,$9C,$AA,$80,$FF ; Custom character 'STARBASE SECTOR'
A0DC 9CAA80FF
A0E0 809880B6 02711                 .BYTE $80,$98,$80,$B6,$80,$8C,$80,$FF ; Custom character '4-ZYLON SECTOR'
A0E4 808C80FF
A0E8 808E80B8 02712                 .BYTE $80,$8E,$80,$B8,$80,$9C,$80,$FF ; Custom character '3-CYCLON SECTOR'
A0EC 809C80FF
A0F0 80B098BE 02713                 .BYTE $80,$B0,$98,$BE,$98,$B0,$80,$FF ; Custom character '2-ZYLON SECTOR'
A0F4 98B080FF
              02714
              02715 ;*** Header text of Long-Range Scan view (shares spaces with following header) *
A0F8 00006C6F 02716 LRSHEADER       .BYTE $00,$00,$6C,$6F,$6E,$67,$00,$72 ; "  LONG RANGE SCAN"
A0FC 6E670072
A100 616E6765 02717                 .BYTE $61,$6E,$67,$65,$00,$73,$63,$61
A104 00736361
A108 6E       02718                 .BYTE $6E
              02719
              02720 ;*** Header text of Aft view (shares spaces with following header) *************
A109 00000000 02721 AFTHEADER       .BYTE $00,$00,$00,$00,$00,$00,$61,$66 ; "      AFT VIEW   "
A10D 00006166
A111 74007669 02722                 .BYTE $74,$00,$76,$69,$65,$77,$00,$00
A115 65770000
A119 00       02723                 .BYTE $00
              02724
              02725 ;*** Header text of Galactic Chart view ****************************************
A11A 00000067 02726 GCHEADER        .BYTE $00,$00,$00,$67,$61,$6C,$61,$63 ; "   GALACTIC CHART   "
A11E 616C6163
A122 74696300 02727                 .BYTE $74,$69,$63,$00,$63,$68,$61,$72
A126 63686172
A12A 74000000 02728                 .BYTE $74,$00,$00,$00
              02729
              02730 ;*** Display List of Galactic Chart view ***************************************
A12E 60       02731 DLSTGC          .BYTE $60                             ; BLK7
A12F 461AA1   02732                 .BYTE $46,<GCHEADER,>GCHEADER         ; GR1 @ GCHEADER
A132 F0       02733                 .BYTE $F0                             ; BLK8 + DLI
A133 47350D   02734                 .BYTE $47,<GCPFMEM,>GCPFMEM           ; GR2 @ GCPFMEM
A136 07       02735                 .BYTE $07                             ; GR2
A137 07       02736                 .BYTE $07                             ; GR2
A138 07       02737                 .BYTE $07                             ; GR2
A139 07       02738                 .BYTE $07                             ; GR2
A13A 07       02739                 .BYTE $07                             ; GR2
A13B 07       02740                 .BYTE $07                             ; GR2
A13C 07       02741                 .BYTE $07                             ; GR2
A13D 07       02742                 .BYTE $07                             ; GR2
A13E 80       02743                 .BYTE $80                             ; BLK1 + DLI
A13F 461F0D   02744                 .BYTE $46,<TITLETXT,>TITLETXT         ; GR1 @ TITLETXT
A142 467109   02745                 .BYTE $46,<GCTXT,>GCTXT               ; GR1 @ GCTXT
A145 06       02746                 .BYTE $06                             ; GR1
A146 06       02747                 .BYTE $06                             ; GR1
A147 418002   02748                 .BYTE $41,<DSPLST,>DSPLST             ; JMP @ DSPLST
              02749
              02750 ;*******************************************************************************
              02751 ;*                                                                             *
              02752 ;*                              G A M E   C O D E                              *
              02753 ;*                                                                             *
              02754 ;*******************************************************************************
              02755
              02756 ;*******************************************************************************
              02757 ;*                                                                             *
              02758 ;*                                  INITCOLD                                   *
              02759 ;*                                                                             *
              02760 ;*                        Initialize game (Cold start)                         *
              02761 ;*                                                                             *
              02762 ;*******************************************************************************
              02763
              02764 ; DESCRIPTION
              02765 ;
              02766 ; Initializes the game, then continues into the game loop at GAMELOOP ($A1F3).
              02767 ;
              02768 ; There are four entry points to initialization:
              02769 ;
              02770 ; (1)  INITCOLD ($A14A) is entered at initial cartridge startup (cold start).
              02771 ;      This initializes POKEY, resets the idle counter, sets the mission level
              02772 ;      to NOVICE mission, and clears the function key code. POKEY is enabled to
              02773 ;      receive keyboard input. Code execution continues into INITSELECT ($A15A)
              02774 ;      below.
              02775 ;
              02776 ; (2)  INITSELECT ($A15A) is entered from GAMELOOP ($A1F3) after the SELECT
              02777 ;      function key has been pressed. This loads the title phrase offset for the
              02778 ;      copyright notice. Code execution continues into INITDEMO ($A15C) below. 
              02779 ;
              02780 ; (3)  INITDEMO ($A15C) is entered when the game switches into demo mode. This
              02781 ;      loads the demo mode flag. Code execution continues into INITSTART ($A15E)
              02782 ;      below.
              02783 ;
              02784 ; (4)  INITSTART ($A15E) is entered from GAMELOOP ($A1F3) after the START
              02785 ;      function key has been pressed. This enqueues the new title phrase and
              02786 ;      enables or disables demo mode, depending on the preloaded value.
              02787 ;
              02788 ; Initialization continues with the following steps: 
              02789 ;
              02790 ; (1)  Clear the custom chip registers and zero page game variables from
              02791 ;      ISVBISYNC ($0067) on.
              02792 ;
              02793 ;      NOTE: Because of loop jamming there is a loop index overshoot. This
              02794 ;      clears memory at $0067..$0166 instead of the game's zero page memory at
              02795 ;      $0067..$00FB. However, this does no harm because memory at $0100..$0166
              02796 ;      is - at this point in time - a yet unused part of the 6502 CPU stack
              02797 ;      (memory addresses $0100..$01FF).
              02798 ;
              02799 ;      NOTE: At address $A175 a hack is necessary in the source code to force an
              02800 ;      STA ISVBISYNC,X instruction with a 16-bit address operand, as opposed to
              02801 ;      an 8-bit (zero page) address operand. The latter would be chosen by
              02802 ;      virtually all 6502 assemblers, as ISVBISYNC ($0067) is located in the
              02803 ;      zero page (memory addresses $0000..$00FF). The reason to force a 16-bit
              02804 ;      address operand is the following: The instruction STA ISVBISYNC,X is used
              02805 ;      in a loop which iterates the CPU's X register from 0 to 255 to clear
              02806 ;      memory. By using this instruction with a 16-bit address operand
              02807 ;      ("indexed, absolute" mode), memory at $0067..$0166 is cleared. Had the
              02808 ;      code been using the same operation with an 8-bit address operand
              02809 ;      ("indexed, zero page" mode), memory at $0067..$00FF would have been
              02810 ;      cleared first, then the indexed address would have wrapped back to $0000
              02811 ;      and cleared memory at $0000..$0066, thus effectively overwriting already
              02812 ;      initialized memory locations.
              02813 ;
              02814 ; (2)  Initialize the 6502 CPU (reset the stack pointer, disable decimal mode).
              02815 ;
              02816 ; (3)  Clear game memory from $0200..$1FFF in subroutine CLRMEM ($AE0F).
              02817 ;
              02818 ; (4)  Set the address vectors of the IRQ, VBI, and DLI handlers.
              02819 ;
              02820 ; (5)  Enable input from Joystick 0.
              02821 ;
              02822 ; (6)  Enable Player/Missile graphics, providing a fifth PLAYER, and set
              02823 ;      PLAYER-PLAYFIELD priority.
              02824 ;
              02825 ;      BUG (at $A1A6): The set PLAYER-PLAYFIELD priority arranges PLAYERs
              02826 ;      (PL0..4) in front of the PLAYFIELD (PF0..4) in this specific order, from
              02827 ;      front to back:
              02828 ;
              02829 ;          PL0 > PL1 > PL2 > PL3 > PL4 > PF0, PF1, PF2 > PF4 (BGR)
              02830 ;
              02831 ;      This makes sense as space objects represented by PLAYERs (for example,
              02832 ;      Zylon ships, photon torpedoes, and meteors) move in front of the stars,
              02833 ;      which are part of the PLAYFIELD. However, PLAYERs also move in front of
              02834 ;      the cross hairs, which are also part of the PLAYFIELD. Suggested fix:
              02835 ;      None, technically not possible.  
              02836 ;
              02837 ; (7)  Do more initialization in subroutine INITIALIZE ($B3BA).
              02838 ;
              02839 ; (8)  Set display to Front view.
              02840 ;
              02841 ; (9)  Show or hide the Control Panel Display (bottom text window) in subroutine
              02842 ;      MODDLST ($ADF1), depending on the demo mode flag.
              02843 ;
              02844 ; (10) Initialize our starship's velocity equivalent to speed key '6'.
              02845 ;
              02846 ; (11) Enable the Display List.
              02847 ;
              02848 ; (12) Initialize the number of space objects to 16 (5 PLAYER space objects + 12
              02849 ;      PLAYFIELD space objects (stars), counted 0..16).
              02850 ;
              02851 ; (13) Set the title phrase to the selected mission level in subroutine SETTITLE
              02852 ;      ($B223).
              02853 ;
              02854 ; (14) Enable the IRQ, DLI, and VBI interrupts.
              02855 ;
              02856 ; Code execution continues into the game loop at GAMELOOP ($A1F3).
              02857
A14A A900     02858 INITCOLD        LDA #0                  ;
A14C 8D0FD2   02859                 STA SKCTL               ; POKEY: Initialization
A14F 8566     02860                 STA IDLECNTHI           ; Reset idle counter
A151 8562     02861                 STA MISSIONLEVEL        ; Mission level := NOVICE mission
A153 8563     02862                 STA FKEYCODE            ; Clear function key code
A155 A903     02863                 LDA #$03                ; POKEY: Enable keyboard scan and debounce
A157 8D0FD2   02864                 STA SKCTL               ;
              02865
              02866 ;*** Entry point when SELECT function key was pressed **************************
A15A A02F     02867 INITSELECT      LDY #$2F                ; Prep title phrase "COPYRIGHT ATARI 1979"
              02868
              02869 ;*** Entry point when game switches into demo mode *****************************
A15C A9FF     02870 INITDEMO        LDA #$FF                ; Prep demo mode flag
              02871
              02872 ;*** Entry point when START function key was pressed ***************************
A15E 8465     02873 INITSTART       STY NEWTITLEPHR         ; Enqueue new title phrase
A160 8564     02874                 STA ISDEMOMODE          ; Store demo mode flag
              02875
              02876 ;*** More initialization *******************************************************
A162 A900     02877                 LDA #0                  ; Clear custom chip registers, zero page variables
A164 AA       02878                 TAX                     ;
A165 9D00D0   02879 LOOP001         STA HPOSP0,X            ; Clear $D000..$D0FF (GTIA registers)
A168 9D00D4   02880                 STA DMACTL,X            ; Clear $D400..$D4FF (ANTIC registers)
A16B E00F     02881                 CPX #$0F                ;
A16D B003     02882                 BCS SKIP001             ;
A16F 9D00D2   02883                 STA AUDF1,X             ; Clear $D200..$D20E (POKEY registers)
              02884
A172 9D00D3   02885 SKIP001         STA PORTA,X             ; Clear $D300..$D3FF (PIA registers)
              02886                                         ; Clear $0067..$0166 (zero page game variables)
A175 9D       02887                 .BYTE $9D               ; HACK: Force ISVBISYNC,X with 16-bit address
A176 6700     02888                 .WORD ISVBISYNC         ; (loop jamming)
A178 E8       02889                 INX                     ;
A179 D0EA     02890                 BNE LOOP001             ;
              02891
A17B CA       02892                 DEX                     ; Reset 6502 CPU stack pointer
A17C 9A       02893                 TXS                     ;
              02894
A17D D8       02895                 CLD                     ; Clear 6502 CPU decimal mode
              02896
A17E A902     02897                 LDA #$02                ; Clear $0200..$1FFF (game memory)
A180 200FAE   02898                 JSR CLRMEM              ;
              02899
A183 A951     02900                 LDA #<IRQHNDLR          ; Set IRQ handler (VIMIRQ)
A185 8D1602   02901                 STA VIMIRQ              ;
A188 A9A7     02902                 LDA #>IRQHNDLR          ;
A18A 8D1702   02903                 STA VIMIRQ+1            ;
              02904
A18D A9D1     02905                 LDA #<VBIHNDLR          ; Set VBI and DLI handler (VVBLKI and VDSLST)
A18F 8D2202   02906                 STA VVBLKI              ;
A192 A918     02907                 LDA #<DLSTHNDLR         ;
A194 8D0002   02908                 STA VDSLST              ;
A197 A9A6     02909                 LDA #>VBIHNDLR          ;
A199 8D2302   02910                 STA VVBLKI+1            ;
A19C A9A7     02911                 LDA #>DLSTHNDLR         ;
A19E 8D0102   02912                 STA VDSLST+1            ;
              02913
A1A1 A904     02914                 LDA #$04                ; PIA: Enable PORTA (Joystick 0)
A1A3 8D02D3   02915                 STA PACTL               ;
A1A6 A911     02916                 LDA #$11                ; GTIA: Enable PLAYER4, prio: PLs > PFs > BGR (!)
A1A8 8D1BD0   02917                 STA PRIOR               ; (PLAYERs in front of stars - and cross hairs)
A1AB A903     02918                 LDA #$03                ; GTIA: Enable DMA for PLAYERs and MISSILEs
A1AD 8D1DD0   02919                 STA GRACTL              ;
              02920
A1B0 20BAB3   02921                 JSR INITIALIZE          ; Init Display List, tables, Galactic Chart, etc.
              02922
A1B3 A20A     02923                 LDX #$0A                ; Set Front view
A1B5 2045B0   02924                 JSR SETVIEW             ;
              02925
A1B8 A564     02926                 LDA ISDEMOMODE          ; If in/not in demo mode hide/show...
A1BA 2980     02927                 AND #$80                ; ...Control Panel Display (bottom text window)
A1BC A8       02928                 TAY                     ;
A1BD A25F     02929                 LDX #$5F                ;
A1BF A908     02930                 LDA #$08                ;
A1C1 20F1AD   02931                 JSR MODDLST             ;
              02932
A1C4 A920     02933                 LDA #32                 ; Init our starship's velocity (= speed key '6')
A1C6 8571     02934                 STA NEWVELOCITY         ;
              02935
A1C8 A980     02936                 LDA #<DSPLST            ; ANTIC: Set Display List
A1CA 8D02D4   02937                 STA DLIST               ;
A1CD A902     02938                 LDA #>DSPLST            ;
A1CF 8D03D4   02939                 STA DLIST+1             ;
              02940
A1D2 A93E     02941                 LDA #$3E                ; ANTIC: Enable Display List DMA, single-line PM
A1D4 8D00D4   02942                 STA DMACTL              ; resolution, PM DMA, normal-width PLAYFIELD
              02943
A1D7 A900     02944                 LDA #0                  ; ANTIC: Set PM memory base address
A1D9 8D07D4   02945                 STA PMBASE              ;
              02946
A1DC A910     02947                 LDA #NUMSPCOBJ.NORM-1   ; Set normal number of space objects
A1DE 8579     02948                 STA MAXSPCOBJIND        ; (5 PLAYER spc objs + 12 PLAYFIELD spc objs (stars))
              02949
A1E0 A662     02950                 LDX MISSIONLEVEL        ; Set title phrase
A1E2 BC0CBF   02951                 LDY MISSIONPHRTAB,X     ; NOVICE, PILOT, WARRIOR, or COMMANDER MISSION
A1E5 2023B2   02952                 JSR SETTITLE            ;
              02953
A1E8 A940     02954                 LDA #$40                ; POKEY: Enable keyboard interrupt (IRQ)
A1EA 8D0ED2   02955                 STA IRQEN               ;
              02956
A1ED 58       02957                 CLI                     ; Enable all IRQs
              02958
A1EE A9C0     02959                 LDA #$C0                ; ANTIC: Enable DLI and VBI
A1F0 8D0ED4   02960                 STA NMIEN               ;
              02961
              02962 ;*******************************************************************************
              02963 ;*                                                                             *
              02964 ;*                                  GAMELOOP                                   *
              02965 ;*                                                                             *
              02966 ;*******************************************************************************
              02967
              02968 ; DESCRIPTION
              02969 ;
              02970 ; The game loop is the main part of the game. It is basically an infinite loop
              02971 ; that collects input, computes the game state, and updates the display. It
              02972 ; executes the following steps:
              02973 ;
              02974 ; (1)  Synchronize the start of the game loop with the vertical blank phase of
              02975 ;      the TV beam, which flagged by the Vertical Blank Interrupt handler
              02976 ;      VBIHNDLR ($A6D1). This prevents screen flicker while the PLAYFIELD is
              02977 ;      redrawn at the beginning of the game loop, because during the vertical
              02978 ;      blank phase the TV beam is turned off and nothing is rendered on the TV
              02979 ;      display. 
              02980 ;
              02981 ; (2)  Erase all PLAYFIELD space objects (stars, explosion fragments) from the
              02982 ;      PLAYFIELD that were drawn in the previous game loop iteration.
              02983 ;
              02984 ; (3)  Draw the updated PLAYFIELD space objects (stars, explosion fragments)
              02985 ;      into the PLAYFIELD (skip this if in hyperspace).
              02986 ;
              02987 ; (4)  If the idle counter has reached its trigger value then clear the center
              02988 ;      of the PLAYFIELD, an 8 x 2 pixel rectangle with a top-left position at
              02989 ;      pixel column number 76 and pixel row number 49 (?).
              02990 ;
              02991 ; (5)  Clear all PLAYER shapes.
              02992 ;
              02993 ; (6)  Update the vertical position of all PLAYERs and update all PLAYER shapes.
              02994 ;
              02995 ; (7)  Update the horizontal position of all PLAYERs.
              02996 ;
              02997 ; (8)  Rotate the position vector of all space objects horizontally and
              02998 ;      vertically, according to the saved joystick position (skip this if in
              02999 ;      Galactic Chart view) using subroutine ROTATE ($B69B).
              03000 ;
              03001 ; (9)  Move our starship forward in space. Our starship is always located at the
              03002 ;      center of the game's 3D coordinate system, so all space objects are moved
              03003 ;      along the z-axis toward our starship by subtracting a displacement from
              03004 ;      their z-coordinate. The amount of the displacement depends on our
              03005 ;      starship's velocity.
              03006 ;
              03007 ;      BUG (at $A3C1): This operation is not applied to Photon torpedoes (?).
              03008 ;      Suggested fix: Remove LDA PL0SHAPTYPE,X and BEQ SKIP011. 
              03009 ;
              03010 ; (10) Add the proper velocity vector of all space objects to their position
              03011 ;      vector (except for stars, which do not have any proper motion).
              03012 ;
              03013 ;      BUG (at $A419): The correct maximum loop index is NUMSPCOBJ.ALL*3 = 147
              03014 ;      instead of 144. Suggested fix: Replace CMP #144 with CMP #147.
              03015 ;
              03016 ; (11) Correct the position vector components (coordinates) of all PLAYER space
              03017 ;      objects if they have over- or underflowed during the calculations of the
              03018 ;      previous steps.
              03019 ;
              03020 ; (12) Calculate the perspective projection of the position vectors of all space
              03021 ;      objects and from that their pixel row and column number (applies to Front
              03022 ;      and Aft view) using subroutines PROJECTION ($AA21), SCREENCOLUMN ($B6FB),
              03023 ;      and SCREENROW ($B71E). If a space object (star, explosion fragment) moved
              03024 ;      offscreen then a new space object is automatically created in subroutine
              03025 ;      SCREENCOLUMN ($B6FB).
              03026 ;
              03027 ; (13) Handle hyperwarp marker selection in the Galactic Chart view in
              03028 ;      subroutine SELECTWARP ($B162).
              03029 ;
              03030 ; (14) If in Long-Range Scan view, compute the pixel column number and the pixel
              03031 ;      row number of all PLAYFIELD space objects (stars, explosion fragments) on
              03032 ;      the plane established by the z and x axis of the 3D coordinate system
              03033 ;      using subroutines SCREENCOLUMN ($B6FB) and SCREENROW ($B71E). Our
              03034 ;      starship's shape is drawn using subroutine DRAWLINES ($A76F). If the
              03035 ;      Long-Range Scan is OK then PLAYFIELD space object pixel numbers are
              03036 ;      computed and drawn. This is skipped if the Long-Range Scan is destroyed. 
              03037 ;
              03038 ; (15) Update all PLAYER shapes, heights, and colors (see detailed description
              03039 ;      below).
              03040 ;
              03041 ; (16) Flash a red alert when leaving hyperspace into a sector containing Zylon
              03042 ;      ships by setting appropriate colors to PLAYFIELD2 and BACKGROUND.
              03043 ;
              03044 ; (17) Update the color of all PLAYFIELD space objects (stars, explosion
              03045 ;      fragments). The color calculation is similar to that of the PLAYER color
              03046 ;      calculation in (15). It also computes a range index and uses the same
              03047 ;      color lookup table FOURCOLORPIXEL ($BA90). If a star in the Aft view
              03048 ;      became too distant (z-coordinate < -$F000 (-4096) <KM>) its position is
              03049 ;      re-initialized in subroutine INITPOSVEC ($B764).
              03050 ;
              03051 ; (18) If in demo mode skip input handling and jump directly to function key
              03052 ;      handling (28).
              03053 ;
              03054 ; (19) Handle keyboard input in subroutine KEYBOARD ($AFFE).
              03055 ;
              03056 ; (20) Handle joystick input. Store the current joystick directions in JOYSTICKX
              03057 ;      ($C8) and JOYSTICKY ($C9).
              03058 ;
              03059 ; (21) Check if our starship's photon torpedoes have hit a target in subroutine
              03060 ;      COLLISION ($AF3D). This subroutine triggers a game over if all Zylon
              03061 ;      ships have been destroyed.
              03062 ;
              03063 ; (22) Handle the joystick trigger in subroutine TRIGGER ($AE29).
              03064 ;
              03065 ; (23) Handle the Attack Computer and Tracking Computer. If the Attack Computer
              03066 ;      is neither destroyed nor switched off then execute the following steps:
              03067 ;
              03068 ;      o   Update the Attack Computer Display's blip and lock-on markers in
              03069 ;          subroutine UPDATTCOMP ($A7BF) (if in Front view).
              03070 ;
              03071 ;      o   Update the tracking index of the currently tracked PLAYER space
              03072 ;          object. If a Zylon ship is tracked, then make sure to always track
              03073 ;          the Zylon ship that launched the last Zylon photon torpedo. If this
              03074 ;          Zylon ship is not alive then track the other Zylon ship - if alive.
              03075 ;
              03076 ;      o   If the Tracking Computer is on then switch to the view that shows the
              03077 ;          tracked PLAYER space object by emulating pressing the 'F' (Front
              03078 ;          view) or 'A' (Aft view) key (only if in Front or Aft view).
              03079 ;
              03080 ; (24) Handle docking at a starbase in subroutine DOCKING ($ACE6).
              03081 ;
              03082 ; (25) Handle maneuvering both of our starship's photon torpedoes, the single
              03083 ;      Zylon photon torpedo, and the attacking Zylon ships in subroutine
              03084 ;      MANEUVER ($AA79). This subroutine also automatically creates meteors and
              03085 ;      new Zylon ships.
              03086 ;
              03087 ; (26) Check if our starship was hit by a Zylon photon torpedo (skip this if in
              03088 ;      a starbase sector): Its x, y, and z coordinates must be within a range of
              03089 ;      -($0100)..+$00FF (-256..+255) <KM> of our starship.
              03090 ;
              03091 ; (27) If our starship was hit then execute the following steps:
              03092 ;
              03093 ;      o   Damage or destroy one of our starship's subsystems in subroutine
              03094 ;          DAMAGE ($AEE1).
              03095 ;
              03096 ;      o   Trigger an explosion in subroutine INITEXPL ($AC6B), 
              03097 ;
              03098 ;      o   Store the severity of the hit.
              03099 ;
              03100 ;      o   End the lifetime of the Zylon photon torpedo.
              03101 ;
              03102 ;      o   Subtract 100 energy units for being hit by the Zylon photon torpedo
              03103 ;          in subroutine DECENERGY ($B86F). 
              03104 ;
              03105 ;      o   Trigger the noise sound pattern SHIELD EXPLOSION in subroutine NOISE
              03106 ;          ($AEA8). 
              03107 ;
              03108 ;      If the Shields were down during the hit, our starship is destroyed.
              03109 ;      Execute the following steps:
              03110 ;
              03111 ;      o   Switch to Front view.
              03112 ;
              03113 ;      o   Flash the title phrase "SHIP DESTROYED BY ZYLON FIRE".
              03114 ;
              03115 ;      o   Add the mission bonus to the internal game score in subroutine
              03116 ;          GAMEOVER ($B10A).
              03117 ;
              03118 ;      o   Hide the Control Panel Display (bottom text window) in subroutine
              03119 ;          MODDLST ($ADF1).
              03120 ;
              03121 ;      o   Clear the PLAYFIELD in subroutine CLRPLAYFIELD ($AE0D).
              03122 ;
              03123 ;      o   Enable the STARSHIP EXPLOSION noise. 
              03124 ;
              03125 ; (28) Handle the function keys START and SELECT. If SELECT has been pressed
              03126 ;      cycle through the next of the 4 mission levels. If either START or SELECT
              03127 ;      have been pressed, reset the idle counter, then jump to the corresponding
              03128 ;      game initialization subroutines INITSTART ($A15E) or INITSELECT ($A15A),
              03129 ;      respectively. 
              03130 ;
              03131 ; (29) Update the Control Panel Display in subroutine UPDPANEL ($B804).
              03132 ;
              03133 ; (30) Handle hyperwarp in subroutine HYPERWARP ($A89B).
              03134 ;
              03135 ; (31) Update the text in the title line in subroutine UPDTITLE ($B216).
              03136 ;
              03137 ; (32) Move Zylon units, decrease lifetime of photon torpedoes, elapse game
              03138 ;      time, etc. in subroutine FLUSHGAMELOOP ($B4E4). This subroutine also
              03139 ;      triggers a game over if our starship's energy is zero.
              03140 ;
              03141 ; (33) Jump back to the start of the game loop for the next game loop iteration.
              03142
    =006A     03143 L.HEIGHTCNT     = $6A                   ; Height counter during copying a PLAYER shape
    =006E     03144 L.ZPOSOFF       = $6E                   ; Offset to z-coordinate
    =006B     03145 L.VELOCITYHI    = $6B                   ; Velocity vector component (high byte)
    =006A     03146 L.VECCOMPIND    = $6A                   ; Position vector component index. Used values are:
              03147                                         ;   0 -> z-component
              03148                                         ;   1 -> x-component
              03149                                         ;   2 -> y-component
    =006A     03150 L.RANGEINDEX    = $6A                   ; Range index for space object, computed from the
              03151                                         ; distance to our starship. Used to pick the shape
              03152                                         ; cell index of the PLAYERs shape data and shape
              03153                                         ; height. Used values are: 0..15.
    =006A     03154 L.FOURCOLORPIX  = $6A                   ; 1-byte bit pattern for 4 pixels of same color
    =006B     03155 L.COLORMASK     = $6B                   ; Color/brightness to modify PLAYER color
              03156
              03157 ;*** (1) Synchronize game loop with execution of VBI ***************************
A1F3 A567     03158 GAMELOOP        LDA ISVBISYNC           ; Wait for execution of VBI
A1F5 F0FC     03159                 BEQ GAMELOOP            ;
              03160
A1F7 A900     03161                 LDA #0                  ; VBI is executed, clear VBI sync flag
A1F9 8567     03162                 STA ISVBISYNC           ;
              03163
              03164 ;*** (2) Erase PLAYFIELD space objects (stars, explosion fragments) ************
A1FB A57A     03165                 LDA OLDMAXSPCOBJIND     ; Skip if no space objects in use
A1FD F020     03166                 BEQ SKIP002             ;
              03167
A1FF A204     03168                 LDX #NUMSPCOBJ.PL-1     ; Loop over all PLAYFIELD space objs (X index > 4)
A201 E8       03169 LOOP002         INX                     ;
A202 BC5B0C   03170                 LDY PIXELROW,X          ; Load pixel row number of PLAYFIELD space object
              03171
A205 B90008   03172                 LDA PFMEMROWLO,Y        ; Point MEMPTR to start of pixel's row...
A208 8568     03173                 STA MEMPTR              ; ...in PLAYFIELD memory
A20A B96408   03174                 LDA PFMEMROWHI,Y        ;
A20D 8569     03175                 STA MEMPTR+1            ;
              03176
A20F BC8C0C   03177                 LDY PIXELBYTEOFF,X      ; Get within-row-offset to byte with space obj pixel
A212 BDBD0C   03178                 LDA PIXELSAVE,X         ; Load saved byte
A215 9168     03179                 STA (MEMPTR),Y          ; Restore byte of PLAYFIELD memory
              03180
A217 E47A     03181                 CPX OLDMAXSPCOBJIND     ;
A219 90E6     03182                 BCC LOOP002             ; Next PLAYFIELD space object
              03183
A21B A900     03184                 LDA #0                  ; Clear number of space objects
A21D 857A     03185                 STA OLDMAXSPCOBJIND     ;
              03186
              03187 ;*** (3) Draw PLAYFIELD space objects (stars, explosion fragments) *************
A21F A5C0     03188 SKIP002         LDA WARPSTATE           ; Skip during hyperspace
A221 302D     03189                 BMI SKIP003             ;
              03190
A223 A679     03191                 LDX MAXSPCOBJIND        ; Update number of space objects
A225 867A     03192                 STX OLDMAXSPCOBJIND     ;
              03193
A227 BDF90B   03194 LOOP003         LDA PIXELROWNEW,X       ; Loop over all PLAYFIELD space objs (X index > 4)
A22A 9D5B0C   03195                 STA PIXELROW,X          ; Update pixel row number of PLAYFIELD space object
              03196
A22D A8       03197                 TAY                     ;
A22E B90008   03198                 LDA PFMEMROWLO,Y        ; Point MEMPTR to start of pixel's row...
A231 8568     03199                 STA MEMPTR              ; ...in PLAYFIELD memory
A233 B96408   03200                 LDA PFMEMROWHI,Y        ;
A236 8569     03201                 STA MEMPTR+1            ;
              03202
A238 BD2A0C   03203                 LDA PIXELCOLUMN,X       ; Convert pixel column number to within-row-offset
A23B 4A       03204                 LSR A                   ; ...of byte with space obj pixel (4 pixels = 1 byte)
A23C 4A       03205                 LSR A                   ;
A23D 9D8C0C   03206                 STA PIXELBYTEOFF,X      ; Store within-row-offset
              03207
A240 A8       03208                 TAY                     ;
A241 B168     03209                 LDA (MEMPTR),Y          ; Load pixel's byte from PLAYFIELD memory
A243 9DBD0C   03210                 STA PIXELSAVE,X         ; Save it (for restoring it in next game loop)
A246 1DEE0C   03211                 ORA PIXELBYTE,X         ; Blend with pixel's color bit-pattern
A249 9168     03212                 STA (MEMPTR),Y          ; Store byte in PLAYFIELD memory
              03213
A24B CA       03214                 DEX                     ;
A24C E004     03215                 CPX #NUMSPCOBJ.PL-1     ;
A24E D0D7     03216                 BNE LOOP003             ; Next PLAYFIELD space object
              03217
              03218 ;*** (4) Clear PLAYFIELD center if idle counter is up (?) **********************
              03219                                         ; PLAYFIELD addresses of...
    =17BB     03220 PFMEM.C76R49    = PFMEM+49*40+76/4      ; ...pixel column number 76, row number 49
    =17BC     03221 PFMEM.C80R49    = PFMEM+49*40+80/4      ; ...pixel column number 80, row number 49
    =17E3     03222 PFMEM.C76R50    = PFMEM+50*40+76/4      ; ...pixel column number 76, row number 50
    =17E4     03223 PFMEM.C80R50    = PFMEM+50*40+80/4      ; ...pixel column number 80, row number 50
              03224
A250 A566     03225 SKIP003         LDA IDLECNTHI           ; Skip if idle counter not negative
A252 100E     03226                 BPL SKIP004             ;
              03227
A254 A900     03228                 LDA #0                  ; Clear pixels of 8 x 2 pixel rectangle...
A256 8DE317   03229                 STA PFMEM.C76R50        ; ...@ column number 76, row number 49 (?)
A259 8DE417   03230                 STA PFMEM.C80R50        ;
A25C 8DBC17   03231                 STA PFMEM.C80R49        ;
A25F 8DBB17   03232                 STA PFMEM.C76R49        ;
              03233
              03234 ;*** (5) Clear all PLAYER shapes ***********************************************
A262 A900     03235 SKIP004         LDA #0                  ; Clear shape of PLAYER4
A264 AC5F0C   03236                 LDY PL4ROW              ;
A267 AEC10C   03237                 LDX PL4HEIGHT           ;
A26A 990003   03238 LOOP004         STA PL4DATA,Y           ;
A26D C8       03239                 INY                     ;
A26E CA       03240                 DEX                     ;
A26F 10F9     03241                 BPL LOOP004             ;
              03242
A271 AC5E0C   03243                 LDY PL3ROW              ; Clear shape of PLAYER3
A274 AEC00C   03244                 LDX PL3HEIGHT           ;
A277 990007   03245 LOOP005         STA PL3DATA,Y           ;
A27A C8       03246                 INY                     ;
A27B CA       03247                 DEX                     ;
A27C 10F9     03248                 BPL LOOP005             ;
              03249
A27E AC5D0C   03250                 LDY PL2ROW              ; Clear shape of PLAYER2
A281 AEBF0C   03251                 LDX PL2HEIGHT           ;
A284 990006   03252 LOOP006         STA PL2DATA,Y           ;
A287 C8       03253                 INY                     ;
A288 CA       03254                 DEX                     ;
A289 10F9     03255                 BPL LOOP006             ;
              03256
A28B AC5C0C   03257                 LDY PL1ROW              ; Clear shape of PLAYER1
A28E AEBE0C   03258                 LDX PL1HEIGHT           ;
A291 990005   03259 LOOP007         STA PL1DATA,Y           ;
A294 C8       03260                 INY                     ;
A295 CA       03261                 DEX                     ;
A296 10F9     03262                 BPL LOOP007             ;
              03263
A298 AC5B0C   03264                 LDY PL0ROW              ; Clear shape of PLAYER0
A29B AEBD0C   03265                 LDX PL0HEIGHT           ;
A29E 990004   03266 LOOP008         STA PL0DATA,Y           ;
A2A1 C8       03267                 INY                     ;
A2A2 CA       03268                 DEX                     ;
A2A3 10F9     03269                 BPL LOOP008             ;
              03270
              03271 ;*** (6) Update PLAYER vertical positions and update PLAYER shapes *************
A2A5 AD900C   03272                 LDA PL4SHAPTYPE         ; CARRY := PLAYER4 a PHOTON TORPEDO (shape type 0)?
A2A8 C901     03273                 CMP #1                  ;
A2AA A4E8     03274                 LDY PL4SHAPOFF          ; Load PLAYER4 shape data offset
              03275
A2AC AEFD0B   03276                 LDX PL4ROWNEW           ; Update vertical position of PLAYER4
A2AF 8E5F0C   03277                 STX PL4ROW              ;
              03278
A2B2 ADF20C   03279                 LDA PL4HEIGHTNEW        ; Update PLAYER4 shape height
A2B5 856A     03280                 STA L.HEIGHTCNT         ;
A2B7 8DC10C   03281                 STA PL4HEIGHT           ;
              03282
A2BA B9E4B8   03283 LOOP009         LDA PLSHAP1TAB,Y        ; Load PLAYER4 shape byte from shape data table
A2BD B003     03284                 BCS SKIP005             ; Skip if PLAYER4 not PHOTON TORPEDO (shape type 0)
A2BF 2D0AD2   03285                 AND RANDOM              ; AND random bits to shape byte
A2C2 9D0003   03286 SKIP005         STA PL4DATA,X           ; Store shape byte in PLAYER4 data area
A2C5 C8       03287                 INY                     ;
A2C6 E8       03288                 INX                     ;
A2C7 C66A     03289                 DEC L.HEIGHTCNT         ;
A2C9 10EF     03290                 BPL LOOP009             ; Next row of PLAYER4 shape
              03291
A2CB AD8F0C   03292                 LDA PL3SHAPTYPE         ; Repeat above with PLAYER3
A2CE C901     03293                 CMP #1                  ;
A2D0 A4E7     03294                 LDY PL3SHAPOFF          ;
A2D2 AEFC0B   03295                 LDX PL3ROWNEW           ;
A2D5 8E5E0C   03296                 STX PL3ROW              ;
A2D8 ADF10C   03297                 LDA PL3HEIGHTNEW        ;
A2DB 856A     03298                 STA L.HEIGHTCNT         ;
A2DD 8DC00C   03299                 STA PL3HEIGHT           ;
A2E0 B9E4B8   03300 LOOP010         LDA PLSHAP1TAB,Y        ;
A2E3 B003     03301                 BCS SKIP006             ;
A2E5 2D0AD2   03302                 AND RANDOM              ;
A2E8 9D0007   03303 SKIP006         STA PL3DATA,X           ;
A2EB E8       03304                 INX                     ;
A2EC C8       03305                 INY                     ;
A2ED C66A     03306                 DEC L.HEIGHTCNT         ;
A2EF 10EF     03307                 BPL LOOP010             ;
              03308
A2F1 AD8E0C   03309                 LDA PL2SHAPTYPE         ; Repeat above with PLAYER2
A2F4 C901     03310                 CMP #1                  ;
A2F6 A4E6     03311                 LDY PL2SHAPOFF          ;
A2F8 AEFB0B   03312                 LDX PL2ROWNEW           ;
A2FB 8E5D0C   03313                 STX PL2ROW              ;
A2FE ADF00C   03314                 LDA PL2HEIGHTNEW        ;
A301 856A     03315                 STA L.HEIGHTCNT         ;
A303 8DBF0C   03316                 STA PL2HEIGHT           ;
A306 B9E4B8   03317 LOOP011         LDA PLSHAP1TAB,Y        ;
A309 B003     03318                 BCS SKIP007             ;
A30B 2D0AD2   03319                 AND RANDOM              ;
A30E 9D0006   03320 SKIP007         STA PL2DATA,X           ;
A311 E8       03321                 INX                     ;
A312 C8       03322                 INY                     ;
A313 C66A     03323                 DEC L.HEIGHTCNT         ;
A315 10EF     03324                 BPL LOOP011             ;
              03325
A317 A4E5     03326                 LDY PL1SHAPOFF          ; Repeat above with PLAYER1 (without torpedo part)
A319 AEFA0B   03327                 LDX PL1ROWNEW           ;
A31C 8E5C0C   03328                 STX PL1ROW              ;
A31F ADEF0C   03329                 LDA PL1HEIGHTNEW        ;
A322 856A     03330                 STA L.HEIGHTCNT         ;
A324 8DBE0C   03331                 STA PL1HEIGHT           ;
A327 B9B1B9   03332 LOOP012         LDA PLSHAP2TAB,Y        ;
A32A 9D0005   03333                 STA PL1DATA,X           ;
A32D E8       03334                 INX                     ;
A32E C8       03335                 INY                     ;
A32F C66A     03336                 DEC L.HEIGHTCNT         ;
A331 10F4     03337                 BPL LOOP012             ;
              03338
A333 A4E4     03339                 LDY PL0SHAPOFF          ; Repeat above with PLAYER0 (without torpedo part)
A335 AEF90B   03340                 LDX PL0ROWNEW           ;
A338 8E5B0C   03341                 STX PL0ROW              ;
A33B ADEE0C   03342                 LDA PL0HEIGHTNEW        ;
A33E 856A     03343                 STA L.HEIGHTCNT         ;
A340 8DBD0C   03344                 STA PL0HEIGHT           ;
A343 B9B1B9   03345 LOOP013         LDA PLSHAP2TAB,Y        ;
A346 9D0004   03346                 STA PL0DATA,X           ;
A349 E8       03347                 INX                     ;
A34A C8       03348                 INY                     ;
A34B C66A     03349                 DEC L.HEIGHTCNT         ;
A34D 10F4     03350                 BPL LOOP013             ;
              03351
              03352 ;*** (7) Update PLAYER horizontal positions ************************************
A34F AD2A0C   03353                 LDA PL0COLUMN           ; Update horizontal position of PLAYER0
A352 8D00D0   03354                 STA HPOSP0              ;
A355 AD2B0C   03355                 LDA PL1COLUMN           ; Update horizontal position of PLAYER1
A358 8D01D0   03356                 STA HPOSP1              ;
A35B AD2C0C   03357                 LDA PL2COLUMN           ; Update horizontal position of PLAYER2
A35E 8D02D0   03358                 STA HPOSP2              ;
A361 AD2D0C   03359                 LDA PL3COLUMN           ; Update horizontal position of PLAYER3
A364 8D03D0   03360                 STA HPOSP3              ;
A367 AD2E0C   03361                 LDA PL4COLUMN           ; Update horizontal position of PLAYER4
A36A 8D07D0   03362                 STA HPOSM3              ;
A36D 18       03363                 CLC                     ;
A36E 6902     03364                 ADC #2                  ;
A370 8D06D0   03365                 STA HPOSM2              ;
A373 6902     03366                 ADC #2                  ;
A375 8D05D0   03367                 STA HPOSM1              ;
A378 6902     03368                 ADC #2                  ;
A37A 8D04D0   03369                 STA HPOSM0              ;
              03370
              03371 ;*** (8) Rotate space objects horizontally and vertically **********************
A37D 24D0     03372                 BIT SHIPVIEW            ; Skip if in Galactic Chart view
A37F 303A     03373                 BMI SKIP009             ;
              03374
              03375 ;*** Rotate horizontally *******************************************************
A381 A5C8     03376                 LDA JOYSTICKX           ; Skip if joystick centered horizontally
A383 F019     03377                 BEQ SKIP008             ;
              03378
A385 856D     03379                 STA JOYSTICKDELTA       ; Save JOYSTICKX (used in subroutine ROTATE)
A387 A479     03380                 LDY MAXSPCOBJIND        ; Loop over all space objects in use
A389 846E     03381 LOOP014         STY L.ZPOSOFF           ; Save offset to z-coordinate
A38B 18       03382                 CLC                     ;
              03383
A38C 98       03384                 TYA                     ;
A38D AA       03385                 TAX                     ; X := offset to z-coordinate
A38E 6931     03386                 ADC #NUMSPCOBJ.ALL      ;
A390 A8       03387                 TAY                     ; Y := offset to x-coordinate
A391 209BB6   03388                 JSR ROTATE              ; Calc new x-coordinate (horizontal rot @ y-axis)
              03389
A394 98       03390                 TYA                     ;
A395 AA       03391                 TAX                     ; X := offset to x-coordinate
A396 A46E     03392                 LDY L.ZPOSOFF           ; Y := offset to z-coordinate
A398 209BB6   03393                 JSR ROTATE              ; Calc new z-coordinate (horizontal rot @ y-axis)
A39B 88       03394                 DEY                     ;
A39C 10EB     03395                 BPL LOOP014             ; Next space object
              03396
              03397 ;*** Rotate vertically *********************************************************
A39E A5C9     03398 SKIP008         LDA JOYSTICKY           ; Skip if joystick centered vertically
A3A0 F019     03399                 BEQ SKIP009             ;
              03400
A3A2 856D     03401                 STA JOYSTICKDELTA       ; Save JOYSTICKY (used in subroutine ROTATE)
A3A4 A479     03402                 LDY MAXSPCOBJIND        ; Loop over all space objects in use
A3A6 846E     03403 LOOP015         STY L.ZPOSOFF           ; Save offset to z-coordinate
A3A8 18       03404                 CLC                     ;
              03405
A3A9 98       03406                 TYA                     ;
A3AA AA       03407                 TAX                     ; X := offset to z-coordinate
A3AB 6962     03408                 ADC #NUMSPCOBJ.ALL*2    ;
A3AD A8       03409                 TAY                     ; Y := offset to y-coordinate
A3AE 209BB6   03410                 JSR ROTATE              ; Calc new y-coordinate (vertical rot @ x-axis)
              03411
A3B1 98       03412                 TYA                     ;
A3B2 AA       03413                 TAX                     ; X := offset to y-coordinate
A3B3 A46E     03414                 LDY L.ZPOSOFF           ; Y := offset to z-coordinate
A3B5 209BB6   03415                 JSR ROTATE              ; Calc new z-coordinate (vertical rot @ x-axis)
A3B8 88       03416                 DEY                     ;
A3B9 10EB     03417                 BPL LOOP015             ; Next space object
              03418
              03419 ;*** (9) Move all space objects along z-axis (toward our starship) *************
A3BB A679     03420 SKIP009         LDX MAXSPCOBJIND        ; Loop over all space objects in use
A3BD E005     03421 LOOP016         CPX #NUMSPCOBJ.PL       ; Skip if PLAYFIELD space object (X index > 4)
A3BF B005     03422                 BCS SKIP010             ;
              03423
A3C1 BD8C0C   03424                 LDA PL0SHAPTYPE,X       ; Skip if next PLAYER space obj is PHOTON TORPEDO (!)
A3C4 F019     03425                 BEQ SKIP011             ;
              03426
A3C6 38       03427 SKIP010         SEC                     ; New z-coordinate := old z-coordinate -
A3C7 BDD30A   03428                 LDA ZPOSLO,X            ; ...our starship's velocity
A3CA E570     03429                 SBC VELOCITYLO          ; (signed 24-bit subtraction)
A3CC 9DD30A   03430                 STA ZPOSLO,X            ;
A3CF BD400A   03431                 LDA ZPOSHI,X            ;
A3D2 E5C1     03432                 SBC VELOCITYHI          ;
A3D4 9D400A   03433                 STA ZPOSHI,X            ;
A3D7 BDAD09   03434                 LDA ZPOSSIGN,X          ;
A3DA E900     03435                 SBC #0                  ;
A3DC 9DAD09   03436                 STA ZPOSSIGN,X          ;
              03437
A3DF CA       03438 SKIP011         DEX                     ;
A3E0 10DB     03439                 BPL LOOP016             ; Next space object
              03440
              03441 ;*** (10) Add space object's velocity vector to space object's position vector *
A3E2 A679     03442                 LDX MAXSPCOBJIND        ; Loop over all space objects in use
A3E4 E010     03443 LOOP017         CPX #NUMSPCOBJ.NORM-1   ; Skip if space object is star (X index 5..16)...
A3E6 D002     03444                 BNE SKIP012             ; ...because stars don't move by themselves
A3E8 A204     03445                 LDX #4                  ;
              03446
A3EA 8A       03447 SKIP012         TXA                     ;
A3EB A8       03448 LOOP018         TAY                     ; Loop over all 3 coordinates
              03449
A3EC A900     03450                 LDA #0                  ; Expand 8-bit velocity vector component to 16-bit:
A3EE 856B     03451                 STA L.VELOCITYHI        ; ...16-bit velocity (high byte) = L.VELOCITYHI := 0
A3F0 B9660B   03452                 LDA ZVEL,Y              ; ...16-bit velocity (low byte)  = A := ZVEL,Y
A3F3 1009     03453                 BPL SKIP013             ; Skip if 16-bit velocity >= 0 (positive)
              03454
A3F5 497F     03455                 EOR #$7F                ; 16-bit velocity < 0 (negative)...
A3F7 18       03456                 CLC                     ; ...calculate two's-complement of 16-bit velocity
A3F8 6901     03457                 ADC #1                  ;
A3FA B002     03458                 BCS SKIP013             ;
A3FC C66B     03459                 DEC L.VELOCITYHI        ;
              03460
A3FE 18       03461 SKIP013         CLC                     ; New coordinate := old coordinate + 16-bit velocity
A3FF 79D30A   03462                 ADC ZPOSLO,Y            ; (signed 24-bit addition)
A402 99D30A   03463                 STA ZPOSLO,Y            ;
A405 B9400A   03464                 LDA ZPOSHI,Y            ;
A408 656B     03465                 ADC L.VELOCITYHI        ;
A40A 99400A   03466                 STA ZPOSHI,Y            ;
A40D B9AD09   03467                 LDA ZPOSSIGN,Y          ;
A410 656B     03468                 ADC L.VELOCITYHI        ;
A412 99AD09   03469                 STA ZPOSSIGN,Y          ;
              03470
A415 98       03471                 TYA                     ;
A416 18       03472                 CLC                     ;
A417 6931     03473                 ADC #NUMSPCOBJ.ALL      ;
A419 C990     03474                 CMP #144                ; (!)
A41B 90CE     03475                 BCC LOOP018             ; Next coordinate
              03476
A41D CA       03477                 DEX                     ;
A41E 10C4     03478                 BPL LOOP017             ; Next space object
              03479
              03480 ;*** (11) Correct over/underflow of PLAYER space objects' position vector ******
A420 A004     03481                 LDY #NUMSPCOBJ.PL-1     ;
A422 98       03482 LOOP019         TYA                     ; Loop over all PLAYER space objects (X index < 5)
A423 AA       03483                 TAX                     ;
              03484
A424 A902     03485                 LDA #2                  ; Loop over all 3 coordinates
A426 856A     03486                 STA L.VECCOMPIND        ;
              03487
A428 BDAD09   03488 LOOP020         LDA ZPOSSIGN,X          ; Load sign of coordinate
A42B C902     03489                 CMP #2                  ;
A42D 9010     03490                 BCC SKIP015             ; Skip if sign = 0 (negative) or 1 (positive)
              03491
A42F 0A       03492                 ASL A                   ; SUMMARY: Space object out-of-bounds correction
A430 A900     03493                 LDA #0                  ; If new coordinate > +65535 <KM> subtract 256 <KM>
A432 9DAD09   03494                 STA ZPOSSIGN,X          ; ...until new coordinate <= +65535 <KM>
A435 B005     03495                 BCS SKIP014             ; If new coordinate < -65536 <KM> add 256 <KM>
A437 FEAD09   03496                 INC ZPOSSIGN,X          ; ...until new coordinate >= -65536 <KM>
A43A 49FF     03497                 EOR #$FF                ;
A43C 9D400A   03498 SKIP014         STA ZPOSHI,X            ;
              03499
A43F 8A       03500 SKIP015         TXA                     ;
A440 18       03501                 CLC                     ;
A441 6931     03502                 ADC #NUMSPCOBJ.ALL      ;
A443 AA       03503                 TAX                     ;
A444 C66A     03504                 DEC L.VECCOMPIND        ;
A446 10E0     03505                 BPL LOOP020             ; Next coordinate
              03506
A448 88       03507                 DEY                     ;
A449 10D7     03508                 BPL LOOP019             ; Next space object
              03509
              03510 ;*** (12) Calc perspective projection of space objects *************************
A44B A5D0     03511                 LDA SHIPVIEW            ; Skip if in Long-Range Scan or Galactic Chart view
A44D C902     03512                 CMP #$02                ;
A44F B05C     03513                 BCS SKIP019             ;
              03514
A451 A679     03515                 LDX MAXSPCOBJIND        ; Loop over all space objects in use
A453 A9FF     03516 LOOP021         LDA #255                ; Prep magic offscreen pixel number value
A455 BCAD09   03517                 LDY ZPOSSIGN,X          ; Compare sign of z-coordinate with view mode
A458 C4D0     03518                 CPY SHIPVIEW            ;
A45A F04B     03519                 BEQ SKIP018             ; Equal? Space object is offscreen -> New space obj!
              03520
A45C BD0F0A   03521                 LDA YPOSSIGN,X          ; Prepare projection division...
A45F D012     03522                 BNE SKIP016             ; DIVIDEND (16-bit value) := ABS(y-coordinate)
A461 38       03523                 SEC                     ; (used in subroutine PROJECTION)
A462 A900     03524                 LDA #0                  ;
A464 FD350B   03525                 SBC YPOSLO,X            ;
A467 856A     03526                 STA DIVIDEND            ;
A469 A900     03527                 LDA #0                  ;
A46B FDA20A   03528                 SBC YPOSHI,X            ;
A46E 856B     03529                 STA DIVIDEND+1          ;
A470 4C7DA4   03530                 JMP JUMP001             ;
A473 BD350B   03531 SKIP016         LDA YPOSLO,X            ;
A476 856A     03532                 STA DIVIDEND            ;
A478 BDA20A   03533                 LDA YPOSHI,X            ;
A47B 856B     03534                 STA DIVIDEND+1          ;
              03535
A47D 2021AA   03536 JUMP001         JSR PROJECTION          ; Calc pixel row number rel. to screen center
A480 201EB7   03537                 JSR SCREENROW           ; Calc pixel row number rel. to top-left of screen
              03538
A483 BDDE09   03539                 LDA XPOSSIGN,X          ; Prepare projection division...
A486 D012     03540                 BNE SKIP017             ; DIVIDEND (16-bit value) := ABS(x-coordinate)
A488 38       03541                 SEC                     ; (used in subroutine PROJECTION)
A489 A900     03542                 LDA #0                  ;
A48B FD040B   03543                 SBC XPOSLO,X            ;
A48E 856A     03544                 STA DIVIDEND            ;
A490 A900     03545                 LDA #0                  ;
A492 FD710A   03546                 SBC XPOSHI,X            ;
A495 856B     03547                 STA DIVIDEND+1          ;
A497 4CA4A4   03548                 JMP JUMP002             ;
A49A BD040B   03549 SKIP017         LDA XPOSLO,X            ;
A49D 856A     03550                 STA DIVIDEND            ;
A49F BD710A   03551                 LDA XPOSHI,X            ;
A4A2 856B     03552                 STA DIVIDEND+1          ;
              03553
A4A4 2021AA   03554 JUMP002         JSR PROJECTION          ; Calc pixel column number rel. to screen center
A4A7 20FBB6   03555 SKIP018         JSR SCREENCOLUMN        ; Calc pixel column number rel. to top-left of screen
A4AA CA       03556                 DEX                     ;
A4AB 10A6     03557                 BPL LOOP021             ; Next space object
              03558
              03559 ;*** (13) Handle hyperwarp marker selection in Galactic Chart view *************
A4AD 2062B1   03560 SKIP019         JSR SELECTWARP          ; Handle hyperwarp marker in Galactic Chart view
              03561
              03562 ;*** (14) Compute and draw Long-Range Scan view star field on z-x plane ********
A4B0 24D0     03563                 BIT SHIPVIEW            ; Skip if not in Long-Range Scan view
A4B2 5031     03564                 BVC SKIP022             ;
              03565
A4B4 A231     03566                 LDX #$31                ; Draw our starship's shape
A4B6 206FA7   03567                 JSR DRAWLINES           ;
              03568
A4B9 2C9609   03569                 BIT GCSTATLRS           ; Skip if Long-Range Scan destroyed
A4BC 7027     03570                 BVS SKIP022             ;
              03571
A4BE A679     03572                 LDX MAXSPCOBJIND        ; Loop over all space objects in use
A4C0 BD400A   03573 LOOP022         LDA ZPOSHI,X            ; Load z-coordinate (high byte)
A4C3 BCAD09   03574                 LDY ZPOSSIGN,X          ; Load sign of z-coordinate
A4C6 D002     03575                 BNE SKIP020             ;
A4C8 49FF     03576                 EOR #$FF                ; A := ABS(z-coordinate (high byte))
A4CA A8       03577 SKIP020         TAY                     ;
A4CB B9E90D   03578                 LDA MAPTO80,Y           ; Calc pixel row number rel. to screen center
A4CE 201EB7   03579                 JSR SCREENROW           ; Calc pixel row number rel. to top-left of screen
              03580
A4D1 BD710A   03581                 LDA XPOSHI,X            ; Load x-coordinate (high byte)
A4D4 BCDE09   03582                 LDY XPOSSIGN,X          ; Load sign of x-coordinate
A4D7 D002     03583                 BNE SKIP021             ;
A4D9 49FF     03584                 EOR #$FF                ; A := ABS(x-coordinate (high byte))
A4DB A8       03585 SKIP021         TAY                     ;
A4DC B9E90D   03586                 LDA MAPTO80,Y           ; Calc pixel column number rel. to screen center
A4DF 20FBB6   03587                 JSR SCREENCOLUMN        ; Calc pixel column number rel. to top-left of screen
              03588
A4E2 CA       03589                 DEX                     ;
A4E3 10DB     03590                 BPL LOOP022             ; Next space object
              03591
              03592 ;*** (15) Update PLAYER shapes, heights, and colors ****************************
              03593
              03594 ; DESCRIPTION
              03595 ;
              03596 ; In a loop over all PLAYERs, the following steps are executed:
              03597 ;
              03598 ; o   Clear the PLAYER shape offset and height.
              03599 ;
              03600 ; o   If in Galactic Chart view or in Long-Range Scan view, preload a random
              03601 ;     color and a magic z-coordinate (distance value) for PLAYER3..4
              03602 ;     (representing hyperwarp markers in Galactic Chart view and blips in the
              03603 ;     Long-Range Scan view, like, for example, Zylon ships, meteors - or even
              03604 ;     the Hyperwarp Target Marker during hyperwarp!).
              03605 ;
              03606 ; o   If in Front or Aft view, execute the following steps:
              03607 ;
              03608 ;      o   Skip dead PLAYERs.
              03609 ;
              03610 ;      o   Preload the distance value for the remaining live PLAYERs.
              03611 ;
              03612 ;      o   If we are in a starbase sector, combine PLAYER0..2 into a three-part
              03613 ;          starbase shape. Compute the pixel column numbers and pixel row
              03614 ;          numbers of PLAYER0..1 such that they are arranged left (PLAYER0) and
              03615 ;          right (PLAYER1) of PLAYER2. In addition, preload a color mask, a
              03616 ;          counter actually, that will make the starbase pulsate in brightness.
              03617 ;
              03618 ;     BUG (at $A512): The code at $A512 that skips the combination operation for
              03619 ;     PLAYER2..4 jumps for PLAYER3..4 to SKIP025 at $A52A instead of SKIP026 at
              03620 ;     $A52E. Thus it stores a color mask which does not only make the starbase
              03621 ;     PLAYER0..2 pulsate in brightness but also PLAYER3..4 in a starbase sector,
              03622 ;     for example the transfer vessel, photon torpedoes, etc. - or even the
              03623 ;     Hyperwarp Target Marker when hyperwarping out of such a sector! Suggested
              03624 ;     fix: None, code hard to untwist.
              03625 ;
              03626 ; o   After storing the color mask, check if the PLAYER shape is still above the
              03627 ;     bottom edge of the PLAYFIELD.
              03628 ;
              03629 ;     BUG (at $A534): The test checks the vertical position of the top edge of
              03630 ;     the PLAYER against the bottom edge of the PLAYFIELD above the Console
              03631 ;     Panel Display (= Player/Missile pixel row number 204). This is not
              03632 ;     completely accurate as the Console Panel Display starts at PM pixel row
              03633 ;     number 208. For example, if you carefully navigate a starbase to the
              03634 ;     bottom edge of the PLAYFIELD, at a certain point the center of the
              03635 ;     starbase shape bleeds over the bottom edge of the PLAYFIELD (while
              03636 ;     sometimes even losing its left and right wings!). Suggested fix: None, as
              03637 ;     a more elaborate test may consume too many bytes of the cartridge ROM
              03638 ;     memory in order to fix a rarely noticed visual glitch.
              03639 ;
              03640 ; o   Convert the preloaded distance value of a PLAYER space object closer than
              03641 ;     $2000 (8192) <KM> into a range index of 0..15. PLAYER space objects more
              03642 ;     distant than $2000 (8192) <KM> are skipped and not displayed.
              03643 ;
              03644 ;     Later, this range index will pick not only the correct brightness for the
              03645 ;     PLAYER (the closer the space object the brighter its PLAYER) but also the
              03646 ;     correct PLAYER shape cell and height (the closer the space object the
              03647 ;     larger the PLAYER shape and height). 
              03648 ;
              03649 ; o   Update the PLAYER's shape offset and height. On the way to the shape
              03650 ;     offset and height add the PLAYER's shape type to the range index and
              03651 ;     divide it by 2 to arrive at the shape offset index and height index (the
              03652 ;     same value). Use this index to pick the correct shape data and shape
              03653 ;     heights from a set of shape cells and their corresponding heights, stored
              03654 ;     in tables PLSHAPOFFTAB ($BE2F) and PLSHAPHEIGHTTAB ($BE7F), respectively.
              03655 ;
              03656 ;     Remember that magic distance value used in the Galactic Chart and
              03657 ;     Long-Range Scan view? Its value of $F2 is actually part of a negative
              03658 ;     z-coordinate which is inverted to $0D00, leading to a range index of 13,
              03659 ;     which, after the division by 2, picks shape cell 6. Shape cell 6 (the
              03660 ;     seventh shape cell) of all space objects (except the starbase) is the
              03661 ;     Long-Range Scan blip's dot (see PLSHAPOFFTAB ($BE2F) and PLSHAPHEIGHTTAB
              03662 ;     ($BE7F)).
              03663 ;
              03664 ; o   Update the PLAYER's color/brightness by picking the appropriate values
              03665 ;     with the range index from lookup tables PLSHAPCOLORTAB ($BFD1) and
              03666 ;     PLSHAPBRITTAB ($BFDB). Apply some special effects to the color/brightness
              03667 ;     of certain PLAYERs, such as using random colors for Zylon basestars, or
              03668 ;     using the precomputed pulsating brightness value for a starbase.
              03669
A4E5 A205     03670 SKIP022         LDX #NUMSPCOBJ.PL       ; Loop over all PLAYER space objects (X index < 5)
A4E7 CA       03671 LOOP023         DEX                     ;
A4E8 1003     03672                 BPL SKIP023             ; Jump into loop body below
A4EA 4C79A5   03673                 JMP JUMP003             ; Loop is finished, skip loop body
              03674
              03675 ;*** Clear PLAYER shape offsets and heights ************************************
A4ED A900     03676 SKIP023         LDA #0                  ;
A4EF 95E4     03677                 STA PL0SHAPOFF,X        ; Clear PLAYER shape offset
A4F1 9DEE0C   03678                 STA PL0HEIGHTNEW,X      ; Clear new PLAYER shape height
              03679
              03680 ;*** Preload stuff for hyperwarp markers and Long-Range Scan blips *************
A4F4 24D0     03681                 BIT SHIPVIEW            ; Skip if not in Galactic Chart view
A4F6 100B     03682                 BPL SKIP024             ;
              03683
A4F8 E003     03684                 CPX #3                  ; Next PLAYER space object if PLAYER0..2
A4FA 90EB     03685                 BCC LOOP023             ;
              03686
A4FC AD0AD2   03687 LOOP024         LDA RANDOM              ; Prep random color mask for warp markers/LRS blips
A4FF A0F2     03688                 LDY #$F2                ; Prep magic z-coordinate for warp markers/LRS blips
A501 302B     03689                 BMI SKIP026             ; Unconditional jump
              03690
A503 D5E9     03691 SKIP024         CMP PL0LIFE,X           ; Next PLAYER space object if this PLAYER not alive
A505 F0E0     03692                 BEQ LOOP023             ;
              03693
A507 70F3     03694                 BVS LOOP024             ; Skip back if in Long-Range Scan view
              03695
              03696 ;*** Preload stuff for other views *********************************************
              03697
A509 BC400A   03698                 LDY PL0ZPOSHI,X         ; Prep z-coordinate (high byte)
              03699
              03700 ;*** Combine PLAYER0..2 to starbase shape **************************************
A50C 247B     03701                 BIT ISSTARBASESECT      ; Skip if no starbase in this sector
A50E 501E     03702                 BVC SKIP026             ;
              03703
A510 E002     03704                 CPX #2                  ; Skip if PLAYER2..4
A512 B016     03705                 BCS SKIP025             ; (!)
              03706
A514 AD2C0C   03707                 LDA PL2COLUMN           ; Calc new PM pixel column number for PLAYER0..1:
A517 18       03708                 CLC                     ; Load PLAYER2 (starbase center) pixel column number
A518 7DDBBE   03709                 ADC PLSTARBAOFFTAB,X    ; ...add PLAYER left/right offset (starbase wings)
A51B 9D2A0C   03710                 STA PL0COLUMN,X         ; Store new PM pixel column number of starbase wing
              03711
A51E ADFB0B   03712                 LDA PL2ROWNEW           ; Calc new PM pixel row number for PLAYER0..1:
A521 18       03713                 CLC                     ; Add vertical offset (= 4 PM pixels) to PLAYER2's
A522 6904     03714                 ADC #4                  ;
A524 9DF90B   03715                 STA PL0ROWNEW,X         ; Store new PM pixel row number of starbase wing
              03716
A527 AC420A   03717                 LDY PL2ZPOSHI           ; Prep Y with z-coordinate (high byte) of starbase
              03718
A52A A576     03719 SKIP025         LDA COUNT256            ; Prep color mask with B3..0 of counter
A52C 290F     03720                 AND #$0F                ; ...(= brightness bits cause pulsating brightness)
              03721
A52E 856B     03722 SKIP026         STA L.COLORMASK         ; Store color mask
              03723
              03724 ;*** Check if PLAYER is below PLAYFIELD bottom edge ****************************
A530 98       03725                 TYA                     ; A := z-coordinate (high byte)
              03726
A531 BCF90B   03727                 LDY PL0ROWNEW,X         ; Next PLAYER space object if top of PM shape...
A534 C0CC     03728                 CPY #204                ; ...is below PLAYFIELD bottom... (!)
A536 B0AF     03729                 BCS LOOP023             ; ...(PM pixel row number >= 204)
              03730
              03731 ;*** Convert PLAYER z-coordinate to range index in 0..15 ***********************
A538 A4D0     03732                 LDY SHIPVIEW            ; Skip if in Front view...
A53A F002     03733                 BEQ SKIP027             ;
A53C 49FF     03734                 EOR #$FF                ; ...else invert z-coordinate (high byte)
              03735
A53E C920     03736 SKIP027         CMP #$20                ; Next PLAYER space object if this one too far away
A540 B0A5     03737                 BCS LOOP023             ; ...(z-coordinate >= $20** (8192) <KM>)
              03738
A542 C910     03739                 CMP #16                 ; Load z-coordinate (high byte) and...
A544 9002     03740                 BCC SKIP028             ;
A546 A90F     03741                 LDA #15                 ;
A548 856A     03742 SKIP028         STA L.RANGEINDEX        ; ...trim to range index in 0..15
              03743
              03744 ;*** Update PLAYER shape offset and height *************************************
A54A 1D8C0C   03745                 ORA PL0SHAPTYPE,X       ; Calc offset to shape table (shape type+range index)
A54D 4A       03746                 LSR A                   ;
A54E A8       03747                 TAY                     ; Divide by 2 to get offset in 0..7 into shape data
A54F B92FBE   03748                 LDA PLSHAPOFFTAB,Y      ; Update new PLAYER shape offset
A552 95E4     03749                 STA PL0SHAPOFF,X        ;
A554 B97FBE   03750                 LDA PLSHAPHEIGHTTAB,Y   ; Update new PLAYER shape height
A557 9DEE0C   03751                 STA PL0HEIGHTNEW,X      ;
              03752
              03753 ;*** Calculate PLAYER color/brightness value ***********************************
A55A 98       03754                 TYA                     ; Pick color (B7..4) using PLAYER shape type
A55B 4A       03755                 LSR A                   ;
A55C 4A       03756                 LSR A                   ;
A55D 4A       03757                 LSR A                   ;
A55E A8       03758                 TAY                     ;
A55F B9D1BF   03759                 LDA PLSHAPCOLORTAB,Y    ;
A562 C008     03760                 CPY #8                  ; Pick random color if ZYLON BASESTAR (shape type 8)
A564 D003     03761                 BNE SKIP029             ;
A566 4D0AD2   03762                 EOR RANDOM              ;
A569 A46A     03763 SKIP029         LDY L.RANGEINDEX        ;
A56B 59DBBF   03764                 EOR PLSHAPBRITTAB,Y     ; Pick brightness (B3..0) using range index and merge
              03765
A56E 456B     03766                 EOR L.COLORMASK         ; Modify color/brightness of PLAYER
              03767
A570 BCDFB8   03768                 LDY PLCOLOROFFTAB,X     ; Get PLAYER color offset
A573 99EE00   03769                 STA PL0COLOR,Y          ; Store color in PLAYER color register
A576 4CE7A4   03770                 JMP LOOP023             ; Next PLAYER space object
              03771
              03772 ;*** (16) Flash red alert ******************************************************
A579 A0AF     03773 JUMP003         LDY #$AF                ; Prep PLAYFIELD2 color {BRIGHT BLUE-GREEN}
A57B A681     03774                 LDX SHIELDSCOLOR        ; Prep Shields color {DARK GREEN} or {BLACK}
              03775
A57D A58B     03776                 LDA REDALERTLIFE        ; Skip if red alert is over
A57F F00C     03777                 BEQ SKIP030             ;
              03778
A581 C68B     03779                 DEC REDALERTLIFE        ; Decrement lifetime of red alert
A583 A04F     03780                 LDY #$4F                ; Prep PLAYFIELD2 color {BRIGHT ORANGE}
              03781
A585 2920     03782                 AND #$20                ; Switch colors every 64 game loops
A587 F004     03783                 BEQ SKIP030             ;
              03784
A589 A242     03785                 LDX #$42                ; Load BACKGROUND color {DARK ORANGE}
A58B A060     03786                 LDY #$60                ; Load PLAYFIELD2 color {DARK PURPLE BLUE}
              03787
A58D 84F4     03788 SKIP030         STY PF2COLOR            ; Store PLAYFIELD2 color
A58F 86F6     03789                 STX BGRCOLOR            ; Store BACKGROUND color
              03790
              03791 ;*** (17) Update color of PLAYFIELD space objects (stars, explosion fragments) *
A591 A679     03792                 LDX MAXSPCOBJIND        ; Loop over all PLAYFIELD space objs (X index > 4)
A593 BD400A   03793 LOOP025         LDA ZPOSHI,X            ; Prep z-coordinate (high byte)
A596 A4D0     03794                 LDY SHIPVIEW            ;
A598 C001     03795                 CPY #1                  ; Skip if not in Aft view
A59A D009     03796                 BNE SKIP032             ;
              03797
A59C C9F0     03798                 CMP #$F0                ; Skip if star not too far (z < $F0** (-4096) <KM>)
A59E B003     03799                 BCS SKIP031             ;
A5A0 2064B7   03800                 JSR INITPOSVEC          ; Re-init position vector
A5A3 49FF     03801 SKIP031         EOR #$FF                ; Invert z-coordinate (high byte)
              03802
A5A5 C910     03803 SKIP032         CMP #16                 ; Convert z-coordinate (high byte)
A5A7 9002     03804                 BCC SKIP033             ; ...into range index 0..15
A5A9 A90F     03805                 LDA #15                 ;
              03806
A5AB 0A       03807 SKIP033         ASL A                   ; Compute index to pixel color table:
A5AC 291C     03808                 AND #$1C                ; Use bits B3..1 from range index as B4..2.
A5AE 0572     03809                 ORA COUNT8              ; Combine with random bits B3..0 from counter
              03810
A5B0 A8       03811                 TAY                     ;
A5B1 B990BA   03812                 LDA FOURCOLORPIXEL,Y    ; Load 1-byte bit pattern for 4 pixels of same color
A5B4 856A     03813                 STA L.FOURCOLORPIX      ; ...and temporarily save it
              03814
A5B6 BD2A0C   03815                 LDA PIXELCOLUMN,X       ; Load pixel mask to mask 1 pixel out of 4 pixels:
A5B9 2903     03816                 AND #$03                ; Use B1..0 from pixel column number...
A5BB A8       03817                 TAY                     ;
A5BC B9B0BA   03818                 LDA PIXELMASKTAB,Y      ; ...to pick mask to filter pixel in byte
A5BF 256A     03819                 AND L.FOURCOLORPIX      ; ...AND with 1-byte bit pattern for 4 pixels
A5C1 9DEE0C   03820                 STA PIXELBYTE,X         ; ...store byte (used in repaint step of game loop)
              03821
A5C4 CA       03822                 DEX                     ;
A5C5 E005     03823                 CPX #NUMSPCOBJ.PL       ;
A5C7 B0CA     03824                 BCS LOOP025             ; Next PLAYFIELD space object
              03825
              03826 ;*** (18) Skip input handling if in demo mode **********************************
A5C9 2464     03827                 BIT ISDEMOMODE          ; If in demo mode skip to function keys
A5CB 5003     03828                 BVC SKIP034             ;
A5CD 4C9BA6   03829                 JMP SKIP040             ;
              03830
              03831 ;*** (19) Handle keyboard input ************************************************
A5D0 20FEAF   03832 SKIP034         JSR KEYBOARD            ; Handle keyboard input
              03833
              03834 ;*** (20) Handle joystick input ************************************************
A5D3 AD00D3   03835                 LDA PORTA               ; Load Joystick 0 directions
A5D6 A8       03836                 TAY                     ; ...Bits B0..3 -> Right, left, down, up.
A5D7 2903     03837                 AND #$03                ; ...Bit = 0/1 -> Stick pressed/not pressed
A5D9 AA       03838                 TAX                     ; JOYSTICKY := +1 -> Up
A5DA BDF5BA   03839                 LDA STICKINCTAB,X       ; JOYSTICKY :=  0 -> Centered
A5DD 85C9     03840                 STA JOYSTICKY           ; JOYSTICKY := -1 -> Down
A5DF 98       03841                 TYA                     ;
A5E0 4A       03842                 LSR A                   ;
A5E1 4A       03843                 LSR A                   ;
A5E2 2903     03844                 AND #$03                ;
A5E4 AA       03845                 TAX                     ; JOYSTICKX := -1 -> Left
A5E5 BDF5BA   03846                 LDA STICKINCTAB,X       ; JOYSTICKX :=  0 -> Centered
A5E8 85C8     03847                 STA JOYSTICKX           ; JOYSTICKX := +1 -> Right
              03848
              03849 ;*** (21) Check if our starship's photon torpedoes have hit a target ***********
A5EA 203DAF   03850                 JSR COLLISION           ; Check if our starship's photon torpedoes have hit
              03851
              03852 ;*** (22) Handle joystick trigger **********************************************
A5ED 2029AE   03853                 JSR TRIGGER             ; Handle joystick trigger
              03854
              03855 ;*** (23) Handle Attack Computer and Tracking Computer *************************
A5F0 2C9509   03856                 BIT GCSTATCOM           ; Skip if Attack Computer destroyed
A5F3 7040     03857                 BVS SKIP038             ;
              03858
A5F5 A57E     03859                 LDA DRAINATTCOMP        ; Skip if Attack Computer off
A5F7 F03C     03860                 BEQ SKIP038             ;
              03861
A5F9 A5D0     03862                 LDA SHIPVIEW            ; Skip if not in Front view
A5FB D003     03863                 BNE SKIP035             ;
              03864
A5FD 20BFA7   03865                 JSR UPDATTCOMP          ; Update Attack Computer Display
              03866
A600 AE5C09   03867 SKIP035         LDX TRACKDIGIT          ; Load index of tracked space object
              03868
A603 A5BF     03869                 LDA ZYLONATTACKER       ; Skip if ship of current Zylon torpedo is tracked
A605 3005     03870                 BMI SKIP036             ;
A607 AA       03871                 TAX                     ; ...else override Tracking Computer...
A608 0980     03872                 ORA #$80                ;
A60A 85BF     03873                 STA ZYLONATTACKER       ; ...and mark Zylon torpedo's ship as being tracked
              03874
A60C B5E9     03875 SKIP036         LDA PL0LIFE,X           ; Skip if tracked space object still alive
A60E D00B     03876                 BNE SKIP037             ;
              03877
A610 8A       03878                 TXA                     ;
A611 4901     03879                 EOR #$01                ;
A613 AA       03880                 TAX                     ;
A614 B5E9     03881                 LDA PL0LIFE,X           ; Check if other Zylon ship still alive
A616 D003     03882                 BNE SKIP037             ; ...yes -> Keep new index
A618 AE5C09   03883                 LDX TRACKDIGIT          ; ...no  -> Revert to old index of tracked space obj
              03884
A61B 8E5C09   03885 SKIP037         STX TRACKDIGIT          ; Store index of tracked space object
              03886
A61E A57C     03887                 LDA ISTRACKCOMPON       ; Skip if tracking computer is turned off
A620 F013     03888                 BEQ SKIP038             ;
              03889
A622 A5D0     03890                 LDA SHIPVIEW            ; Skip if in Long-Range Scan or Galactic Chart view
A624 C902     03891                 CMP #2                  ;
A626 B00D     03892                 BCS SKIP038             ;
              03893
A628 4901     03894                 EOR #$01                ;
A62A DDAD09   03895                 CMP ZPOSSIGN,X          ; Skip if tracked space object in our starship's...
A62D F006     03896                 BEQ SKIP038             ; ...view direction
              03897
A62F AA       03898                 TAX                     ;
A630 BDCFBE   03899                 LDA TRACKKEYSTAB,X      ; Pick 'F' or 'A' (Front or Aft view) keyboard code
A633 85CA     03900                 STA KEYCODE             ; ...and store it (= emulate pressing 'F' or 'A' key)
              03901
              03902 ;*** (24) Handle docking to starbase *******************************************
A635 20E6AC   03903 SKIP038         JSR DOCKING             ; Handle docking to starbase
              03904
              03905 ;*** (25) Handle maneuvering ***************************************************
A638 2079AA   03906                 JSR MANEUVER            ; Handle maneuvering photon torpedoes and Zylon ships
              03907
              03908 ;*** (26) Was our starship hit by Zylon photon torpedo? ************************
A63B A57B     03909                 LDA ISSTARBASESECT      ; Skip hit check if in starbase sector
A63D D05C     03910                 BNE SKIP040             ;
              03911
A63F A5EB     03912                 LDA PL2LIFE             ; Skip hit check if PLAYER2 (Zylon photon torpedo)...
A641 F058     03913                 BEQ SKIP040             ; ...not alive
              03914
A643 AC420A   03915                 LDY PL2ZPOSHI           ; Our starship was not hit if Zylon photon torpedo's
A646 C8       03916                 INY                     ; ...z-coordinate is not in -256..255 <KM> or...
A647 C002     03917                 CPY #$02                ;
A649 B050     03918                 BCS SKIP040             ;
              03919
A64B AC730A   03920                 LDY PL2XPOSHI           ; ...x-coordinate is not in -256..255 <KM> or...
A64E C8       03921                 INY                     ;
A64F C002     03922                 CPY #$02                ;
A651 B048     03923                 BCS SKIP040             ;
              03924
A653 ACA40A   03925                 LDY PL2YPOSHI           ; ...y-coordinate is not in -256..255 <KM>.
A656 C8       03926                 INY                     ;
A657 C002     03927                 CPY #$02                ;
A659 B040     03928                 BCS SKIP040             ;
              03929
              03930 ;*** (27) Our starship was hit! ************************************************
A65B 20E1AE   03931                 JSR DAMAGE              ; Damage or destroy some subsystem
              03932
A65E A002     03933                 LDY #2                  ; Trigger explosion at PLAYER2 (Zylon photon torpedo)
A660 206BAC   03934                 JSR INITEXPL            ;
              03935
A663 A27F     03936                 LDX #$7F                ; Prep HITBADNESS := SHIELDS HIT
A665 A581     03937                 LDA SHIELDSCOLOR        ; Skip if Shields are up (SHIELDSCOLOR not {BLACK}).
A667 D01E     03938                 BNE SKIP039             ;
              03939
A669 A20A     03940                 LDX #$0A                ; Set Front view
A66B 2045B0   03941                 JSR SETVIEW             ;
              03942
A66E A023     03943                 LDY #$23                ; Set title phrase "SHIP DESTROYED BY ZYLON FIRE"
A670 A208     03944                 LDX #8                  ; Set mission bonus offset
A672 200AB1   03945                 JSR GAMEOVER            ; Game over
              03946
A675 A25F     03947                 LDX #$5F                ; Hide Control Panel Display (bottom text window)
A677 A080     03948                 LDY #$80                ;
A679 A908     03949                 LDA #$08                ;
A67B 20F1AD   03950                 JSR MODDLST             ;
              03951
A67E 200DAE   03952                 JSR CLRPLAYFIELD        ; Clear PLAYFIELD
              03953
A681 A240     03954                 LDX #64                 ; Enable STARSHIP EXPLOSION noise (see SOUND)
A683 86E3     03955                 STX NOISEHITLIFE        ;
              03956
A685 A2FF     03957                 LDX #$FF                ; Prep HITBADNESS := STARSHIP DESTROYED
              03958
A687 868A     03959 SKIP039         STX HITBADNESS          ; Store HITBADNESS
A689 A900     03960                 LDA #0                  ; Zylon photon torpedo lifetime := 0 game loops
A68B 85EB     03961                 STA PL2LIFE             ;
A68D A902     03962                 LDA #2                  ; Init Zylon photon torpedo trigger
A68F 85BE     03963                 STA TORPEDODELAY        ;
              03964
A691 A201     03965                 LDX #1                  ; ENERGY := ENERGY - 100 after photon torpedo hit
A693 206FB8   03966                 JSR DECENERGY           ;
              03967
A696 A20A     03968                 LDX #$0A                ; Play noise sound pattern SHIELD EXPLOSION
A698 20A8AE   03969                 JSR NOISE               ;
              03970
              03971 ;*** (28) Handle function keys *************************************************
A69B A463     03972 SKIP040         LDY FKEYCODE            ; Prep old function key code
A69D AD1FD0   03973                 LDA CONSOL              ; POKEY: Load function key code
              03974
A6A0 49FF     03975                 EOR #$FF                ; Store inverted and masked function key code
A6A2 2903     03976                 AND #$03                ;
A6A4 8563     03977                 STA FKEYCODE            ;
A6A6 F01A     03978                 BEQ SKIP042             ; Skip if no function key pressed
              03979
A6A8 88       03980                 DEY                     ;
A6A9 1017     03981                 BPL SKIP042             ; Skip if SELECT or START still pressed
A6AB 8566     03982                 STA IDLECNTHI           ; Reset idle counter to a value in 1..3 (?)
A6AD C902     03983                 CMP #2                  ; Skip if SELECT function key pressed
A6AF B006     03984                 BCS SKIP041             ;
              03985
A6B1 A900     03986                 LDA #0                  ; START function key pressed:
A6B3 A8       03987                 TAY                     ; Prep empty title phrase offset
A6B4 4C5EA1   03988                 JMP INITSTART           ; Reenter game loop via INITSTART
              03989
A6B7 E662     03990 SKIP041         INC MISSIONLEVEL        ; SELECT function key pressed:
A6B9 A562     03991                 LDA MISSIONLEVEL        ; Cycle through next of 4 mission levels
A6BB 2903     03992                 AND #$03                ;
A6BD 8562     03993                 STA MISSIONLEVEL        ;
A6BF 4C5AA1   03994                 JMP INITSELECT          ; Reenter game loop via INITSELECT
              03995
              03996 ;*** (29) Update Control Panel Display *****************************************
A6C2 2004B8   03997 SKIP042         JSR UPDPANEL            ; Update Control Panel Display
              03998
              03999 ;*** (30) Handle hyperwarp *****************************************************
A6C5 209BA8   04000                 JSR HYPERWARP           ; Handle hyperwarp
              04001
              04002 ;*** (31) Update title line ****************************************************
A6C8 2016B2   04003                 JSR UPDTITLE            ; Update title line
              04004
              04005 ;*** (32) Flush game loop iteration ********************************************
A6CB 20E4B4   04006                 JSR FLUSHGAMELOOP       ; Move Zylon units, age torpedoes, elapse time
              04007
              04008 ;*** (33) Jump back to begin of game loop **************************************
A6CE 4CF3A1   04009                 JMP GAMELOOP            ; Next game loop iteration
              04010
              04011 ;*******************************************************************************
              04012 ;*                                                                             *
              04013 ;*                                  VBIHNDLR                                   *
              04014 ;*                                                                             *
              04015 ;*                      Vertical Blank Interrupt Handler                       *
              04016 ;*                                                                             *
              04017 ;*******************************************************************************
              04018
              04019 ; DESCRIPTION
              04020 ;
              04021 ; This subroutine is executed during the Vertical Blank Interrupt (VBI) when the
              04022 ; TV beam has reached the bottom-right corner of the TV screen and is switched
              04023 ; off to return to the top-left position. This situation is called the "vertical
              04024 ; blank phase".
              04025 ;
              04026 ; This subroutine signals its execution with flag ISVBISYNC ($67) (which is
              04027 ; examined by GAMELOOP ($A1F3) to synchronize the execution of the game loop
              04028 ; with the start of this subroutine). Then it switches the character set to the
              04029 ; ROM character set, sets the BACKGROUND color depending on the severity of a
              04030 ; Zylon photon torpedo hit and view mode, copies PLAYER and PLAYFIELD color
              04031 ; registers to their corresponding hardware registers, clears the Player/Missile
              04032 ; collision registers, calls the sound effects code in subroutine SOUND ($B2AB),
              04033 ; and increments the idle counter. If the idle counter reaches the value $8000
              04034 ; the title phrase is cleared and the game is switched to demo mode.
              04035 ;
              04036 ; BUG (at $A6EC): Because the values of SHIPVIEW ($D0) are $00, $01, $40, and
              04037 ; $80, a value of 3 overspecifies the comparison. Suggested fix: Replace CMP #3
              04038 ; with CMP #2, which may make the code clearer.
              04039 ;
              04040 ; BUG (at $A712): Demo mode is entered via a JMP instruction, which proceeds
              04041 ; directly into GAMELOOP ($A1F3). Thus code execution never returns to pop the
              04042 ; registers pushed on the stack during entry of this subroutine. Suggested fix:
              04043 ; None.
              04044
A6D1 A9FF     04045 VBIHNDLR        LDA #$FF                ; Signals entering Vertical Blank Interrupt
A6D3 8567     04046                 STA ISVBISYNC           ;
              04047
A6D5 A9E0     04048                 LDA #>ROMCHARSET        ; Switch character set to ROM character set
A6D7 8D09D4   04049                 STA CHBASE              ;
              04050
A6DA A6F6     04051                 LDX BGRCOLOR            ; Preload BACKGROUND color
A6DC AD0AD2   04052                 LDA RANDOM              ; Preload random number
A6DF 248A     04053                 BIT HITBADNESS          ; Check if our starship was hit
A6E1 5007     04054                 BVC SKIP044             ; If HITBADNESS has a value of...
A6E3 3004     04055                 BMI SKIP043             ; $00 -> NO HIT             (BGR color := unchanged)
A6E5 2972     04056                 AND #$72                ; $7F -> SHIELDS HIT        (BGR color := %01rr00r0)
A6E7 0940     04057                 ORA #$40                ; $FF -> STARSHIP DESTROYED (BGR color := %01rr00r0)
A6E9 AA       04058 SKIP043         TAX                     ;
A6EA A5D0     04059 SKIP044         LDA SHIPVIEW            ; Skip if in Front or Aft view
A6EC C903     04060                 CMP #3                  ; (!)
A6EE 9002     04061                 BCC SKIP045             ;
A6F0 A2A0     04062                 LDX #$A0                ; Preload BACKGROUND color {DARK BLUE GREEN}...
A6F2 86F6     04063 SKIP045         STX BGRCOLOR            ; Store BACKGROUND color
              04064
A6F4 A208     04065                 LDX #8                  ; Copy all color registers to hardware registers
A6F6 B5EE     04066 LOOP026         LDA PL0COLOR,X          ;
A6F8 9D12D0   04067                 STA COLPM0,X            ;
A6FB CA       04068                 DEX                     ;
A6FC 10F8     04069                 BPL LOOP026             ;
              04070
A6FE 8D1ED0   04071                 STA HITCLR              ; Clear Player/Missile collision registers
              04072
A701 20ABB2   04073                 JSR SOUND               ; Call sound effects
              04074
A704 E677     04075                 INC IDLECNTLO           ; Increment 16-bit idle counter
A706 D00D     04076                 BNE SKIP046             ;
A708 A566     04077                 LDA IDLECNTHI           ;
A70A 3009     04078                 BMI SKIP046             ;
A70C E666     04079                 INC IDLECNTHI           ;
A70E 1005     04080                 BPL SKIP046             ; Skip if idle counter value of $8000 not reached yet
              04081
A710 A000     04082                 LDY #$00                ; Prep empty title phrase offset
A712 4C5CA1   04083                 JMP INITDEMO            ; Enter demo mode (!)
              04084
A715 4C4BA7   04085 SKIP046         JMP JUMP004             ; Return via DLI return code
              04086
              04087 ;*******************************************************************************
              04088 ;*                                                                             *
              04089 ;*                                  DLSTHNDLR                                  *
              04090 ;*                                                                             *
              04091 ;*                       Display List Interrupt Handler                        *
              04092 ;*                                                                             *
              04093 ;*******************************************************************************
              04094
              04095 ; DESCRIPTION
              04096 ;
              04097 ; This subroutine is executed during the Display List Interrupt (DLI). It
              04098 ; switches the character set to the ROM character set if the DLI occurs at ANTIC
              04099 ; line 96 (video line 192), otherwise to the custom character set. The former
              04100 ; happens in the Galactic Chart view where the ROM character set is used in the
              04101 ; Galactic Chart Panel Display.
              04102 ;
              04103 ; Then, the DLI PLAYFIELD colors are copied to the corresponding hardware
              04104 ; registers and the values of the collision hardware registers for PLAYER3..4
              04105 ; (our starship's photon torpedoes) are copied to the corresponding zero page
              04106 ; variables PL3HIT ($82) and PL4HIT ($83).
              04107
A718 48       04108 DLSTHNDLR       PHA                     ; Push A
A719 8A       04109                 TXA                     ;
A71A 48       04110                 PHA                     ; Push X
A71B 98       04111                 TYA                     ;
A71C 48       04112                 PHA                     ; Push Y
              04113
A71D A9E0     04114                 LDA #>ROMCHARSET        ; Switch to ROM charset if ANTIC line counter = 96
A71F AC0BD4   04115                 LDY VCOUNT              ; ...else switch to custom character set
A722 C060     04116                 CPY #96                 ;
A724 F002     04117                 BEQ SKIP047             ;
A726 A9A0     04118                 LDA #>CHARSET           ;
A728 8D09D4   04119 SKIP047         STA CHBASE              ;
              04120
A72B A204     04121                 LDX #4                  ; Loop over all PLAYFIELD colors
A72D 8D0AD4   04122                 STA WSYNC               ; Stop and wait for horizontal TV beam sync
A730 B5F7     04123 LOOP027         LDA PF0COLORDLI,X       ; Copy DLI PLAYFIELD colors to hardware registers
A732 9D16D0   04124                 STA COLPF0,X            ;
A735 CA       04125                 DEX                     ;
A736 10F8     04126                 BPL LOOP027             ; Next PLAYFIELD color
              04127
A738 AD08D0   04128                 LDA M0PL                ; Merge MISSILE-to-PLAYER collision registers...
A73B 0D09D0   04129                 ORA M1PL                ;
A73E 0D0AD0   04130                 ORA M2PL                ;
A741 0D0BD0   04131                 ORA M3PL                ;
A744 8583     04132                 STA PL4HIT              ; ...and store them in PL4HIT
A746 AD0FD0   04133                 LDA P3PL                ; Copy PLAYER3-to-PLAYER coll. register to PL3HIT
A749 8582     04134                 STA PL3HIT              ;
              04135
A74B 68       04136 JUMP004         PLA                     ; Pop Y
A74C A8       04137                 TAY                     ;
A74D 68       04138                 PLA                     ; Pop X
A74E AA       04139                 TAX                     ;
A74F 68       04140                 PLA                     ; Pop A
A750 40       04141                 RTI                     ; Return from interrupt
              04142
              04143 ;*******************************************************************************
              04144 ;*                                                                             *
              04145 ;*                                  IRQHNDLR                                   *
              04146 ;*                                                                             *
              04147 ;*                       Interrupt Request (IRQ) Handler                       *
              04148 ;*                                                                             *
              04149 ;*******************************************************************************
              04150
              04151 ; DESCRIPTION
              04152 ;
              04153 ; This subroutine is executed during immediate interrupt requests (IRQs), such
              04154 ; as after pressing a key on the keyboard. It clears and disables all IRQs
              04155 ; except the interrupt raised by a pressed key. If a key has been pressed, its
              04156 ; hardware code is collected and the bits of the SHIFT and CONTROL keys are
              04157 ; added. The resulting keyboard code is stored in KEYCODE ($CA).
              04158
A751 48       04159 IRQHNDLR        PHA                     ; Push A
A752 A900     04160                 LDA #0                  ; POKEY: Disable all IRQs
A754 8D0ED2   04161                 STA IRQEN               ;
A757 A940     04162                 LDA #$40                ; POKEY: Enable keyboard interrupt (IRQ)
A759 8D0ED2   04163                 STA IRQEN               ;
A75C AD09D2   04164                 LDA KBCODE              ; POKEY: Load keyboard key code
A75F 09C0     04165                 ORA #$C0                ; Combine with SHIFT and CONTROL key bits
A761 85CA     04166                 STA KEYCODE             ; Store keyboard code
A763 68       04167                 PLA                     ; Pop A
A764 40       04168                 RTI                     ; Return from interrupt
              04169
              04170 ;*******************************************************************************
              04171 ;*                                                                             *
              04172 ;*                                  DRAWLINES                                  *
              04173 ;*                                                                             *
              04174 ;*                     Draw horizontal and vertical lines                      *
              04175 ;*                                                                             *
              04176 ;*******************************************************************************
              04177
              04178 ; DESCRIPTION
              04179 ;
              04180 ; Draws the Attack Computer Display (in Front view), cross hairs (in Front and
              04181 ; Aft view), and our starship's shape (in Long-Range Scan view) on the PLAYFIELD
              04182 ; (if the Attack Computer is not destroyed) by being passed an offset to table
              04183 ; DRAWLINESTAB ($BAF9). This table consists of a list of 3-byte elements,
              04184 ; terminated by an end marker byte ($FE). Each such element defines a single
              04185 ; horizontal or vertical line, and is passed via memory addresses DIRLEN ($A4),
              04186 ; PENROW ($A5), and PENCOLUMN ($A6) to subroutine DRAWLINE ($A782), which
              04187 ; executes the actual drawing. See subroutine DRAWLINE ($A782) and table
              04188 ; DRAWLINESTAB ($BAF9) for a description of the 3-byte elements. 
              04189 ;
              04190 ; With every call of this subroutine the blip cycle counter is initialized to
              04191 ; the start of the DELAY phase (see subroutine UPDATTCOMP ($A7BF)).
              04192 ;
              04193 ; NOTE: The entry to this subroutine is in mid-code, not at the beginning.
              04194 ;
              04195 ; INPUT
              04196 ;
              04197 ;   X = Offset into DRAWLINESTAB ($BAF9). Used values are:
              04198 ;     $00 -> Draw Attack Computer Display and cross hairs (Front view)
              04199 ;     $2A -> Draw Aft view cross hairs (Aft view)
              04200 ;     $31 -> Draw our starship's shape (Long-Range Scan view)
              04201
A765 99A400   04202 LOOP028         STA DIRLEN,Y            ; Store byte of 3-byte element
A768 E8       04203                 INX                     ;
A769 88       04204                 DEY                     ;
A76A 100E     04205                 BPL SKIP048             ; Next byte of 3-byte element until 3 bytes copied
A76C 2082A7   04206                 JSR DRAWLINE            ; Draw line on PLAYFIELD
              04207
A76F A905     04208 DRAWLINES       LDA #5                  ; Init blip cycle to DELAY phase...
A771 85A2     04209                 STA BLIPCYCLECNT        ; ...delays drawing each row
              04210
A773 2C9509   04211                 BIT GCSTATCOM           ; Return if Attack Computer destroyed
A776 7009     04212                 BVS SKIP049             ;
              04213
A778 A002     04214                 LDY #2                  ;
A77A BDF9BA   04215 SKIP048         LDA DRAWLINESTAB,X      ; Load byte of 3-byte element
A77D C9FE     04216                 CMP #$FE                ; Loop until end marker byte ($FE) encountered
A77F D0E4     04217                 BNE LOOP028             ;
A781 60       04218 SKIP049         RTS                     ; Return
              04219
              04220 ;*******************************************************************************
              04221 ;*                                                                             *
              04222 ;*                                  DRAWLINE                                   *
              04223 ;*                                                                             *
              04224 ;*                  Draw a single horizontal or vertical line                  *
              04225 ;*                                                                             *
              04226 ;*******************************************************************************
              04227
              04228 ; DESCRIPTION
              04229 ;
              04230 ; Draws a single horizontal or vertical transparent line.
              04231 ;
              04232 ; There are two entries to this subroutine:
              04233 ;
              04234 ; (1)  DRAWLINE ($A782) is entered from subroutine DRAWLINES ($A76F) to draw a
              04235 ;      line in COLOR1.
              04236 ;
              04237 ; (2)  DRAWLINE2 ($A784) is entered from subroutine UPDATTCOMP ($A7BF) to draw
              04238 ;      the blip in COLOR2 in the Attack Computer Display.
              04239 ;
              04240 ; The position, direction, and length of the line is defined by three bytes
              04241 ; passed in memory addresses DIRLEN ($A4), PENROW ($A5), and PENCOLUMN ($A6). 
              04242 ;
              04243 ; A drawing operation draws one transparent line. It uses both the color
              04244 ; register number of the overwritten (old) and the overwriting (new) pixel to
              04245 ; decide on the new pixel color register number. This results in a transparent
              04246 ; drawing effect. See the table below for all resulting combinations of color
              04247 ; registers.
              04248 ;
              04249 ; +-----------+---------------+
              04250 ; |           |   Old Color   |
              04251 ; |           |   Register    |
              04252 ; | New Color +---------------+
              04253 ; | Register  | 0 | 1 | 2 | 3 |
              04254 ; +-----------+---+---+---+---+
              04255 ; |         0 | 0 | 1 | 2 | 3 |
              04256 ; +-----------+---+---+---+---+
              04257 ; |         1 | 1 | 1 | 3 | 3 |
              04258 ; +-----------+---+---+---+---+
              04259 ; |         2 | 2 | 3 | 2 | 3 |
              04260 ; +-----------+---+---+---+---+
              04261 ; |         3 | 3 | 3 | 3 | 3 |
              04262 ; +-----------+---+---+---+---+
              04263 ;
              04264 ; For example, COLOR1 overwritten by COLOR2 yields COLOR3. If you look closely
              04265 ; at the blip (in COLOR2) on the Attack Computer Display (in COLOR1) the lines
              04266 ; of the Attack Computer Display shine through (in COLOR3) where they overlap.
              04267 ;
              04268 ; INPUT
              04269 ;
              04270 ;   DIRLEN    ($A4) = B7 = 0 -> Draw line to the right
              04271 ;                     B7 = 1 -> Draw line downward
              04272 ;                     B6..0  -> Length of line in pixels
              04273 ;   PENROW    ($A5) = Start pixel row number of line
              04274 ;   PENCOLUMN ($A6) = Start pixel column number of line
              04275
    =006A     04276 L.PIXELBYTEOFF  = $6A                   ; Within-row-offset to byte with pixel in PLAYFIELD
    =006B     04277 L.BITPAT        = $6B                   ; 1-byte bit pattern for 4 pixels of same color
    =006E     04278 L.DIRSAV        = $6E                   ; Saves DIRLEN
              04279
A782 A955     04280 DRAWLINE        LDA #$55                ; Copy 1-byte bit pattern for 4 pixels of COLOR1
A784 856B     04281 DRAWLINE2       STA L.BITPAT            ;
A786 A5A4     04282                 LDA DIRLEN              ; Copy direction (and length) of line
A788 856E     04283                 STA L.DIRSAV            ;
A78A 297F     04284                 AND #$7F                ; Strip direction bit
A78C 85A4     04285                 STA DIRLEN              ; Store length of line
              04286
A78E A4A5     04287 LOOP029         LDY PENROW              ; Loop over length of line to be drawn
A790 B90008   04288                 LDA PFMEMROWLO,Y        ; Point MEMPTR to start of pen's pixel row...
A793 8568     04289                 STA MEMPTR              ; ...in PLAYFIELD memory
A795 B96408   04290                 LDA PFMEMROWHI,Y        ;
A798 8569     04291                 STA MEMPTR+1            ;
              04292
A79A A5A6     04293                 LDA PENCOLUMN           ; Calc and store pen's byte-within-row offset
A79C 4A       04294                 LSR A                   ;
A79D 4A       04295                 LSR A                   ;
A79E 856A     04296                 STA L.PIXELBYTEOFF      ;
              04297
A7A0 A5A6     04298                 LDA PENCOLUMN           ; Calc pixel-within-byte index
A7A2 2903     04299                 AND #$03                ;
A7A4 A8       04300                 TAY                     ;
              04301
A7A5 B9B0BA   04302                 LDA PIXELMASKTAB,Y      ; Pick mask to filter pixel in byte
A7A8 256B     04303                 AND L.BITPAT            ; ...AND with bit pattern for 4 pixels of same color
A7AA A46A     04304                 LDY L.PIXELBYTEOFF      ;
A7AC 1168     04305                 ORA (MEMPTR),Y          ; Blend byte with new pixel and PLAYFIELD byte
A7AE 9168     04306                 STA (MEMPTR),Y          ; ...and store it back in PLAYFIELD memory
              04307
A7B0 246E     04308                 BIT L.DIRSAV            ; Check direction bit B7
A7B2 1004     04309                 BPL SKIP050             ;
A7B4 E6A5     04310                 INC PENROW              ; If B7 = 1 -> Increment pen's pixel row number
A7B6 D002     04311                 BNE SKIP051             ;
A7B8 E6A6     04312 SKIP050         INC PENCOLUMN           ; If B7 = 0 -> Increment pen's pixel column number
              04313
A7BA C6A4     04314 SKIP051         DEC DIRLEN              ;
A7BC D0D0     04315                 BNE LOOP029             ; Next pixel of line
A7BE 60       04316                 RTS                     ; Return
              04317
              04318 ;*******************************************************************************
              04319 ;*                                                                             *
              04320 ;*                                 UPDATTCOMP                                  *
              04321 ;*                                                                             *
              04322 ;*                       Update Attack Computer Display                        *
              04323 ;*                                                                             *
              04324 ;*******************************************************************************
              04325
              04326 ; DESCRIPTION
              04327 ;
              04328 ; Draws the blip of the tracked space object and the lock-on markers into the
              04329 ; Attack Computer Display. The actual drawing follows a cycle of 11 game loop
              04330 ; iterations (numbered by this subroutine as "blip cycles" 0..10), which can be
              04331 ; divided into three phases:
              04332 ;
              04333 ; (1)  Blip cycle 0..4: Draw blip shape row-by-row
              04334 ;
              04335 ;      Draw the blip's shape into the Attack Computer Display, one row each blip
              04336 ;      cycle. After 5 blip cycles the blip shape is complete and completely
              04337 ;      visible because between blip cycles, that is, game loop iterations, the
              04338 ;      PLAYFIELD is not erased (only the PLAYFIELD space objects are). Drawing
              04339 ;      is executed by branching to entry DRAWLINE2 ($A784) of subroutine
              04340 ;      DRAWLINE ($A782). The blip shape is retrieved from table BLIPSHAPTAB
              04341 ;      ($BF6E).
              04342 ;
              04343 ; (2)  Blip cycle 5..9: Delay
              04344 ;
              04345 ;      Delay the execution of blip cycle 10.
              04346 ;
              04347 ; (3)  Blip cycle 10: Update Attack Computer Display
              04348 ;
              04349 ;      After verifying that the tracked space object is alive, calculate the
              04350 ;      blip's relative top-left pixel column and row number. The resulting
              04351 ;      values are in -11..11 and -6..4, relative to the blip's top-left
              04352 ;      reference position at pixel column number 131 and pixel row number 77,
              04353 ;      respectively. 
              04354 ;
              04355 ;      Filter the Attack Computer Display area: Only pixels of COLOR1 within the
              04356 ;      inner frame area (a 28 pixel wide x 15 pixel high rectangle with its
              04357 ;      top-left corner at pixel column number 120 and pixel row number 71) pass
              04358 ;      the filter operation. This effectively erases the blip.
              04359 ;
              04360 ;      If the blip is within -2..+2 pixels off its horizontal reference position
              04361 ;      (pixel column numbers 129..132) then the tracked space object is in x
              04362 ;      lock-on. Draw the x lock-on marker. 
              04363 ;
              04364 ;      If the tracked space object is in x lock-on and the blip is within -2..+1
              04365 ;      pixels off its vertical reference position (pixel column numbers 75..78)
              04366 ;      then the tracked space object is in x and y lock-on. Draw also the y
              04367 ;      lock-on marker. 
              04368 ;
              04369 ;      If the tracked space object is in x and y lock-on and the tracked space
              04370 ;      object's z-coordinate < +3072 (+$0C**) <KM> then the tracked space object
              04371 ;      is in x, y and z lock-on. Draw also the z lock-on marker. 
              04372 ;
              04373 ;      If the tracked space object is in x, y, and z lock-on (and thus in
              04374 ;      optimal firing range) set the ISINLOCKON ($A3) flag.
              04375 ;
              04376 ;      The following sketches show the Attack Computer Display area overlaid
              04377 ;      with the Attack Computer Display frame:
              04378 ;
              04379 ;          119                                 119
              04380 ;      70 ##############################    70 ##############################
              04381 ;         #         ....#....          #       #             #              #
              04382 ;         #         ....#....          #       #             #              #
              04383 ;         #         ....#....          #       #             #              #
              04384 ;         #         ....#....          #       #             #              #
              04385 ;         #      ###############       #       #......###############.......#
              04386 ;         #XXXX  #  .........  #   XXXX#       #......#.............#.......#
              04387 ;         #      #  ..$......  #       #       #......#....$........#.......#
              04388 ;         ########  .........  #########       ########.............#########
              04389 ;         #      #  .........  #       #       #......#.............#.......#
              04390 ;         #      #  .........  #       #       #YYYY..#.............#...YYYY#
              04391 ;         #      ###############       #       #......###############.......#
              04392 ;         #         ....#....          #       #.............#..............#
              04393 ;         #         ....#....          #       #             #              #
              04394 ;         #         ....#....          #       #             #              #
              04395 ;         #         ....#....          #       #             #              #
              04396 ;         ##############################       ##############################
              04397 ;
              04398 ;         X = x lock-on marker                 Y = y lock-on marker
              04399 ;         . = x lock-on blip zone              . = y lock-on blip zone
              04400 ;         $ = Blip's top-left reference        $ = Blip's top-left reference
              04401 ;             position                             position
              04402 ;
              04403 ;         119
              04404 ;      70 ##############################
              04405 ;         #             #              #
              04406 ;         #             #              #
              04407 ;         #             #              #
              04408 ;         #             #              #
              04409 ;         #      ###############       #
              04410 ;         #      #             #       #
              04411 ;         #      #    $        #       #
              04412 ;         ########             #########
              04413 ;         #      #             #       #
              04414 ;         #      #             #       #
              04415 ;         #      ###############       #
              04416 ;         #             #              #
              04417 ;         #             #              #
              04418 ;         #        ZZ   #  ZZ          #
              04419 ;         #        ZZ   #  ZZ          #
              04420 ;         ##############################
              04421 ;
              04422 ;         Z = z lock-on marker
              04423 ;         $ = Blip's top-left reference
              04424 ;             position
              04425
    =006C     04426 L.SHIFTSHAP     = $6C                   ; Saves shifted byte of blip shape bit pattern
              04427
A7BF AE5C09   04428 UPDATTCOMP      LDX TRACKDIGIT          ; Load index of tracked space object
A7C2 A4A2     04429                 LDY BLIPCYCLECNT        ; Load blip cycle counter
A7C4 C005     04430                 CPY #5                  ;
A7C6 B024     04431                 BCS SKIP054             ; Skip drawing blip if blip cycle > 5
              04432
              04433 ;*** Blip cycle 0..4: Draw blip shape one row each cycle ***********************
A7C8 A5A0     04434                 LDA BLIPCOLUMN          ; Init pen's pixel column number...
A7CA 85A6     04435                 STA PENCOLUMN           ; ...with top position of blip shape
A7CC B96EBF   04436                 LDA BLIPSHAPTAB,Y       ; Load bit pattern of one row of blip shape
A7CF 0A       04437 LOOP030         ASL A                   ; Shift bit pattern one position to the left
A7D0 856C     04438                 STA L.SHIFTSHAP         ; Temporarily save shifted shape byte
A7D2 900D     04439                 BCC SKIP052             ; Skip if shifted-out bit = 0
              04440
A7D4 A981     04441                 LDA #$81                ; Store "draw a line of 1 pixel length downward"
A7D6 85A4     04442                 STA DIRLEN              ; ...for call to DRAWLINE2
              04443
A7D8 A5A1     04444                 LDA BLIPROW             ; Init pen's pixel row number...
A7DA 85A5     04445                 STA PENROW              ; ...with leftmost position of blip shape
A7DC A9AA     04446                 LDA #$AA                ; Load 1-byte bit pattern for 4 pixels of COLOR2
A7DE 2084A7   04447                 JSR DRAWLINE2           ; Draw pixel on PLAYFIELD
              04448
A7E1 E6A6     04449 SKIP052         INC PENCOLUMN           ; Move pen one pixel to the right
A7E3 A56C     04450                 LDA L.SHIFTSHAP         ; Reload shifted shape byte
A7E5 D0E8     04451                 BNE LOOP030             ; Next horizontal pixel of blip shape
              04452
A7E7 E6A1     04453                 INC BLIPROW             ; Move pen one pixel downward
A7E9 E6A2     04454 SKIP053         INC BLIPCYCLECNT        ; Increment blip cycle counter
A7EB 60       04455                 RTS                     ; Return
              04456
              04457 ;*** Blip cycle 5..9: Delay ****************************************************
A7EC C00A     04458 SKIP054         CPY #10                 ; Return if blip cycle < 10
A7EE 90F9     04459                 BCC SKIP053             ;
              04460
              04461 ;*** Blip cycle 10: Calculate new blip pixel row and column numbers ************
A7F0 B5E9     04462                 LDA PL0LIFE,X           ; Skip if tracked object not alive
A7F2 F03C     04463                 BEQ SKIP059             ;
              04464
A7F4 BD710A   04465                 LDA XPOSHI,X            ; Map x-coordinate of tracked space obj to -11..11:
A7F7 BCDE09   04466                 LDY XPOSSIGN,X          ; Skip if tracked object on left screen half (x >= 0)
A7FA F008     04467                 BEQ SKIP055             ;
              04468
A7FC C90C     04469                 CMP #12                 ; Skip if x of tracked obj < +$0C** (< 3327) <KM>
A7FE 900A     04470                 BCC SKIP056             ;
A800 A90B     04471                 LDA #11                 ; Prep relative pixel column number of 11, skip
A802 1006     04472                 BPL SKIP056             ;
              04473
A804 C9F5     04474 SKIP055         CMP #-11                ; Skip if x of tracked obj >= -($0B**) (>=-2816) <KM>
A806 B002     04475                 BCS SKIP056             ;
A808 A9F5     04476                 LDA #-11                ; Prep relative pixel column number of -11
              04477
A80A 18       04478 SKIP056         CLC                     ; Add 131 (= blip's top-left reference pixel column)
A80B 6983     04479                 ADC #131                ;
A80D 85A0     04480                 STA BLIPCOLUMN          ; BLIPCOLUMN := 131 + -11..11
              04481
A80F BDA20A   04482                 LDA YPOSHI,X            ; Map y-coordinate of tracked space obj to -6..4:
A812 49FF     04483                 EOR #$FF                ; Mirror y-coordinate on y-axis (displacement of +1)
A814 BC0F0A   04484                 LDY YPOSSIGN,X          ; Skip if tracked obj on lower screen half (y < 0)
A817 D008     04485                 BNE SKIP057             ;
              04486
A819 C905     04487                 CMP #5                  ; Skip if mirrored y of tracked obj < +$05** <KM>
A81B 900A     04488                 BCC SKIP058             ;
A81D A904     04489                 LDA #4                  ; Prep relative pixel row number of 4, skip
A81F 1006     04490                 BPL SKIP058             ;
              04491
A821 C9FA     04492 SKIP057         CMP #-6                 ; Skip if mirrored y of tracked obj >= -($06**) <KM>
A823 B002     04493                 BCS SKIP058             ;
A825 A9FA     04494                 LDA #-6                 ; Prep relative pixel row number of -6
              04495
A827 18       04496 SKIP058         CLC                     ; Add 77 (= blip's top-left ref. pixel row number)
A828 694D     04497                 ADC #77                 ;
A82A 85A1     04498                 STA BLIPROW             ; BLIPROW := 77 + -6..4
              04499
A82C A900     04500                 LDA #0                  ; Reset blip cycle
A82E 85A2     04501                 STA BLIPCYCLECNT        ;
              04502
              04503 ;*** Filter Attack Computer Display frame area *********************************
              04504                                         ; PLAYFIELD address of top-left of Attack Computer
    =1B36     04505 PFMEM.C120R71   = PFMEM+71*40+120/4     ; Display's inner frame @ pixel column 120, row 71
              04506
A830 A936     04507 SKIP059         LDA #<PFMEM.C120R71     ; Point MEMPTR to start of frame's...
A832 8568     04508                 STA MEMPTR              ; ...inner top-left corner at column 120, row 71...
A834 A91B     04509                 LDA #>PFMEM.C120R71     ; ...in PLAYFIELD memory
A836 8569     04510                 STA MEMPTR+1            ;
              04511
A838 A20E     04512                 LDX #14                 ; Traverse a 28 x 15 pixel rect of PLAYFIELD memory
A83A A006     04513 LOOP031         LDY #6                  ;
A83C B168     04514 LOOP032         LDA (MEMPTR),Y          ; Load byte (4 pixels) from PLAYFIELD memory
A83E 2955     04515                 AND #$55                ; Filter COLOR1 pixels
A840 9168     04516                 STA (MEMPTR),Y          ; Store byte (4 pixels) back to PLAYFIELD memory
A842 88       04517                 DEY                     ;
A843 10F7     04518                 BPL LOOP032             ; Next 4 pixels in x-direction
              04519
A845 18       04520                 CLC                     ; Add 40 to MEMPTR
A846 A568     04521                 LDA MEMPTR              ; (40 bytes = 160 pixels = 1 PLAYFIELD row of pixels)
A848 6928     04522                 ADC #40                 ;
A84A 8568     04523                 STA MEMPTR              ;
A84C 9002     04524                 BCC SKIP060             ;
A84E E669     04525                 INC MEMPTR+1            ;
              04526
A850 CA       04527 SKIP060         DEX                     ;
A851 10E7     04528                 BPL LOOP031             ; Next row of pixels in y-direction
              04529
              04530 ;*** Prepare lock-on marker checks *********************************************
A853 AE5C09   04531                 LDX TRACKDIGIT          ; Preload index of tracked space obj to check z-range
A856 C8       04532                 INY                     ; Y := 0, preloaded value of ISINLOCKON
              04533
              04534 ;*** Draw lock-on markers ******************************************************
              04535                                         ; PLAYFIELD addresses of
    =1BFE     04536 PFMEM.C120R76   = PFMEM+76*40+120/4     ; ...x lock-on marker @ pixel column 120, row 76
    =1C04     04537 PFMEM.C144R76   = PFMEM+76*40+144/4     ; ...x lock-on marker @ pixel column 144, row 76
    =1C9E     04538 PFMEM.C120R80   = PFMEM+80*40+120/4     ; ...y lock-on marker @ pixel column 120, row 80
    =1CA4     04539 PFMEM.C144R80   = PFMEM+80*40+144/4     ; ...y lock-on marker @ pixel column 144, row 80
    =1D40     04540 PFMEM.C128R84   = PFMEM+84*40+128/4     ; ...z lock-on marker @ pixel column 128, row 84
    =1D68     04541 PFMEM.C128R85   = PFMEM+85*40+128/4     ; ...z lock-on marker @ pixel column 128, row 85
    =1D42     04542 PFMEM.C136R84   = PFMEM+84*40+136/4     ; ...z lock-on marker @ pixel column 136, row 84
    =1D6A     04543 PFMEM.C136R85   = PFMEM+85*40+136/4     ; ...z lock-on marker @ pixel column 136, row 85
              04544
A857 A588     04545                 LDA LOCKONLIFE          ; If lock-on lifetime expired redraw lock-on markers
A859 F004     04546                 BEQ SKIP061             ;
              04547
A85B C688     04548                 DEC LOCKONLIFE          ; else decrem. lock-on lifetime, skip drawing markers
A85D D039     04549                 BNE SKIP062             ;
              04550
A85F A5A0     04551 SKIP061         LDA BLIPCOLUMN          ; Skip x, y, and z lock-on marker if blip's...
A861 C981     04552                 CMP #129                ; ...top-left pixel column number not in 129..132
A863 9033     04553                 BCC SKIP062             ;
A865 C985     04554                 CMP #133                ;
A867 B02F     04555                 BCS SKIP062             ;
              04556
A869 A9AA     04557                 LDA #$AA                ; Draw x lock-on marker (4 horiz. pixels of COLOR2)
A86B 8DFE1B   04558                 STA PFMEM.C120R76       ; ...at pixel column 120, row 76
A86E 8D041C   04559                 STA PFMEM.C144R76       ; ...at pixel column 144, row 76
              04560
A871 A5A1     04561                 LDA BLIPROW             ; Skip y and z lock-on marker if blip's...
A873 C94B     04562                 CMP #75                 ; ...top-left pixel row number not in 75...78
A875 9021     04563                 BCC SKIP062             ;
A877 C94F     04564                 CMP #79                 ;
A879 B01D     04565                 BCS SKIP062             ;
              04566
A87B A9AA     04567                 LDA #$AA                ; Draw y lock-on marker (4 horiz. pixels of COLOR2)
A87D 8D9E1C   04568                 STA PFMEM.C120R80       ; ...at pixel column 120, row 80
A880 8DA41C   04569                 STA PFMEM.C144R80       ; ...at pixel column 144, row 80
              04570
A883 BD400A   04571                 LDA ZPOSHI,X            ; Skip z lock-on marker if z >= +$0C** (>= 3072) <KM>
A886 C90C     04572                 CMP #12                 ;
A888 B00E     04573                 BCS SKIP062             ;
              04574
A88A A0A0     04575                 LDY #$A0                ; Draw z lock-on marker (2 horiz. pixels of COLOR2)
A88C 8C401D   04576                 STY PFMEM.C128R84       ; ...at pixel column 128, row 84 (prep lock-on flag)
A88F 8C681D   04577                 STY PFMEM.C128R85       ; ...at pixel column 128, row 85
A892 8C421D   04578                 STY PFMEM.C136R84       ; ...at pixel column 136, row 84
A895 8C6A1D   04579                 STY PFMEM.C136R85       ; ...at pixel column 136, row 85
              04580
A898 84A3     04581 SKIP062         STY ISINLOCKON          ; Store lock-on flag (> 0 -> Tracked obj locked on)
A89A 60       04582                 RTS                     ; Return
              04583
              04584 ;*******************************************************************************
              04585 ;*                                                                             *
              04586 ;*                                  HYPERWARP                                  *
              04587 ;*                                                                             *
              04588 ;*                              Handle hyperwarp                               *
              04589 ;*                                                                             *
              04590 ;*******************************************************************************
              04591
              04592 ; DESCRIPTION
              04593 ;
              04594 ; Handles the hyperwarp sequence, which transports our starship from one sector
              04595 ; to another. It can be divided into four phases:
              04596 ;
              04597 ; (1)  ACCELERATION PHASE
              04598 ;
              04599 ;      The ACCELERATION PHASE is entered after the hyperwarp sequence has been
              04600 ;      engaged in subroutine KEYBOARD ($AFFE) by pressing the 'H' key.
              04601 ;
              04602 ;      The Hyperwarp Target Marker appears and our starship begins to
              04603 ;      accelerate. When our starship's velocity reaches 128 <KM/H> (the VELOCITY
              04604 ;      readout of the Control Panel Display displays "50"), the STAR TRAIL phase
              04605 ;      is entered. 
              04606 ;
              04607 ;      The Hyperwarp Target Marker is represented by a space object some fixed
              04608 ;      distance away in front of our starship as PLAYER3. It has a lifetime of
              04609 ;      144 game loop iterations and is tracked. Thus, tracking handling in
              04610 ;      subroutine UPDATTCOMP ($A7BF) provides drawing the x and y lock-on
              04611 ;      markers in the Attack Computer Display when the Hyperwarp Target Marker
              04612 ;      is centered. 
              04613 ;
              04614 ;      A temporary arrival location on the Galactic Chart was saved when the
              04615 ;      hyperwarp was engaged in subroutine KEYBOARD ($AFFE). During the
              04616 ;      ACCELERATION PHASE (and the subsequent STAR TRAIL PHASE) this location is
              04617 ;      constantly updated depending on how much the Hyperwarp Target Marker
              04618 ;      veers off its center position.
              04619 ;
              04620 ;      The actual arrival hyperwarp marker row and column numbers on the
              04621 ;      Galactic Chart are the sum of the temporary arrival hyperwarp marker row
              04622 ;      and column numbers stored when engaging the hyperwarp in subroutine
              04623 ;      KEYBOARD ($AFFE) and the number of Player/Missile (PM) pixels which the
              04624 ;      Hyperwarp Target Marker is off-center vertically and horizontally,
              04625 ;      respectively, at the end of the STAR TRAIL PHASE.
              04626 ;
              04627 ;      NOTE: The used vertical center value of 119 PM pixels is the PM pixel row
              04628 ;      number of the top edge of the centered Hyperwarp Target Marker (from top
              04629 ;      to bottom: 8 PM pixels to the start of Display List + 16 PM pixels blank
              04630 ;      lines + 100 PM pixels to the vertical PLAYFIELD center - 5 PM pixels
              04631 ;      relative offset of the Hyperwarp Target Marker's shape center to the
              04632 ;      shape's top edge = 119 PM pixels). Recall also that PLAYERs at
              04633 ;      single-line resolution have PM pixels that are half as high as they are
              04634 ;      wide.
              04635 ;
              04636 ;      NOTE: The used horizontal center value of 125 PM pixels is the PM pixel
              04637 ;      row number of the left edge of the centered Hyperwarp Target Marker (from
              04638 ;      left to right: 127 PM pixels to the PLAYFIELD center - 3 PM pixels
              04639 ;      relative offset of the Hyperwarp Target Marker's shape center to the
              04640 ;      shape's left edge = 125 PM pixels).
              04641 ;
              04642 ;      If during the ACCELERATION PHASE (and the subsequent STAR TRAIL PHASE)
              04643 ;      you switch the Front view to another view, the Hyperwarp Target Marker
              04644 ;      changes to a random position which results in arriving at a random
              04645 ;      destination sector.
              04646 ;
              04647 ;      During the ACCELERATION PHASE (and the subsequent STAR TRAIL PHASE) in
              04648 ;      all but NOVICE missions, the Hyperwarp Target Marker veers off with
              04649 ;      random velocity in x and y direction, which is changed during 6% of game
              04650 ;      loop iterations. Table VEERMASKTAB ($BED7) limits the maximum veer-off
              04651 ;      velocity depending on the mission level:
              04652 ;
              04653 ;      +-----------+-----------------------------+
              04654 ;      |  Mission  |      Veer-Off Velocity      |
              04655 ;      +-----------+-----------------------------+
              04656 ;      | NOVICE    |                   0  <KM/H> |
              04657 ;      | PILOT     |  -63..-16, +16..+63  <KM/H> |
              04658 ;      | WARRIOR   |  -95..-16, +16..+95  <KM/H> |
              04659 ;      | COMMANDER | -127..-16, +16..+127 <KM/H> |
              04660 ;      +-----------+-----------------------------+
              04661 ;
              04662 ; (2)  STAR TRAIL PHASE
              04663 ;
              04664 ;      When our starship's velocity reaches a velocity of 128 <KM/H> (the
              04665 ;      VELOCITY readout of the Control Panel Display displays "50"), in addition
              04666 ;      to all effects of the ACCELERATION PHASE, multiple star trails begin to
              04667 ;      appear while our starship continues to accelerate. Each star trail is
              04668 ;      initialized in subroutine INITTRAIL ($A9B4).
              04669 ;
              04670 ; (3)  HYPERSPACE PHASE
              04671 ;
              04672 ;      When our starship's velocity reaches a velocity of 254 <KM/H> (the
              04673 ;      VELOCITY readout of the Control Panel Display displays "99") our starship
              04674 ;      enters the HYPERSPACE PHASE (the VELOCITY readout of the Control Panel
              04675 ;      Display displays the infinity symbol).
              04676 ;
              04677 ;      During the first pass of the HYPERSPACE PHASE the hyperwarp state is set
              04678 ;      to HYPERSPACE. This makes the stars and the Hyperwarp Target Marker
              04679 ;      disappear in GAMELOOP ($A1F3). Then, the beeper sound pattern HYPERWARP
              04680 ;      TRANSIT is played in subroutine BEEP ($B3A6), the hyperwarp distance and
              04681 ;      required hyperwarp energy is calculated in subroutine CALCWARP ($B1A7),
              04682 ;      and the title line is preloaded with "HYPERSPACE". Code execution returns
              04683 ;      via calling subroutine CLEANUPWARP ($A98D) where game variables are
              04684 ;      already initialized to their post-hyperwarp values.
              04685 ;
              04686 ;      During subsequent passes of the HYPERSPACE PHASE, the calculated
              04687 ;      hyperwarp energy is decremented in chunks of 10 energy units. Code
              04688 ;      execution returns via calling subroutine DECENERGY ($B86F), which
              04689 ;      decrements our starship's energy. After the calculated hyperwarp energy
              04690 ;      is spent the DECELERATION PHASE is entered.
              04691 ;
              04692 ; (4)  DECELERATION PHASE
              04693 ;
              04694 ;      The title line flashes "HYPERWARP COMPLETE", the star field reappears and
              04695 ;      our starship decelerates to a stop. The Engines and the hyperwarp are
              04696 ;      disengaged and stopped in subroutine ENDWARP ($A987), the arrival
              04697 ;      coordinates on the Galactic Chart are initialized, as well as the
              04698 ;      vicinity mask.
              04699 ;
              04700 ;      The vicinity mask limits the position vector components (coordinates) of
              04701 ;      space objects in the arrival sector relative to our starship. The
              04702 ;      vicinity mask is picked from table VICINITYMASKTAB ($BFB3) by an index
              04703 ;      calculated by the arrival y-coordinate modulo 8: The more you have placed
              04704 ;      the arrival hyperwarp marker in the vertical center of a sector on the
              04705 ;      Galactic Chart, the closer space objects in this sector will be to our
              04706 ;      starship. For example, if you placed the arrival hyperwarp marker exactly
              04707 ;      in the vertical middle of the sector the index will be 3, thus the space
              04708 ;      objects inside the arrival sector will be in the vicinity of <= 4095 <KM>
              04709 ;      of our starship. The following table lists the possible coordinates
              04710 ;      depending on the calculated index:
              04711 ;
              04712 ;      +-------+-----------------------+
              04713 ;      | Index |    ABS(Coordinate)    |
              04714 ;      +-------+-----------------------+
              04715 ;      |   0   | <= 65535 ($FF**) <KM> |
              04716 ;      |   1   | <= 65535 ($FF**) <KM> |
              04717 ;      |   2   | <= 16383 ($3F**) <KM> |
              04718 ;      |   3   | <=  4095 ($0F**) <KM> |
              04719 ;      |   4   | <= 16383 ($3F**) <KM> |
              04720 ;      |   5   | <= 32767 ($7F**) <KM> |
              04721 ;      |   6   | <= 65535 ($FF**) <KM> |
              04722 ;      |   7   | <= 65535 ($FF**) <KM> |
              04723 ;      +-------+-----------------------+
              04724 ;
              04725 ;      If there is a starbase in the arrival sector, its x and y coordinates are
              04726 ;      initialized to random values within the interval defined by the vicinity
              04727 ;      mask by using subroutine RNDINVXY ($B7BE). Its z-coordinate is forced to
              04728 ;      a value >= +$71** (+28928) <KM>. Its velocity vector components are set
              04729 ;      to 0 <KM/H>. 
              04730 ;
              04731 ;      If there are Zylon ships in the arrival sector then a red alert is
              04732 ;      initialized by setting the red alert lifetime to 255 game loop
              04733 ;      iterations, playing the beeper sound pattern RED ALERT in subroutine BEEP
              04734 ;      ($B3A6) and setting the title phrase to "RED ALERT".
              04735
A89B A4C0     04736 HYPERWARP       LDY WARPSTATE           ; Return if hyperwarp not engaged
A89D F061     04737                 BEQ SKIP066             ;
              04738
A89F A570     04739                 LDA VELOCITYLO          ; If velocity >= 254 <KM/H> skip to HYPERSPACE PHASE
A8A1 C9FE     04740                 CMP #254                ;
A8A3 B05C     04741                 BCS SKIP067             ;
              04742
A8A5 C980     04743                 CMP #128                ; If velocity < 128 <KM/H> skip to ACCELERATION PHASE
A8A7 9003     04744                 BCC SKIP063             ;
              04745
              04746 ;*** STAR TRAIL PHASE **********************************************************
A8A9 20B4A9   04747                 JSR INITTRAIL           ; Init star trail
              04748
              04749 ;*** ACCELERATION PHASE ********************************************************
A8AC A903     04750 SKIP063         LDA #3                  ; Track Hyperwarp Target Marker (PLAYER3)
A8AE 8D5C09   04751                 STA TRACKDIGIT          ;
              04752
A8B1 A990     04753                 LDA #SHAP.HYPERWARP     ; PLAYER3 is HYPERWARP TARGET MARKER (shape type 9)
A8B3 8D8F0C   04754                 STA PL3SHAPTYPE         ;
A8B6 85EC     04755                 STA PL3LIFE             ; PLAYER3 lifetime := 144 game loops
              04756
A8B8 A91F     04757                 LDA #$1F                ; PLAYER3 z-coordinate := $1F** (7936..8191) <KM>
A8BA 8D430A   04758                 STA PL3ZPOSHI           ;
              04759
A8BD 38       04760                 SEC                     ; New arrival hyperwarp marker row number is...
A8BE ADFC0B   04761                 LDA PL3ROWNEW           ; WARPARRVROW := WARPTEMPROW + PL3ROWNEW...
A8C1 E977     04762                 SBC #119                ; ... - 119 PM pixels (top edge of centered...
A8C3 18       04763                 CLC                     ; ...Hyperwarp Target Marker)
A8C4 65C5     04764                 ADC WARPTEMPROW         ;
A8C6 297F     04765                 AND #$7F                ; Limit WARPARRVROW to 0..127
A8C8 858E     04766                 STA WARPARRVROW         ;
              04767
A8CA 38       04768                 SEC                     ; New arrival hyperwarp marker column number is...
A8CB AD2D0C   04769                 LDA PL3COLUMN           ; WARPARRVCOLUMN := WARPTEMPCOLUMN + PL3COLUMN...
A8CE E97D     04770                 SBC #125                ; ... - 125 PM pixels (left edge of centered...
A8D0 18       04771                 CLC                     ; ...Hyperwarp Target Marker)
A8D1 65C4     04772                 ADC WARPTEMPCOLUMN      ;
A8D3 297F     04773                 AND #$7F                ; Limit WARPARRVCOLUMN to 0..127
A8D5 858F     04774                 STA WARPARRVCOLUMN      ;
              04775
A8D7 A562     04776                 LDA MISSIONLEVEL        ; Skip if NOVICE mission
A8D9 F011     04777                 BEQ SKIP065             ;
              04778
A8DB AD0AD2   04779                 LDA RANDOM              ; Prep random number
A8DE A4D0     04780                 LDY SHIPVIEW            ; Skip if in Front view
A8E0 F006     04781                 BEQ SKIP064             ;
              04782
A8E2 8D2D0C   04783                 STA PL3COLUMN           ; Randomize PM pixel row and column number...
A8E5 8DFC0B   04784                 STA PL3ROWNEW           ; ...of Hyperwarp Target Marker
              04785
A8E8 C910     04786 SKIP064         CMP #16                 ; Return in 94% (240:256) of game loops
A8EA B014     04787                 BCS SKIP066             ;
              04788
              04789 ;*** Veer off Hyperwarp Target Marker and return *******************************
A8EC AD0AD2   04790 SKIP065         LDA RANDOM              ; Prep random x-velocity of Hyperwarp Target Marker
A8EF 0910     04791                 ORA #$10                ; Velocity value >= 16 <KM/H>
A8F1 25C6     04792                 AND VEERMASK            ; Limit velocity value by mission level
A8F3 8D9A0B   04793                 STA PL3XVEL             ; PLAYER3 x-velocity := velocity value
              04794
A8F6 AD0AD2   04795                 LDA RANDOM              ; Prep random y-velocity of Hyperwarp Target Marker
A8F9 0910     04796                 ORA #$10                ; Velocity value >= 16 <KM/H>
A8FB 25C6     04797                 AND VEERMASK            ; Limit velocity value by mission level
A8FD 8DCB0B   04798                 STA PL3YVEL             ; PLAYER3 y-velocity := velocity value
A900 60       04799 SKIP066         RTS                     ; Return
              04800
              04801 ;*** HYPERSPACE PHASE **********************************************************
A901 98       04802 SKIP067         TYA                     ; Skip if already in HYPERSPACE PHASE
A902 3011     04803                 BMI SKIP068             ;
              04804
              04805 ;*** HYPERSPACE PHASE (First pass) *********************************************
A904 A9FF     04806                 LDA #$FF                ; Set hyperwarp state to HYPERSPACE PHASE
A906 85C0     04807                 STA WARPSTATE           ;
              04808
A908 A200     04809                 LDX #$00                ; Play beeper sound pattern HYPERWARP TRANSIT
A90A 20A6B3   04810                 JSR BEEP                ;
              04811
A90D 20A7B1   04812                 JSR CALCWARP            ; Calc hyperwarp energy
              04813
A910 A01B     04814                 LDY #$1B                ; Prep title phrase "HYPERSPACE"
A912 4C8DA9   04815                 JMP CLEANUPWARP         ; Return via CLEANUPWARP
              04816
              04817 ;*** HYPERSPACE PHASE (Second and later passes) ********************************
A915 C691     04818 SKIP068         DEC WARPENERGY          ; Decrement energy in chunks of 10 energy units
A917 F005     04819                 BEQ SKIP069             ; Skip to DECELERATION PHASE if hyperwarp energy zero
              04820
A919 A202     04821                 LDX #2                  ; ENERGY := ENERGY - 10 and return
A91B 4C6FB8   04822                 JMP DECENERGY           ;
              04823
              04824 ;*** DECELERATION PHASE ********************************************************
A91E A019     04825 SKIP069         LDY #$19                ; Prep title phrase "HYPERWARP COMPLETE"
A920 2087A9   04826                 JSR ENDWARP             ; Stop our starship
              04827
A923 A58F     04828                 LDA WARPARRVCOLUMN      ; Make the arrival hyperwarp marker column number...
A925 858D     04829                 STA WARPDEPRCOLUMN      ; ...the departure hyperwarp marker column number
A927 A58E     04830                 LDA WARPARRVROW         ; Make the arrival hyperwarp marker row number...
A929 858C     04831                 STA WARPDEPRROW         ; ...the departure hyperwarp marker row number
              04832
A92B 4A       04833                 LSR A                   ; B3..1 of arrival hyperwarp marker row number...
A92C 2907     04834                 AND #$07                ; ...pick vicinity mask
A92E AA       04835                 TAX                     ;
A92F BDB3BF   04836                 LDA VICINITYMASKTAB,X   ;
A932 85C7     04837                 STA VICINITYMASK        ; Store vicinity mask (limits space obj coordinates)
              04838
A934 A492     04839                 LDY ARRVSECTOR          ; Make the arrival sector the current sector
A936 8490     04840                 STY CURRSECTOR          ;
              04841
              04842 ;*** Init starbase in arrival sector *******************************************
A938 A900     04843                 LDA #0                  ; Clear starbase-in-sector flag
A93A 857B     04844                 STA ISSTARBASESECT      ;
              04845
A93C BEC908   04846                 LDX GCMEMMAP,Y          ; Skip if no starbase in arrival sector
A93F 102E     04847                 BPL SKIP070             ;
              04848
A941 A9FF     04849                 LDA #$FF                ; Set starbase-in-sector flag
A943 857B     04850                 STA ISSTARBASESECT      ;
              04851
              04852 ;*** Set position vector and velocity vector of starbase ***********************
A945 A000     04853                 LDY #0                  ;
A947 A900     04854 LOOP033         LDA #0                  ; Loop over all coordinates of starbase
A949 99680B   04855                 STA PL2ZVEL,Y           ; Starbase velocity vector component := 0 <KM/H>
A94C A901     04856                 LDA #1                  ;
A94E 99AF09   04857                 STA PL2ZPOSSIGN,Y       ; Starbase coordinate sign := + (positive)
A951 AD0AD2   04858                 LDA RANDOM              ; Prep random number...
A954 25C7     04859                 AND VICINITYMASK        ; ...limit number range by vicinity mask, then...
A956 99420A   04860                 STA PL2ZPOSHI,Y         ; ...store in starbase coordinate (high byte)
              04861
A959 98       04862                 TYA                     ;
A95A 18       04863                 CLC                     ;
A95B 6931     04864                 ADC #NUMSPCOBJ.ALL      ;
A95D A8       04865                 TAY                     ;
A95E C993     04866                 CMP #NUMSPCOBJ.ALL*3    ;
A960 90E5     04867                 BCC LOOP033             ; Next starbase coordinate
              04868
A962 AD420A   04869                 LDA PL2ZPOSHI           ; Force starbase z-coordinate >= +$71** <KM>
A965 0971     04870                 ORA #$71                ;
A967 8D420A   04871                 STA PL2ZPOSHI           ;
A96A A202     04872                 LDX #2                  ; Randomly invert starbase x and y coordinates...
A96C 4CBEB7   04873                 JMP RNDINVXY            ; ...and return
              04874
              04875 ;*** Flash red alert if Zylon sector entered ***********************************
A96F F00E     04876 SKIP070         BEQ SKIP071             ; Skip if no Zylon ships in sector
              04877
A971 A9FF     04878                 LDA #255                ; Red alert lifetime := 255 game loops
A973 858B     04879                 STA REDALERTLIFE        ;
              04880
A975 A206     04881                 LDX #$06                ; Play beeper sound pattern RED ALERT
A977 20A6B3   04882                 JSR BEEP                ;
              04883
A97A A075     04884                 LDY #$75                ; Set title phrase "RED ALERT"
A97C 2023B2   04885                 JSR SETTITLE            ;
              04886
A97F 60       04887 SKIP071         RTS                     ; Return
              04888
              04889 ;*******************************************************************************
              04890 ;*                                                                             *
              04891 ;*                                  ABORTWARP                                  *
              04892 ;*                                                                             *
              04893 ;*                               Abort hyperwarp                               *
              04894 ;*                                                                             *
              04895 ;*******************************************************************************
              04896
              04897 ; DESCRIPTION
              04898 ;
              04899 ; Aborts hyperwarp.
              04900 ;
              04901 ; This subroutine is entered from subroutine KEYBOARD ($AFFE). It subtracts 100
              04902 ; energy units for aborting the hyperwarp and preloads the title phrase with
              04903 ; "HYPERWARP ABORTED". Code execution continues into subroutine ENDWARP
              04904 ; ($A987). 
              04905
A980 A201     04906 ABORTWARP       LDX #1                  ; ENERGY := ENERGY - 100 after hyperwarp abort
A982 206FB8   04907                 JSR DECENERGY           ;
              04908
A985 A017     04909                 LDY #$17                ; Prep title phrase "HYPERWARP ABORTED"
              04910
              04911 ;*******************************************************************************
              04912 ;*                                                                             *
              04913 ;*                                   ENDWARP                                   *
              04914 ;*                                                                             *
              04915 ;*                                End hyperwarp                                *
              04916 ;*                                                                             *
              04917 ;*******************************************************************************
              04918
              04919 ; DESCRIPTION
              04920 ;
              04921 ; Ends hyperwarp.
              04922 ;
              04923 ; This subroutine stops our starship's Engines and resets the hyperwarp state.
              04924 ; Code execution continues into subroutine CLEANUPWARP ($A98D).
              04925
A987 A900     04926 ENDWARP         LDA #0                  ; Stop Engines
A989 8571     04927                 STA NEWVELOCITY         ;
A98B 85C0     04928                 STA WARPSTATE           ; Disengage hyperwarp
              04929
              04930 ;*******************************************************************************
              04931 ;*                                                                             *
              04932 ;*                                 CLEANUPWARP                                 *
              04933 ;*                                                                             *
              04934 ;*                        Clean up hyperwarp variables                         *
              04935 ;*                                                                             *
              04936 ;*******************************************************************************
              04937
              04938 ; DESCRIPTION
              04939 ;
              04940 ; Cleans up after a hyperwarp.
              04941 ;
              04942 ; This subroutine restores many hyperwarp related variables to their
              04943 ; post-hyperwarp values: The number of used space objects is set to the regular
              04944 ; value of 16 (5 PLAYER space objects + 12 PLAYFIELD space objects (stars),
              04945 ; counted 0..16), our starship's velocity (high byte) is cleared as well as the
              04946 ; explosion lifetime, the hit badness, the PLAYER3 shape type (Hyperwarp Target
              04947 ; Marker), the Engines energy drain rate, and the lifetimes of the PLAYERs. The
              04948 ; docking state is reset as well as the tracking digit. The title phrase is
              04949 ; updated with either "HYPERSPACE" or "HYPERWARP ABORTED".
              04950 ;
              04951 ; INPUT
              04952 ;
              04953 ;   Y = Title phrase offset. Used values are: 
              04954 ;     $17 -> "HYPERWARP ABORTED"
              04955 ;     $1B -> "HYPERSPACE"
              04956
A98D A910     04957 CLEANUPWARP     LDA #NUMSPCOBJ.NORM-1   ; Set normal number of space objects
A98F 8579     04958                 STA MAXSPCOBJIND        ; (5 PLAYER spc objs + 12 PLAYFIELD spc objs (stars))
              04959
A991 A900     04960                 LDA #0                  ;
A993 85C1     04961                 STA VELOCITYHI          ; Turn off hyperwarp velocity
A995 8573     04962                 STA EXPLLIFE            ; Explosion lifetime := 0 game loops
A997 858A     04963                 STA HITBADNESS          ; HITBADNESS := NO HIT
A999 8D8F0C   04964                 STA PL3SHAPTYPE         ; Clear PLAYER3 shape type
A99C 8580     04965                 STA DRAINENGINES        ; Clear Engines energy drain rate
A99E C017     04966                 CPY #$17                ; Skip if hyperwarp was aborted
A9A0 F004     04967                 BEQ SKIP072             ;
              04968
A9A2 85E9     04969                 STA PL0LIFE             ; Zylon ship 0 lifetime := 0 game loops
A9A4 85EA     04970                 STA PL1LIFE             ; Zylon ship 1 lifetime := 0 game loops
              04971
A9A6 85EB     04972 SKIP072         STA PL2LIFE             ; Zylon photon torpedo lifetime := 0 game loops
A9A8 85EC     04973                 STA PL3LIFE             ; Hyperwarp Target Marker lifetime := 0 game loops
A9AA 85ED     04974                 STA PL4LIFE             ; Photon torpedo 1 lifetime := 0  game loops
A9AC 8575     04975                 STA DOCKSTATE           ; DOCKSTATE := NO DOCKING
A9AE 8D5C09   04976                 STA TRACKDIGIT          ; Clear index of tracked space object
A9B1 4C23B2   04977                 JMP SETTITLE            ; Set title phrase and return
              04978
              04979 ;*******************************************************************************
              04980 ;*                                                                             *
              04981 ;*                                  INITTRAIL                                  *
              04982 ;*                                                                             *
              04983 ;*         Initialize star trail during STAR TRAIL PHASE of hyperwarp          *
              04984 ;*                                                                             *
              04985 ;*******************************************************************************
              04986
              04987 ; DESCRIPTION
              04988 ;
              04989 ; BACKGROUND
              04990 ;
              04991 ; Star trails are displayed during the STAR TRAIL PHASE, that is, after the
              04992 ; ACCELERATION PHASE and before the HYPERSPACE PHASE of the hyperwarp. 
              04993 ;
              04994 ; A star trail is formed by 6 stars represented by 6 PLAYFIELD space objects
              04995 ; with continuous position vector indices in 17..48 (indices are wrapped around
              04996 ; when greater than 48). Between the creations of two star trails there is delay
              04997 ; of 4 game loop iterations.
              04998 ;
              04999 ; DETAILS
              05000 ;
              05001 ; This subroutine first decrements this star trail creation delay, returning if
              05002 ; the delay is still counting down. If the delay falls below 0 then it continues
              05003 ; accelerating our starship's velocity toward hyperwarp speed and then creates a
              05004 ; new star trail:
              05005 ;
              05006 ; First, it raises the maximum index of used space objects to 48 (increasing the
              05007 ; number of displayed space objects to 49), resets the star trail creation delay
              05008 ; to 4 game loop iterations, and then forms a new star trail of 6 stars
              05009 ; represented by 6 PLAYFIELD space objects. The x and y coordinates for all 6
              05010 ; stars are the same, picked randomly from tables WARPSTARXTAB ($BB3A) and
              05011 ; WARPSTARYTAB ($BB3E), respectively, with their signs changed randomly. Their
              05012 ; z-coordinates are computed in increasing depth from at least +4608 (+$12**)
              05013 ; <KM> in intervals of +80 (+$0050) <KM>. Their velocity vector components are
              05014 ; set to 0 <KM/H>.
              05015
    =0068     05016 L.RANGE         = $68                   ; z-coordinate of star in star trail (16-bit value)
    =006E     05017 L.TRAILCNT      = $6E                   ; Star's index in star trail. Used values are: 0..5.
              05018
A9B4 C6C2     05019 INITTRAIL       DEC TRAILDELAY          ; Decrement star trail delay
A9B6 1068     05020                 BPL SKIP074             ; Return if delay still counting
              05021
A9B8 A901     05022                 LDA #1                  ; Turn on hyperwarp velocity
A9BA 85C1     05023                 STA VELOCITYHI          ;
              05024
A9BC A930     05025                 LDA #NUMSPCOBJ.ALL-1    ; Max index of space objects (for star trail stars)
A9BE 8579     05026                 STA MAXSPCOBJIND        ;
              05027
A9C0 A903     05028                 LDA #3                  ; Star trail delay := 3(+1) game loops
A9C2 85C2     05029                 STA TRAILDELAY          ;
              05030
A9C4 A6C3     05031                 LDX TRAILIND            ; Next avail. space obj index for star of star trail
              05032
A9C6 A912     05033                 LDA #$12                ; Star z-coordinate := >= +$12** (+4608) <KM>
A9C8 8569     05034                 STA L.RANGE+1           ;
              05035
A9CA AD0AD2   05036                 LDA RANDOM              ; Calc random index to pick initial star coordinates
A9CD 2903     05037                 AND #$03                ;
A9CF A8       05038                 TAY                     ;
A9D0 B93ABB   05039                 LDA WARPSTARXTAB,Y      ; Pick x-coordinate (high byte) of star from table
A9D3 9D710A   05040                 STA XPOSHI,X            ;
A9D6 B93EBB   05041                 LDA WARPSTARYTAB,Y      ;
A9D9 9DA20A   05042                 STA YPOSHI,X            ; Pick y-coordinate (high byte) of star from table
A9DC 20BEB7   05043                 JSR RNDINVXY            ; Randomize signs of x and y coordinates of star
              05044
A9DF 8A       05045                 TXA                     ; Save space object index
A9E0 A8       05046                 TAY                     ;
A9E1 A905     05047                 LDA #5                  ; Loop over 5(+1) stars that form the star trail
A9E3 856E     05048                 STA L.TRAILCNT          ; Store star counter of star trail
              05049
A9E5 18       05050 LOOP034         CLC                     ; Place stars in z-coordinate intervals of +80 <KM>
A9E6 A568     05051                 LDA L.RANGE             ;
A9E8 6950     05052                 ADC #80                 ;
A9EA 8568     05053                 STA L.RANGE             ;
A9EC 9DD30A   05054                 STA ZPOSLO,X            ;
A9EF A569     05055                 LDA L.RANGE+1           ;
A9F1 6900     05056                 ADC #0                  ;
A9F3 8569     05057                 STA L.RANGE+1           ;
A9F5 9D400A   05058                 STA ZPOSHI,X            ;
              05059
A9F8 A900     05060                 LDA #0                  ; Star's velocity vector components := 0 <KM/H>
A9FA 9D660B   05061                 STA ZVEL,X              ;
A9FD 9D970B   05062                 STA XVEL,X              ;
AA00 9DC80B   05063                 STA YVEL,X              ;
AA03 A901     05064                 LDA #1                  ; Star's z-coordinate sign := + (= ahead of starship)
AA05 9DAD09   05065                 STA ZPOSSIGN,X          ;
              05066
AA08 A963     05067                 LDA #99                 ; Init pixel row and column numbers to magic...
AA0A 9DF90B   05068                 STA PIXELROWNEW,X       ; ...offscreen value (triggers automatic recalc in...
AA0D 9D2A0C   05069                 STA PIXELCOLUMN,X       ; ...GAMELOOP's calls to SCREENCOLUMN and SCREENROW)
              05070
AA10 20C1AC   05071                 JSR COPYPOSXY           ; Copy x and y coordinate from previous star in trail
              05072
AA13 CA       05073                 DEX                     ; Decrement space object index to next star
AA14 E011     05074                 CPX #NUMSPCOBJ.NORM     ; If index reaches minimum value...
AA16 B002     05075                 BCS SKIP073             ;
AA18 A230     05076                 LDX #NUMSPCOBJ.ALL-1    ; ...wrap-around to maximum space object index
AA1A C66E     05077 SKIP073         DEC L.TRAILCNT          ;
AA1C 10C7     05078                 BPL LOOP034             ; Next star of star trail
              05079
AA1E 86C3     05080                 STX TRAILIND            ; Save space object index of star trail's last star
AA20 60       05081 SKIP074         RTS                     ; Return
              05082
              05083 ;*******************************************************************************
              05084 ;*                                                                             *
              05085 ;*                                 PROJECTION                                  *
              05086 ;*                                                                             *
              05087 ;*         Calculate pixel column (or row) number from position vector         *
              05088 ;*                                                                             *
              05089 ;*******************************************************************************
              05090
              05091 ; Calculates the pixel column (or row) number of a position vector x (or y)
              05092 ; component relative to the PLAYFIELD center by computing the perspective
              05093 ; projection quotient
              05094 ;
              05095 ;     QUOTIENT := DIVIDEND / DIVISOR * 128
              05096 ;
              05097 ; with
              05098 ;
              05099 ;     DIVIDEND := ABS(x-coordinate (or y-coordinate)) / 2
              05100 ;     DIVISOR  := ABS(z-coordinate) / 2  
              05101 ;
              05102 ; If the QUOTIENT is in 0..255, it is used as an index to pick the pixel column
              05103 ; (or row) number from table MAPTO80 ($0DE9), returning values in 0..80.
              05104 ;
              05105 ; If the QUOTIENT is larger than 255 ("dividend overflow") or if the
              05106 ; z-coordinate = 0 ("division by zero") then the error value 255 is returned.
              05107 ;
              05108 ; INPUT
              05109 ;
              05110 ;   X                   = Position vector index. Used values are: 0..48.
              05111 ;   DIVIDEND ($6A..$6B) = Dividend (positive 16-bit value), contains the
              05112 ;                         absolute value of the x (or y) coordinate.
              05113 ;
              05114 ; OUTPUT
              05115 ;
              05116 ;   A = Pixel column (or row) number relative to PLAYFIELD center. Used values
              05117 ;       are: 
              05118 ;     0..80 -> Pixel number
              05119 ;     255   -> Error value indicating "dividend overflow" or "division by zero"
              05120
    =0068     05121 L.DIVISOR       = $68                   ; Divisor (16-bit value)
    =006D     05122 L.QUOTIENT      = $6D                   ; Division result (unsigned 8-bit value)
    =006E     05123 L.LOOPCNT       = $6E                   ; Division loop counter. Used values are: 7..0.
              05124
AA21 A900     05125 PROJECTION      LDA #0                  ; Init quotient result
AA23 856D     05126                 STA L.QUOTIENT          ;
              05127
AA25 A907     05128                 LDA #7                  ; Init division loop counter
AA27 856E     05129                 STA L.LOOPCNT           ;
              05130
AA29 466B     05131                 LSR DIVIDEND+1          ; DIVIDEND := x-coordinate (or y-coordinate) / 2
AA2B 666A     05132                 ROR DIVIDEND            ; (division by 2 to make B15 = 0?) (?)
              05133
AA2D A5D0     05134                 LDA SHIPVIEW            ; Skip if in Aft view
AA2F D00F     05135                 BNE SKIP075             ;
              05136
AA31 BD400A   05137                 LDA ZPOSHI,X            ; If in Front view -> DIVISOR := z-coordinate / 2
AA34 4A       05138                 LSR A                   ; (division by 2 to make B15 = 0?) (?)
AA35 8569     05139                 STA L.DIVISOR+1         ;
AA37 BDD30A   05140                 LDA ZPOSLO,X            ;
AA3A 6A       05141                 ROR A                   ;
AA3B 8568     05142                 STA L.DIVISOR           ;
AA3D 4C52AA   05143                 JMP LOOP035             ;
              05144
AA40 38       05145 SKIP075         SEC                     ; If in Aft view -> DIVISOR := - z-coordinate / 2
AA41 A900     05146                 LDA #0                  ; (division by 2 to make B15 = 0?) (?)
AA43 FDD30A   05147                 SBC ZPOSLO,X            ;
AA46 8568     05148                 STA L.DIVISOR           ;
AA48 A900     05149                 LDA #0                  ;
AA4A FD400A   05150                 SBC ZPOSHI,X            ;
AA4D 4A       05151                 LSR A                   ;
AA4E 8569     05152                 STA L.DIVISOR+1         ;
AA50 6668     05153                 ROR L.DIVISOR           ;
              05154
AA52 066D     05155 LOOP035         ASL L.QUOTIENT          ; QUOTIENT := DIVIDEND / DIVISOR * 128
AA54 38       05156                 SEC                     ;
AA55 A56A     05157                 LDA DIVIDEND            ;
AA57 E568     05158                 SBC L.DIVISOR           ;
AA59 A8       05159                 TAY                     ;
AA5A A56B     05160                 LDA DIVIDEND+1          ;
AA5C E569     05161                 SBC L.DIVISOR+1         ;
AA5E 9006     05162                 BCC SKIP076             ;
              05163
AA60 856B     05164                 STA DIVIDEND+1          ;
AA62 846A     05165                 STY DIVIDEND            ;
AA64 E66D     05166                 INC L.QUOTIENT          ;
              05167
AA66 066A     05168 SKIP076         ASL DIVIDEND            ;
AA68 266B     05169                 ROL DIVIDEND+1          ;
AA6A 9003     05170                 BCC SKIP077             ;
              05171
AA6C A9FF     05172                 LDA #255                ; Return 255 if division by zero or dividend overflow
AA6E 60       05173                 RTS                     ;
              05174
AA6F C66E     05175 SKIP077         DEC L.LOOPCNT           ;
AA71 10DF     05176                 BPL LOOP035             ; Next division loop iteration
              05177
AA73 A46D     05178                 LDY L.QUOTIENT          ; Prep with quotient
AA75 B9E90D   05179                 LDA MAPTO80,Y           ; Pick and return pixel column (or row) number...
AA78 60       05180 SKIP078         RTS                     ; ...relative to PLAYFIELD center
              05181
              05182 ;*******************************************************************************
              05183 ;*                                                                             *
              05184 ;*                                  MANEUVER                                   *
              05185 ;*                                                                             *
              05186 ;*     Maneuver our starship's and Zylon photon torpedoes and Zylon ships      *
              05187 ;*                                                                             *
              05188 ;*******************************************************************************
              05189
              05190 ; DESCRIPTION
              05191 ;
              05192 ; This subroutine maneuvers both of our starship's photon torpedoes, the single
              05193 ; Zylon photon torpedo, and the one or two Zylon ships that are simultaneously
              05194 ; displayed on the screen. It also creates meteors and new Zylon ships. This
              05195 ; subroutine is executed only if our starship is not in a starbase sector and
              05196 ; hyperwarp is not engaged.
              05197 ;
              05198 ; BACKGROUND
              05199 ;
              05200 ; When a Zylon ship is initialized, a "flight pattern" is assigned to it. There
              05201 ; are 3 flight patterns (0, 1, and 4) which are picked from table ZYLONFLPATTAB
              05202 ; ($BF91).
              05203 ;
              05204 ; The flight pattern determines the maximum velocity with which a Zylon ship can
              05205 ; move along each axis of the 3D coordinate system, that is, the maximum value
              05206 ; of a velocity vector component. Velocity vector components for Zylon ships are
              05207 ; picked from the Zylon velocity table ZYLONVELTAB ($BF99):
              05208 ;
              05209 ; +-----------------+-----+-----+-----+-----+-----+-----+-----+-----+
              05210 ; | Velocity Index  |  0  |  1  |  2  |  3  |  4  |  5  |  6  |  7  |
              05211 ; +-----------------+-----+-----+-----+-----+-----+-----+-----+-----+
              05212 ; | Velocity <KM/H> | +62 | +30 | +16 |  +8 |  +4 |  +2 |  +1 |  0  |
              05213 ; +-----------------+-----+-----+-----+-----+-----+-----+-----+-----+
              05214 ; +-----------------+-----+-----+-----+-----+-----+-----+-----+-----+
              05215 ; | Velocity Index  |  8  |  9  |  10 |  11 |  12 |  13 |  14 |  15 |
              05216 ; +-----------------+-----+-----+-----+-----+-----+-----+-----+-----+
              05217 ; | Velocity <KM/H> |  0  |  -1 |  -2 |  -4 |  -8 | -16 | -30 | -62 |
              05218 ; +-----------------+-----+-----+-----+-----+-----+-----+-----+-----+
              05219 ;
              05220 ; The index into the Zylon velocity table ZYLONVELTAB ($BF99) corresponding to
              05221 ; the maximum velocity is called the "maximum velocity index". The following
              05222 ; table shows the flight patterns, their maximum velocity indices, and their
              05223 ; corresponding velocities:
              05224 ;
              05225 ; +----------------+------------------+------------------+
              05226 ; | Flight Pattern | Maximum Velocity | Maximum Velocity |
              05227 ; |                |      Index       |                  |
              05228 ; +----------------+------------------+------------------+
              05229 ; |       0        |         0        |    +62 <KM/H>    |
              05230 ; |       0        |        15        |    -62 <KM/H>    |
              05231 ; |       1        |         1        |    +30 <KM/H>    |
              05232 ; |       1        |        14        |    -30 <KM/H>    |
              05233 ; |       4        |         4        |     +4 <KM/H>    |
              05234 ; |       4        |        11        |     -4 <KM/H>    |
              05235 ; +----------------+------------------+------------------+
              05236 ;
              05237 ; Because flight pattern 0 produces the fastest-moving Zylon ships, which
              05238 ; maneuver aggressively, it is called the "attack flight pattern".
              05239 ;
              05240 ; Each Zylon ship has a set of 3 maximum velocity indices, one for each of its
              05241 ; velocity vector components.
              05242 ;
              05243 ; Each Zylon ship has also one more set of 3 velocity indices, called "Zylon
              05244 ; velocity indices", one for each of its velocity vector components. They are
              05245 ; used to pick the current values of the velocity vector components from the
              05246 ; Zylon velocity table ZYLONVELTAB ($BF99).
              05247 ;
              05248 ; In order to maneuver Zylon ships this subroutine uses the concept of
              05249 ; "milestone velocity indices". By using delay timers, called "Zylon timers",
              05250 ; this subroutine gradually increases or decreases the Zylon velocity indices
              05251 ; with every game loop iteration to eventually match the corresponding milestone
              05252 ; velocity indices. By incrementing a Zylon velocity index a Zylon ship
              05253 ; accelerates toward the negative direction of a coordinate axis. By
              05254 ; decrementing a Zylon velocity index a Zylon ship accelerates toward the
              05255 ; positive direction of a coordinate axis. If one milestone velocity index is
              05256 ; matched or a "milestone timer" has counted down to 0, a new milestone velocity
              05257 ; index is calculated and the matching of the current Zylon velocity indices
              05258 ; with the new milestone velocity indices repeats.
              05259 ;
              05260 ; DETAILS
              05261 ;
              05262 ; For quick lookup, the following table lists the PLAYERs and what space objects
              05263 ; they represent in this subroutine:
              05264 ;
              05265 ; +--------+---------------------------------+
              05266 ; | PLAYER |           Represents            |
              05267 ; +--------+---------------------------------+
              05268 ; |    0   | Zylon Ship 0                    |
              05269 ; |    1   | Zylon Ship 1                    |
              05270 ; |    2   | Zylon Photon Torpedo, Meteor    |
              05271 ; |    3   | Our starship's Photon Torpedo 0 |
              05272 ; |    4   | Our starship's Photon Torpedo 1 |
              05273 ; +--------+---------------------------------+
              05274 ;
              05275 ; This subroutine executes the following steps:
              05276 ;
              05277 ; (1)  Update the x and y velocity vector components of both of our starship's
              05278 ;      photon torpedoes 0 and 1.
              05279 ;
              05280 ;      The x and y velocity vector components of both of our starship's photon
              05281 ;      torpedoes 0 and 1 are only updated if they are tracking (homing in on) a
              05282 ;      target.
              05283 ;
              05284 ;      To update the y-velocity vector components of both of our starship's
              05285 ;      photon torpedoes 0 and 1 the PLAYER row number difference between the
              05286 ;      PLAYER of tracked target space object and the current location of the
              05287 ;      PLAYER of our starship's photon torpedo 0 is passed to subroutine
              05288 ;      HOMINGVEL ($AECA). It returns the new y-velocity vector component value
              05289 ;      for both of our starship's photon torpedoes in <KM/H>. If the target is
              05290 ;      located below our starship's photon torpedo 0 a value of 0 <KM/H> is
              05291 ;      used.
              05292 ;
              05293 ;      NOTE: The new y-velocity vector components depend only on the PLAYER row
              05294 ;      number of our starship's photon torpedo 0.
              05295 ;
              05296 ;      To update the x-velocity vector components of both of our starship's
              05297 ;      photon torpedoes, the above calculation is repeated for the PLAYER column
              05298 ;      numbers of each of our starship's photon torpedoes 0 and 1.
              05299 ;
              05300 ; (2)  Make the Zylon ships follow the rotation of our starship.
              05301 ;
              05302 ;      If you rotate our starship away from Zylon ships they adjust their course
              05303 ;      such that they reappear in our starship's view.
              05304 ;
              05305 ;      This is achieved by 4 Zylon timers, one for each of both Zylon ships'
              05306 ;      current x and y Zylon velocity indices. The Zylon timers are decremented
              05307 ;      every game loop iteration. If any of them reach a value of 0, the
              05308 ;      corresponding Zylon velocity index is incremented or decremented
              05309 ;      depending on the current joystick position.
              05310 ;
              05311 ;      For example, if the Zylon timer for the x-velocity of Zylon ship 0
              05312 ;      reaches 0 and at the same time the joystick is pushed left then the
              05313 ;      x-Zylon velocity index of this Zylon ship is incremented. This
              05314 ;      accelerates the Zylon ship toward negative x-direction ("left"): The
              05315 ;      Zylon ship follows our starship's rotation. This works in Aft view, too,
              05316 ;      where the direction of change of the Zylon velocity index is reversed.
              05317 ;      After setting the new Zylon velocity index, it is used to pick a new
              05318 ;      Zylon timer value for this Zylon velocity index: 
              05319 ;
              05320 ;      +--------------------------------+----+----+----+----+----+----+----+----+
              05321 ;      | Velocity Index                 |  0 |  1 |  2 |  3 |  4 |  5 |  6 |  7 |
              05322 ;      +--------------------------------+----+----+----+----+----+----+----+----+
              05323 ;      | Zylon Timer Value (Game Loops) |  0 |  2 |  4 |  6 |  8 | 10 | 12 | 14 |
              05324 ;      +--------------------------------+----+----+----+----+----+----+----+----+
              05325 ;      +--------------------------------+----+----+----+----+----+----+----+----+
              05326 ;      | Velocity Index                 |  8 |  9 | 10 | 11 | 12 | 13 | 14 | 15 |
              05327 ;      +--------------------------------+----+----+----+----+----+----+----+----+
              05328 ;      | Zylon Timer Value (Game Loops) | 14 | 12 | 10 |  8 |  6 |  4 |  2 |  0 |
              05329 ;      +--------------------------------+----+----+----+----+----+----+----+----+
              05330 ;
              05331 ; (3)  Update the x and y velocity vector components of the single Zylon photon
              05332 ;      torpedo.
              05333 ;
              05334 ;      If a Zylon photon torpedo is moving toward our starship then update its x
              05335 ;      and y velocity vector components. They are picked from table
              05336 ;      ZYLONHOMVELTAB ($BF85) and depend on the mission level. The signs of the
              05337 ;      velocity vector components are always set such that the Zylon photon
              05338 ;      torpedo is guided toward our starship. 
              05339 ;
              05340 ; (4)  Create a meteor?
              05341 ;
              05342 ;      If PLAYER2, the PLAYER to represent a meteor, is either initial or not
              05343 ;      alive, then attempt in 7 out of 8 game loop iterations to create a new
              05344 ;      meteor. 
              05345 ;
              05346 ;      With a probability of 2% (4:256) a new meteor is created: Its shape type
              05347 ;      is set to METEOR, its position vector components to random coordinates in
              05348 ;      subroutine INITPOSVEC ($B764), its lifetime to 60 game loop iterations,
              05349 ;      and its velocity vector components (velocities) to x-velocity: 0 <KM/H>,
              05350 ;      y-velocity: 0 <KM/H>, z-velocity: -8 <KM/H>. Then code execution returns.
              05351 ;
              05352 ; (5)  Toggle Zylon ship control.
              05353 ;
              05354 ;      Every other game loop iteration, the game takes control of and maneuvers
              05355 ;      the other Zylon ship.
              05356 ;
              05357 ; (6)  Create new Zylon ship?
              05358 ;
              05359 ;      If the game-controlled Zylon ship is not alive, check if both Zylon ships
              05360 ;      are not alive and this is an empty sector. If so, then attempt to create
              05361 ;      a meteor. Otherwise create a new Zylon ship with infinite lifetime.
              05362 ;      Randomly pick its shape type from table ZYLONSHAPTAB ($BF89) (ZYLON
              05363 ;      BASESTAR, ZYLON CRUISER, or ZYLON FIGHTER) and its flight pattern from
              05364 ;      table ZYLONFLPATTAB ($BF91) (attack flight pattern 0 is always picked in
              05365 ;      a NOVICE mission). Then set the milestone timer to 1 game loop iteration
              05366 ;      and the position vector of the Zylon ship to a position of at least
              05367 ;      +28928 (+$71**) <KM> in front of our starship. The y-coordinate depends
              05368 ;      on the value of VICINITYMASK ($C7). The x-coordinate is the sum of the
              05369 ;      y-coordinate plus at least 4864..5119 ($13**) <KM>. Randomly choose the
              05370 ;      signs of the x and y coordinates.
              05371 ;
              05372 ; (7)  Set the current flight pattern to attack flight pattern?
              05373 ;
              05374 ;      The current flight pattern of the Zylon ship will change to attack flight
              05375 ;      pattern if it is close enough (z-coordinate < +8192 (+$20**) <KM>) and
              05376 ;      one of the following conditions is met:
              05377 ;
              05378 ;      o   The Zylon ship is located behind our starship.
              05379 ;
              05380 ;      o   The shape of the Zylon ship is not initial and does not currently
              05381 ;          appear as a blip in the Long-Range Scan view.
              05382 ;
              05383 ; (8)  Update the back-attack flag and the milestone velocity indices.
              05384 ;
              05385 ;      The milestone timer is decremented for the game-controlled Zylon ship. If
              05386 ;      this timer reaches a value of 0 the following steps are executed:
              05387 ;
              05388 ;      o   The milestone timer is reset to a value of 120 game loop iterations.
              05389 ;
              05390 ;      o   The back-attack flag is updated. It determines if the game-controlled
              05391 ;          Zylon ship not only attacks from the front of our starship but also
              05392 ;          from the back. A back-attack takes place with a probability of 19%
              05393 ;          (48:256) in WARRIOR or COMMANDER missions.
              05394 ;
              05395 ;      o   Course corrections are prepared for the game-controlled Zylon ship by
              05396 ;          computing the new milestone vector indices, resulting in new velocity
              05397 ;          vector components for this Zylon ship. The new milestone velocity
              05398 ;          indices for each velocity vector component are randomly chosen
              05399 ;          depending of the flight pattern. Recall that the Zylon velocity index
              05400 ;          is changed gradually to match the milestone velocity index. It
              05401 ;          corresponds to a maximum velocity vector component when using this
              05402 ;          index to pick a velocity vector component from Zylon velocity table
              05403 ;          ZYLONVELTAB ($BF99):
              05404 ;
              05405 ;          +----------------+----------------+------------------+
              05406 ;          | Flight Pattern | New Milestone  | Maximum Velocity |
              05407 ;          |                | Velocity Index | Vector Component |
              05408 ;          +----------------+----------------+------------------+
              05409 ;          |       0        |        0       |    +62 <KM/H>    |
              05410 ;          |       0        |       15       |    -62 <KM/H>    |
              05411 ;          |       1        |        1       |    +30 <KM/H>    |
              05412 ;          |       1        |       14       |    -30 <KM/H>    |
              05413 ;          |       4        |        4       |     +4 <KM/H>    |
              05414 ;          |       4        |       11       |     -4 <KM/H>    |
              05415 ;          +----------------+----------------+------------------+
              05416 ;
              05417 ; (9)  Update milestone velocity indices in attack flight pattern.
              05418 ;
              05419 ;      If a Zylon ship executes the attack flight pattern, its milestone
              05420 ;      velocity indices are changed depending on the current location of the
              05421 ;      Zylon ship as follows:
              05422 ;
              05423 ;      +--------------+-------------+----------------+------------+----------------+
              05424 ;      | x-Coordinate |  Where on   |   Milestone    |  Velocity  | Zylon Ship     |
              05425 ;      |              |   Screen    | Velocity Index |            | Accelerates... |
              05426 ;      +--------------+-------------+----------------+------------+----------------+
              05427 ;      | x <  0 <KM>  | left half   |       0        | +62 <KM/H> | to the right   |
              05428 ;      | x >= 0 <KM>  | right half  |      15        | -62 <KM/H> | to the left    |
              05429 ;      +--------------+-------------+----------------+------------+----------------+
              05430 ;      +--------------+-------------+----------------+------------+----------------+
              05431 ;      | y-Coordinate |  Where on   |   Milestone    |  Velocity  | Zylon Ship     |
              05432 ;      |              |   Screen    | Velocity Index |            | Accelerates... |
              05433 ;      +--------------+-------------+----------------+------------+----------------+
              05434 ;      | y <  0 <KM>  | bottom half |       0        | +62 <KM/H> | up             |
              05435 ;      | y >= 0 <KM>  | top half    |      15        | -62 <KM/H> | down           |
              05436 ;      +--------------+-------------+----------------+------------+----------------+
              05437 ;
              05438 ;      Thus, with respect to its x and y coordinates, the Zylon ship oscillates
              05439 ;      around the center of the Front or Aft view.
              05440 ;
              05441 ;      This is the behavior of the Zylon ship along the z-axis:
              05442 ;
              05443 ;      If the Zylon ship attacks from the front:
              05444 ;
              05445 ;      +--------------------------+----------------+------------+----------------+
              05446 ;      |       z-Coordinate       |   Milestone    |  Velocity  | Zylon Ship     |
              05447 ;      |                          | Velocity Index |            | Accelerates... |
              05448 ;      +--------------------------+----------------+------------+----------------+
              05449 ;      | z <  +2560 (+$0A00) <KM> |       0        | +62 <KM/H> | outbound       |
              05450 ;      | z >= +2560 (+$0A00) <KM> |      15        | -62 <KM/H> | inbound        |
              05451 ;      +--------------------------+----------------+------------+----------------+
              05452 ;
              05453 ;      In other words, the Zylon ship accelerates into positive z-direction
              05454 ;      (outbound) up to a distance of +2560 (+$0A00) <KM>, then reverses its
              05455 ;      course and returns back to our starship (inbound).
              05456 ;
              05457 ;      If the Zylon ship attacks from the back:
              05458 ;
              05459 ;      +--------------------------+----------------+------------+----------------+
              05460 ;      |       z-Coordinate       |   Milestone    |  Velocity  | Zylon Ship     |
              05461 ;      |                          | Velocity Index |            | Accelerates... |
              05462 ;      +--------------------------+----------------+------------+----------------+
              05463 ;      | z <  -2816 (-$F500) <KM> |       0        | +62 <KM/H> | inbound        |
              05464 ;      | z >= -2816 (-$F500) <KM> |      15        | -62 <KM/H> | outbound       |
              05465 ;      +--------------------------+----------------+------------+----------------+
              05466 ;
              05467 ;      In other words, the Zylon ship accelerates into negative z-direction
              05468 ;      (outbound) up to a distance of -2816 (-$(0B00)) <KM>, then reverses its
              05469 ;      course and returns back to our starship (inbound).
              05470 ;
              05471 ; (10) Change Zylon velocity index toward milestone velocity index.
              05472 ;
              05473 ;      Compare all 3 Zylon velocity indices of the game-controlled Zylon ship
              05474 ;      with their corresponding milestone velocity indices. Increment or
              05475 ;      decrement the former to better match the latter. Use the new Zylon
              05476 ;      velocity indices to pick the current velocity values from Zylon velocity
              05477 ;      table ZYLONVELTAB ($BF99). 
              05478 ;
              05479 ; (11) Launch a Zylon photon torpedo?
              05480 ;
              05481 ;      Prepare launching a Zylon photon torpedo if either of the following
              05482 ;      conditions are met:
              05483 ;
              05484 ;      o   PLAYER2 is not used as a photon torpedo
              05485 ;
              05486 ;      o   The y-coordinate of the Zylon ship is in the range of -768..+767
              05487 ;          (-$0300..+$2FF) <KM>. 
              05488 ;
              05489 ;      or if
              05490 ;
              05491 ;      o   The Zylon photon torpedo is not alive
              05492 ;
              05493 ;      o   The corresponding Zylon photon torpedo delay timer has reached a
              05494 ;          value of 0
              05495 ;
              05496 ;      o   The y-coordinate of the Zylon ship is in the range of -768..+767
              05497 ;          (-$0300..+$2FF) <KM>. 
              05498 ;
              05499 ;      At this point the z-velocity vector component of the Zylon photon torpedo
              05500 ;      is preloaded with a value of -80 or +80 <KM/H> depending on the Zylon
              05501 ;      ship being in front or behind of our starship, respectively. 
              05502 ;
              05503 ;      Launch a Zylon photon torpedo if both of the following conditions are
              05504 ;      met:
              05505 ;
              05506 ;      o   The Zylon ship is in front or behind of our starship, with the
              05507 ;          exception of a Zylon ship behind our starship in a NOVICE mission
              05508 ;          (our starship will never be shot in the back in a NOVICE mission).
              05509 ;
              05510 ;      o   The z-coordinate of the Zylon ship (no matter if in front or behind
              05511 ;          our starship) is closer than 8192 ($20**) <KM>.
              05512 ;
              05513 ;      Finally, the Zylon photon torpedo is launched with a lifetime of 62 game
              05514 ;      loop iterations. Its position vector is copied from the launching Zylon
              05515 ;      ship in subroutine COPYPOSVEC ($ACAF). In addition, the Zylon ship is
              05516 ;      earmarked for the tracking computer.
              05517
    =006A     05518 L.CTRLDZYLON    = $6A                   ; Index of currently game-controlled Zylon ship.
              05519                                         ; Used values are:
              05520                                         ;   0 -> Control Zylon ship 0
              05521                                         ;   1 -> Control Zylon ship 1
    =0080     05522 NEG             = $80                   ; Negative sign bit for velocity vector component
              05523
AA79 A5C0     05524 MANEUVER        LDA WARPSTATE           ; Return if in starbase sector or hyperwarp engaged
AA7B 057B     05525                 ORA ISSTARBASESECT      ;
AA7D D0F9     05526                 BNE SKIP078             ;
              05527
              05528 ;*** Update x and y velocity of both our starship's photon torpedoes 0 and 1 ***
AA7F A586     05529                 LDA ISTRACKING          ; Skip this if ship's torpedoes not tracking a target
AA81 F030     05530                 BEQ SKIP080             ;
              05531
AA83 A689     05532                 LDX PLTRACKED           ; Load PLAYER index of tracked target space object
              05533
AA85 38       05534                 SEC                     ; Prep A := PLAYER row number of target...
AA86 BDF90B   05535                 LDA PL0ROWNEW,X         ; ...- PLAYER row number photon torpedo 0
AA89 EDFC0B   05536                 SBC PL3ROWNEW           ;
AA8C 9002     05537                 BCC SKIP079             ; Skip if target above our starship's photon torpedo
AA8E A900     05538                 LDA #0                  ; Prep A := 0
AA90 20CAAE   05539 SKIP079         JSR HOMINGVEL           ; Get y-velocity for homing photon torpedo 0 and 1
AA93 8DCB0B   05540                 STA PL3YVEL             ; Store y-velocity photon torpedo 0
AA96 8DCC0B   05541                 STA PL4YVEL             ; Store y-velocity photon torpedo 1
              05542
AA99 38       05543                 SEC                     ; Prep A := PLAYER column number of target...
AA9A AD2D0C   05544                 LDA PL3COLUMN           ; ...- PLAYER column number of photon torpedo 0
AA9D FD2A0C   05545                 SBC PL0COLUMN,X         ;
AAA0 20CAAE   05546                 JSR HOMINGVEL           ; Get x-velocity for homing photon torpedo 0
AAA3 8D9A0B   05547                 STA PL3XVEL             ; Store x-velocity of photon torpedo 0
              05548
AAA6 38       05549                 SEC                     ; Prep A := PLAYER column number of target...
AAA7 AD2E0C   05550                 LDA PL4COLUMN           ; ...- PLAYER column number of photon torpedo 1
AAAA FD2A0C   05551                 SBC PL0COLUMN,X         ;
AAAD 20CAAE   05552                 JSR HOMINGVEL           ; Get x-velocity for homing photon torpedo 1
AAB0 8D9B0B   05553                 STA PL4XVEL             ; Store x-velocity of photon torpedo 1
              05554
              05555 ;*** Make Zylon ships follow rotation of our starship **************************
AAB3 A203     05556 SKIP080         LDX #3                  ; Loop over x and y velocity indices of both Zylons
AAB5 D6BA     05557 LOOP036         DEC ZYLONTIMX0,X        ; Decrement Zylon timer
AAB7 1027     05558                 BPL SKIP085             ; Next timer if this one still counting down
              05559
AAB9 8A       05560                 TXA                     ; Prep joystick (x or y) value in -1, 0, +1
AABA 4A       05561                 LSR A                   ;
AABB A8       05562                 TAY                     ;
AABC B9C800   05563                 LDA JOYSTICKX,Y         ;
              05564
AABF A4D0     05565                 LDY SHIPVIEW            ; Skip if in Front view
AAC1 F005     05566                 BEQ SKIP081             ;
              05567
AAC3 49FF     05568                 EOR #$FF                ; Invert joystick value (when in Aft view)
AAC5 18       05569                 CLC                     ; (two's-complement)
AAC6 6901     05570                 ADC #1                  ;
              05571
AAC8 18       05572 SKIP081         CLC                     ; Add joystick value to Zylon velocity index
AAC9 75B4     05573                 ADC ZYLONVELINDX0,X     ;
AACB 1002     05574                 BPL SKIP082             ;
AACD A900     05575                 LDA #0                  ;
AACF C910     05576 SKIP082         CMP #16                 ; Limit new Zylon velocity index to 0..15 ...
AAD1 9002     05577                 BCC SKIP083             ;
AAD3 A90F     05578                 LDA #15                 ;
AAD5 95B4     05579 SKIP083         STA ZYLONVELINDX0,X     ; ...and store new Zylon velocity index
              05580
AAD7 C908     05581                 CMP #8                  ; Calc new Zylon timer value in 0, 2, ..., 14
AAD9 9002     05582                 BCC SKIP084             ;
AADB 490F     05583                 EOR #$0F                ;
AADD 0A       05584 SKIP084         ASL A                   ;
AADE 95BA     05585                 STA ZYLONTIMX0,X        ; ...and store new Zylon timer value
              05586
AAE0 CA       05587 SKIP085         DEX                     ;
AAE1 10D2     05588                 BPL LOOP036             ; Next Zylon timer
              05589
              05590 ;*** Update x and y velocity of single Zylon photon torpedo ********************
AAE3 AD8E0C   05591                 LDA PL2SHAPTYPE         ; Skip if PLAYER2 not PHOTON TORPEDO (shape type 0)
AAE6 D01B     05592                 BNE SKIP088             ;
              05593
AAE8 A462     05594                 LDY MISSIONLEVEL        ; Depending on mission level...
AAEA B985BF   05595                 LDA ZYLONHOMVELTAB,Y    ; ...pick (initially negative) Zylon torpedo velocity
              05596
AAED AEA40A   05597                 LDX PL2YPOSHI           ; If photon torpedo in upper screen half (y >= 0)...
AAF0 1002     05598                 BPL SKIP086             ; ...don't toggle velocity sign -> torpedo goes down
AAF2 297F     05599                 AND #$7F                ; ...toggle velocity sign       -> torpedo goes up
AAF4 8DCA0B   05600 SKIP086         STA PL2YVEL             ; Store new y-velocity of Zylon photon torpedo
              05601
AAF7 0980     05602                 ORA #NEG                ; Restore negative sign bit of velocity
              05603
AAF9 AE730A   05604                 LDX PL2XPOSHI           ; If photon torpedo in right screen half (x >= 0)...
AAFC 1002     05605                 BPL SKIP087             ; ...don't toggle velocity sign -> torpedo goes left
AAFE 297F     05606                 AND #$7F                ; ...toggle velocity sign       -> torpedo goes right
AB00 8D990B   05607 SKIP087         STA PL2XVEL             ; Store new x-velocity of Zylon photon torpedo
              05608
              05609 ;*** Create new meteor? ********************************************************
AB03 A576     05610 SKIP088         LDA COUNT256            ; Attempt meteor creation in 7 out of 8 game loops
AB05 2903     05611                 AND #$03                ;
AB07 F02E     05612                 BEQ SKIP092             ;
              05613
AB09 A5E6     05614 SKIP089         LDA PL2SHAPOFF          ; If PLAYER2 shape is initial try to create a meteor
AB0B F004     05615                 BEQ SKIP090             ;
              05616
AB0D A5EB     05617                 LDA PL2LIFE             ; Return if PLAYER2 alive
AB0F D025     05618                 BNE SKIP091             ;
              05619
AB11 AD0AD2   05620 SKIP090         LDA RANDOM              ; Return in 98% (252:256) (do not create meteor)
AB14 C904     05621                 CMP #4                  ;
AB16 B01E     05622                 BCS SKIP091             ;
              05623
              05624 ;*** Create new meteor! ********************************************************
AB18 A960     05625                 LDA #SHAP.METEOR        ; PLAYER2 is METEOR (shape type 6)
AB1A 8D8E0C   05626                 STA PL2SHAPTYPE         ;
AB1D A202     05627                 LDX #2                  ; Randomize position vector of meteor
AB1F 2064B7   05628                 JSR INITPOSVEC          ;
AB22 A93C     05629                 LDA #60                 ; Meteor lifetime := 60 game loops
AB24 85EB     05630                 STA PL2LIFE             ;
AB26 A988     05631                 LDA #NEG!8              ; SUMMARY:
AB28 8D680B   05632                 STA PL2ZVEL             ; x-velocity :=  0 <KM/H>
AB2B A900     05633                 LDA #0                  ; y-velocity :=  0 <KM/H>
AB2D 8D2C0C   05634                 STA PL2COLUMN           ; z-velocity := -8 <KM/H>
AB30 8D990B   05635                 STA PL2XVEL             ;
AB33 8DCA0B   05636                 STA PL2YVEL             ; PLAYER2 column number := 0 (offscreen)
AB36 60       05637 SKIP091         RTS                     ; Return
              05638
              05639 ;*** Toggle Zylon ship control *************************************************
AB37 A5A7     05640 SKIP092         LDA CTRLDZYLON          ; Toggle control to the other Zylon ship
AB39 4901     05641                 EOR #$01                ;
AB3B 85A7     05642                 STA CTRLDZYLON          ;
              05643
              05644 ;*** Create a new Zylon ship? **************************************************
AB3D AA       05645                 TAX                     ; Save index of controlled Zylon ship
AB3E B5E9     05646                 LDA PL0LIFE,X           ; Skip creating Zylon ship if its PLAYER still alive
AB40 D042     05647                 BNE SKIP094             ;
              05648
AB42 A5E9     05649                 LDA PL0LIFE             ; If both Zylon ships are not alive...
AB44 05EA     05650                 ORA PL1LIFE             ;
AB46 2901     05651                 AND #$01                ;
AB48 A490     05652                 LDY CURRSECTOR          ; ...and this an empty sector...
AB4A D9C908   05653                 CMP GCMEMMAP,Y          ;
AB4D B0BA     05654                 BCS SKIP089             ; ...attempt to create meteor and return
              05655
              05656 ;*** Create a new Zylon ship! **************************************************
AB4F A9FF     05657                 LDA #255                ; Zylon ship lifetime := 255 game loops (infinite)
AB51 95E9     05658                 STA PL0LIFE,X           ;
              05659
AB53 AD0AD2   05660                 LDA RANDOM              ; Pick a Zylon ship shape type (1 out of 8)
AB56 2907     05661                 AND #$07                ;
AB58 A8       05662                 TAY                     ;
AB59 B989BF   05663                 LDA ZYLONSHAPTAB,Y      ;
AB5C 9D8C0C   05664                 STA PL0SHAPTYPE,X       ;
              05665
AB5F A562     05666                 LDA MISSIONLEVEL        ; Init Zylon's flight pattern (0 if NOVICE mission)
AB61 F003     05667                 BEQ SKIP093             ;
AB63 B991BF   05668                 LDA ZYLONFLPATTAB,Y     ;
AB66 95A8     05669 SKIP093         STA ZYLONFLPAT0,X       ;
              05670
AB68 A901     05671                 LDA #1                  ; Zylon ship's milestone timer := 1 game loop
AB6A 95AA     05672                 STA MILESTTIM0,X        ;
              05673
AB6C 9DAD09   05674                 STA ZPOSSIGN,X          ; Put Zylon ship in front of our starship
AB6F AD0AD2   05675                 LDA RANDOM              ;
AB72 25C7     05676                 AND VICINITYMASK        ; y-coordinate (high byte) := RND(0..VICINITYMASK)
AB74 9DA20A   05677                 STA YPOSHI,X            ;
AB77 6913     05678                 ADC #19                 ; x-coordinate (high byte) := y (high byte) + 19
AB79 9D710A   05679                 STA XPOSHI,X            ;
AB7C 0971     05680                 ORA #$71                ; z-coordinate (high byte) := >= +28928 (+$71**) <KM>
AB7E 9D400A   05681                 STA ZPOSHI,X            ;
AB81 20BEB7   05682                 JSR RNDINVXY            ; Randomly invert x and y coordinate of pos vector
              05683
              05684 ;*** Set current flight pattern to attack flight pattern? **********************
AB84 BD400A   05685 SKIP094         LDA ZPOSHI,X            ; Skip if Zylon too distant (z >= +$20** <KM>)
AB87 C920     05686                 CMP #$20                ;
AB89 B011     05687                 BCS SKIP096             ;
              05688
AB8B BDAD09   05689                 LDA ZPOSSIGN,X          ; Set attack flight pattern if Zylon is behind
AB8E F008     05690                 BEQ SKIP095             ;
              05691
AB90 B5E4     05692                 LDA PL0SHAPOFF,X        ; Skip if Zylon shape initial
AB92 F008     05693                 BEQ SKIP096             ;
              05694
AB94 C929     05695                 CMP #$29                ; Skip if Zylon shape is Long-Range Scan blip
AB96 F004     05696                 BEQ SKIP096             ;
              05697
AB98 A900     05698 SKIP095         LDA #0                  ; Set attack flight pattern
AB9A 95A8     05699                 STA ZYLONFLPAT0,X       ;
              05700
              05701 ;*** Update back-attack flag and milestone velocity indices ********************
AB9C D6AA     05702 SKIP096         DEC MILESTTIM0,X        ; Skip if milestone timer still counting down
AB9E 1024     05703                 BPL SKIP099             ;
              05704
ABA0 A978     05705                 LDA #120                ; Milestone timer := 120 game loops
ABA2 95AA     05706                 STA MILESTTIM0,X        ;
              05707
ABA4 A562     05708                 LDA MISSIONLEVEL        ; Back-attack flag := 1 in 19% (48:256) of...
ABA6 AC0AD2   05709                 LDY RANDOM              ; ...WARRIOR or COMMANDER missions
ABA9 C030     05710                 CPY #48                 ; ...              := 0 otherwise
ABAB 9001     05711                 BCC SKIP097             ;
ABAD 4A       05712                 LSR A                   ;
ABAE 4A       05713 SKIP097         LSR A                   ;
ABAF 95B8     05714                 STA ISBACKATTACK0,X     ;
              05715
              05716                                         ; Loop over all 3 milestone velocity indices
ABB1 B5A8     05717                 LDA ZYLONFLPAT0,X       ; Set new milestone velocity index:
ABB3 2C0AD2   05718 LOOP037         BIT RANDOM              ; If Zylon flight pattern is...
ABB6 1002     05719                 BPL SKIP098             ; ...0 -> milestone velocity index := either 0 or 15
ABB8 490F     05720                 EOR #$0F                ; ...1 -> milestone velocity index := either 1 or 14
ABBA 95AC     05721 SKIP098         STA MILESTVELINDZ0,X    ; ...4 -> milestone velocity index := either 4 or 11
ABBC E8       05722                 INX                     ;
ABBD E8       05723                 INX                     ;
ABBE E006     05724                 CPX #6                  ;
ABC0 90F1     05725                 BCC LOOP037             ; Next Zylon milestone velocity index
              05726
              05727 ;*** Update milestone velocity indices in attack flight pattern ****************
ABC2 A6A7     05728                 LDX CTRLDZYLON          ; Reload index of controlled Zylon ship
              05729
ABC4 B5A8     05730 SKIP099         LDA ZYLONFLPAT0,X       ; Skip if not in attack flight pattern
ABC6 D032     05731                 BNE SKIP105             ;
              05732
ABC8 A4A7     05733                 LDY CTRLDZYLON          ; Reload index of controlled Zylon ship
              05734
              05735                                         ; Loop over all 3 milestone velocity indices
ABCA C031     05736 LOOP038         CPY #$31                ; Skip to handle x and y velocity index
ABCC B013     05737                 BCS SKIP101             ;
              05738                                         ; SUMMARY:
ABCE B9B800   05739                 LDA ISBACKATTACK0,Y     ; Handle z-velocity index:
ABD1 4A       05740                 LSR A                   ;
ABD2 B9400A   05741                 LDA ZPOSHI,Y            ; If Zylon attacks from front...
ABD5 B006     05742                 BCS SKIP100             ; z <  $0A00 <KM> -> mil vel index := 0  (+62 <KM/H>)
ABD7 C90A     05743                 CMP #$0A                ; z >= $0A00 <KM> -> mil vel index := 15 (-62 <KM/H>)
ABD9 900E     05744                 BCC SKIP103             ;
ABDB B004     05745                 BCS SKIP101             ; If Zylon attacks from back...
ABDD C9F5     05746 SKIP100         CMP #$F5                ; z >= $F500 <KM> -> mil vel index := 15 (-62 <KM/H>)
ABDF B004     05747                 BCS SKIP102             ; z <  $F500 <KM> -> mil vel index := 0  (+62 <KM/H>)
              05748
ABE1 B9AD09   05749 SKIP101         LDA ZPOSSIGN,Y          ; Handle x and y velocity index:
ABE4 4A       05750                 LSR A                   ;
ABE5 A90F     05751 SKIP102         LDA #15                 ; x >= 0 <KM> -> mil vel index := 15 (-62 <KM/H>)
ABE7 B002     05752                 BCS SKIP104             ; x <  0 <KM> -> mil vel index := 0  (+62 <KM/H>)
ABE9 A900     05753 SKIP103         LDA #0                  ; y >= 0 <KM> -> mil vel index := 15 (-62 <KM/H>)
ABEB 95AC     05754 SKIP104         STA MILESTVELINDZ0,X    ; y <  0 <KM> -> mil vel index := 0  (+62 <KM/H>)
              05755
ABED 18       05756                 CLC                     ; Adjust position vector component index
ABEE 98       05757                 TYA                     ;
ABEF 6931     05758                 ADC #NUMSPCOBJ.ALL      ;
ABF1 A8       05759                 TAY                     ;
              05760
ABF2 E8       05761                 INX                     ;
ABF3 E8       05762                 INX                     ;
ABF4 E006     05763                 CPX #6                  ;
ABF6 90D2     05764                 BCC LOOP038             ; Next milestone velocity index
              05765
              05766 ;*** Acceleration: Change Zylon velocity index toward milestone velocity index *
ABF8 A6A7     05767                 LDX CTRLDZYLON          ; Reload index of controlled Zylon ship
ABFA A4A7     05768 SKIP105         LDY CTRLDZYLON          ; Reload index of controlled Zylon ship
              05769
              05770                                         ; Loop over all 3 milestone velocity indices
ABFC B5B2     05771 LOOP039         LDA ZYLONVELINDZ0,X     ; Compare Zylon velocity index with milestone index
ABFE D5AC     05772                 CMP MILESTVELINDZ0,X    ;
AC00 F008     05773                 BEQ SKIP107             ; Skip if equal
AC02 B004     05774                 BCS SKIP106             ;
AC04 F6B2     05775                 INC ZYLONVELINDZ0,X     ; Increm. Zylon velocity index if < milestone index
AC06 9002     05776                 BCC SKIP107             ;
AC08 D6B2     05777 SKIP106         DEC ZYLONVELINDZ0,X     ; Decrem. Zylon velocity index if >= milestone index
              05778
AC0A 866A     05779 SKIP107         STX L.CTRLDZYLON        ; Save index of controlled Zylon ship
AC0C AA       05780                 TAX                     ;
AC0D BD99BF   05781                 LDA ZYLONVELTAB,X       ; Pick new velocity value by Zylon velocity index
AC10 A66A     05782                 LDX L.CTRLDZYLON        ; Reload index of controlled Zylon ship
AC12 99660B   05783                 STA ZVEL,Y              ; Store new velocity vector component of Zylon ship
              05784
AC15 98       05785                 TYA                     ; Next velocity vector component
AC16 18       05786                 CLC                     ;
AC17 6931     05787                 ADC #NUMSPCOBJ.ALL      ;
AC19 A8       05788                 TAY                     ;
              05789
AC1A E8       05790                 INX                     ;
AC1B E8       05791                 INX                     ;
AC1C E006     05792                 CPX #6                  ;
AC1E 90DC     05793                 BCC LOOP039             ; Next milestone velocity index
              05794
              05795 ;*** Launch Zylon photon torpedo? **********************************************
              05796
              05797 ;*** Check PLAYER2 shape and lifetime ******************************************
AC20 A6A7     05798                 LDX CTRLDZYLON          ; Reload index of controlled Zylon ship
              05799
AC22 AD8E0C   05800                 LDA PL2SHAPTYPE         ; Skip if PLAYER2 not PHOTON TORPEDO (shape type 0)
AC25 D00B     05801                 BNE SKIP109             ;
              05802
AC27 A5EB     05803                 LDA PL2LIFE             ; Return if Zylon photon torpedo still alive
AC29 D006     05804                 BNE SKIP108             ;
              05805
AC2B A5BE     05806                 LDA TORPEDODELAY        ; Count down Zylon photon torpedo delay timer...
AC2D F003     05807                 BEQ SKIP109             ; ...before launching next Zylon photon torpedo
AC2F C6BE     05808                 DEC TORPEDODELAY        ;
AC31 60       05809 SKIP108         RTS                     ; Return
              05810
              05811 ;*** Check y-coordinate of Zylon ship ******************************************
AC32 18       05812 SKIP109         CLC                     ; Return if Zylon ship's y-coordinate not...
AC33 BDA20A   05813                 LDA YPOSHI,X            ; ...in -768..+767 (-$(0300)..+$2FF) <KM>.
AC36 6902     05814                 ADC #2                  ;
AC38 C905     05815                 CMP #5                  ;
AC3A B0F5     05816                 BCS SKIP108             ;
              05817
              05818 ;*** Set Zylon photon torpedo's z-velocity *************************************
AC3C A0D0     05819                 LDY #NEG!80             ; Prep Zylon torpedo's z-velocity := -80 <KM/H>
              05820
AC3E BDAD09   05821                 LDA ZPOSSIGN,X          ; Prep Zylon ship's sign of z-coordinate
AC41 4A       05822                 LSR A                   ;
AC42 BD400A   05823                 LDA ZPOSHI,X            ; Prep Zylon ship's z-coordinate
AC45 B008     05824                 BCS SKIP110             ; Skip if Zylon ship in front...
AC47 49FF     05825                 EOR #$FF                ; ...else invert loaded Zylon ship's z-coordinate
              05826
AC49 A462     05827                 LDY MISSIONLEVEL        ; Return (no torpedo from back) if NOVICE mission
AC4B F0E4     05828                 BEQ SKIP108             ;
              05829
AC4D A050     05830                 LDY #80                 ; Preload Zylon torpedo's z-velocity := +80 <KM/H>
              05831
              05832 ;*** Is Zylon ship in range? ***************************************************
AC4F C920     05833 SKIP110         CMP #$20                ; Return if Zylon ship too far...
AC51 B0DE     05834                 BCS SKIP108             ; ... (ABS(z-coordinate) > 8192 ($20**) <KM>)
              05835
AC53 8C680B   05836                 STY PL2ZVEL             ; Store Zylon photon torpedo's z-velocity
              05837
              05838 ;*** Launch Zylon photon torpedo! **********************************************
              05839
AC56 A900     05840                 LDA #0                  ; PLAYER2 is PHOTON TORPEDO (shape type 0)
AC58 8D8E0C   05841                 STA PL2SHAPTYPE         ;
AC5B 8D2C0C   05842                 STA PL2COLUMN           ; Zylon torpedo PLAYER column number := 0 (offscreen)
AC5E A93E     05843                 LDA #62                 ;
AC60 85EB     05844                 STA PL2LIFE             ; Zylon torpedo lifetime := 62 game loops
              05845
AC62 A202     05846                 LDX #2                  ; Prep source index for position vector copy
AC64 A4A7     05847                 LDY CTRLDZYLON          ; Prep destination index for position vector copy
AC66 84BF     05848                 STY ZYLONATTACKER       ; Save Zylon ship index for tracking computer
AC68 4CAFAC   05849                 JMP COPYPOSVEC          ; Copy position vector from Zylon ship to its torpedo
              05850
              05851 ;*******************************************************************************
              05852 ;*                                                                             *
              05853 ;*                                  INITEXPL                                   *
              05854 ;*                                                                             *
              05855 ;*                            Initialize explosion                             *
              05856 ;*                                                                             *
              05857 ;*******************************************************************************
              05858
              05859 ; DESCRIPTION
              05860 ;
              05861 ; Initializes the explosion's lifetime, the explosion fragments' position and
              05862 ; velocity vectors as well as their pixel row and column numbers.
              05863 ;
              05864 ; An explosion has a lifetime of 128 game loop iterations. It consists of 32
              05865 ; explosion fragment space objects with indices 17..48. The position vector of
              05866 ; each explosion fragment is copied from the exploding PLAYER space object.
              05867 ;
              05868 ; The pixel column number of each explosion fragment is initialized to
              05869 ;
              05870 ;     PIXEL COLUMN NUMBER := PLAYER column number - 48 + RND(0..15)
              05871 ;
              05872 ; To convert PLAYER column numbers (in Player/Missile (PM) pixels) into pixel
              05873 ; column numbers, the PLAYER column number of the left PLAYFIELD border (= 48)
              05874 ; is subtracted and a random number is added.
              05875 ;
              05876 ; BUG (at $AC76): The added random number should not be in 0..15 but in 0..7
              05877 ; because the exploding PLAYER is 8 pixels wide. The PLAYER column number
              05878 ; represents the left edge of the PLAYER shape. When using a random number in
              05879 ; 0..15, half of the pixels are located off to the right of the PLAYER, outside
              05880 ; the PLAYER area. Suggested fix: Replace instruction AND #$0F with AND #$07. 
              05881 ;
              05882 ; The pixel row number of each explosion fragment is initialized to
              05883 ;
              05884 ;     PIXEL ROW NUMBER := (PLAYER row number - RND(0..15)) / 2 - 16
              05885 ;
              05886 ; BUG (at $AC88): To convert PLAYER row numbers (in PM pixels) into pixel row
              05887 ; numbers, the PLAYER row number to the top PLAYFIELD border (= 16) should be
              05888 ; subtracted first, then the division by 2 (instruction LRS A) should be applied
              05889 ; to reduce the double-line PM resolution to the single-line PLAYFIELD
              05890 ; resolution. Suggested fix: Swap instruction LRS A with SBC #16 which leads to
              05891 ; the following formula for the pixel row number:
              05892 ;
              05893 ;     PIXEL ROW NUMBER := (PLAYER row number - 16 + RND(0..15)) / 2
              05894 ;
              05895 ; Incidentally, adding a random number in 0..15 is correct. PLAYER row number
              05896 ; represents the top edge of the PLAYER shape, which is typically 16 PM pixels
              05897 ; tall when representing a close space object.
              05898 ;
              05899 ; The velocity vector of explosion fragments is set to random x, y, and z
              05900 ; velocity vector components in -7..+7 <KM/H>.
              05901 ;
              05902 ; INPUT
              05903 ;
              05904 ;   Y = PLAYER index from which the explosion originates. Used values are:
              05905 ;     0 -> Explosion of PLAYER0 (Zylon ship 0)
              05906 ;     1 -> Explosion of PLAYER1 (Zylon ship 1)
              05907 ;     2 -> Explosion of PLAYER2 (Zylon photon torpedo, starbase, or meteor)
              05908
AC6B A980     05909 INITEXPL        LDA #128                ; Explosion lifetime := 128 game loops
AC6D 8573     05910                 STA EXPLLIFE            ;
              05911
AC6F A230     05912                 LDX #NUMSPCOBJ.ALL-1    ; Max index of space objects (for explosion frags)
AC71 8679     05913                 STX MAXSPCOBJIND        ;
              05914
              05915                                         ; Loop over all explosion fragment position vectors
              05916                                         ; (index 48..17)
AC73 AD0AD2   05917 LOOP040         LDA RANDOM              ; PIXEL COLUMN NUM := PLAYER column - 48 + RND(0..15)
AC76 290F     05918                 AND #$0F                ; (!)
AC78 792A0C   05919                 ADC PL0COLUMN,Y         ;
AC7B E930     05920                 SBC #48                 ;
AC7D 9D2A0C   05921                 STA PIXELCOLUMN,X       ;
              05922
AC80 AD0AD2   05923                 LDA RANDOM              ; PIXEL ROW NUM := (PLAYER row + RND(0..15)) / 2 - 16
AC83 290F     05924                 AND #$0F                ;
AC85 79F90B   05925                 ADC PL0ROWNEW,Y         ;
AC88 4A       05926                 LSR A                   ; (!)
AC89 E910     05927                 SBC #16                 ;
AC8B 9DF90B   05928                 STA PIXELROWNEW,X       ;
              05929
AC8E 20AFAC   05930                 JSR COPYPOSVEC          ; Copy position vector of PLAYER to explosion frag
              05931
AC91 AD0AD2   05932                 LDA RANDOM              ; z-velocity := RND(-7..+7) <KM/H>
AC94 2987     05933                 AND #NEG!7              ;
AC96 9D660B   05934                 STA ZVEL,X              ;
AC99 AD0AD2   05935                 LDA RANDOM              ; x-velocity := RND(-7..+7) <KM/H>
AC9C 2987     05936                 AND #NEG!7              ;
AC9E 9D970B   05937                 STA XVEL,X              ;
ACA1 AD0AD2   05938                 LDA RANDOM              ; y-velocity := RND(-7..+7) <KM/H>
ACA4 2987     05939                 AND #NEG!7              ;
ACA6 9DC80B   05940                 STA YVEL,X              ;
              05941
ACA9 CA       05942                 DEX                     ; Next explosion fragment position vector
ACAA E010     05943                 CPX #16                 ;
ACAC D0C5     05944                 BNE LOOP040             ;
ACAE 60       05945                 RTS                     ; Return
              05946
              05947 ;*******************************************************************************
              05948 ;*                                                                             *
              05949 ;*                                 COPYPOSVEC                                  *
              05950 ;*                                                                             *
              05951 ;*                           Copy a position vector                            *
              05952 ;*                                                                             *
              05953 ;*******************************************************************************
              05954
              05955 ; DESCRIPTION
              05956 ;
              05957 ; Copies a position vector.
              05958 ;
              05959 ; Actually, this subroutine copies the z-coordinate only, then code execution
              05960 ; continues into subroutine COPYPOSXY ($ACC1) to copy the x and y coordinate.
              05961 ;
              05962 ; INPUT
              05963 ;
              05964 ;   X = Destination position vector index. Used values are: 0..48.
              05965 ;   Y = Source position vector index. Used values are: 0..48.
              05966
ACAF B9AD09   05967 COPYPOSVEC      LDA ZPOSSIGN,Y          ;
ACB2 9DAD09   05968                 STA ZPOSSIGN,X          ;
ACB5 B9400A   05969                 LDA ZPOSHI,Y            ;
ACB8 9D400A   05970                 STA ZPOSHI,X            ;
ACBB B9D30A   05971                 LDA ZPOSLO,Y            ;
ACBE 9DD30A   05972                 STA ZPOSLO,X            ;
              05973
              05974 ;*******************************************************************************
              05975 ;*                                                                             *
              05976 ;*                                  COPYPOSXY                                  *
              05977 ;*                                                                             *
              05978 ;*          Copy x and y components (coordinates) of position vector           *
              05979 ;*                                                                             *
              05980 ;*******************************************************************************
              05981
              05982 ; DESCRIPTION
              05983 ;
              05984 ; Copies the x and y components (coordinates) of a position vector.
              05985 ;
              05986 ; INPUT
              05987 ;
              05988 ;   X = Destination position vector index. Used values are: 0..48.
              05989 ;   Y = Source position vector index. Used values are: 0..48.
              05990
ACC1 B9DE09   05991 COPYPOSXY       LDA XPOSSIGN,Y          ;
ACC4 9DDE09   05992                 STA XPOSSIGN,X          ;
ACC7 B9710A   05993                 LDA XPOSHI,Y            ;
ACCA 9D710A   05994                 STA XPOSHI,X            ;
ACCD B90F0A   05995                 LDA YPOSSIGN,Y          ;
ACD0 9D0F0A   05996                 STA YPOSSIGN,X          ;
ACD3 B9A20A   05997                 LDA YPOSHI,Y            ;
ACD6 9DA20A   05998                 STA YPOSHI,X            ;
ACD9 B9040B   05999                 LDA XPOSLO,Y            ;
ACDC 9D040B   06000                 STA XPOSLO,X            ;
ACDF B9350B   06001                 LDA YPOSLO,Y            ;
ACE2 9D350B   06002                 STA YPOSLO,X            ;
ACE5 60       06003 SKIP111         RTS                     ; Return
              06004
              06005 ;*******************************************************************************
              06006 ;*                                                                             *
              06007 ;*                                   DOCKING                                   *
              06008 ;*                                                                             *
              06009 ;*      Handle docking at starbase, launch and return of transfer vessel       *
              06010 ;*                                                                             *
              06011 ;*******************************************************************************
              06012
              06013 ; DESCRIPTION
              06014 ;
              06015 ; Handles docking at a starbase, launching and returning the transfer vessel,
              06016 ; and repairing our starship's subsystems. 
              06017 ;
              06018 ; This subroutine changes, if in Front view, the PLAYER-PLAYFIELD priority such
              06019 ; that PLAYERs like the starbase appear behind the cross hairs, which are part
              06020 ; of the PLAYFIELD.
              06021 ;
              06022 ; BUG (at $ACEE): In Front view, the specific order of PLAYERs (PL0..4) and
              06023 ; PLAYFIELD colors (PF0..4) is, from front to back:
              06024 ;
              06025 ;     PL4 > PF0, PF1, PF2 > PL0 > PL1 > PL2 > PL3 > PF4 (BGR)
              06026 ;
              06027 ; This makes the starbase appear behind the cross hairs, but also behind the
              06028 ; stars, as both cross hairs and stars are part of the PLAYFIELD - a rarely
              06029 ; noticed glitch.
              06030 ;
              06031 ; Note also that, as an exception of the rule, PLAYER4 (transfer vessel) is
              06032 ; displayed before the PLAYFIELD. Thus, the transfer vessel appears in front of
              06033 ; the cross hairs!
              06034 ;
              06035 ; In Aft view, the arrangement is reversed: PLAYERs are arranged in front of the
              06036 ; PLAYFIELD. The specific order of PLAYERs (PL0..4) and PLAYFIELD colors
              06037 ; (PF0..4) is, from front to back:
              06038 ;
              06039 ;     PL0 > PL1 > PL2 > PL3 > PL4 > PF0, PF1, PF2 > PF4 (BGR)
              06040 ;
              06041 ; In this case, both the starbase and the transfer vessel appear in front of the
              06042 ; cross hairs! Suggested fix: None, technically not possible.
              06043 ;
              06044 ;
              06045 ; The starbase is tracked and the PLAYER0..2 shape types are set to STARBASE
              06046 ; RIGHT, STARBASE LEFT, and STARBASE CENTER, respectively, combining them into a
              06047 ; 3-part starbase shape. 
              06048 ;
              06049 ; If this sector is still marked as a starbase sector but no more so on the
              06050 ; Galactic Chart (if in the meantime either Zylon units have surrounded this
              06051 ; sector and destroyed the starbase or you have destroyed the starbase with a
              06052 ; photon torpedo) then the noise sound pattern SHIELD EXPLOSION is played in
              06053 ; subroutine NOISE ($AEA8) and code execution returns.
              06054 ;
              06055 ; Otherwise a minimum distance to the starbase of +32 (+$0020) <KM> is enforced
              06056 ; and the conditions for a successful docking are checked:
              06057 ;
              06058 ; DOCKING CONDITIONS
              06059 ;
              06060 ; A docking is successful if all of the following conditions are met:
              06061 ;
              06062 ; (1)  The PLAYER2 (STARBASE CENTER) column number is in 120..135. 
              06063 ;
              06064 ;      BUG (at $AD39): At first glance, the PLAYER column interval of 120..135
              06065 ;      corresponds to an almost symmetric interval of -8..+7 PM pixels relative
              06066 ;      to the horizontal center of the PLAYFIELD, at PLAYER column number 128
              06067 ;      (48 PM pixels offset to left PLAYFIELD border + 80 PM pixels to the
              06068 ;      PLAYFIELD center). This is correct only if the PLAYER column number were
              06069 ;      to designate the horizontal center of the PLAYER. However it designates
              06070 ;      its left edge! Thus the used pixel column number range 120..135 creates
              06071 ;      an asymmetric horizontal docking position: A docking is successful if the
              06072 ;      horizontal position of the starbase shape's center is roughly -5..+10 PM
              06073 ;      pixels relative to the horizontal center of the PLAYFIELD. Suggested fix:
              06074 ;      Replace SBC #120 with SBC #117. This leads to an interval of -8..+7
              06075 ;      pixels relative to the horizontal center of the PLAYFIELD and better
              06076 ;      symmetry in the horizontal docking position.
              06077 ;
              06078 ; (2)  The PLAYER2 (STARBASE CENTER) row number is in 104..119.
              06079 ;
              06080 ;      BUG (at $AD43): The PLAYER row interval of 104..119 corresponds to an
              06081 ;      asymmetric interval of -20..-5 PM pixels relative to the vertical center
              06082 ;      of the PLAYFIELD, at pixel row number 80 or PLAYER row number 124. It
              06083 ;      lets you dock at a starbase that "sits" on top of the horizontal cross
              06084 ;      hairs but not at one that "hangs" from them. Suggested fix: Replace SBC
              06085 ;      #104 with SBC #108. This leads to an interval of -8..+7 pixels relative
              06086 ;      to the vertical center of the PLAYFIELD (assuming a PLAYER2 shape of 16
              06087 ;      pixel height, which is typical during docking) and better symmetry in the
              06088 ;      vertical docking position. 
              06089 ;
              06090 ; (3)  The starbase is in correct distance in front of our starship: The
              06091 ;      starbase's z-coordinate must be < +512 (+$02**) <KM>.
              06092 ;
              06093 ; (4)  Our starship is horizontally level with the starbase: The starbase's
              06094 ;      y-coordinate must be < +256 (+$01**) <KM>.
              06095 ;
              06096 ; (5)  Our starship is at a complete halt.
              06097 ;
              06098 ; DOCKING SUCCESSFUL
              06099 ;
              06100 ; If the conditions for a successful docking are met, the subsequent docking and
              06101 ; transfer operation can be divided in the following states, starting with state
              06102 ; NOT DOCKED:
              06103 ;
              06104 ; (1)  NOT DOCKED 
              06105 ;
              06106 ;      The docking state is set to ORBIT ESTABLISHED and the title line is
              06107 ;      updated with "ORBIT ESTABLISHED".
              06108 ;
              06109 ; (2)  ORBIT ESTABLISHED 
              06110 ;
              06111 ;      After waiting until the title line "ORBIT ESTABLISHED" has disappeared,
              06112 ;      the transfer vessel is initialized and launched: The PLAYER4 shape type
              06113 ;      is set to TRANSFER VESSEL. Its position vector is set to a position above
              06114 ;      and in front of our starship, but behind the starbase:
              06115 ;
              06116 ;          x-coordinate :=     +0..+255 (+$00**) <KM>
              06117 ;          y-coordinate :=   +256..+511 (+$01**) <KM> 
              06118 ;          z-coordinate := +4096..+4351 (+$10**) <KM>
              06119 ;
              06120 ;      Its velocity vector is set to
              06121 ;
              06122 ;          x-velocity   := +1 <KM/H> 
              06123 ;          y-velocity   := -1 <KM/H> 
              06124 ;          z-velocity   := -7 <KM/H>
              06125 ;
              06126 ;      This will move the transfer vessel from behind the starbase into a
              06127 ;      direction toward and a little to the lower right of our starship. The
              06128 ;      lifetime of the transfer vessel (and its return journey) is set to 129
              06129 ;      game loop iterations. Finally, the docking state is set to RETURN
              06130 ;      TRANSFER VESSEL.
              06131 ;
              06132 ; (3)  RETURN TRANSFER VESSEL 
              06133 ;
              06134 ;      After checking if the transfer vessel has passed behind our starship, the
              06135 ;      beeper sound pattern ACKNOWLEDGE is played in subroutine BEEP ($B3A6),
              06136 ;      the title line is updated with "TRANSFER COMPLETE", our starship's
              06137 ;      subsystems are repaired, and our starship's ENERGY readout is restored to
              06138 ;      9999 energy units. by inverting the z-velocity the velocity vector of the
              06139 ;      transfer vessel is changed to
              06140 ;
              06141 ;          x-velocity   := +1 <KM/H> 
              06142 ;          y-velocity   := -1 <KM/H> 
              06143 ;          z-velocity   := +7 <KM/H>
              06144 ;
              06145 ;      thus launching the transfer vessel on its return journey to the starbase.
              06146 ;      The docking state is set to TRANSFER COMPLETE. Finally, the screen is
              06147 ;      updated in subroutine UPDSCREEN ($B07B).
              06148 ;
              06149 ; (4)  TRANSFER COMPLETE 
              06150 ;
              06151 ;      This docking state marks the end of a successful docking and transfer
              06152 ;      operation.
              06153 ;
              06154 ; DOCKING ABORTED
              06155 ;
              06156 ; If the docking conditions above are not met and the docking state is already
              06157 ; ORBIT ESTABLISHED or RETURN TRANSFER VESSEL then the message "DOCKING ABORTED"
              06158 ; is displayed and the docking state is set to NOT DOCKED.
              06159
ACE6 A57B     06160 DOCKING         LDA ISSTARBASESECT      ; Return if not in starbase sector
ACE8 F0FB     06161                 BEQ SKIP111             ;
              06162
ACEA A5D0     06163                 LDA SHIPVIEW            ; Skip if not in Front view
ACEC D005     06164                 BNE SKIP112             ;
ACEE A914     06165                 LDA #$14                ; GTIA: Enable PLAYER4, prio: PFs > PLs > BGR (!)
ACF0 8D1BD0   06166                 STA PRIOR               ; (Cross hairs in front of PLAYERs)
              06167
ACF3 A902     06168 SKIP112         LDA #2                  ; Track starbase (PLAYER2)
ACF5 8D5C09   06169                 STA TRACKDIGIT          ;
              06170
              06171 ;** Initialize starbase shape **************************************************
ACF8 A930     06172                 LDA #SHAP.STARBASEC     ; PLAYER2 is STARBASE CENTER (shape type 3)
ACFA 8D8E0C   06173                 STA PL2SHAPTYPE         ;
ACFD A920     06174                 LDA #SHAP.STARBASEL     ; PLAYER1 is STARBASE LEFT (shape type 2)
ACFF 8D8D0C   06175                 STA PL1SHAPTYPE         ;
AD02 A940     06176                 LDA #SHAP.STARBASER     ; PLAYER0 is STARBASE RIGHT (shape type 4)
AD04 8D8C0C   06177                 STA PL0SHAPTYPE         ;
              06178
AD07 A9FF     06179                 LDA #255                ; Prep starbase lifetime := 255 game loops (infinite)
              06180
AD09 A690     06181                 LDX CURRSECTOR          ; Skip if starbase in current sector
AD0B BCC908   06182                 LDY GCMEMMAP,X          ;
AD0E 3002     06183                 BMI SKIP113             ;
              06184
AD10 A900     06185                 LDA #0                  ; Prep starbase lifetime := 0 game loops (fast death)
              06186
AD12 85E9     06187 SKIP113         STA PL0LIFE             ; PLAYER0 lifetime := either 0 or 255 game loops
AD14 85EA     06188                 STA PL1LIFE             ; PLAYER1 lifetime := either 0 or 255 game loops
AD16 85EB     06189                 STA PL2LIFE             ; PLAYER2 lifetime := either 0 or 255 game loops
AD18 857B     06190                 STA ISSTARBASESECT      ; Store starbase-in-sector flag
AD1A 300A     06191                 BMI SKIP114             ; Skip if starbase in current sector
              06192
AD1C A002     06193                 LDY #2                  ; Init explosion at PLAYER2 (STARBASE CENTER)
AD1E 206BAC   06194                 JSR INITEXPL            ;
              06195
AD21 A20A     06196                 LDX #$0A                ; Play noise sound pattern SHIELD EXPLOSION, return
AD23 4CA8AE   06197                 JMP NOISE               ;
              06198
              06199 ;*** Keep minimum distance to starbase *****************************************
AD26 AD420A   06200 SKIP114         LDA PL2ZPOSHI           ; Skip if starbase z-coordinate > +255 (+$00**) <KM>
AD29 D00A     06201                 BNE SKIP115             ;
              06202
AD2B ADD50A   06203                 LDA PL2ZPOSLO           ; Approach starbase not closer than +32 (+$0020) <KM>
AD2E C920     06204                 CMP #32                 ;
AD30 B003     06205                 BCS SKIP115             ;
AD32 EED50A   06206                 INC PL2ZPOSLO           ; ...else push starbase back
              06207
              06208 ;*** Check if in docking range *************************************************
AD35 AD2C0C   06209 SKIP115         LDA PL2COLUMN           ; Abort docking if PLAYER column number of...
AD38 38       06210                 SEC                     ; ...PLAYER2 (STARBASE CENTER) not in 120..135.
AD39 E978     06211                 SBC #120                ; (!)
AD3B C910     06212                 CMP #16                 ;
AD3D B022     06213                 BCS SKIP116             ;
              06214
AD3F ADFB0B   06215                 LDA PL2ROWNEW           ; Abort docking if PLAYER row number of...
AD42 38       06216                 SEC                     ; ...PLAYER2 (STARBASE CENTER) not in 104..119.
AD43 E968     06217                 SBC #104                ; (!)
AD45 C910     06218                 CMP #16                 ;
AD47 B018     06219                 BCS SKIP116             ;
              06220
AD49 AD420A   06221                 LDA PL2ZPOSHI           ; Abort docking if...
AD4C C902     06222                 CMP #2                  ; ... z-coordinate of starbase >= +512 (+$02**) <KM>
AD4E B011     06223                 BCS SKIP116             ;
              06224
AD50 ADAF09   06225                 LDA PL2ZPOSSIGN         ; Abort docking...
AD53 2D110A   06226                 AND PL2YPOSSIGN         ; ...if starbase not in front and upper screen half
AD56 4901     06227                 EOR #$01                ;
AD58 0570     06228                 ORA VELOCITYLO          ; ...if our starship's velocity not zero
AD5A 0DA40A   06229                 ORA PL2YPOSHI           ; ...if starbase not roughly vertically centered
AD5D 0571     06230                 ORA NEWVELOCITY         ; ...if our starship's new velocity not zero
AD5F F010     06231                 BEQ SKIP119             ; Else skip and handle docking
              06232
              06233 ;*** Docking aborted ***********************************************************
AD61 A575     06234 SKIP116         LDA DOCKSTATE           ; Skip if DOCKSTATE is NOT DOCKED, TRANSFER COMPLETE
AD63 C902     06235                 CMP #2                  ;
AD65 9005     06236                 BCC SKIP117             ;
              06237
AD67 A01F     06238                 LDY #$1F                ; Set title phrase "DOCKING ABORTED"
AD69 2023B2   06239                 JSR SETTITLE            ;
              06240
AD6C A900     06241 SKIP117         LDA #0                  ; DOCKSTATE := NOT DOCKED
AD6E 8575     06242                 STA DOCKSTATE           ;
AD70 60       06243 SKIP118         RTS                     ; Return
              06244
              06245 ;*** Docking successful, check docking state ***********************************
AD71 2475     06246 SKIP119         BIT DOCKSTATE           ; Check DOCKSTATE
AD73 700D     06247                 BVS SKIP120             ; If DOCKSTATE = ORBIT ESTABLISHED hide title line
AD75 3042     06248                 BMI SKIP122             ; If DOCKSTATE = RETURN TRANSFER VESSEL return it
AD77 A575     06249                 LDA DOCKSTATE           ;
AD79 D0F5     06250                 BNE SKIP118             ; Return if DOCKSTATE not NOT DOCKED
AD7B C675     06251                 DEC DOCKSTATE           ; DOCKSTATE := ORBIT ESTABLISHED
              06252
AD7D A01C     06253                 LDY #$1C                ; Set title phrase "ORBIT ESTABLISHED" and return
AD7F 4C23B2   06254                 JMP SETTITLE            ;
              06255
              06256 ;*** Orbit established *********************************************************
AD82 A200     06257 SKIP120         LDX #0                  ; Enqueue new, empty title phrase
AD84 8665     06258                 STX NEWTITLEPHR         ;
              06259
AD86 A4D1     06260                 LDY TITLEPHR            ; Return if "ORBIT ESTABLISHED" still displayed
AD88 D0E6     06261                 BNE SKIP118             ;
              06262
              06263 ;*** Launch transfer vessel ****************************************************
AD8A A950     06264                 LDA #SHAP.TRANSVSSL     ; PLAYER4 is TRANSFER VESSEL (shape 5)
AD8C 8D900C   06265                 STA PL4SHAPTYPE         ;
              06266
AD8F A901     06267                 LDA #1                  ; Place transfer vessel behind starbase:
AD91 8DB109   06268                 STA PL4ZPOSSIGN         ; x-coordinate :=    +0..+255  (+$00**) <KM>
AD94 8DE209   06269                 STA PL4XPOSSIGN         ; y-coordinate :=  +256..+511  (+$01**) <KM>
AD97 8D130A   06270                 STA PL4YPOSSIGN         ; z-coordinate := +4096..+4351 (+$10**) <KM>
AD9A 8DA60A   06271                 STA PL4YPOSHI           ;
AD9D 8D9B0B   06272                 STA PL4XVEL             ; Move transfer vessel toward our starship:
ADA0 A910     06273                 LDA #$10                ; x-velocity := +1 <KM/H>
ADA2 8D440A   06274                 STA PL4ZPOSHI           ; y-velocity := -1 <KM/H>
ADA5 A900     06275                 LDA #$00                ; z-velocity := -7 <KM/H>
ADA7 8D750A   06276                 STA PL4XPOSHI           ;
ADAA A987     06277                 LDA #NEG!7              ;
ADAC 8D6A0B   06278                 STA PL4ZVEL             ;
ADAF A981     06279                 LDA #NEG!1              ; DOCKSTATE := RETURN TRANSFER VESSEL
ADB1 8575     06280                 STA DOCKSTATE           ;
ADB3 8DCC0B   06281                 STA PL4YVEL             ;
ADB6 85ED     06282                 STA PL4LIFE             ; Transfer vessel lifetime := 129 game loops
ADB8 60       06283 SKIP121         RTS                     ; Return
              06284
              06285 ;*** Return transfer vessel ****************************************************
ADB9 ADB109   06286 SKIP122         LDA PL4ZPOSSIGN         ; Return if transfer vessel in front of our starship
ADBC D0FA     06287                 BNE SKIP121             ;
              06288
ADBE A20C     06289                 LDX #$0C                ; Play beeper sound pattern ACKNOWLEGDE
ADC0 20A6B3   06290                 JSR BEEP                ;
              06291
ADC3 A021     06292                 LDY #$21                ; Set title phrase "TRANSFER COMPLETE"
ADC5 2023B2   06293                 JSR SETTITLE            ;
              06294
ADC8 A205     06295                 LDX #5                  ; Repair all 6 subsystems
ADCA BD8BBB   06296 LOOP041         LDA PANELTXTTAB+73,X    ;
ADCD 9D9209   06297                 STA GCSTATPHO,X         ;
ADD0 CA       06298                 DEX                     ;
ADD1 10F7     06299                 BPL LOOP041             ;
              06300
ADD3 A989     06301                 LDA #CCS.COL2!CCS.9     ; Set starship's ENERGY readout to "9999" in COLOR2
ADD5 A203     06302                 LDX #3                  ;
ADD7 9D5509   06303 LOOP042         STA ENERGYD1,X          ;
ADDA CA       06304                 DEX                     ;
ADDB 10FA     06305                 BPL LOOP042             ;
              06306
ADDD A907     06307                 LDA #7                  ; Move transfer vessel back toward starbase:
ADDF 8D6A0B   06308                 STA PL4ZVEL             ; x-velocity := -1 <KM/H>
ADE2 A981     06309                 LDA #NEG!1              ; y-velocity := +1 <KM/H>
ADE4 8D9B0B   06310                 STA PL4XVEL             ; z-velocity := +7 <KM/H>
ADE7 A901     06311                 LDA #1                  ;
ADE9 8DCC0B   06312                 STA PL4YVEL             ;
              06313
ADEC 8575     06314                 STA DOCKSTATE           ; DOCKSTATE := TRANSFER COMPLETE
ADEE 4C7BB0   06315                 JMP UPDSCREEN           ; Update screen and return
              06316
              06317 ;*******************************************************************************
              06318 ;*                                                                             *
              06319 ;*                                   MODDLST                                   *
              06320 ;*                                                                             *
              06321 ;*                             Modify Display List                             *
              06322 ;*                                                                             *
              06323 ;*******************************************************************************
              06324
              06325 ; DESCRIPTION
              06326 ;
              06327 ; Modifies the Display List to show and hide title, headers, and the Control
              06328 ; Panel Display.
              06329 ;
              06330 ; INPUT
              06331 ;
              06332 ;   A = Number of bytes to copy into the Display List
              06333 ;   X = Offset into Display List DSPLST ($0280)
              06334 ;   Y = Offset into Display List fragment table DLSTFRAG ($BA62). If Y = $80
              06335 ;       then no bytes are copied but the specified locations of the Display List
              06336 ;       are overwritten with Display List instruction $0D (one row of
              06337 ;       GRAPHICS7).
              06338 ;
              06339 ;   Used values are:
              06340 ;
              06341 ;    A    X    Y
              06342 ;   $08  $5F  $00 -> Show Control Panel Display (bottom text window)
              06343 ;   $08  $5F  $80 -> Hide Control Panel Display (bottom text window)
              06344 ;   $07  $0F  $23 -> Show title line
              06345 ;   $07  $0F  $80 -> Hide title line
              06346 ;   $08  $02  $1B -> Show Display List header line of Front view
              06347 ;   $08  $02  $13 -> Show Display List header line of Aft view
              06348 ;   $08  $02  $0B -> Show Display List header line of Long-Range Scan view
              06349 ;   $08  $02  $08 -> Show Display List header line of Galactic Chart view
              06350
    =006A     06351 L.NUMBYTES      = $6A                   ; Number of bytes to copy
              06352
ADF1 78       06353 MODDLST         SEI                     ; Disable IRQ
ADF2 856A     06354                 STA L.NUMBYTES          ; Save number of bytes to copy
              06355
ADF4 AD0BD4   06356 LOOP043         LDA VCOUNT              ; Wait for ANTIC line counter >= 124 (PLAYFIELD...
ADF7 C97C     06357                 CMP #124                ; ...bottom) before changing the Display List
ADF9 90F9     06358                 BCC LOOP043             ;
              06359
ADFB B962BA   06360 LOOP044         LDA DLSTFRAG,Y          ; Load byte from Display List fragment table
ADFE C8       06361                 INY                     ;
ADFF 1002     06362                 BPL SKIP123             ; Skip if fragment table index < $80
AE01 A90D     06363                 LDA #$0D                ; Prep Display List instruction $0D (GRAPHICS7)
AE03 9D8002   06364 SKIP123         STA DSPLST,X            ; Store byte in Display List
AE06 E8       06365                 INX                     ;
AE07 C66A     06366                 DEC L.NUMBYTES          ;
AE09 D0F0     06367                 BNE LOOP044             ; Copy next byte
              06368
AE0B 58       06369                 CLI                     ; Enable IRQ
AE0C 60       06370                 RTS                     ; Return
              06371
              06372 ;*******************************************************************************
              06373 ;*                                                                             *
              06374 ;*                                CLRPLAYFIELD                                 *
              06375 ;*                                                                             *
              06376 ;*                           Clear PLAYFIELD memory                            *
              06377 ;*                                                                             *
              06378 ;*******************************************************************************
              06379
              06380 ; DESCRIPTION
              06381 ;
              06382 ; Clears PLAYFIELD memory from $1000 to $1FFF.
              06383 ;
              06384 ; This subroutine sets the start address of the memory to be cleared then code
              06385 ; execution continues into subroutine CLRMEM ($AE0F) where the memory is
              06386 ; actually cleared.
              06387
AE0D A910     06388 CLRPLAYFIELD    LDA #$10
              06389
              06390 ;*******************************************************************************
              06391 ;*                                                                             *
              06392 ;*                                   CLRMEM                                    *
              06393 ;*                                                                             *
              06394 ;*                                Clear memory                                 *
              06395 ;*                                                                             *
              06396 ;*******************************************************************************
              06397
              06398 ; DESCRIPTION
              06399 ;
              06400 ; Clears memory from a given start address to memory address $1FFF. This
              06401 ; subroutine is called in the following situations:
              06402 ;
              06403 ; (1)  In routine INITCOLD ($A14A) at the beginning of the game to initialize
              06404 ;      the game's variables 
              06405 ;
              06406 ; (2)  In subroutine CLRPLAYFIELD ($AE0D) to clear PLAYFIELD memory.
              06407 ;
              06408 ; As a side effect this subroutine also clears the saved number of space objects
              06409 ; and the lock-on flag.
              06410 ;
              06411 ; INPUT
              06412 ;
              06413 ;   A = Start address (high byte) of memory to be cleared. Used values are:
              06414 ;     $02 -> Clear memory $0200..$1FFF during game initialization
              06415 ;     $10 -> Clear PLAYFIELD memory $1000..$1FFF
              06416
AE0F 8569     06417 CLRMEM          STA MEMPTR+1            ; Store start address (high byte) to be cleared
AE11 A900     06418                 LDA #0                  ; Store start address (low byte) to be cleared
AE13 A8       06419                 TAY                     ;
AE14 8568     06420                 STA MEMPTR              ;
              06421
AE16 85A3     06422                 STA ISINLOCKON          ; Clear lock-on flag
AE18 857A     06423                 STA OLDMAXSPCOBJIND     ; Clear saved number of space objects
              06424
AE1A 9168     06425 LOOP045         STA (MEMPTR),Y          ; Clear memory location
AE1C C8       06426                 INY                     ;
AE1D D0FB     06427                 BNE LOOP045             ;
              06428
AE1F E669     06429                 INC MEMPTR+1            ; Next page (= 256-byte block)
AE21 A469     06430                 LDY MEMPTR+1            ;
AE23 C020     06431                 CPY #$20                ;
AE25 A8       06432                 TAY                     ;
AE26 90F2     06433                 BCC LOOP045             ; Loop until memory address $2000 reached
AE28 60       06434                 RTS                     ; Return
              06435
              06436 ;*******************************************************************************
              06437 ;*                                                                             *
              06438 ;*                                   TRIGGER                                   *
              06439 ;*                                                                             *
              06440 ;*                           Handle joystick trigger                           *
              06441 ;*                                                                             *
              06442 ;*******************************************************************************
              06443
              06444 ; DESCRIPTION
              06445 ;
              06446 ; This subroutine handles the joystick trigger and launches one of our
              06447 ; starship's photon torpedo. If a target is in full lock-on then a second photon
              06448 ; torpedo is prepared for automatic launch in the next game loop iteration.
              06449 ;
              06450 ; DETAILS
              06451 ;
              06452 ; If the trigger is pressed then reset the idle counter and, if not in
              06453 ; hyperwarp, launch a photon torpedo with the following steps:
              06454 ;
              06455 ; (1)  If the trigger was pressed in this game loop iteration, a photon torpedo
              06456 ;      will be launched if a previously launched photon torpedo is already under
              06457 ;      way for at least 255 - 232 = 23 game loop iterations. This avoids firing
              06458 ;      photon torpedoes too rapidly. 
              06459 ;
              06460 ; (2)  Start tracking a space object. If it is in full lock-on, set up the
              06461 ;      lock-on timer, activate photon torpedo tracking, and tweak the last saved
              06462 ;      trigger state such that our other photon torpedo (if available) is
              06463 ;      launched automatically in the next game loop iteration.
              06464 ;
              06465 ; (3)  If the Photon Torpedoes are destroyed, do nothing.
              06466 ;
              06467 ; (4)  If the Photon Torpedoes are damaged, launch a photon torpedo from the
              06468 ;      same barrel than the previous one. 
              06469 ;
              06470 ; (5)  If the Photon Torpedoes are not damaged, launch a photon torpedo from the
              06471 ;      other barrel. 
              06472 ;
              06473 ; (6)  Set the lifetime of our starship's photon torpedo to infinite, set the
              06474 ;      PLAYER shape to PHOTON TORPEDO. 
              06475 ;
              06476 ; (7)  Initialize the position vector of our starship's photon torpedo to:
              06477 ;
              06478 ;          x-coordinate := +256 (+$0100) <KM> (Right barrel)
              06479 ;                          -256 (-$FF00) <KM> (Left barrel)
              06480 ;          y-coordinate := -256 (-$FF00) <KM>
              06481 ;          z-coordinate :=   +1 (+$0001) <KM>
              06482 ;
              06483 ; (8)  Initialize the velocity vector of our starship's photon torpedo to:
              06484 ;
              06485 ;          x-velocity   :=   +0 <KM/H>
              06486 ;          y-velocity   :=   +0 <KM/H>
              06487 ;          z-velocity   := +102 <KM/H> (All views but Aft view)
              06488 ;                          -102 <KM/H> (Aft view)
              06489 ;
              06490 ; (9)  Subtract 10 energy units for launching our starship's photon torpedo.
              06491 ;
              06492 ; (10) Play the noise sound pattern PHOTON TORPEDO LAUNCHED by continuing code
              06493 ;      execution into subroutine NOISE ($AEA8).
              06494
AE29 A584     06495 TRIGGER         LDA OLDTRIG0            ; Prep last trigger state
              06496
AE2B AC10D0   06497                 LDY TRIG0               ; Copy current trigger state
AE2E 8484     06498                 STY OLDTRIG0            ;
AE30 D00E     06499                 BNE SKIP124             ; Return if trigger currently not pressed
              06500
AE32 8466     06501                 STY IDLECNTHI           ; Reset idle counter
              06502
AE34 A6C0     06503                 LDX WARPSTATE           ; Return if hyperwarp engaged
AE36 D008     06504                 BNE SKIP124             ;
              06505
AE38 A687     06506                 LDX BARRELNR            ; Prep barrel number (0 -> left, 1 -> right)
              06507
AE3A C901     06508                 CMP #1                  ; If trigger is newly pressed -> handle tracking...
AE3C F003     06509                 BEQ SKIP125             ; ...and launch our starship's photon torpedo...
AE3E B018     06510                 BCS SKIP127             ; ...else launch our starship's photon torpedo only
AE40 60       06511 SKIP124         RTS                     ; Return
              06512
              06513 ;*** Set up our starship's photon torpedo tracking *****************************
AE41 B5EC     06514 SKIP125         LDA PL3LIFE,X           ; Return if torpedo's lifetime >= 232 game loops
AE43 C9E8     06515                 CMP #232                ;
AE45 B0F9     06516                 BCS SKIP124             ;
              06517
AE47 AC5C09   06518                 LDY TRACKDIGIT          ; Store index of tracked space object
AE4A 8489     06519                 STY PLTRACKED           ;
              06520
AE4C A90C     06521                 LDA #12                 ; Prep lock-on lifetime := 12 game loops
AE4E A4A3     06522                 LDY ISINLOCKON          ; If target is in full lock-on...
AE50 8486     06523                 STY ISTRACKING          ; ...activate photon torpedo tracking
              06524
AE52 F002     06525                 BEQ SKIP126             ; Skip if target not in full lock-on
AE54 A900     06526                 LDA #0                  ; Prep lock-on lifetime := 0 game loops
AE56 8588     06527 SKIP126         STA LOCKONLIFE          ; Store lock-on lifetime (either 0 or 12 game loops)
              06528
              06529 ;*** Launch our starship's photon torpedo **************************************
AE58 8484     06530 SKIP127         STY OLDTRIG0            ; Update last trigger state
AE5A 2C9209   06531                 BIT GCSTATPHO           ; Return if Photon Torpedoes are destroyed
AE5D 70E1     06532                 BVS SKIP124             ;
              06533
AE5F 3005     06534                 BMI SKIP128             ; If Photon Torpedoes damaged launch from same barrel
AE61 8A       06535                 TXA                     ; ...else switch barrel from which to launch torpedo
AE62 4901     06536                 EOR #$01                ;
AE64 8587     06537                 STA BARRELNR            ;
              06538
AE66 8A       06539 SKIP128         TXA                     ; SUMMARY: Our starship's photon torpedo's...
AE67 9DE109   06540                 STA PL3XPOSSIGN,X       ; x-coordinate := +256 (+$0100) <KM> (right barrel)
AE6A BD73BF   06541                 LDA BARRELXTAB,X        ; x-coordinate := -256 (-$FF00) <KM> (left barrel)
AE6D 9D740A   06542                 STA PL3XPOSHI,X         ; y-coordinate := -256 (-$FF00) <KM>
AE70 A9FF     06543                 LDA #255                ; z-coordinate :=   +1 (+$0001) <KM>
AE72 95EC     06544                 STA PL3LIFE,X           ; ...lifetime := 255 game loops
AE74 9DA50A   06545                 STA PL3YPOSHI,X         ;
AE77 A900     06546                 LDA #0                  ;
AE79 9D8F0C   06547                 STA PL3SHAPTYPE,X       ; PLAYER3 or PLAYER4 is PHOTON TORPEDO (shape type 0)
AE7C 9D430A   06548                 STA PL3ZPOSHI,X         ;
AE7F 9D070B   06549                 STA PL3XPOSLO,X         ;
AE82 9D120A   06550                 STA PL3YPOSSIGN,X       ;
AE85 9D380B   06551                 STA PL3YPOSLO,X         ;
AE88 A901     06552                 LDA #1                  ;
AE8A 9DB009   06553                 STA PL3ZPOSSIGN,X       ;
AE8D 9DD60A   06554                 STA PL3ZPOSLO,X         ;
              06555
AE90 A5D0     06556                 LDA SHIPVIEW            ; SUMMARY: Our starship's photon torpedo's...
AE92 4A       06557                 LSR A                   ; x-velocity :=   +0 <KM/H>
AE93 6A       06558                 ROR A                   ; y-velocity :=   +0 <KM/H>
AE94 0966     06559                 ORA #102                ; z-velocity := +102 <KM/H> (Other views)
AE96 9D690B   06560                 STA PL3ZVEL,X           ; z-velocity := -102 <KM/H> (Aft view)
AE99 A900     06561                 LDA #0                  ;
AE9B 9D9A0B   06562                 STA PL3XVEL,X           ;
AE9E 9DCB0B   06563                 STA PL3YVEL,X           ;
              06564
AEA1 A202     06565                 LDX #2                  ; ENERGY := ENERGY - 10 for launching photon torpedo
AEA3 206FB8   06566                 JSR DECENERGY           ;
              06567
AEA6 A200     06568                 LDX #$00                ; Play noise sound pattern PHOTON TORPEDO LAUNCHED
              06569
              06570 ;*******************************************************************************
              06571 ;*                                                                             *
              06572 ;*                                    NOISE                                    *
              06573 ;*                                                                             *
              06574 ;*                          Copy noise sound pattern                           *
              06575 ;*                                                                             *
              06576 ;*******************************************************************************
              06577
              06578 ; DESCRIPTION
              06579 ;
              06580 ; Copies a 10-byte noise sound pattern from table NOISEPATTAB ($BF20). The first
              06581 ; 8 bytes are copied to the noise sound pattern area NOISETORPTIM
              06582 ; ($DA)..NOISELIFE ($E1), the remaining 2 bytes are copied to audio registers
              06583 ; AUDCTL ($D208) and AUDF3 ($D204). The noise sound pattern is automatically
              06584 ; played in subroutine SOUND ($B2AB).
              06585 ;
              06586 ; NOTE: The first 8 bytes of each pattern in table NOISEPATTAB ($BF20) are
              06587 ; copied in reverse order from memory. See subroutine SOUND ($B2AB) for details
              06588 ; on the noise sound patterns stored in NOISEPATTAB ($BF20).
              06589 ;
              06590 ; Playing a SHIELD EXPLOSION or ZYLON EXPLOSION noise sound pattern overrides a
              06591 ; currently playing PHOTON TORPEDO LAUNCHED noise sound pattern.
              06592 ;
              06593 ; Playing a PHOTON TORPEDO LAUNCHED noise sound pattern overrides a currently
              06594 ; playing PHOTON TORPEDO LAUNCHED noise sound pattern if the latter has < 24
              06595 ; TICKs to play.
              06596 ;
              06597 ; INPUT
              06598 ;
              06599 ;   X = Offset into table NOISEPATTAB ($BF20) to index noise sound patterns.
              06600 ;       Used values are:
              06601 ;     $00 -> PHOTON TORPEDO LAUNCHED
              06602 ;     $0A -> SHIELD EXPLOSION (either our starship or a starbase explodes)
              06603 ;     $14 -> ZYLON EXPLOSION
              06604
AEA8 8A       06605 NOISE           TXA                     ; Skip if SHIELD EXPLOSION or ZYLON EXPLOSION playing
AEA9 D006     06606                 BNE SKIP129             ;
              06607
AEAB A5E1     06608                 LDA NOISELIFE           ; Return if PHOTON TORPEDO LAUNCHED noise sound pat.
AEAD C918     06609                 CMP #24                 ; ...playing for yet more than 24 TICKs
AEAF B018     06610                 BCS SKIP130             ;
              06611
AEB1 A007     06612 SKIP129         LDY #7                  ; Copy noise sound pattern (in reverse order)
AEB3 BD20BF   06613 LOOP046         LDA NOISEPATTAB,X       ;
AEB6 99DA00   06614                 STA NOISETORPTIM,Y      ;
AEB9 E8       06615                 INX                     ;
AEBA 88       06616                 DEY                     ;
AEBB 10F6     06617                 BPL LOOP046             ;
              06618
AEBD BD20BF   06619                 LDA NOISEPATTAB,X       ; Copy AUDCTL from noise sound pattern table
AEC0 8D08D2   06620                 STA AUDCTL              ;
AEC3 BD21BF   06621                 LDA NOISEPATTAB+1,X     ; Copy AUDF3 from noise sound pattern table
AEC6 8D04D2   06622                 STA AUDF3               ;
              06623
AEC9 60       06624 SKIP130         RTS                     ; Return
              06625
              06626 ;*******************************************************************************
              06627 ;*                                                                             *
              06628 ;*                                  HOMINGVEL                                  *
              06629 ;*                                                                             *
              06630 ;*      Calculate homing velocity of our starship's photon torpedo 0 or 1      *
              06631 ;*                                                                             *
              06632 ;*******************************************************************************
              06633
              06634 ; DESCRIPTION
              06635 ;
              06636 ; Calculates the x (or y) velocity vector component of our starship's photon
              06637 ; torpedo 0 or 1 when it is tracking (homing in on) a target space object.
              06638 ;
              06639 ; Our starship's photon torpedo's x (or y) velocity vector component depends on
              06640 ; the PLAYER column (or row) number difference between the target PLAYER and our
              06641 ; starship's photon torpedo PLAYER in Player/Missile (PM) pixels. This
              06642 ; difference is used as an index to pick the new x (or y) velocity vector
              06643 ; component of our starship's photon torpedo from table HOMVELTAB ($BFC9):
              06644 ;
              06645 ; +---------------+--------------+
              06646 ; | Difference in | New Velocity |
              06647 ; |   PM Pixels   |  Component   |
              06648 ; +---------------+--------------+
              06649 ; |    >= +7      |   -64 <KM/H> |
              06650 ; |       +6      |   -56 <KM/H> |
              06651 ; |       +5      |   -48 <KM/H> |    
              06652 ; |       +4      |   -40 <KM/H> |
              06653 ; |       +3      |   -24 <KM/H> |
              06654 ; |       +2      |   -16 <KM/H> |    
              06655 ; |       +1      |    -8 <KM/H> |
              06656 ; |        0      |     0 <KM/H> |
              06657 ; |       -1      |    +8 <KM/H> |    
              06658 ; |       -2      |   +16 <KM/H> |
              06659 ; |       -3      |   +24 <KM/H> |
              06660 ; |       -4      |   +40 <KM/H> |    
              06661 ; |       -5      |   +48 <KM/H> |
              06662 ; |       -6      |   +56 <KM/H> |    
              06663 ; |    <= -7      |   +64 <KM/H> |
              06664 ; +---------------+--------------+      
              06665 ;
              06666 ; INPUT
              06667 ;
              06668 ;   A     = PLAYER column (or row) number difference between the target PLAYER
              06669 ;           and our starship's photon torpedo PLAYER in Player/Missile pixels
              06670 ;
              06671 ;   CARRY = Sign of the PLAYER column (or row) number difference. Used values
              06672 ;           are:
              06673 ;     0 -> Negative difference (target PLAYER column (or row) number < our
              06674 ;          starship's photon torpedo PLAYER column (or row) number
              06675 ;     1 -> Positive difference (target PLAYER column (or row) number >= our
              06676 ;          starship's photon torpedo PLAYER column (or row) number
              06677 ;
              06678 ; OUTPUT
              06679 ;
              06680 ;   A = New velocity vector component of our starship's photon torpedo in <KM/H>
              06681
    =006A     06682 L.VELSIGN       = $6A                   ; Saves velocity sign
              06683
AECA A080     06684 HOMINGVEL       LDY #NEG                ; Preload negative velocity sign
AECC B004     06685                 BCS SKIP131             ; Skip if difference is positive
              06686
AECE 49FF     06687                 EOR #$FF                ; Invert to get absolute value of difference
AED0 A000     06688                 LDY #0                  ; Preload positive velocity sign
              06689
AED2 846A     06690 SKIP131         STY L.VELSIGN           ; Save velocity sign
AED4 C908     06691                 CMP #8                  ;
AED6 9002     06692                 BCC SKIP132             ;
AED8 A907     06693                 LDA #7                  ; Limit difference to 0..7
AEDA A8       06694 SKIP132         TAY                     ;
AEDB A56A     06695                 LDA L.VELSIGN           ; Reload velocity sign
AEDD 19C9BF   06696                 ORA HOMVELTAB,Y         ; Combine with homing velocity from table
AEE0 60       06697                 RTS                     ; Return
              06698
              06699 ;*******************************************************************************
              06700 ;*                                                                             *
              06701 ;*                                   DAMAGE                                    *
              06702 ;*                                                                             *
              06703 ;*             Damage or destroy one of our starship's subsystems              *
              06704 ;*                                                                             *
              06705 ;*******************************************************************************
              06706
              06707 ; DESCRIPTION
              06708 ;
              06709 ; Damages or destroys one of our starship's subsystems. There are 6 subsystems:
              06710 ;
              06711 ; (1)  Photon Torpedoes
              06712 ; (2)  Engines
              06713 ; (3)  Shields
              06714 ; (4)  Attack Computer
              06715 ; (5)  Long-Range Scan
              06716 ; (6)  Subspace Radio
              06717 ;
              06718 ; Their status is stored and displayed in the Galactic Chart Panel Display by
              06719 ; the colored letters PESCLR. The color of each letter represents the
              06720 ; subsystem's status:
              06721 ;
              06722 ; +---------------+------------------+
              06723 ; | Letter Color  | Subsystem Status |
              06724 ; +---------------+------------------+
              06725 ; | {LIGHT GREEN} | OK               |
              06726 ; | {CORN YELLOW} | Damaged          |
              06727 ; | {PINK}        | Destroyed        |
              06728 ; +---------------+------------------+
              06729 ;
              06730 ; This subroutine first makes sure that we are not in demo mode. Then it picks a
              06731 ; random value in 0..255 and the damage probability value. The latter value
              06732 ; depends on the mission level and is picked from table DAMAGEPROBTAB ($BF10):
              06733 ;
              06734 ; +-----------+-------------------+---------------+
              06735 ; |  Mission  |       Damage      |    Damage     |
              06736 ; |   Level   | Probability Value |  Probability  |
              06737 ; +-----------+-------------------+---------------+
              06738 ; | NOVICE    |          0        |  0% (  0:256) | 
              06739 ; | PILOT     |         80        | 31% ( 80:256) |
              06740 ; | WARRIOR   |        180        | 70% (180:256) |
              06741 ; | COMMANDER |        254        | 99% (254:256) |
              06742 ; +-----------+-------------------+---------------+
              06743 ;
              06744 ; If the random number is lower than the damage probability value, a randomly
              06745 ; picked subsystem is about to get damaged (or destroyed). There is a built-in
              06746 ; upfront probability of 25% (2:8) that no subsystem gets harmed.
              06747 ;
              06748 ; If the picked subsystem is already destroyed then another subsystem is picked.
              06749 ;
              06750 ; Then the title phrase offset is picked from table DAMAGEPHRTAB ($BF14) to
              06751 ; display the damaged subsystem in the title line. Next, color bits are picked
              06752 ; that indicate a damaged system.
              06753 ;
              06754 ; If the Zylon photon torpedo's lifetime >= 30 game loop iterations the
              06755 ; subsystem will not only be damaged but destroyed.
              06756 ;
              06757 ; NOTE: The Zylon photon torpedo lifetime decreases from 62 to 0 game loop
              06758 ; iterations. With a remaining lifetime >= 30 game loop iterations it is
              06759 ; considered strong enough to destroy one of our starship's subsystems. There
              06760 ; are two exceptions to this rule: If the Attack Computer was picked to be
              06761 ; destroyed it will be damaged only - not destroyed - if the Long-Range Scan has
              06762 ; been already destroyed, and vice versa.
              06763 ;
              06764 ; Then the title phrase offset from table DESTROYPHRTAB ($BF1A) is picked to
              06765 ; display the destroyed subsystem in the title line. Next, color bits are picked
              06766 ; that indicate a destroyed system.
              06767 ;
              06768 ; The color of the subsystem's status letter is adjusted in the Galactic Chart
              06769 ; Panel Display. Next, the title phrase describing the subsystem's status is
              06770 ; enqueued for display in the title line. If the Attack Computer has been
              06771 ; destroyed it is switched off and the PLAYFIELD is cleared. The title line is
              06772 ; updated with the "DAMAGE CONTROL" message. Finally, the beeper sound pattern
              06773 ; DAMAGE REPORT is played in subroutine BEEP ($B3A6).
              06774
AEE1 2464     06775 DAMAGE          BIT ISDEMOMODE          ; Return if in demo mode
AEE3 3057     06776                 BMI SKIP137             ;
              06777
              06778 ;*** Damage some subsystem *****************************************************
AEE5 A662     06779                 LDX MISSIONLEVEL        ; Prep mission level
AEE7 AD0AD2   06780 LOOP047         LDA RANDOM              ; Return if random number >= damage probability
AEEA DD10BF   06781                 CMP DAMAGEPROBTAB,X     ; ...(the latter depends on mission level)
AEED B04D     06782                 BCS SKIP137             ;
              06783
AEEF 2907     06784                 AND #$07                ; Randomly pick 1 of 6 subsystems
AEF1 C906     06785                 CMP #6                  ; Return if no subsystem picked
AEF3 B047     06786                 BCS SKIP137             ;
              06787
AEF5 AA       06788                 TAX                     ;
AEF6 BD9209   06789                 LDA GCSTATPHO,X         ; Get picked subsystem status letter
AEF9 0A       06790                 ASL A                   ; Check bit B6 (= destroyed) of letter code
AEFA 30EB     06791                 BMI LOOP047             ; Try again if subsystem already destroyed
              06792
AEFC A5EB     06793                 LDA PL2LIFE             ; Load Zylon photon torpedo lifetime...
AEFE C91E     06794                 CMP #30                 ; ...and compare it to 30 game loops
              06795
AF00 A980     06796                 LDA #CCS.COL2           ; Preload COLOR2 text color bits (= damaged status)
AF02 BC14BF   06797                 LDY DAMAGEPHRTAB,X      ; Preload title phrase offset of damaged subsystem
              06798
AF05 9017     06799                 BCC SKIP135             ; Skip if Zylon torpedo lifetime < 30 game loops
              06800
AF07 E003     06801                 CPX #3                  ; Skip if selected subsystem not Attack Computer
AF09 D005     06802                 BNE SKIP133             ;
AF0B 2C9609   06803                 BIT GCSTATLRS           ; Skip if Long-Range Scan already destroyed
AF0E 700E     06804                 BVS SKIP135             ;
AF10 E004     06805 SKIP133         CPX #4                  ; Skip if selected subsystem is not Long-Range Scan
AF12 D005     06806                 BNE SKIP134             ;
AF14 2C9509   06807                 BIT GCSTATCOM           ; Skip if Attack Computer already destroyed
AF17 7005     06808                 BVS SKIP135             ;
              06809
AF19 A9C0     06810 SKIP134         LDA #CCS.COL3           ; Preload COLOR3 text color bits (= destroyed status)
AF1B BC1ABF   06811                 LDY DESTROYPHRTAB,X     ; Preload title phrase offset of destroyed subsystem
              06812
AF1E 1D9209   06813 SKIP135         ORA GCSTATPHO,X         ; Combine status letter with new color
AF21 9D9209   06814                 STA GCSTATPHO,X         ;
AF24 8465     06815                 STY NEWTITLEPHR         ; Enqueue damage status title phrase
AF26 2C9509   06816                 BIT GCSTATCOM           ; Skip if Attack Computer OK or damaged
AF29 5007     06817                 BVC SKIP136             ;
              06818
AF2B A900     06819                 LDA #0                  ; Switch Attack Computer off
AF2D 857E     06820                 STA DRAINATTCOMP        ;
AF2F 200DAE   06821                 JSR CLRPLAYFIELD        ; Clear PLAYFIELD
              06822
AF32 A052     06823 SKIP136         LDY #$52                ; Set title phrase "DAMAGE CONTROL..."
AF34 2023B2   06824                 JSR SETTITLE            ;
              06825
AF37 A212     06826                 LDX #$12                ; Play beeper sound pattern DAMAGE REPORT
AF39 20A6B3   06827                 JSR BEEP                ;
              06828
AF3C 60       06829 SKIP137         RTS                     ; Return
              06830
              06831 ;*******************************************************************************
              06832 ;*                                                                             *
              06833 ;*                                  COLLISION                                  *
              06834 ;*                                                                             *
              06835 ;*            Detect a collision of our starship's photon torpedoes            *
              06836 ;*                                                                             *
              06837 ;*******************************************************************************
              06838
              06839 ; DESCRIPTION
              06840 ;
              06841 ; Both of our starship's photon torpedoes are checked if they have collided with
              06842 ; a space object represented by PLAYER0..2, such as a Zylon ship, a Zylon photon
              06843 ; torpedo, a starbase, or a meteor. 
              06844 ;
              06845 ; For quick lookup, the following table lists the PLAYERs and what space objects
              06846 ; they represent:
              06847 ;
              06848 ; +--------+--------------------------------------------------+
              06849 ; | PLAYER |                   Represents                     |
              06850 ; +--------+--------------------------------------------------+
              06851 ; |   0    | Zylon ship 0, Starbase Left                      |
              06852 ; |   1    | Zylon ship 1, Starbase Right                     |
              06853 ; |   2    | Zylon photon torpedo, Starbase Center, Meteor    | 
              06854 ; |   3    | Our starship's photon torpedo 0                  |
              06855 ; |   4    | Our starship's photon torpedo 1, Transfer Vessel |
              06856 ; +--------+--------------------------------------------------+
              06857 ;
              06858 ; NOTE: Only space objects represented by PLAYER0..2 are checked for collisions.
              06859 ; The transfer vessel of the starbase, represented by PLAYER4, is not checked
              06860 ; and therefore cannot be destroyed by one of our starship's photon torpedoes.
              06861 ;
              06862 ; This subroutine first checks if our starship's photon torpedoes are
              06863 ; represented by alive PLAYERs with PHOTON TORPEDO shape.
              06864 ;
              06865 ; In order to detect a collision with a space object, our starship's photon
              06866 ; torpedo must compare its x, y, and z coordinates with the ones of the space
              06867 ; object.
              06868 ;
              06869 ; Instead of comparing the x and y coordinates, however, this subroutines uses a
              06870 ; much more efficient method by inspecting the Player/Missile collision
              06871 ; registers, as the x and y axis of the 3D coordinate system establish the plane
              06872 ; in which the TV screen lies. Each of our starship's photon torpedoes has its
              06873 ; own Player/Missile collision register: PL3HIT ($82) for our starship's photon
              06874 ; torpedo 0 and PL4HIT ($83) for our starship's photon torpedo 1. By inspecting
              06875 ; these registers the hit space object is determined: 
              06876 ;
              06877 ; +---------------------------------------------------+-------------------------+
              06878 ; |          Bits B2..0 of Collision Register         |        Hit PLAYER       |
              06879 ; |              (0 -> Not Hit, 1 -> Hit)             |                         |
              06880 ; +-----------------+----------------+----------------+                         |
              06881 ; |     PLAYER2     |     PLAYER1    |    PLAYER0     |                         |
              06882 ; | (Zylon torpedo) | (Zylon ship 1) | (Zylon ship 0) |                         |
              06883 ; +-----------------+----------------+----------------+-------------------------+
              06884 ; |        0        |        0       |        0       | None                    |
              06885 ; |        0        |        0       |        1       | PLAYER0 (Zylon ship 0)  |
              06886 ; |        0        |        1       |        0       | PLAYER1 (Zylon ship 1)  |
              06887 ; |        0        |        1       |        1       | PLAYER1 (Zylon ship 1)  |
              06888 ; |        1        |        0       |        0       | PLAYER2 (Zylon torpedo) |
              06889 ; |        1        |        0       |        1       | PLAYER2 (Zylon torpedo) |
              06890 ; |        1        |        1       |        0       | PLAYER1 (Zylon ship 1)  |
              06891 ; |        1        |        1       |        1       | PLAYER1 (Zylon ship 1)  |
              06892 ; +-----------------+----------------+----------------+-------------------------+
              06893 ;
              06894 ; If the lifetime of the hit space object has already expired, then the hit is
              06895 ; ignored.
              06896 ;
              06897 ; A collision along the z-axis happens if the z-coordinate of our starship's
              06898 ; photon torpedo is close enough to the z-coordinate of the space object. This
              06899 ; is determined as follows:
              06900 ;
              06901 ; The absolute value of the z-coordinate of the space object is converted into a
              06902 ; range index in 0..7. This index picks a minimum and a maximum z-coordinate
              06903 ; from tables HITMINZTAB ($BF7D) and HITMAXZTAB ($BF75). If the absolute value
              06904 ; of the z-coordinate of our starship's photon torpedo is inside this interval,
              06905 ; then our starship's photon torpedo has hit the space object. The following
              06906 ; table lists the relevant values: 
              06907 ;
              06908 ; +-----------------------+-------+--------------------------+--------------------------+
              06909 ; | ABS(z-Coordinate)     | Range | Min ABS(z-Coordinate)    | Max ABS(z-Coordinate)    |
              06910 ; | of Space Object       | Index | of Photon Torpedo to Hit | of Photon Torpedo to Hit |
              06911 ; +-----------------------+-------+--------------------------+--------------------------+
              06912 ; | <=   511 ($01**) <KM> |   0   |           0 ($00**) <KM> |      < 3328 ($0C**) <KM> |
              06913 ; | <=  1023 ($03**) <KM> |   1   |           0 ($00**) <KM> |      < 3328 ($0C**) <KM> |
              06914 ; | <=  1535 ($05**) <KM> |   2   |           0 ($00**) <KM> |      < 3328 ($0C**) <KM> |
              06915 ; | <=  2047 ($07**) <KM> |   3   |         512 ($02**) <KM> |      < 3328 ($0C**) <KM> |
              06916 ; | <=  2559 ($09**) <KM> |   4   |        1024 ($04**) <KM> |      < 3840 ($0E**) <KM> |
              06917 ; | <=  3071 ($0B**) <KM> |   5   |        1536 ($06**) <KM> |      < 3840 ($0E**) <KM> |
              06918 ; | <=  3583 ($0D**) <KM> |   6   |        2048 ($08**) <KM> |      < 3840 ($0E**) <KM> |
              06919 ; | <= 65535 ($FF**) <KM> |   7   |        3072 ($0C**) <KM> |      < 8448 ($20**) <KM> |
              06920 ; +-----------------------+-------+--------------------------+--------------------------+
              06921 ;
              06922 ; If a collision has been detected, the "age" (= initial lifetime - remaining
              06923 ; lifetime) of our starship's photon torpedo is calculated. This age is used to
              06924 ; delay playing the ZYLON EXPLOSION noise sound pattern. It is also used to
              06925 ; determine the strength of our starship's photon torpedo. Only photon torpedoes
              06926 ; of an age < 15 game loop iterations can destroy a Zylon basestar.
              06927 ;
              06928 ; Some clean-up work is done before the actual explosion: The lock-on timer, our
              06929 ; starship's photon torpedo lifetime, and the hit space object's PLAYER lifetime
              06930 ; is set to 0. 
              06931 ;
              06932 ; If a meteor or a Zylon photon torpedo have been hit, then the score is not
              06933 ; changed, skipping right to the explosion part. Otherwise, our starship's
              06934 ; photon torpedo tracking flag is cleared and the Galactic Chart Map is updated.
              06935 ; If a starbase was destroyed, then 3 points are subtracted from the score. If a
              06936 ; Zylon ship was destroyed, then 6 points are added to the score and the Zylon
              06937 ; KILL COUNTER readout of the Control Panel Display is incremented. Next, the
              06938 ; explosion is initialized in subroutine INITEXPL ($AC6B).
              06939 ;
              06940 ; NOTE: This subroutine lacks proper explosion initialization if the starbase
              06941 ; was hit. The actual explosion initialization is done in subroutine DOCKING
              06942 ; ($ACE6) when the code finds out that the starbase sector is no more marked as
              06943 ; such in the Galactic Chart.
              06944 ;
              06945 ; Finally, the Galactic Chart Map is searched for a remaining Zylon unit. If
              06946 ; none is found then the mission is complete and code execution continues into
              06947 ; subroutine GAMEOVER2 ($B121), ending the game. 
              06948
    =006B     06949 L.PLHIT         = $6B                   ; Saves PLAYER (and space object) index of hit PLAYER
    =006C     06950 L.VIEWDIR       = $6C                   ; Saves view direction. Used values are:
              06951                                         ;   $00 -> Front view
              06952                                         ;   $FF -> Aft view
              06953
AF3D A202     06954 COLLISION       LDX #2                  ; Loop over our starship's two photon torpedoes
AF3F CA       06955 LOOP048         DEX                     ;
AF40 1001     06956                 BPL SKIP138             ; Branch into loop body below
AF42 60       06957                 RTS                     ; Return
              06958
              06959 ;*** Photon torpedo sanity checks **********************************************
AF43 BD8F0C   06960 SKIP138         LDA PL3SHAPTYPE,X       ; Next photon torpedo if PLAYER not a PHOTON TORPEDO
AF46 D0F7     06961                 BNE LOOP048             ;
              06962
AF48 B5EC     06963                 LDA PL3LIFE,X           ; Next photon torpedo if PLAYER not alive
AF4A F0F3     06964                 BEQ LOOP048             ;
              06965
              06966 ;*** Check if our starship's photon torpedo has hit in x-y plane ***************
AF4C B582     06967                 LDA PL3HIT,X            ; Check Player/Missile collision register
AF4E 2907     06968                 AND #$07                ; Next torpedo if no torpedo-to-PLAYER collision
AF50 F0ED     06969                 BEQ LOOP048             ;
              06970
AF52 4A       06971                 LSR A                   ; Find out which of PLAYER0..2 was hit in PLAYFIELD
AF53 C903     06972                 CMP #3                  ;
AF55 D001     06973                 BNE SKIP139             ;
AF57 4A       06974                 LSR A                   ;
AF58 A8       06975 SKIP139         TAY                     ; Save resulting index of hit PLAYER
              06976
AF59 B9E900   06977                 LDA PL0LIFE,Y           ; Next torpedo if PLAYER0..2 (= targets) not alive
AF5C F0E1     06978                 BEQ LOOP048             ;
              06979
              06980 ;*** Has our starship's photon torpedo hit within valid z-coordinate interval? *
AF5E A5D0     06981                 LDA SHIPVIEW            ; Skip if in Front view
AF60 F002     06982                 BEQ SKIP140             ;
AF62 A9FF     06983                 LDA #$FF                ; Calculate range index...
AF64 856C     06984 SKIP140         STA L.VIEWDIR           ; Saves view direction
AF66 59400A   06985                 EOR ZPOSHI,Y            ; Calc ABS(z-coordinate (high byte)) of hit object
AF69 C910     06986                 CMP #16                 ; Limit range index to 0..7
AF6B 9002     06987                 BCC SKIP141             ;
AF6D A90F     06988                 LDA #15                 ;
AF6F 4A       06989 SKIP141         LSR A                   ;
AF70 846B     06990                 STY L.PLHIT             ; Save index of hit PLAYER
              06991
AF72 A8       06992                 TAY                     ;
AF73 A56C     06993                 LDA L.VIEWDIR           ; Reload view direction
AF75 5D430A   06994                 EOR PL3ZPOSHI,X         ; Calc ABS(z-coordinate (high byte)) of torpedo
              06995
AF78 D975BF   06996                 CMP HITMAXZTAB,Y        ; Next torpedo if torpedo >= max hit z-coordinate
AF7B B0C2     06997                 BCS LOOP048             ;
              06998
AF7D D97DBF   06999                 CMP HITMINZTAB,Y        ; Next torpedo if torpedo < min hit z-coordinate
AF80 90BD     07000                 BCC LOOP048             ;
              07001
              07002 ;*** Our starship's photon torpedo has hit within valid z-coordinate interval! *
AF82 A46B     07003                 LDY L.PLHIT             ; Reload index of hit PLAYER
AF84 38       07004                 SEC                     ; Calc "age" of photon torpedo in game loops to...
AF85 A9FF     07005                 LDA #255                ; delay playing ZYLON EXPLOSION noise sound pattern
AF87 F5EC     07006                 SBC PL3LIFE,X           ;
AF89 85E2     07007                 STA NOISEZYLONTIM       ;
              07008
AF8B C90F     07009                 CMP #15                 ; Skip if photon torpedo "age" < 15
AF8D 9005     07010                 BCC SKIP142             ;
AF8F B98C0C   07011                 LDA PL0SHAPTYPE,Y       ; CARRY := PLAYER is ZYLON BASESTAR (shape type 8)
AF92 C980     07012                 CMP #SHAP.ZBASESTAR     ; (and torpedo "age" good to destroy ZYLON BASESTAR)
              07013
              07014 ;*** Clean up our starship's photon torpedo and hit PLAYER *********************
AF94 A900     07015 SKIP142         LDA #0                  ; Lock-on lifetime := 0 game loops
AF96 8588     07016                 STA LOCKONLIFE          ;
AF98 95EC     07017                 STA PL3LIFE,X           ; Photon torpedo's lifetime := 0 game loops
AF9A B04B     07018                 BCS SKIP144             ; If CARRY set do not score, just do explosion
              07019
AF9C 99E900   07020                 STA PL0LIFE,Y           ; Hit PLAYER lifetime := 0 game loops
              07021
AF9F B98C0C   07022                 LDA PL0SHAPTYPE,Y       ; If hit PLAYER is...
AFA2 F043     07023                 BEQ SKIP144             ; ...a PHOTON TORPEDO (shape type 0)...
AFA4 C960     07024                 CMP #SHAP.METEOR        ; ...or a METEOR (shape type 6)...
AFA6 F03F     07025                 BEQ SKIP144             ; ...do not score, just do explosion
              07026
AFA8 A900     07027                 LDA #0                  ; Clear photon torpedo tracking flag
AFAA 8586     07028                 STA ISTRACKING          ;
              07029
              07030 ;*** Zylon ship (or starbase) destroyed! ***************************************
AFAC A690     07031                 LDX CURRSECTOR          ; Decrement Zylon count on Galactic Chart
AFAE DEC908   07032                 DEC GCMEMMAP,X          ;
AFB1 1013     07033                 BPL SKIP143             ; Skip if destroyed space object was Zylon ship
              07034
              07035 ;*** Starbase destroyed! *******************************************************
AFB3 A900     07036                 LDA #0                  ; Remove destroyed starbase from Galactic Chart
AFB5 9DC908   07037                 STA GCMEMMAP,X          ;
AFB8 38       07038                 SEC                     ; SCORE := SCORE - 3 for destroying starbase
AFB9 A5CB     07039                 LDA SCORE               ;
AFBB E903     07040                 SBC #3                  ;
AFBD 85CB     07041                 STA SCORE               ;
AFBF A5CC     07042                 LDA SCORE+1             ;
AFC1 E900     07043                 SBC #0                  ;
AFC3 85CC     07044                 STA SCORE+1             ;
AFC5 60       07045                 RTS                     ; Return
              07046
              07047 ;*** Zylon ship destroyed! *****************************************************
AFC6 18       07048 SKIP143         CLC                     ; SCORE := SCORE + 6 for destroying Zylon ship
AFC7 A5CB     07049                 LDA SCORE               ;
AFC9 6906     07050                 ADC #6                  ;
AFCB 85CB     07051                 STA SCORE               ;
AFCD A5CC     07052                 LDA SCORE+1             ;
AFCF 6900     07053                 ADC #0                  ;
AFD1 85CC     07054                 STA SCORE+1             ;
              07055
AFD3 A201     07056                 LDX #1                  ; Increment Zylon KILL COUNTER readout...
AFD5 FE5009   07057 LOOP049         INC KILLCNTD1,X         ; ...of Control Panel Display
AFD8 BD5009   07058                 LDA KILLCNTD1,X         ;
AFDB C94A     07059                 CMP #[CCS.COL1!CCS.9]+1 ;
AFDD 9008     07060                 BCC SKIP144             ;
AFDF A940     07061                 LDA #[CCS.COL1!CCS.0]   ;
AFE1 9D5009   07062                 STA KILLCNTD1,X         ;
AFE4 CA       07063                 DEX                     ;
AFE5 10EE     07064                 BPL LOOP049             ;
              07065
AFE7 206BAC   07066 SKIP144         JSR INITEXPL            ; Init explosion at hit PLAYER
              07067
              07068 ;*** Any Zylon ships left? *****************************************************
AFEA A27F     07069                 LDX #127                ; Scan all sectors of Galactic Chart
AFEC BDC908   07070 LOOP050         LDA GCMEMMAP,X          ;
AFEF 3002     07071                 BMI SKIP145             ;
AFF1 D00A     07072                 BNE SKIP146             ; Return if Zylon sector found
AFF3 CA       07073 SKIP145         DEX                     ;
AFF4 10F6     07074                 BPL LOOP050             ;
              07075
              07076 ;*** Game over (Mission Complete) **********************************************
AFF6 A03F     07077                 LDY #$3F                ; Set title phrase "MISSION COMPLETE"
AFF8 A200     07078                 LDX #0                  ; Set mission bonus offset
AFFA 2021B1   07079                 JSR GAMEOVER2           ; Game over
AFFD 60       07080 SKIP146         RTS                     ; Return
              07081
              07082 ;*******************************************************************************
              07083 ;*                                                                             *
              07084 ;*                                  KEYBOARD                                   *
              07085 ;*                                                                             *
              07086 ;*                            Handle Keyboard Input                            *
              07087 ;*                                                                             *
              07088 ;*******************************************************************************
              07089
              07090 ; DESCRIPTION
              07091 ;
              07092 ; If a keyboard code has been collected during a keyboard IRQ in the Immediate
              07093 ; Interrupt Request handler IRQHNDLR ($A751), the idle counter is reset and the
              07094 ; PLAYER-PLAYFIELD priority arranges the PLAYERs in front of the PLAYFIELD.
              07095 ;
              07096 ; Then, the keyboard code is compared with keyboard codes of table KEYTAB
              07097 ; ($BABE). If no match is found the "WHAT'S WRONG" message is displayed in the
              07098 ; title line and code execution returns.
              07099 ;
              07100 ; If one of the speed keys '0'..'9' has been pressed, a pending hyperwarp is
              07101 ; aborted in subroutine ABORTWARP ($A980) and code execution returns. Otherwise
              07102 ; the Engines drain rate is adjusted as well as the new velocity of our
              07103 ; starship. If the Engines are damaged, a maximum speed is possible equivalent
              07104 ; to speed key '5'.
              07105 ;
              07106 ; If one of our starship's view keys 'F' (Front), 'A' (Aft), 'G' (Galactic
              07107 ; Chart), or 'L' (Long-Range Scan) have been pressed, the Display List is
              07108 ; modified accordingly in subroutine MODDLST ($ADF1) and a new star field of 12
              07109 ; stars is created with the help of subroutine INITPOSVEC ($B764). Code
              07110 ; execution returns via subroutine UPDSCREEN ($B07B).
              07111 ;
              07112 ; If one of the 'T' (Tracking Computer), 'S' (Shields) or 'C' (Attack Computer)
              07113 ; keys have been pressed, the corresponding status bits are toggled and the
              07114 ; title line is updated with the corresponding title phrase. The beeper sound
              07115 ; pattern ACKNOWLEDGE is played in subroutine BEEP ($B3A6). The tracking letter
              07116 ; of the Control Panel Display is updated and the PLAYFIELD is cleared in
              07117 ; subroutine CLRPLAYFIELD ($AE0D). If the Attack Computer is on, the Front or
              07118 ; Aft view cross hairs are drawn, depending on the current view of our starship,
              07119 ; via subroutine DRAWLINES ($A76F).
              07120 ;
              07121 ; If the 'H' (Hyperwarp) key has been pressed then the hyperwarp is engaged. Our
              07122 ; starship's velocity is set to the maximum value, the Engines drain rate is
              07123 ; increased to the equivalent of speed key '7'. Star trails are prepared. The
              07124 ; position vector of the Hyperwarp Target Marker (PLAYER3) is set to the
              07125 ; following values:
              07126 ;
              07127 ;     x-coordinate :=   +0 (+$0000) <KM>
              07128 ;     y-coordinate := +256 (+$0100) <KM>
              07129 ;     z-coordinate :=    + (+$****) <KM> (sign only)
              07130 ;
              07131 ; The velocity vector is set to the following values:
              07132 ;
              07133 ;     x-velocity   :=  (not initialized)
              07134 ;     y-velocity   :=  (not initialized)
              07135 ;     z-velocity   :=          +0 <KM/H>
              07136 ;
              07137 ; The temporary arrival hyperwarp marker column and row numbers are saved. If we
              07138 ; are not in a NOVICE mission, the maximum veer-off velocity of the Hyperwarp
              07139 ; Target Marker during hyperwarp is picked from table VEERMASKTAB ($BED7). This
              07140 ; value depends on the selected hyperwarp energy (and thus on the distance to
              07141 ; hyperwarp). Finally, the title line displays the "HYPERWARP ENGAGED" message.
              07142 ;
              07143 ; If the 'M' (Manual target selector) key has been pressed, the tracked target
              07144 ; space object is swapped and the corresponding digit of the Control Panel
              07145 ; Display is toggled between 0 and 1.
              07146 ;
              07147 ; If the 'P' (Pause) key has been pressed, an endless loop waits until the
              07148 ; joystick is pushed.
              07149 ;
              07150 ; BUG (at $B103): The endless loop branches back one instruction too far.
              07151 ; Suggested fix: Branch to instruction LDA PORTA at $B0FE.
              07152 ;
              07153 ; If the 'INV' (Abort mission) key has been pressed, the mission is aborted by
              07154 ; setting the mission bonus offset, then displaying the "MISSION ABORTED"
              07155 ; message in the title line. Code execution continues into subroutine GAMEOVER
              07156 ; ($B10A).
              07157 ;
              07158 ; NOTE: This subroutine has two additional entry points:
              07159 ;
              07160 ; (1)  SETVIEW ($B045), which is used to enforce the Front view. It is entered
              07161 ;      from the game loop GAMELOOP ($A1F3) and subroutines INITSTART ($A15E) and
              07162 ;      DECENERGY ($B86F).
              07163 ;
              07164 ; (2)  UPDSCREEN ($B07B), which draws the cross hairs and the Attack Computer
              07165 ;      Display, and then sets the tracking letter of the Control Panel Display.
              07166 ;      It is entered from subroutine DOCKING ($ACE6).
              07167
    =006A     07168 L.KEYCODE       = $6A                   ; Saves pressed keyboard code
              07169
AFFE A5CA     07170 KEYBOARD        LDA KEYCODE             ; Return if no keyboard code collected
B000 F03E     07171                 BEQ SKIP150             ;
              07172
B002 A214     07173                 LDX #20                 ; Prep keyboard code table loop index
B004 856A     07174                 STA L.KEYCODE           ; Save keyboard code
              07175
B006 A900     07176                 LDA #0                  ; Reset idle counter
B008 8566     07177                 STA IDLECNTHI           ;
B00A 85CA     07178                 STA KEYCODE             ; Clear keyboard code
              07179
B00C A911     07180                 LDA #$11                ; GTIA: Enable PLAYER4, prio: PLs > PFs > BGR
B00E 8D1BD0   07181                 STA PRIOR               ; (PLAYERs in front of stars - and cross hairs)
              07182
              07183 ;*** Search keyboard code in lookup table **************************************
              07184
B011 BDBEBA   07185 LOOP051         LDA KEYTAB,X            ; Loop over all valid keyboard codes
B014 C56A     07186                 CMP L.KEYCODE           ;
B016 F008     07187                 BEQ SKIP147             ; Branch if matching entry found
B018 CA       07188                 DEX                     ;
B019 10F6     07189                 BPL LOOP051             ; Next keyboard code
              07190
B01B A010     07191                 LDY #$10                ; No match found...
B01D 4C23B2   07192                 JMP SETTITLE            ; ...set title phrase "WHATS WRONG?" and return
              07193
              07194 ;*** Handle '0'..'9' keyboard keys (speed) *************************************
B020 E00A     07195 SKIP147         CPX #10                 ; Skip section if keyboard code does not match
B022 B01D     07196                 BCS SKIP151             ;
              07197
B024 A5C0     07198                 LDA WARPSTATE           ; Skip if hyperwarp disengaged...
B026 F003     07199                 BEQ SKIP148             ;
B028 4C80A9   07200                 JMP ABORTWARP           ; ...else abort hyperwarp
              07201
B02B 2C9309   07202 SKIP148         BIT GCSTATENG           ; Skip if Engines are OK or destroyed
B02E 5006     07203                 BVC SKIP149             ;
B030 E006     07204                 CPX #6                  ; Allow max velocity equivalent to speed key '5'
B032 9002     07205                 BCC SKIP149             ;
B034 A205     07206                 LDX #5                  ;
              07207
B036 BDD3BA   07208 SKIP149         LDA DRAINRATETAB,X      ; Set Engines energy drain rate
B039 8580     07209                 STA DRAINENGINES        ;
B03B BDB4BA   07210                 LDA VELOCITYTAB,X       ; Set new velocity
B03E 8571     07211                 STA NEWVELOCITY         ;
B040 60       07212 SKIP150         RTS                     ; Return
              07213
              07214 ;*** Handle 'F', 'A', 'L', 'G' keyboard keys (our starship's views) ************
B041 E00E     07215 SKIP151         CPX #14                 ; Skip section if keyboard code does not match
B043 B01B     07216                 BCS SKIP152             ;
              07217
              07218 ;*** Entry to force Front view after game init and failed missions *************
B045 BD18BE   07219 SETVIEW         LDA VIEWMODETAB-10,X    ; Store our starship's view type
B048 85D0     07220                 STA SHIPVIEW            ;
              07221
B04A BC82BA   07222                 LDY DLSTFRAGOFFTAB-10,X ; Get DL fragment offset (Front, Aft, LRS, GC)
B04D A202     07223                 LDX #$02                ; Switch to corresponding view
B04F A908     07224                 LDA #$08                ;
B051 20F1AD   07225                 JSR MODDLST             ;
              07226
B054 A210     07227                 LDX #NUMSPCOBJ.NORM-1   ; Create new star field of 12 stars
B056 2064B7   07228 LOOP052         JSR INITPOSVEC          ;
B059 CA       07229                 DEX                     ;
B05A E005     07230                 CPX #NUMSPCOBJ.PL       ;
B05C B0F8     07231                 BCS LOOP052             ;
              07232
B05E 901B     07233                 BCC UPDSCREEN           ; Return via updating screen (below)
              07234
              07235 ;*** Handle 'T', 'S', 'C' keyboard keys (Tracking, Shields, Attack Computer) ***
B060 E011     07236 SKIP152         CPX #17                 ; Skip section if keyboard code does not match
B062 B035     07237                 BCS SKIP156             ;
              07238
B064 BC18BE   07239                 LDY MSGOFFTAB-14,X      ; Prep title phrase offset "... OFF"
B067 B56E     07240                 LDA ISTRACKCOMPON-14,X  ; Toggle status bits (also energy consumption values)
B069 5D1BBE   07241                 EOR MSGBITTAB-14,X      ;
B06C 956E     07242                 STA ISTRACKCOMPON-14,X  ;
B06E F003     07243                 BEQ SKIP153             ;
B070 BC1EBE   07244                 LDY MSGONTAB-14,X       ; Prep title phrase offset "... ON"
B073 2023B2   07245 SKIP153         JSR SETTITLE            ; Set title phrase to "... ON" or "... OFF" version
              07246
B076 A20C     07247                 LDX #$0C                ; Play beeper sound pattern ACKNOWLEDGE
B078 20A6B3   07248                 JSR BEEP                ;
              07249
              07250 ;*** Update PLAYFIELD (Cross hairs, Attack Computer, set tracking letter) ******
B07B A216     07251 UPDSCREEN       LDX #CCS.T              ; Get custom char 'T' (entry point TRANSFER COMPLETE)
B07D A47C     07252                 LDY ISTRACKCOMPON       ;
B07F F001     07253                 BEQ SKIP154             ; Skip if Tracking Computer is on
              07254
B081 E8       07255                 INX                     ; Get custom char 'C'
              07256
B082 8E5A09   07257 SKIP154         STX TRACKC1             ; Store tracking character in Control Panel Display
B085 200DAE   07258                 JSR CLRPLAYFIELD        ; Clear PLAYFIELD
B088 A57E     07259                 LDA DRAINATTCOMP        ; Return if Attack Computer off
B08A F0B4     07260                 BEQ SKIP150             ;
              07261
B08C A6D0     07262                 LDX SHIPVIEW            ; If Aft view   -> Draw Aft cross hairs and return
B08E F006     07263                 BEQ SKIP155             ; If Front view -> Draw Front cross hairs and ...
B090 E001     07264                 CPX #$01                ;                  ...Attack Computer and return
B092 D0AC     07265                 BNE SKIP150             ;
B094 A22A     07266                 LDX #$2A                ;
B096 4C6FA7   07267 SKIP155         JMP DRAWLINES           ;
              07268
              07269 ;*** Handle 'H' keyboard key (Hyperwarp) ***************************************
B099 E011     07270 SKIP156         CPX #17                 ; Skip if keyboard code does not match
B09B D050     07271                 BNE SKIP158             ;
              07272
              07273 ;*** Engage Hyperwarp **********************************************************
B09D A5C0     07274                 LDA WARPSTATE           ; Return if hyperwarp engaged
B09F D05A     07275                 BNE SKIP159             ;
              07276
B0A1 A97F     07277                 LDA #$7F                ; Engage hyperwarp
B0A3 85C0     07278                 STA WARPSTATE           ;
B0A5 A9FF     07279                 LDA #255                ; Set new velocity
B0A7 8571     07280                 STA NEWVELOCITY         ;
B0A9 A91E     07281                 LDA #30                 ; Set Engines energy drain rate (= speed key '7')
B0AB 8580     07282                 STA DRAINENGINES        ;
              07283
B0AD A930     07284                 LDA #NUMSPCOBJ.ALL-1    ; Set space obj index of first star of star trail
B0AF 85C3     07285                 STA TRAILIND            ;
B0B1 A900     07286                 LDA #0                  ; Clear star trail delay
B0B3 85C2     07287                 STA TRAILDELAY          ;
              07288
B0B5 8D740A   07289                 STA PL3XPOSHI           ; Init position vector and velocity vector of...
B0B8 8D070B   07290                 STA PL3XPOSLO           ; ... Hyperwarp Target Marker (PLAYER3):
B0BB 8D380B   07291                 STA PL3YPOSLO           ; x-coordinate :=   +0 (+$0000) <KM>
B0BE 8D690B   07292                 STA PL3ZVEL             ; y-coordinate := +256 (+$0100) <KM>
B0C1 A901     07293                 LDA #1                  ; z-coordinate :=    + (+$****) <KM> (sign only)
B0C3 8DB009   07294                 STA PL3ZPOSSIGN         ; z-velocity := +0 <KM/H>
B0C6 8DE109   07295                 STA PL3XPOSSIGN         ;
B0C9 8D120A   07296                 STA PL3YPOSSIGN         ;
B0CC 8DA50A   07297                 STA PL3YPOSHI           ;
              07298
B0CF A58F     07299                 LDA WARPARRVCOLUMN      ; Store temp arrival hyperwarp marker column number
B0D1 85C4     07300                 STA WARPTEMPCOLUMN      ;
B0D3 A58E     07301                 LDA WARPARRVROW         ; Store temp arrival hyperwarp marker row number
B0D5 85C5     07302                 STA WARPTEMPROW         ;
              07303
B0D7 A562     07304                 LDA MISSIONLEVEL        ; Skip if NOVICE mission
B0D9 F00B     07305                 BEQ SKIP157             ;
              07306
B0DB A591     07307                 LDA WARPENERGY          ; Bits B0..1 of hyperwarp energy index a table...
B0DD 2A       07308                 ROL A                   ; ...containing the maximum value of how much the...
B0DE 2A       07309                 ROL A                   ; ...Hyperwarp Target Marker will veer off during...
B0DF 2A       07310                 ROL A                   ; ...hyperwarp
B0E0 2903     07311                 AND #$03                ;
B0E2 A8       07312                 TAY                     ;
B0E3 B9D7BE   07313                 LDA VEERMASKTAB,Y       ;
              07314
B0E6 85C6     07315 SKIP157         STA VEERMASK            ; Store veer-off velocity limitation mask
              07316
B0E8 A011     07317                 LDY #$11                ; Set title phrase "HYPERWARP ENGAGED" and return
B0EA 4C23B2   07318                 JMP SETTITLE            ;
              07319
              07320 ;*** Handle 'M' keyboard key (Manual Target Selector) key **********************
B0ED E013     07321 SKIP158         CPX #19                 ; Skip if keyboard code does not match
B0EF B00B     07322                 BCS SKIP160             ;
              07323
B0F1 AD5C09   07324                 LDA TRACKDIGIT          ; Toggle digit of tracked space object of...
B0F4 4901     07325                 EOR #$01                ; ... Control Panel Display
B0F6 2901     07326                 AND #$01                ;
B0F8 8D5C09   07327                 STA TRACKDIGIT          ;
B0FB 60       07328 SKIP159         RTS                     ; Return
              07329
              07330 ;*** Handle 'P' keyboard key (Pause) *******************************************
B0FC D008     07331 SKIP160         BNE SKIP161             ; Skip if keyboard code does not match
              07332
B0FE AD00D3   07333                 LDA PORTA               ; Push joystick to resume action
B101 C9FF     07334                 CMP #$FF                ;
B103 F0F7     07335                 BEQ SKIP160             ; (!)
B105 60       07336                 RTS                     ; Return
              07337
              07338 ;*** Handle 'INV' keyboard key (Abort Mission) *********************************
B106 A076     07339 SKIP161         LDY #$76                ; Preload title phrase "MISSION ABORTED..."
B108 A204     07340                 LDX #$04                ; Set mission bonus offset
              07341
              07342 ;*******************************************************************************
              07343 ;*                                                                             *
              07344 ;*                                  GAMEOVER                                   *
              07345 ;*                                                                             *
              07346 ;*                              Handle game over                               *
              07347 ;*                                                                             *
              07348 ;*******************************************************************************
              07349
              07350 ; DESCRIPTION
              07351 ;
              07352 ; Handles game over, including calculating the scored rank and class.
              07353 ;
              07354 ; This subroutine has two entry points: 
              07355 ;
              07356 ; (1)  GAMEOVER ($B10A) is entered at the end of a failed mission (mission
              07357 ;      aborted, zero energy, or starship destroyed by Zylon fire), essentially
              07358 ;      shutting down our starship. Code execution continues into GAMEOVER2
              07359 ;      ($B121) below.
              07360 ;
              07361 ; (2)  GAMEOVER2 ($B121) is entered at the end of a successful mission (all
              07362 ;      Zylon ships destroyed). It puts the game in demo mode, enqueues the
              07363 ;      corresponding game over message, and calculates the scored rank and
              07364 ;      class.
              07365 ;
              07366 ;      The scored rank and class are based on the total score. This is the score
              07367 ;      accumulated during the game plus a mission bonus, which depends on the
              07368 ;      mission level and on how the mission ended (mission complete, mission
              07369 ;      aborted, or starship destroyed by Zylon fire). The mission bonus is
              07370 ;      picked from table BONUSTAB ($BEDD).
              07371 ;
              07372 ;      The scored rank index is taken from bits B8..4 of the total score and
              07373 ;      limited to values of 0..18. It indexes table RANKTAB ($BEE9) for the rank
              07374 ;      string. The rank string is displayed in subroutine SETTITLE ($B223).
              07375 ;
              07376 ;      The scored class index is taken from bits B3..0 (for rank indices 0,
              07377 ;      11..14) and computed from bits B4..1 (for rank indices 1..10 and 15..18).
              07378 ;      It takes values of 0..15. It indexes table CLASSTAB ($BEFC) for the class
              07379 ;      digit. The class digit is displayed in subroutine SETTITLE ($B223).
              07380 ;
              07381 ;      For quick lookup, the following table lists rank and class from the total
              07382 ;      score. Use the table as follows: Pick the cell with the closest value
              07383 ;      less or equal to your score then read the rank and class off the left and
              07384 ;      the top of the table, respectively.
              07385 ;
              07386 ;      For example: A score of 90 results in a ranking of "Novice Class 4", a
              07387 ;      score of 161 results in a ranking of "Pilot Class 3".
              07388 ;
              07389 ; +------------------------------+---------------------------------------------------------------+
              07390 ; |     Minimum Total Score      |                        Class Index                            |
              07391 ; |                              |  0   1   2   3   4   5   6   7   8   9  10  11  12  13  14  15|
              07392 ; +-------+----------------------+---------------------------------------------------------------+
              07393 ; | Rank  |                      |                           Class                               |
              07394 ; | Index |         Rank         |  5   5   5   4   4   4   4   3   3   3   2   2   2   1   1   1|
              07395 ; +-------+----------------------+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
              07396 ; |     0 | Galactic Cook        |  0|  1|  2|  3|  4|  5|  6|  7|  8|  9| 10| 11| 12| 13| 14| 15|
              07397 ; |     1 | Garbage Scow Captain | 16| 18| 20| 22| 24| 26| 28| 30|   |   |   |   |   |   |   |   |
              07398 ; |     2 | Garbage Scow Captain |   |   |   |   |   |   |   |   | 32| 34| 36| 38| 40| 42| 44| 46|
              07399 ; |     3 | Rookie               | 48| 50| 52| 54| 56| 58| 60| 62|   |   |   |   |   |   |   |   |
              07400 ; |     4 | Rookie               |   |   |   |   |   |   |   |   | 64| 66| 68| 70| 72| 74| 76| 78|
              07401 ; |     5 | Novice               | 80| 82| 84| 86| 88| 90| 92| 94|   |   |   |   |   |   |   |   |
              07402 ; |     6 | Novice               |   |   |   |   |   |   |   |   | 96| 98|100|102|104|106|108|110|
              07403 ; |     7 | Ensign               |112|114|116|118|120|122|124|126|   |   |   |   |   |   |   |   |
              07404 ; |     8 | Ensign               |   |   |   |   |   |   |   |   |128|130|132|134|136|138|140|142|
              07405 ; |     9 | Pilot                |144|146|148|150|152|154|156|158|   |   |   |   |   |   |   |   |
              07406 ; |    10 | Pilot                |   |   |   |   |   |   |   |   |160|162|164|166|168|170|172|174|
              07407 ; |    11 | Ace                  |176|177|178|179|180|181|182|183|184|185|186|187|188|189|190|191|
              07408 ; |    12 | Lieutenant           |192|193|194|195|196|197|198|199|200|201|202|203|204|205|206|207|
              07409 ; |    13 | Warrior              |208|209|210|211|212|213|214|215|216|217|218|219|220|221|222|223|
              07410 ; |    14 | Captain              |224|225|226|227|228|229|230|231|232|233|234|235|236|237|238|239|
              07411 ; |    15 | Commander            |240|242|244|246|248|250|252|254|   |   |   |   |   |   |   |   |
              07412 ; |    16 | Commander            |   |   |   |   |   |   |   |   |256|258|260|262|264|266|268|270|
              07413 ; |    17 | Star Commander       |272|274|276|278|280|282|284|286|   |   |   |   |   |   |   |   |
              07414 ; |    18 | Star Commander       |   |   |   |   |   |   |   |   |288|290|292|294|296|298|300|302|
              07415 ; +-------+----------------------+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
              07416 ;
              07417 ;      NOTE: This subroutine also clears the vertical and horizontal joystick
              07418 ;      directions.
              07419 ;
              07420 ; INPUT
              07421 ;
              07422 ;   X = Offset to index table BONUSTAB ($BEDD) of mission bonus values. Used
              07423 ;       values are:
              07424 ;     $00 -> Mission complete
              07425 ;     $04 -> Mission was aborted due to zero energy
              07426 ;     $08 -> Our starship was destroyed by Zylon fire
              07427 ;
              07428 ;   Y = Title phrase offset. Used values are:
              07429 ;     $3F -> "MISSION COMPLETE"
              07430 ;     $31 -> "MISSION ABORTED ZERO ENERGY"
              07431 ;     $23 -> "SHIP DESTROYED BY ZYLON FIRE"
              07432
              07433 ;*** Game over (Mission failed) ************************************************
B10A A900     07434 GAMEOVER        LDA #0                  ;
B10C 85EC     07435                 STA PL3LIFE             ; PLAYER3 lifetime := 0 game loops
B10E 85D6     07436                 STA BEEPPRIORITY        ; Mute beeper
B110 85D1     07437                 STA TITLEPHR            ; Clear title line
B112 858B     07438                 STA REDALERTLIFE        ; Red alert flash lifetime := 0 game loops
B114 8D07D2   07439                 STA AUDC4               ; Mute audio channel 4
B117 8571     07440                 STA NEWVELOCITY         ; Shut down Engines
B119 8581     07441                 STA SHIELDSCOLOR        ; Set Shields color to {BLACK}
B11B 857D     07442                 STA DRAINSHIELDS        ; Switch off Shields
B11D 85C0     07443                 STA WARPSTATE           ; Disengage hyperwarp
B11F 85C1     07444                 STA VELOCITYHI          ; Turn off hyperwarp velocity
              07445
              07446 ;*** Game over (Mission successful) ********************************************
B121 A9FF     07447 GAMEOVER2       LDA #$FF                ; Enter demo mode
B123 8564     07448                 STA ISDEMOMODE          ;
              07449
B125 8465     07450                 STY NEWTITLEPHR         ; Enqueue title phrase
              07451
              07452 ;*** Calculate total score *****************************************************
B127 8A       07453                 TXA                     ;
B128 0562     07454                 ORA MISSIONLEVEL        ;
B12A AA       07455                 TAX                     ;
B12B BDDDBE   07456                 LDA BONUSTAB,X          ; Retrieve mission bonus
B12E 18       07457                 CLC                     ; Add mission bonus and game score
B12F 65CB     07458                 ADC SCORE               ;
B131 AA       07459                 TAX                     ;
B132 A900     07460                 LDA #0                  ;
              07461
B134 85C9     07462                 STA JOYSTICKY           ; Clear vertical joystick delta
B136 85C8     07463                 STA JOYSTICKX           ; Clear horizontal joystick delta
              07464
B138 65CC     07465                 ADC SCORE+1             ;
B13A 3025     07466                 BMI SKIP165             ; Return if total score < 0 (= total score of 0)
              07467
              07468 ;*** Calculate scored rank *****************************************************
B13C 4A       07469                 LSR A                   ;
B13D 8A       07470                 TXA                     ;
B13E 6A       07471                 ROR A                   ;
B13F 4A       07472                 LSR A                   ;
B140 4A       07473                 LSR A                   ;
B141 4A       07474                 LSR A                   ; Use bits B8..4 of total score as rank index
B142 C913     07475                 CMP #19                 ; Limit scored rank index to 0..18
B144 9004     07476                 BCC SKIP162             ;
B146 A912     07477                 LDA #18                 ;
B148 A20F     07478                 LDX #15                 ; Prep class index of 15
B14A 85CD     07479 SKIP162         STA SCOREDRANKIND       ; Store scored rank index
              07480
              07481 ;*** Calculate scored class ****************************************************
B14C A8       07482                 TAY                     ;
B14D 8A       07483                 TXA                     ;
B14E C000     07484                 CPY #0                  ;
B150 F00B     07485                 BEQ SKIP164             ;
B152 C00B     07486                 CPY #11                 ;
B154 9004     07487                 BCC SKIP163             ;
B156 C00F     07488                 CPY #15                 ;
B158 9003     07489                 BCC SKIP164             ;
B15A 4A       07490 SKIP163         LSR A                   ;
B15B 4908     07491                 EOR #$08                ;
B15D 290F     07492 SKIP164         AND #$0F                ;
B15F 85CE     07493                 STA SCOREDCLASSIND      ; Store scored class index, is 0..15
              07494
B161 60       07495 SKIP165         RTS                     ; Return
              07496
              07497 ;*******************************************************************************
              07498 ;*                                                                             *
              07499 ;*                                 SELECTWARP                                  *
              07500 ;*                                                                             *
              07501 ;*             Select hyperwarp arrival location on Galactic Chart             *
              07502 ;*                                                                             *
              07503 ;*******************************************************************************
              07504
              07505 ; DESCRIPTION
              07506 ;
              07507 ; This subroutine executes the following steps:
              07508 ;
              07509 ; (1)  Check if we are in Galactic Chart view and not in hyperwarp.
              07510 ;
              07511 ; (2)  Update the Galactic Chart in subroutine DRAWGC ($B4B9) if the Subspace
              07512 ;      Radio is not damaged.
              07513 ;
              07514 ; (3)  Move the arrival hyperwarp marker (PLAYER4) across the Galactic Chart
              07515 ;      every other game loop iteration. The current location of our starship is
              07516 ;      indicated by the departure hyperwarp marker (PLAYER3).
              07517 ;
              07518 ; Code execution continues into subroutine CALCWARP ($B1A7) to calculate the
              07519 ; required hyperwarp energy to hyperwarp from the departure hyperwarp marker
              07520 ; position to the arrival hyperwarp marker position.
              07521 ;
              07522 ; NOTE: To calculate the horizontal position of PLAYER3..4 an offset of 61 is
              07523 ; added (from left to right: 48 Player/Missile (PM) pixels to the left edge of
              07524 ; the screen + 16 PM pixels to the left border of the Galactic Chart - 3 PM
              07525 ; pixels relative offset of the PLAYER shape's horizontal center to its left
              07526 ; edge = 61 PM pixels).
              07527 ;
              07528 ; NOTE: To calculate the vertical position of PLAYER3..4 an offset of 63 is
              07529 ; added (from top to bottom: 8 Player/Missile (PM) pixels to the start of the
              07530 ; Display List + 56 PM pixels to the first row of sectors - 1 PM pixel relative
              07531 ; offset of the PLAYER shape's vertical center to its top edge (?) = 63 PM
              07532 ; pixels).
              07533
B162 A5C0     07534 SELECTWARP      LDA WARPSTATE           ; Return if hyperwarp engaged
B164 D004     07535                 BNE SKIP166             ;
              07536
B166 A5D0     07537                 LDA SHIPVIEW            ; Return if not in Galactic Chart view
B168 3001     07538                 BMI SKIP167             ;
B16A 60       07539 SKIP166         RTS                     ; Return
              07540
B16B 2C9709   07541 SKIP167         BIT GCSTATRAD           ; Skip if Subspace Radio is damaged or destroyed
B16E 3003     07542                 BMI SKIP168             ;
              07543
B170 20B9B4   07544                 JSR DRAWGC              ; Redraw Galactic Chart
              07545
B173 A572     07546 SKIP168         LDA COUNT8              ; Move hyperwarp markers only every other game loop
B175 2901     07547                 AND #$01                ; (slowing down movement of hyperwarp markers)
B177 D02E     07548                 BNE CALCWARP            ;
              07549
              07550 ;*** Calc arrival hyperwarp marker column and row numbers, update PLAYER4 pos **
B179 18       07551                 CLC                     ;
B17A A58F     07552                 LDA WARPARRVCOLUMN      ; Load arrival hyperwarp marker column number
B17C 65C8     07553                 ADC JOYSTICKX           ; Add joystick x-delta
B17E 297F     07554                 AND #$7F                ; Limit value to 0..127
B180 858F     07555                 STA WARPARRVCOLUMN      ; Save new arrival hyperwarp marker column number
B182 18       07556                 CLC                     ;
B183 693D     07557                 ADC #61                 ; Add offset of 61
B185 8D2E0C   07558                 STA PL4COLUMN           ; Store as PLAYER4 column number
              07559
B188 18       07560                 CLC                     ;
B189 A58E     07561                 LDA WARPARRVROW         ; Load arrival hyperwarp marker row number
B18B 65C9     07562                 ADC JOYSTICKY           ; Add joystick y-delta
B18D 297F     07563                 AND #$7F                ; Limit value to 0..127
B18F 858E     07564                 STA WARPARRVROW         ; Save new arrival hyperwarp marker row number
B191 18       07565                 CLC                     ;
B192 693F     07566                 ADC #63                 ; Add offset of 63
B194 8DFD0B   07567                 STA PL4ROWNEW           ; Store as PLAYER4 row number
              07568
              07569 ;*** Calc departure hyperwarp marker column and row numbers, update PLAYER3 pos 
B197 A58C     07570                 LDA WARPDEPRROW         ; Load departure hyperwarp marker row number
B199 18       07571                 CLC                     ;
B19A 693F     07572                 ADC #63                 ; Add offset of 63
B19C 8DFC0B   07573                 STA PL3ROWNEW           ; Store as PLAYER3 row number
              07574
B19F A58D     07575                 LDA WARPDEPRCOLUMN      ; Load departure hyperwarp marker column number
B1A1 18       07576                 CLC                     ;
B1A2 693D     07577                 ADC #61                 ; Add offset of 61
B1A4 8D2D0C   07578                 STA PL3COLUMN           ; Store as PLAYER3 column number
              07579
              07580 ;*******************************************************************************
              07581 ;*                                                                             *
              07582 ;*                                  CALCWARP                                   *
              07583 ;*                                                                             *
              07584 ;*                   Calculate and display hyperwarp energy                    *
              07585 ;*                                                                             *
              07586 ;*******************************************************************************
              07587
              07588 ; DESCRIPTION
              07589 ;
              07590 ; Calculates and displays the hyperwarp energy in the Galactic Chart view.
              07591 ;
              07592 ; This subroutine executes the following steps:
              07593 ;
              07594 ; (1)  Determine the arrival sector from the arrival hyperwarp marker position.
              07595 ;
              07596 ; (2)  If the Subspace Radio is not destroyed, update the target number digit of
              07597 ;      the Galactic Chart Panel Display.
              07598 ;
              07599 ; (3)  Calculate the hyperwarp energy that is required to hyperwarp from the
              07600 ;      departure hyperwarp marker to the arrival hyperwarp marker based on the
              07601 ;      "block-distance":
              07602 ;
              07603 ;          DISTANCE := DELTAR / 2 + DELTAC
              07604 ;
              07605 ;          where
              07606 ;
              07607 ;          DELTAR := ABS(WARPARRVROW - WARPDEPRROW)
              07608 ;          DELTAC := ABS(WARPARRVCOLUMN - WARPDEPRCOLUMN)
              07609 ;
              07610 ;      NOTE: Dividing DELTAR by 2 compensates for PLAYERs at single-line
              07611 ;      resolution having Player/Missile pixels that are half as high as they are
              07612 ;      wide.
              07613 ;
              07614 ;      The hyperwarp energy, divided by 10, is the sum of a value picked from
              07615 ;      the hyperwarp energy table WARPENERGYTAB ($BADD) indexed by DISTANCE / 8)
              07616 ;      plus a remainder computed from Bits B1..0 of DISTANCE. 
              07617 ;
              07618 ; (4)  Store the hyperwarp energy value in WARPENERGY ($91).
              07619 ;
              07620 ; (5)  Update the HYPERWARP ENERGY readout of the Galactic Chart Panel Display.
              07621
    =006A     07622 L.WARPARRVCOL   = $6A                   ; Saves arrival sector column number
    =006A     07623 L.DELTAC        = $6A                   ; Saves diff column value
              07624
              07625 ;*** Calculate arrival sector **************************************************
B1A7 A58F     07626 CALCWARP        LDA WARPARRVCOLUMN      ;
B1A9 4A       07627                 LSR A                   ;
B1AA 4A       07628                 LSR A                   ;
B1AB 4A       07629                 LSR A                   ;
B1AC 856A     07630                 STA L.WARPARRVCOL       ; A := arrival sector column 0..15
B1AE A58E     07631                 LDA WARPARRVROW         ;
B1B0 2970     07632                 AND #$70                ; A := arrival sector row (0..7) * 16
B1B2 056A     07633                 ORA L.WARPARRVCOL       ;
B1B4 8592     07634                 STA ARRVSECTOR          ; Save arrival sector (format %0rrrcccc)
              07635
              07636 ;*** Update target number digit of Galactic Chart Panel Display ****************
B1B6 AA       07637                 TAX                     ;
B1B7 BDC908   07638                 LDA GCMEMMAP,X          ; Get number of Zylon ships in arrival sector
B1BA 1002     07639                 BPL SKIP169             ; Skip if no starbase in arrival sector
B1BC A900     07640                 LDA #0                  ; Clear number of Zylon ships
B1BE 0990     07641 SKIP169         ORA #CCS.COL2!ROM.0     ; Merge COLOR2 bits with number of Zylon ships
B1C0 2C9709   07642                 BIT GCSTATRAD           ; Skip if Subspace Radio destroyed
B1C3 7003     07643                 BVS SKIP170             ;
              07644
B1C5 8D8D09   07645                 STA GCTRGCNT            ; Set target number digit of Galactic Chart Panel
              07646
              07647 ;*** Calculate energy to hyperwarp between hyperwarp markers *******************
B1C8 38       07648 SKIP170         SEC                     ; A := DELTAC := ABS(WARPARRVCOLUMN - WARPDEPRCOLUMN)
B1C9 A58F     07649                 LDA WARPARRVCOLUMN      ; (Column value difference)
B1CB E58D     07650                 SBC WARPDEPRCOLUMN      ;
B1CD B004     07651                 BCS SKIP171             ;
B1CF 49FF     07652                 EOR #$FF                ;
B1D1 6901     07653                 ADC #1                  ;
B1D3 856A     07654 SKIP171         STA L.DELTAC            ;
              07655
B1D5 38       07656                 SEC                     ; A := DELTAR := ABS(WARPARRVROW - WARPDEPRROW)
B1D6 A58E     07657                 LDA WARPARRVROW         ; (Row value difference)
B1D8 E58C     07658                 SBC WARPDEPRROW         ;
B1DA B004     07659                 BCS SKIP172             ;
B1DC 49FF     07660                 EOR #$FF                ;
B1DE 6901     07661                 ADC #1                  ;
              07662
B1E0 4A       07663 SKIP172         LSR A                   ; A := DISTANCE := DELTAR / 2 + DELTAC
B1E1 18       07664                 CLC                     ;
B1E2 656A     07665                 ADC L.DELTAC            ;
              07666
B1E4 A8       07667                 TAY                     ; Save DISTANCE
B1E5 4A       07668                 LSR A                   ; Calc index into hyperwarp energy table
B1E6 4A       07669                 LSR A                   ;
B1E7 4A       07670                 LSR A                   ;
B1E8 AA       07671                 TAX                     ;
              07672
B1E9 98       07673                 TYA                     ; Load DISTANCE value
B1EA 2903     07674                 AND #$03                ; Get DISTANCE bits B1..0
B1EC 18       07675                 CLC                     ;
B1ED 7DDDBA   07676                 ADC WARPENERGYTAB,X     ; Add hyperwarp energy from table
B1F0 8591     07677                 STA WARPENERGY          ; Save hyperwarp energy
              07678
              07679 ;*** Update HYPERWARP ENERGY readout of Galactic Chart Panel Display ***********
B1F2 A8       07680                 TAY                     ; Prep with hyperwarp energy value
              07681
B1F3 A910     07682                 LDA #ROM.0              ; Set HYPERWARP ENERGY readout digit1..3 to '0'
B1F5 8D7D09   07683                 STA GCWARPD1            ;
B1F8 8D7E09   07684                 STA GCWARPD1+1          ;
B1FB 8D7F09   07685                 STA GCWARPD1+2          ;
              07686
B1FE A202     07687 LOOP053         LDX #2                  ; Loop over HYPERWARP ENERGY readout digit3..1
B200 FE7D09   07688 LOOP054         INC GCWARPD1,X          ; Increment digit value
B203 BD7D09   07689                 LDA GCWARPD1,X          ;
B206 C91A     07690                 CMP #ROM.9+1            ;
B208 9008     07691                 BCC SKIP173             ; Skip if energy digit <= '9'
              07692
B20A A910     07693                 LDA #ROM.0              ; Replace energy digit with '0'
B20C 9D7D09   07694                 STA GCWARPD1,X          ;
B20F CA       07695                 DEX                     ;
B210 10EE     07696                 BPL LOOP054             ; Next energy digit
              07697
B212 88       07698 SKIP173         DEY                     ; Decrement HYPERWARP ENERGY readout value
B213 D0E9     07699                 BNE LOOP053             ;
B215 60       07700                 RTS                     ; Return
              07701
              07702 ;*******************************************************************************
              07703 ;*                                                                             *
              07704 ;*                                  UPDTITLE                                   *
              07705 ;*                                                                             *
              07706 ;*                              Update title line                              *
              07707 ;*                                                                             *
              07708 ;*******************************************************************************
              07709
              07710 ; DESCRIPTION
              07711 ;
              07712 ; Updates the title phrase displayed in the title line.
              07713 ;
              07714 ; If no title phrase has been set then fetch the offset of the next ("enqueued")
              07715 ; title phrase to be displayed. If one has been set then code execution
              07716 ; continues into subroutine SETTITLE ($B223), otherwise code execution returns.
              07717 ;
              07718 ; If a title phrase has been set then decrement the lifetime of the currently
              07719 ; displayed title phrase segment. If its lifetime has reached a value of 0 then
              07720 ; branch to subroutine SETTITLE ($B223) to display the next segment.
              07721
B216 A5D1     07722 UPDTITLE        LDA TITLEPHR            ; Skip if no title phrase set
B218 F005     07723                 BEQ SKIP175             ;
              07724
B21A C6CF     07725                 DEC TITLELIFE           ; Decrement title phrase segment lifetime
B21C F010     07726                 BEQ SKIP176             ; If lifetime expired show next title segment
              07727
B21E 60       07728 SKIP174         RTS                     ; Return
              07729
B21F A465     07730 SKIP175         LDY NEWTITLEPHR         ; Prep enqueued new title phrase
B221 F0FB     07731                 BEQ SKIP174             ; Return if not set
              07732
              07733 ;*******************************************************************************
              07734 ;*                                                                             *
              07735 ;*                                  SETTITLE                                   *
              07736 ;*                                                                             *
              07737 ;*                       Set title phrase in title line                        *
              07738 ;*                                                                             *
              07739 ;*******************************************************************************
              07740
              07741 ; DESCRIPTION
              07742 ;
              07743 ; Displays a title phrase in the title line. 
              07744 ;
              07745 ; INTRODUCTION
              07746 ;
              07747 ; Title phrases are picked from the title phrase table PHRASETAB ($BBAA). They
              07748 ; consist of one or more phrase tokens. Each token is a byte representing a word
              07749 ; in word table WORDTAB ($BC2B). Two special tokens are placeholders for the
              07750 ; scored class string ($FC) and scored rank string ($FD).
              07751 ;
              07752 ; A title phrase is split up into one or more title phrase segments, each
              07753 ; fitting into the title line. One title phrase segment is displayed after the
              07754 ; other after a delay called the "title segment lifetime".
              07755 ;
              07756 ; Phrase tokens, except the tokens for the scored class ($FC) and for the scored
              07757 ; rank ($FD), contain the number of a word in word table WORDTAB ($BC2B) and may
              07758 ; contain an end-of-segment or end-of-phrase marker bit.
              07759 ;
              07760 ; DETAILS
              07761 ;
              07762 ; The Display List is modified by subroutine MODDLST ($ADF1) to display the
              07763 ; title line. Then, the title line is cleared and the words of the title phrase
              07764 ; are copied into it using the passed offset into title phrase table PHRASETAB
              07765 ; ($BBAA). If the offset has a value of $FF the title line is hidden in
              07766 ; subroutine MODDLST ($ADF1). 
              07767 ;
              07768 ; INPUT
              07769 ;
              07770 ;   Y = Offset into title phrase table PHRASETAB ($BBAA). Used values are:
              07771 ;     $FF  -> Hide title line
              07772 ;     else -> Offset into title phrase table PHRASETAB ($BBAA), with explicitly
              07773 ;             used values:
              07774 ;
              07775 ;     $01 -> "COMPUTER ON"
              07776 ;     $04 -> "COMPUTER OFF"
              07777 ;     $07 -> "SHIELDS ON"
              07778 ;     $09 -> "SHIELDS OFF"
              07779 ;     $0B -> "COMPUTER TRACKING ON"
              07780 ;     $0E -> "TRACKING OFF"
              07781 ;     $13 -> "STARBASE SURROUNDED"
              07782 ;     $15 -> "STARBASE DESTROYED"
              07783 ;     $1F -> "DOCKING ABORTED"
              07784 ;     $21 -> "TRANSFER COMPLETE"
              07785 ;     $4A -> "NOVICE MISSION"
              07786 ;     $4C -> "PILOT MISSION"
              07787 ;     $4E -> "WARRIOR MISSION"
              07788 ;     $50 -> "COMMANDER MISSION"
              07789 ;     $52 -> "DAMAGE CONTROL..."
              07790 ;     $75 -> "RED ALERT"
              07791
    =006A     07792 L.WORD          = $6A                   ; Saves word number of WORDTAB ($BC2A). Used values
              07793                                         ; are $00..$3F.
    =006B     07794 L.COLUMNPOS     = $6B                   ; Saves cursor column position during copying text
              07795                                         ; into title line
    =006C     07796 L.TOKEN         = $6C                   ; Saves title phrase token from PHRASETAB ($BBAA),
              07797                                         ; contains bit-encoded information about one word in
              07798                                         ; the title phrase:
              07799                                         ; B7..6 = %00 -> Copy next word to title line
              07800                                         ; B7..6 = %01 -> End-of-phrase reached, apply short
              07801                                         ;                delay, then hide title line. Title
              07802                                         ;                segment lifetime = 60 game loops.
              07803                                         ; B7..6 = %10 -> End-of-segment reached. Title
              07804                                         ;                segment lifetime = 60 game loops
              07805                                         ; B7..6 = %11 -> End-of-phrase reached, apply long
              07806                                         ;                delay, then hide title line. Title
              07807                                         ;                segment lifetime = 254 game loops.
              07808                                         ;                Used with title phrases
              07809                                         ;                  "STARBASE SURROUNDED"
              07810                                         ;                  "STARBASE DESTROYED"
              07811                                         ;                  "HYPERSPACE"
              07812                                         ;                  "RED ALERT"
              07813                                         ; B5..0       -> Word number of WORDTAB ($BC2A)
              07814
B223 84D1     07815 SETTITLE        STY TITLEPHR            ; Save title phrase offset
              07816
B225 A023     07817                 LDY #$23                ; Show title line
B227 A20F     07818                 LDX #$0F                ;
B229 A907     07819                 LDA #$07                ;
B22B 20F1AD   07820                 JSR MODDLST             ;
              07821
              07822 ;*** Init cursor column position and clear title line **************************
B22E A213     07823 SKIP176         LDX #19                 ; There are 19(+1) characters to clear
B230 A900     07824                 LDA #0                  ;
B232 856B     07825                 STA L.COLUMNPOS         ; Init cursor column position
              07826
B234 9D1F0D   07827 LOOP055         STA TITLETXT,X          ; Clear character in title line
B237 CA       07828                 DEX                     ;
B238 10FA     07829                 BPL LOOP055             ;
              07830
              07831 ;*** If title phrase offset = $FF then hide title line *************************
B23A A6D1     07832 SKIP177         LDX TITLEPHR            ; Load title phrase offset
B23C E6D1     07833                 INC TITLEPHR            ; Prepare title phrase offset for next word
B23E D009     07834                 BNE SKIP178             ; ...skip if it turned 0
              07835
B240 A20F     07836                 LDX #$0F                ; Remove title line and return
B242 A080     07837                 LDY #$80                ;
B244 A907     07838                 LDA #$07                ;
B246 4CF1AD   07839                 JMP MODDLST             ;
              07840
B249 BDAABB   07841 SKIP178         LDA PHRASETAB,X         ; Get phrase token
              07842
              07843 ;*** Display scored class? *****************************************************
B24C C9FC     07844                 CMP #$FC                ; Skip if not "scored class" token
B24E D00F     07845                 BNE SKIP179             ;
              07846
B250 A4CE     07847                 LDY SCOREDCLASSIND      ; Get scored class index, is in 0..15
B252 B9FCBE   07848                 LDA CLASSTAB,Y          ; Load scored class number digit
B255 A66B     07849                 LDX L.COLUMNPOS         ; Load cursor position
B257 9D1F0D   07850                 STA TITLETXT,X          ; Store class in title line
B25A A93C     07851                 LDA #60                 ; Title segment lifetime := 60 game loops
B25C 85CF     07852                 STA TITLELIFE           ;
B25E 60       07853                 RTS                     ; Return
              07854
              07855 ;*** Display scored rank? ******************************************************
B25F C9FD     07856 SKIP179         CMP #$FD                ; Skip if not "scored rank" token
B261 D005     07857                 BNE SKIP180             ;
              07858
B263 A4CD     07859                 LDY SCOREDRANKIND       ; Get scored rank index, is in 0..18
B265 B9E9BE   07860                 LDA RANKTAB,Y           ; Load rank word number
              07861
              07862 ;*** Search word of token in word table ****************************************
B268 856C     07863 SKIP180         STA L.TOKEN             ; Save phrase token
B26A 293F     07864                 AND #$3F                ; Strip bits B6..7 from phrase token
B26C 856A     07865                 STA L.WORD              ; Store word number (bits B5..0)
              07866
B26E A92A     07867                 LDA #<[WORDTAB-1]       ; Point MEMPTR to WORDTAB-1
B270 8568     07868                 STA MEMPTR              ;
B272 A9BC     07869                 LDA #>[WORDTAB-1]       ;
B274 8569     07870                 STA MEMPTR+1            ;
              07871
B276 E668     07872 LOOP056         INC MEMPTR              ; Increment MEMPTR
B278 D002     07873                 BNE SKIP181             ;
B27A E669     07874                 INC MEMPTR+1            ;
              07875
B27C A000     07876 SKIP181         LDY #0                  ;
B27E B168     07877                 LDA (MEMPTR),Y          ; Load character of word
B280 10F4     07878                 BPL LOOP056             ; Loop until end-of-word marker (bit B7) found
B282 C66A     07879                 DEC L.WORD              ;
B284 D0F0     07880                 BNE LOOP056             ; Loop until word found
              07881
              07882 ;*** Copy word to title line, add space ****************************************
B286 293F     07883 LOOP057         AND #$3F                ; Strip color bits B6..7 from character
B288 49A0     07884                 EOR #CCS.COL2!$20       ; Merge COLOR2 bits and convert to ATASCII
B28A A66B     07885                 LDX L.COLUMNPOS         ; Copy character to title line
B28C E66B     07886                 INC L.COLUMNPOS         ; Increment cursor column position
B28E 9D1F0D   07887                 STA TITLETXT,X          ;
B291 C8       07888                 INY                     ;
B292 B168     07889                 LDA (MEMPTR),Y          ; Load next character of word
B294 10F0     07890                 BPL LOOP057             ; Next character of word if no end-of-word marker
B296 E66B     07891                 INC L.COLUMNPOS         ; Word was copied. Add space after word.
              07892
              07893 ;*** Decide to copy another word, etc. *****************************************
B298 A93C     07894                 LDA #60                 ; SUMMARY:
B29A 246C     07895                 BIT L.TOKEN             ; If bits B7..6 of phrase token...
B29C 1004     07896                 BPL SKIP182             ; %00 -> Copy next word to title line
B29E 5008     07897                 BVC SKIP183             ; %01 -> End-of-phrase, short delay, hide title line
B2A0 A9FE     07898                 LDA #254                ;        Title segment lifetime := 60 game loops
B2A2 5096     07899 SKIP182         BVC SKIP177             ; %10 -> End-of-segment.
B2A4 A0FF     07900                 LDY #$FF                ;        Title segment lifetime := 60 game loops
B2A6 84D1     07901                 STY TITLEPHR            ; %11 -> End-of-phrase, long delay, hide title line
B2A8 85CF     07902 SKIP183         STA TITLELIFE           ;        Title segment lifetime := 254 game loops
B2AA 60       07903                 RTS                     ; Return
              07904
              07905 ;*******************************************************************************
              07906 ;*                                                                             *
              07907 ;*                                    SOUND                                    *
              07908 ;*                                                                             *
              07909 ;*                            Handle sound effects                             *
              07910 ;*                                                                             *
              07911 ;*******************************************************************************
              07912
              07913 ; DESCRIPTION
              07914 ;
              07915 ; This subroutine handles the sound effects. It is called every vertical blank
              07916 ; phase, that is, every TICK (1/60 s on an NTSC Atari 8-bit Home Computer
              07917 ; system, 1/50 s on a PAL Atari 8-bit Home Computer system) from the Vertical
              07918 ; Blank Interrupt handler VBIHNDLR ($A6D1).
              07919 ;
              07920 ; The game uses all of the available 4 audio channels: Audio channels 1, 2, and
              07921 ; 3 are shared among the Engines sound effects and the "noise sound patterns"
              07922 ; (explosion and photon torpedo sound effects), while audio channel 4 is used
              07923 ; for "beeper sound patterns" (status report sound effects). The following
              07924 ; sections explain the beeper sound patterns and the noise sound patterns:
              07925 ;
              07926 ; o   BEEPER SOUND PATTERNS
              07927 ;
              07928 ;     There are the following beeper sound patterns:
              07929 ;
              07930 ;     (1)  HYPERWARP TRANSIT
              07931 ;     (2)  RED ALERT
              07932 ;     (3)  ACKNOWLEDGE
              07933 ;     (4)  DAMAGE REPORT
              07934 ;     (5)  MESSAGE FROM STARBASE
              07935 ;
              07936 ;     They are encoded in table BEEPPATTAB ($BF3E) in 6-byte long "beeper sound
              07937 ;     patterns". 
              07938 ;
              07939 ;     Another table, BEEPFRQTAB ($BF5C), stores the frequencies for the tones
              07940 ;     of each beeper sound pattern, terminated by a marker byte ($FF).
              07941 ;
              07942 ;     BUG (at $BF5C): The pattern frequencies in table BEEPFRQTAB ($BF5C) at
              07943 ;     offset $00 are unused. Suggested Fix: Remove from code.
              07944 ;
              07945 ;     Whenever the game calls subroutine BEEP ($B3A6), that subroutine sets up a
              07946 ;     beeper sound pattern for playing by copying 6 bytes from the pattern table
              07947 ;     BEEPPATTAB ($BF3E) to BEEPFRQIND ($D2)..BEEPFRQSTART ($D7). Subroutine
              07948 ;     SOUND ($B2AB) detects the copied beeper sound pattern and plays the
              07949 ;     encoded tones and pauses.
              07950 ;
              07951 ;     The relevant variables for playing a beeper sound pattern are the
              07952 ;     following (see also figures at BEEPPATTAB ($BF3E)):
              07953 ;
              07954 ;     BEEPFRQIND    ($D2)   = Running index into table BEEPFRQTAB ($BF5C)
              07955 ;     BEEPREPEAT    ($D3)   = Number of times that the beeper sound pattern is
              07956 ;                             repeated - 1
              07957 ;     BEEPTONELIFE  ($D4)   = Lifetime of tone in TICKs - 1
              07958 ;     BEEPPAUSELIFE ($D5)   = Lifetime of pause in TICKs - 1 ($FF -> No pause)
              07959 ;     BEEPPRIORITY  ($D6)   = Beeper sound pattern priority. A playing beeper
              07960 ;                             sound pattern is stopped if a beeper sound pattern
              07961 ;                             of higher priority is about to be played. A value
              07962 ;                             of 0 indicates that no beeper sound pattern is
              07963 ;                             playing at the moment.
              07964 ;     BEEPFRQSTART  ($D7)   = Index to first byte of the beeper sound pattern in
              07965 ;                             table BEEPFRQTAB ($BF5C)
              07966 ;
              07967 ;     BEEPLIFE      ($D8)   = Lifetime of the current tone or pause in TICKs
              07968 ;     BEEPTOGGLE    ($D9)   = Indicates that either a tone (0) or a pause (not
              07969 ;                             0) is currently playing.
              07970 ;
              07971 ; o   NOISE SOUND PATTERNS
              07972 ;
              07973 ;     There are the following noise sound patterns:
              07974 ;
              07975 ;     (1)  PHOTON TORPEDO LAUNCHED
              07976 ;     (2)  SHIELD EXPLOSION
              07977 ;     (3)  ZYLON EXPLOSION
              07978 ;
              07979 ;     They are encoded in table NOISEPATTAB ($BF20) in 10-byte long "noise sound
              07980 ;     patterns". 
              07981 ;
              07982 ;     Whenever the game calls subroutine NOISE ($AEA8), that subroutine sets up
              07983 ;     a noise sound pattern for being played by copying 10 bytes from the
              07984 ;     pattern table NOISEPATTAB ($BF20) to NOISETORPTIM ($DA)..NOISELIFE ($E1)
              07985 ;     and hardware sound registers AUDCTL ($D208) and AUDF3 ($D204).
              07986 ;
              07987 ;     The relevant variables for playing a noise sound pattern are the
              07988 ;     following:
              07989 ;
              07990 ;     NOISETORPTIM  ($DA)   = Delay timer for PHOTON TORPEDO LAUNCHED noise
              07991 ;                             sound pattern
              07992 ;     NOISEEXPLTIM  ($DB)   = Delay timer for SHIELD EXPLOSION and ZYLON
              07993 ;                             EXPLOSION noise sound patterns
              07994 ;     NOISEAUDC2    ($DC)   = Audio channel 1/2 control shadow register
              07995 ;     NOISEAUDC3    ($DD)   = Audio channel 3   control shadow register
              07996 ;     NOISEAUDF1    ($DE)   = Audio channel 1 frequency shadow register
              07997 ;     NOISEAUDF2    ($DF)   = Audio channel 2 frequency shadow register
              07998 ;     NOISEFRQINC   ($E0)   = Audio channel 1/2 frequency increment
              07999 ;     NOISELIFE     ($E1)   = Noise sound pattern lifetime
              08000 ;
              08001 ;     AUDCTL        ($D208) = POKEY: Audio control
              08002 ;     AUDF3         ($D204) = POKEY: Audio channel 3 frequency audio register
              08003 ;
              08004 ;     There are two more variables that trigger noise effects. They are not part
              08005 ;     of the noise sound pattern table:
              08006 ;
              08007 ;     NOISEZYLONTIM ($E2)   = Delay timer to trigger the ZYLON EXPLOSION noise
              08008 ;                             sound pattern. It is set in subroutine COLLISION
              08009 ;                             ($AF3D) when the impact of one of our starship's
              08010 ;                             photon torpedoes with a target is imminent. The
              08011 ;                             timer is decremented every TICK. When it reaches a
              08012 ;                             value of 0 the ZYLON EXPLOSION noise sound pattern
              08013 ;                             is played in subroutine SOUND ($B2AB). 
              08014 ;     NOISEHITLIFE ($E3)    = Lifetime of the STARSHIP EXPLOSION noise when our
              08015 ;                             starship was destroyed by a Zylon photon torpedo.
              08016 ;                             It is set in GAMELOOP ($A1F3) to a value of 64
              08017 ;                             TICKs. When it reaches a value of 0 the STARSHIP
              08018 ;                             EXPLOSION noise is played in subroutine SOUND
              08019 ;                             ($B2AB).
              08020 ;
              08021 ; SUBROUTINE DETAILS
              08022 ;
              08023 ; This subroutine executes the following steps:
              08024 ;
              08025 ; (1)  Play beeper sound pattern
              08026 ;
              08027 ;      The playing of a beeper sound pattern is started, continued, or stopped.
              08028 ;
              08029 ; (2)  Play ZYLON EXPLOSION noise sound pattern
              08030 ;
              08031 ;      If the explosion of a target space object is imminent (subroutine
              08032 ;      COLLISION ($AF3D) has set NOISEZYLONTIM ($E2) to the number of game loop
              08033 ;      iterations that will pass until our starship's photon torpedo will hit
              08034 ;      the target), the timer NOISEZYLONTIM ($E2) is decremented every TICK. If
              08035 ;      it reaches a value of 0, then the noise sound pattern ZYLON EXPLOSION is
              08036 ;      played.
              08037 ;
              08038 ; (3)  Play starship's Engines sound
              08039 ;
              08040 ;      If the Engines are louder than the current noise sound pattern then the
              08041 ;      noise sound pattern is terminated and the values for the audio channels
              08042 ;      1..3 are updated: 
              08043 ;
              08044 ;      The velocity of our starship determines the pitch and the volume of the
              08045 ;      Engines: the higher the velocity, the higher the pitch and the volume of
              08046 ;      the Engines. The incremented value of VELOCITYLO ($70) is used as a "base
              08047 ;      value" %abcdefgh.
              08048 ;
              08049 ;      Audio channels 1 and 2 are combined to a 16-bit audio channel 1/2,
              08050 ;      clocked at 1.79 MHz. The inverted bits (represented by an overscore)
              08051 ;      B7..0 of the base value form bits B12..5 of the 16-bit frequency value of
              08052 ;      audio channel 1/2. Bits B7..4 of the base value form bits B3..0 of the
              08053 ;      volume of audio channel 1/2, with noise distortion bit B7 set:
              08054 ;                               ________
              08055 ;      AUDF1/2 ($D202..3) := %000abcdefgh00000
              08056 ;      AUDC2   ($D203)    := %1000abcd
              08057 ;
              08058 ;      Audio channel 3 is also clocked at 1.79 MHz. The inverted bits B7..0 of
              08059 ;      the base value form bits B7..0 of the frequency value of audio channel 3.
              08060 ;      Bits B6..4 of the base value form bits B3..0 of the volume of audio
              08061 ;      channel 3, with noise distortion bit B7 set:
              08062 ;                            ________
              08063 ;      AUDF3   ($D204)    := %abcdefgh
              08064 ;      AUDC3   ($D205)    := %10000bcd
              08065 ;
              08066 ;      Code execution returns at this point.
              08067 ;
              08068 ; (4)  Play ZYLON EXPLOSION or SHIELD EXPLOSION noise sound pattern
              08069 ;
              08070 ;      If the ZYLON EXPLOSION or SHIELD EXPLOSION noise sound pattern was set
              08071 ;      up, the explosion noise timer NOISEEXPLTIM ($DB) is decremented every
              08072 ;      TICK. It starts either with a value of 4 TICKs with a ZYLON EXPLOSION
              08073 ;      noise sound pattern or with a value of 8 TICKs with a SHIELD EXPLOSION
              08074 ;      noise sound pattern, set up in subroutine NOISE ($AEA8). If it reaches a
              08075 ;      value of 0, then the shadow control register of audio channel 1/2
              08076 ;      switches to "noise distortion" at maximum volume.
              08077 ;
              08078 ; (5)  Play PHOTON TORPEDO LAUNCHED noise sound pattern
              08079 ;
              08080 ;      If the PHOTON TORPEDO LAUNCHED noise sound pattern was set up, the photon
              08081 ;      torpedo noise timer NOISETORPTIM ($DA) is decremented every TICK. It
              08082 ;      starts with a value of 8 TICKs, set in subroutine TRIGGER ($AE29). The
              08083 ;      noise distortion and volume for the shadow control register of audio
              08084 ;      channel 3 is picked from table NOISETORPVOLTAB ($BFEB), the noise
              08085 ;      frequency for audio channel 3 is picked from table NOISETORPFRQTAB
              08086 ;      ($BFF3). If the photon torpedo noise timer reaches a value of 0, then the
              08087 ;      shadow control registers of audio channel 1/2 switch to "tone distortion"
              08088 ;      at maximum volume and a frequency of $0202.
              08089 ;
              08090 ;      NOTE: Using a real-time volume envelope stored in table NOISETORPVOLTAB
              08091 ;      ($BFEB) for a launched photon torpedo results in producing the
              08092 ;      distinctive "whooshing" photon torpedo sound.
              08093 ;
              08094 ; (6)  Play STARSHIP EXPLOSION noise
              08095 ;
              08096 ;      If our starship was hit by a Zylon photon torpedo then NOISEHITLIFE ($E3)
              08097 ;      was set to 64 TICKs in routine GAMELOOP ($A1F3). While this value is
              08098 ;      decremented every TICK, a random frequency value is stored to audio
              08099 ;      channel 3 and the distortion bit of the shadow control register of audio
              08100 ;      channel 3 is randomly toggled.
              08101 ;
              08102 ; (7)  Increase audio channels 1/2 frequency
              08103 ;
              08104 ;      The 16-bit frequency value of audio channels 1/2 (both shadow registers
              08105 ;      and audio registers) is increased every TICK by an increment picked from
              08106 ;      the currently playing noise sound pattern.
              08107 ;
              08108 ; (8)  Mute audio channels gradually
              08109 ;
              08110 ;      Toward the end of a noise sound pattern's lifetime all audio channels
              08111 ;      gradually mute their volume every other TICK until completely silent. 
              08112
              08113 ;*** Play beeper sound pattern *************************************************
B2AB A5D6     08114 SOUND           LDA BEEPPRIORITY        ; Skip if beeper sound pattern not in use
B2AD F037     08115                 BEQ SKIP185             ;
              08116
B2AF C6D8     08117                 DEC BEEPLIFE            ; Decrement beeper lifetime
B2B1 1033     08118                 BPL SKIP185             ; Skip if beeper lifetime still counting down
              08119
B2B3 A5D9     08120                 LDA BEEPTOGGLE          ; Load tone/pause toggle
B2B5 F00A     08121                 BEQ LOOP058             ; Skip if a tone is playing or is to be played
              08122
B2B7 A5D5     08123                 LDA BEEPPAUSELIFE       ; Load pause lifetime
B2B9 3006     08124                 BMI LOOP058             ; Skip if duration = $FF (no pause)
B2BB 85D8     08125                 STA BEEPLIFE            ; Store pause lifetime as beeper lifetime
B2BD A000     08126                 LDY #0                  ; Prep AUDC4 (zero volume)
B2BF F020     08127                 BEQ SKIP184             ; Skip unconditionally
              08128
B2C1 A5D4     08129 LOOP058         LDA BEEPTONELIFE        ; Load tone lifetime
B2C3 85D8     08130                 STA BEEPLIFE            ; Store tone lifetime as beeper lifetime
B2C5 A6D2     08131                 LDX BEEPFRQIND          ; Load frequency index
B2C7 E6D2     08132                 INC BEEPFRQIND          ; Increment frequency index
B2C9 BD5CBF   08133                 LDA BEEPFRQTAB,X        ; Store tone frequency from frequency table in AUDF4
B2CC 8D06D2   08134                 STA AUDF4               ;
B2CF A0A8     08135                 LDY #$A8                ; Prep AUDC4 (tone distortion + medium volume)
B2D1 C9FF     08136                 CMP #$FF                ; Skip if frequency not $FF (there are more tones)
B2D3 D00C     08137                 BNE SKIP184             ;
              08138
B2D5 A5D7     08139                 LDA BEEPFRQSTART        ; Rewind pattern frequency pointer
B2D7 85D2     08140                 STA BEEPFRQIND          ;
B2D9 C6D3     08141                 DEC BEEPREPEAT          ; Decrement sequence counter
B2DB 10E4     08142                 BPL LOOP058             ; Keep playing until sequence counter < 0
              08143
B2DD A000     08144                 LDY #0                  ; Prep AUDC4 with zero volume
B2DF 84D6     08145                 STY BEEPPRIORITY        ; Stop playing beeper sound pattern
              08146
B2E1 8C07D2   08147 SKIP184         STY AUDC4               ; Store in AUDC4
B2E4 84D9     08148                 STY BEEPTOGGLE          ; Store in BEEPTOGGLE
              08149
              08150 ;*** Play ZYLON EXPLOSION noise sound pattern **********************************
B2E6 A5E2     08151 SKIP185         LDA NOISEZYLONTIM       ; Skip if ZYLON EXPLOSION timer not in use
B2E8 F009     08152                 BEQ SKIP186             ;
              08153
B2EA C6E2     08154                 DEC NOISEZYLONTIM       ; Decrement ZYLON EXPLOSION timer
B2EC D005     08155                 BNE SKIP186             ; Skip if ZYLON EXPLOSION timer still counting down
              08156
B2EE A214     08157                 LDX #$14                ; Play noise sound pattern ZYLON EXPLOSION
B2F0 20A8AE   08158                 JSR NOISE               ;
              08159
              08160 ;*** Play our starship's Engines sound *****************************************
B2F3 A670     08161 SKIP186         LDX VELOCITYLO          ; Skip if Engines softer than noise sound pattern
B2F5 8A       08162                 TXA                     ;
B2F6 4A       08163                 LSR A                   ;
B2F7 4A       08164                 LSR A                   ;
B2F8 4A       08165                 LSR A                   ;
B2F9 4A       08166                 LSR A                   ;
B2FA 4A       08167                 LSR A                   ;
B2FB C5E1     08168                 CMP NOISELIFE           ;
B2FD 902C     08169                 BCC SKIP187             ;
              08170
B2FF A900     08171                 LDA #0                  ; Terminate noise sound pattern
B301 85E1     08172                 STA NOISELIFE           ;
              08173
B303 E8       08174                 INX                     ;
B304 8A       08175                 TXA                     ; A := %abcdefgh = VELOCITYLO + 1
B305 49FF     08176                 EOR #$FF                ;           ________
B307 8D04D2   08177                 STA AUDF3               ; AUDF3 := %abcdefgh
              08178
B30A AA       08179                 TAX                     ;                ________
B30B 0A       08180                 ASL A                   ; AUDF2/1 := %000abcdefgh00000
B30C 0A       08181                 ASL A                   ;
B30D 0A       08182                 ASL A                   ;
B30E 0A       08183                 ASL A                   ;
B30F 0A       08184                 ASL A                   ;
B310 8D00D2   08185                 STA AUDF1               ;
B313 8A       08186                 TXA                     ;
B314 4A       08187                 LSR A                   ;
B315 4A       08188                 LSR A                   ;
B316 4A       08189                 LSR A                   ;
B317 8D02D2   08190                 STA AUDF2               ;
              08191
B31A 4A       08192                 LSR A                   ; AUDC2 := %1000abcd
B31B 498F     08193                 EOR #$8F                ; (noise distortion + B7..B4 bits for volume)
B31D 8D03D2   08194                 STA AUDC2               ;
              08195
B320 2987     08196                 AND #$87                ; AUDC3 := %10000bcd
B322 8D05D2   08197                 STA AUDC3               ; (noise distortion + B6..B4 bits for volume)
              08198
B325 A970     08199                 LDA #$70                ; Clock audio channel 1 and 3 @ 1.79 MHz and...
B327 8D08D2   08200                 STA AUDCTL              ; ...combine audio channel 1/2 to 16-bit channel
              08201
B32A 60       08202                 RTS                     ; Return
              08203
              08204 ;*** Play ZYLON EXPLOSION or SHIELD EXPLOSION noise ****************************
B32B A5DB     08205 SKIP187         LDA NOISEEXPLTIM        ; Skip if explosion noise timer not in use
B32D F008     08206                 BEQ SKIP188             ;
              08207
B32F C6DB     08208                 DEC NOISEEXPLTIM        ; Decrement explosion noise timer (4 or 8 TICKs long)
B331 D004     08209                 BNE SKIP188             ; Skip if explosion noise timer still counting down
              08210
B333 A98F     08211                 LDA #$8F                ; Shadow register AUDC2 := (noise dist. + max volume)
B335 85DC     08212                 STA NOISEAUDC2          ;
              08213
              08214 ;*** Play PHOTON TORPEDO LAUNCHED noise sound **********************************
B337 A6DA     08215 SKIP188         LDX NOISETORPTIM        ; Skip if photon torpedo noise timer not in use
B339 F01C     08216                 BEQ SKIP190             ;
              08217
B33B C6DA     08218                 DEC NOISETORPTIM        ; Decrement photon torpedo noise timer (8 TICKs long)
B33D D00A     08219                 BNE SKIP189             ; Skip if torpedo noise timer still counting down
              08220
B33F A9AF     08221                 LDA #$AF                ; Shadow register AUDC2 := (tone dist. + max volume)
B341 85DC     08222                 STA NOISEAUDC2          ;
B343 A902     08223                 LDA #$02                ; Set frequency $0202 to AUDF1/2's shadow...
B345 85DE     08224                 STA NOISEAUDF1          ; ...registers
B347 85DF     08225                 STA NOISEAUDF2          ;
              08226
B349 BDEABF   08227 SKIP189         LDA NOISETORPVOLTAB-1,X ; Pick torpedo noise + volume shape (X in 1..8)...
B34C 85DD     08228                 STA NOISEAUDC3          ; ...and store it in AUDC3's shadow register
B34E BDF2BF   08229                 LDA NOISETORPFRQTAB-1,X ; Pick photon torpedo noise frequency (X in 1..8)...
B351 8D04D2   08230                 STA AUDF3               ; ...and store it in AUDF3
B354 8D09D2   08231                 STA STIMER              ; Reset POKEY audio timers
              08232
              08233 ;*** Play STARSHIP EXPLOSION noise when our starship is hit ********************
B357 A5E3     08234 SKIP190         LDA NOISEHITLIFE        ; Skip if STARSHIP EXPLOSION noise not in use
B359 F00E     08235                 BEQ SKIP191             ;
              08236
B35B C6E3     08237                 DEC NOISEHITLIFE        ; Decrement STARSHIP EXPLOSION noise lifetime
B35D AD0AD2   08238                 LDA RANDOM              ; Set random frequency to AUDF3
B360 8D04D2   08239                 STA AUDF3               ;
B363 2920     08240                 AND #$20                ; Toggle noise/tone dist. of AUDC3's shadow register
B365 45DD     08241                 EOR NOISEAUDC3          ; ...randomly
B367 85DD     08242                 STA NOISEAUDC3          ;
              08243
              08244 ;*** Increase 16-bit frequency of audio channels 1/2 (shadow registers also) ***
B369 18       08245 SKIP191         CLC                     ; Increase 16-bit frequency value of AUDF1/2...
B36A A5DE     08246                 LDA NOISEAUDF1          ; ...and its shadow register by...
B36C 65E0     08247                 ADC NOISEFRQINC         ; ...noise sound pattern frequency increment
B36E 85DE     08248                 STA NOISEAUDF1          ; AUDF1/2 := NOISEAUDF1/2 := ...
B370 8D00D2   08249                 STA AUDF1               ; ...NOISEAUDF1/2 + NOISEFRQINC
B373 A5DF     08250                 LDA NOISEAUDF2          ;
B375 6900     08251                 ADC #0                  ;
B377 85DF     08252                 STA NOISEAUDF2          ;
B379 8D02D2   08253                 STA AUDF2               ;
              08254
              08255 ;*** Gradually mute audio channels while noise sound pattern expires ***********
B37C A6DC     08256                 LDX NOISEAUDC2          ; Prep AUDC2's shadow register value
B37E A4DD     08257                 LDY NOISEAUDC3          ; Prep AUDC3's shadow register value
              08258
B380 A572     08259                 LDA COUNT8              ; Decrement volumes every other TICK
B382 4A       08260                 LSR A                   ;
B383 901A     08261                 BCC SKIP193             ;
              08262
B385 A5E1     08263                 LDA NOISELIFE           ; Skip if noise sound pattern not in use
B387 F016     08264                 BEQ SKIP193             ;
              08265
B389 C6E1     08266                 DEC NOISELIFE           ; Decrement noise sound pattern lifetime
              08267
B38B C911     08268                 CMP #17                 ; Mute noise sound pattern only in...
B38D B010     08269                 BCS SKIP193             ; ...the last 16 TICKs of its lifetime
              08270
B38F 8A       08271                 TXA                     ; Decrement volume of AUDC2's shadow register
B390 290F     08272                 AND #$0F                ;
B392 F003     08273                 BEQ SKIP192             ;
B394 CA       08274                 DEX                     ;
B395 86DC     08275                 STX NOISEAUDC2          ;
              08276
B397 98       08277 SKIP192         TYA                     ; Decrement volume of AUDC3's shadow register
B398 290F     08278                 AND #$0F                ;
B39A F003     08279                 BEQ SKIP193             ;
B39C 88       08280                 DEY                     ;
B39D 84DD     08281                 STY NOISEAUDC3          ;
              08282
B39F 8E03D2   08283 SKIP193         STX AUDC2               ; Store shadow register values to audio registers
B3A2 8C05D2   08284                 STY AUDC3               ;
              08285
B3A5 60       08286                 RTS                     ; Return
              08287
              08288 ;*******************************************************************************
              08289 ;*                                                                             *
              08290 ;*                                    BEEP                                     *
              08291 ;*                                                                             *
              08292 ;*                          Copy beeper sound pattern                          *
              08293 ;*                                                                             *
              08294 ;*******************************************************************************
              08295
              08296 ; DESCRIPTION
              08297 ;
              08298 ; Copies a 6-byte beeper sound pattern from beeper sound pattern table
              08299 ; BEEPPATTAB ($BF3E) to BEEPFRQIND ($D2)..BEEPFRQSTART ($D7), provided that no
              08300 ; beeper sound pattern with higher priority is currently playing. The beeper
              08301 ; sound pattern will then be automatically played in subroutine SOUND ($B2AB).
              08302 ; See subroutine SOUND ($B2AB) for more information on beeper sound patterns. 
              08303 ;
              08304 ; NOTE: The bytes from table BEEPPATTAB ($BF3E) are copied in reverse order.
              08305 ;
              08306 ; INPUT
              08307 ;
              08308 ;   X = Offset to beeper sound pattern in table BEEPPATTAB ($BF3E). Used values
              08309 ;       are:
              08310 ;     $00 -> HYPERWARP TRANSIT
              08311 ;     $06 -> RED ALERT
              08312 ;     $0C -> ACKNOWLEDGE
              08313 ;     $12 -> DAMAGE REPORT
              08314 ;     $18 -> MESSAGE FROM STARBASE
              08315
B3A6 BD3EBF   08316 BEEP            LDA BEEPPATTAB,X        ; Return if beeper sound pattern of...
B3A9 C5D6     08317                 CMP BEEPPRIORITY        ; ...higher priority is playing
B3AB 900C     08318                 BCC SKIP194             ;
              08319
B3AD A005     08320                 LDY #5                  ; Copy 6-byte beeper sound pattern (in reverse order)
B3AF BD3EBF   08321 LOOP059         LDA BEEPPATTAB,X        ;
B3B2 99D200   08322                 STA BEEPFRQIND,Y        ;
B3B5 E8       08323                 INX                     ;
B3B6 88       08324                 DEY                     ;
B3B7 10F6     08325                 BPL LOOP059             ;
              08326
B3B9 60       08327 SKIP194         RTS                     ; Return
              08328
              08329 ;*******************************************************************************
              08330 ;*                                                                             *
              08331 ;*                                 INITIALIZE                                  *
              08332 ;*                                                                             *
              08333 ;*                          More game initialization                           *
              08334 ;*                                                                             *
              08335 ;*******************************************************************************
              08336
              08337 ; DESCRIPTION
              08338 ;
              08339 ; This subroutine executes the following initialization steps:
              08340 ;
              08341 ; (1)  Set up Display List
              08342 ;
              08343 ;      A Display List is created at DSPLST ($0280). It starts with 2 x 8 = 16
              08344 ;      blank video lines, followed by 90 GRAPHICS7 rows. After a deliberate gap
              08345 ;      in Display List instructions, which will be filled dynamically during the
              08346 ;      game by calls to subroutine MODDLST ($ADF1), it ends with a Display List
              08347 ;      wait-and-jump-back instruction to the start of the Display List at DSPLST
              08348 ;      ($0280).
              08349 ;
              08350 ;      NOTE: The PLAYFIELD color table PFCOLORTAB ($BFA9) is copied to zero page
              08351 ;      table PF0COLOR ($F2) by loop jamming.
              08352 ;
              08353 ; (2)  Create lookup tables
              08354 ;
              08355 ;      The first lookup table MAPTO80 ($0DE9) maps a byte value of 0..255 to
              08356 ;      0..80. This table is used to map unsigned (absolute) position vector
              08357 ;      components (coordinates) to pixel (or PLAYER) row and column numbers.
              08358 ;
              08359 ;      NOTE: The PLAYFIELD is 160 pixels wide. Pixel column numbers relative the
              08360 ;      horizontal PLAYFIELD center are in -80..79, hence the range of this
              08361 ;      lookup table. Pixel row numbers relative the vertical PLAYFIELD center
              08362 ;      are in -50..49, thus they also fit in the range of this lookup table.
              08363 ;
              08364 ;      The second lookup table MAPTOBCD99 ($0EE9) maps a byte value of 0..255 to
              08365 ;      a BCD-encoded value in 00..99. This table is used to convert byte values
              08366 ;      into decimal 2-digit values displayed by the THETA (in "gradons"), PHI
              08367 ;      (in "gradons"), RANGE (in "centrons"), and VELOCITY (in "metrons per
              08368 ;      second") readouts of the Console Panel Display.
              08369 ;
              08370 ;      The third and fourth lookup tables accelerate drawing of PLAYFIELD space
              08371 ;      objects: In combination they contain the 16-bit start addresses of each
              08372 ;      of the 100 rows of PLAYFIELD memory. The low bytes of the 16-bit
              08373 ;      addresses are stored in table PFMEMROWLO ($0800). The high bytes are
              08374 ;      stored in table PFMEMROWHI ($0864).
              08375 ;
              08376 ;      NOTE: The address increment is 40 (40 bytes = 160 pixels in GRAPHICS7
              08377 ;      mode = 1 PLAYFIELD row of pixels). 
              08378 ;
              08379 ;      NOTE: The PLAYFIELD consists of 90 GRAPHICS7 rows when the Control Panel
              08380 ;      Display is displayed at the bottom. When the Control Panel Display is not
              08381 ;      displayed, for example in demo mode, the PLAYFIELD contains additional
              08382 ;      GRAPHICS7 rows.  
              08383 ;
              08384 ; (3)  Copy Control Panel Display and Galactic Chart Panel Display texts
              08385 ;
              08386 ;      The texts of the Control Panel Display and the Galactic Chart Panel
              08387 ;      Display are copied to their respective locations in memory by loop
              08388 ;      jamming.
              08389 ;
              08390 ; (4)  Initialize Zylon unit movement timer
              08391 ;
              08392 ;      The timer that triggers the movement of Zylon units in the Galactic Chart
              08393 ;      is initialized to a value of 99. See subroutine FLUSHGAMELOOP ($B4E4) for
              08394 ;      more information on Zylon unit movement.
              08395 ;
              08396 ; (5)  Create Galactic Chart
              08397 ;
              08398 ;      The Galactic Chart memory map GCMEMMAP ($08C9) is initialized. It
              08399 ;      represents 16 columns x 8 rows of sectors. Each sector contains one of
              08400 ;      the 4 sector types stored in table SECTORTYPETAB ($BBA6) (starbase, 4
              08401 ;      Zylon ships, 3 Zylon ships, and 2 or 1 Zylon ships), and empty sectors.
              08402 ;      Before distributing the sector types, the initial position of our
              08403 ;      starship is blocked on the Galactic Chart at sector row 4, sector column
              08404 ;      8, so that it will not be inadvertently occupied while other sector types
              08405 ;      are distributed. The number of each of the sector types to be distributed
              08406 ;      is the mission level plus 2. While Zylon units can be placed anywhere,
              08407 ;      starbases are placed neither at the borders of the Galactic Chart nor in
              08408 ;      a sector adjacent to an occupied sector. 
              08409 ;
              08410 ;      After having initialized the Galactic Chart memory map, the top border of
              08411 ;      the Galactic Chart is drawn with characters from the custom character
              08412 ;      set.
              08413 ;
              08414 ;      Finally, the sector in which our starship is located and the arrival and
              08415 ;      departure hyperwarp marker column and row numbers are initialized.
              08416 ;
              08417 ; (6)  Apply a final tweak
              08418 ;
              08419 ;      The last entry of lookup table MAPTOBCD99 ($0EE9) is tweaked to a value
              08420 ;      of CCS.INF * 16 + CCS.SPC. It is used to display an infinity symbol by
              08421 ;      the RANGE readout of the Control Panel Display in subroutine SHOWCOORD
              08422 ;      ($B8A7).
              08423 ;
              08424 ; Code execution continues into subroutine DRAWGC ($B4B9), which draws the
              08425 ; content of the Galactic Chart with characters from the custom character set.
              08426
    =0068     08427 L.MEMPTR1       = $68                   ; 16-bit memory pointer
    =006A     08428 L.MEMPTR2       = $6A                   ; 16-bit memory pointer
    =006A     08429 L.SECTORTYPE    = $6A                   ; Saves sector type. Used values are:
              08430                                         ;   $CF -> Sector contains starbase
              08431                                         ;   $04 -> Sector contains 4 Zylon ships
              08432                                         ;   $03 -> Sector contains 3 Zylon ships
              08433                                         ;   $02 -> Sector contains 2 or 1 Zylon ships
    =006B     08434 L.SECTORCNT     = $6B                   ; Saves number of sectors of the current sector type
              08435
              08436 ;*** Initialize Display List and copy color table ******************************
B3BA A259     08437 INITIALIZE      LDX #89                 ; Set 89(+1) GRAPHICS7 rows from DSPLST+5 on
B3BC A90D     08438 LOOP060         LDA #$0D                ; Prep DL instruction $0D (one row of GRAPHICS7)
B3BE 9D8502   08439                 STA DSPLST+5,X          ; DSPLST+5,X := one row of GRAPHICS7
B3C1 E00A     08440                 CPX #10                 ;
B3C3 B005     08441                 BCS SKIP195             ;
B3C5 BDA9BF   08442                 LDA PFCOLORTAB,X        ; Copy PLAYFIELD color table to zero page table
B3C8 95F2     08443                 STA PF0COLOR,X          ; (loop jamming)
B3CA CA       08444 SKIP195         DEX                     ;
B3CB 10EF     08445                 BPL LOOP060             ;
              08446
B3CD A970     08447                 LDA #$70                ; DSPLST     := BLK8
B3CF 8D8002   08448                 STA DSPLST              ; DSPLST+1   := BLK8
B3D2 8D8102   08449                 STA DSPLST+1            ;
B3D5 A941     08450                 LDA #$41                ; DSPLST+103 := WAITJMP @ DSPLST
B3D7 8DE702   08451                 STA DSPLST+103          ;
B3DA A980     08452                 LDA #<DSPLST            ;
B3DC 8DE802   08453                 STA DSPLST+104          ;
B3DF A902     08454                 LDA #>DSPLST            ;
B3E1 8DE902   08455                 STA DSPLST+105          ;
              08456
              08457 ;*** Calculate lookup tables ***************************************************
B3E4 A200     08458                 LDX #0                  ; Clear both 16-bit memory pointers
B3E6 8668     08459                 STX L.MEMPTR1           ;
B3E8 8669     08460                 STX L.MEMPTR1+1         ;
B3EA 866A     08461                 STX L.MEMPTR2           ;
B3EC 866B     08462                 STX L.MEMPTR2+1         ;
              08463
              08464 ;*** Calc MAPTO80 map (converts value of $00..$FF to value in 0..80) ***********
B3EE 18       08465 LOOP061         CLC                     ;
B3EF A568     08466                 LDA L.MEMPTR1           ;
B3F1 6951     08467                 ADC #81                 ;
B3F3 8568     08468                 STA L.MEMPTR1           ;
B3F5 A569     08469                 LDA L.MEMPTR1+1         ;
B3F7 9DE90D   08470                 STA MAPTO80,X           ;
B3FA 6900     08471                 ADC #0                  ;
B3FC 8569     08472                 STA L.MEMPTR1+1         ;
              08473
              08474 ;*** Calc MAPTOBCD99 map (converts value of $00..$FF to BCD-value in 00..99) ***
B3FE 18       08475                 CLC                     ;
B3FF A56A     08476                 LDA L.MEMPTR2           ;
B401 6964     08477                 ADC #100                ;
B403 856A     08478                 STA L.MEMPTR2           ;
B405 A56B     08479                 LDA L.MEMPTR2+1         ;
B407 9DE90E   08480                 STA MAPTOBCD99,X        ;
B40A F8       08481                 SED                     ;
B40B 6900     08482                 ADC #0                  ;
B40D D8       08483                 CLD                     ;
B40E 856B     08484                 STA L.MEMPTR2+1         ;
B410 E8       08485                 INX                     ;
B411 D0DB     08486                 BNE LOOP061             ;
              08487
              08488 ;*** Calculate PLAYFIELD memory row addresses, copy Panel Display texts ********
B413 A200     08489                 LDX #<PFMEM             ; Point L.MEMPTR1 to start of PLAYFIELD memory
B415 8668     08490                 STX L.MEMPTR1           ; (X = 0, because PFMEM is at $1000)
B417 A910     08491                 LDA #>PFMEM             ;
B419 8569     08492                 STA L.MEMPTR1+1         ;
              08493
B41B 18       08494 LOOP062         CLC                     ;
B41C A568     08495                 LDA L.MEMPTR1           ;
B41E 9D0008   08496                 STA PFMEMROWLO,X        ; Store 16-bit value of L.MEMPTR1 in PFMEMROWHI/LO
B421 6928     08497                 ADC #40                 ; Add 40 to L.MEMPTR
B423 8568     08498                 STA L.MEMPTR1           ; (40 bytes = 160 pixels = 1 PLAYFIELD row)
B425 A569     08499                 LDA L.MEMPTR1+1         ;
B427 9D6408   08500                 STA PFMEMROWHI,X        ;
B42A 6900     08501                 ADC #0                  ;
B42C 8569     08502                 STA L.MEMPTR1+1         ;
              08503
B42E BD42BB   08504                 LDA PANELTXTTAB,X       ; Copy Control and Galactic Chart Panel Display texts
B431 9D4909   08505                 STA PANELTXT,X          ; (loop jamming)
              08506
B434 E8       08507                 INX                     ;
B435 E064     08508                 CPX #100                ;
B437 90E2     08509                 BCC LOOP062             ; Loop 100 times
              08510
              08511 ;*** Set Zylon unit movement timer *********************************************
B439 CA       08512                 DEX                     ;
B43A 8678     08513                 STX ZYLONUNITTIM        ; Init Zylon unit movement timer to 99 game loops
              08514
              08515 ;*** Create memory map of the Galactic Chart ***********************************
B43C A203     08516                 LDX #3                  ; Loop over all 3(+1) sector types
B43E 8E1109   08517                 STX GCMEMMAP+4*16+8     ; Block our starship's initial position at center of
              08518                                         ; ...Galactic Chart (sector row 4, sector column 8)
              08519
B441 BDA6BB   08520 LOOP063         LDA SECTORTYPETAB,X     ; Prep sector type
B444 856A     08521                 STA L.SECTORTYPE        ;
              08522
B446 A462     08523                 LDY MISSIONLEVEL        ; Number sectors of current type := mission level + 2
B448 C8       08524                 INY                     ;
B449 C8       08525                 INY                     ;
B44A 846B     08526                 STY L.SECTORCNT         ;
              08527
B44C AD0AD2   08528 LOOP064         LDA RANDOM              ; Load random sector 0..127 from GC memory map
B44F 297F     08529                 AND #$7F                ;
B451 A8       08530                 TAY                     ;
B452 B9C908   08531                 LDA GCMEMMAP,Y          ;
B455 D0F5     08532                 BNE LOOP064             ; If sector already occupied, pick another
              08533
B457 A56A     08534                 LDA L.SECTORTYPE        ; Reload sector type
B459 1021     08535                 BPL SKIP196             ; Skip if sector not to be occupied by starbase
              08536
B45B C010     08537                 CPY #$10                ; Place starbase...
B45D 90ED     08538                 BCC LOOP064             ; ...not in first sector row of Galactic Chart
B45F C070     08539                 CPY #$70                ;
B461 B0E9     08540                 BCS LOOP064             ; ...not in last sector row of Galactic Chart
B463 98       08541                 TYA                     ;
B464 290F     08542                 AND #$0F                ;
B466 F0E4     08543                 BEQ LOOP064             ; ...not in first sector column of Galactic Chart
B468 C90F     08544                 CMP #15                 ;
B46A F0E0     08545                 BEQ LOOP064             ; ...not in last sector column of Galactic Chart
B46C B9C808   08546                 LDA GCMEMMAP-1,Y        ; ...not east  of an occupied sector
B46F 19CA08   08547                 ORA GCMEMMAP+1,Y        ; ...not west  of an occupied sector
B472 19D908   08548                 ORA GCMEMMAP+16,Y       ; ...not south of an occupied sector
B475 19B908   08549                 ORA GCMEMMAP-16,Y       ; ...not north of an occupied sector
B478 D0D2     08550                 BNE LOOP064             ;
              08551
B47A A56A     08552                 LDA L.SECTORTYPE        ; Reload sector type
              08553
B47C 99C908   08554 SKIP196         STA GCMEMMAP,Y          ; Store sector type in Galactic Chart memory map
B47F C66B     08555                 DEC L.SECTORCNT         ;
B481 10C9     08556                 BPL LOOP064             ; Next sector
B483 CA       08557                 DEX                     ;
B484 10BB     08558                 BPL LOOP063             ; Next sector type
              08559
              08560 ;*** Clear Galactic Chart and draw top border **********************************
B486 A2B4     08561                 LDX #180                ; Clear Galactic Chart PLAYFIELD
B488 A90A     08562 LOOP065         LDA #CCS.SPC            ;
B48A 9D340D   08563                 STA GCPFMEM-1,X         ;
B48D CA       08564                 DEX                     ;
B48E D0F8     08565                 BNE LOOP065             ;
              08566
B490 A20F     08567                 LDX #15                 ; Draw top border (15(+1) characters)
B492 A918     08568 LOOP066         LDA #CCS.BORDERS        ;
B494 9D370D   08569                 STA GCPFMEM+2,X         ;
B497 CA       08570                 DEX                     ;
B498 10F8     08571                 BPL LOOP066             ;
              08572
B49A A91A     08573                 LDA #CCS.CORNERSW       ; Draw NORTHEAST corner (1 character)
B49C 8D470D   08574                 STA GCPFMEM+18          ;
              08575
B49F A900     08576                 LDA #0                  ; Release starship's position at center of Galactic
B4A1 8D1109   08577                 STA GCMEMMAP+4*16+8     ; ...Chart (sector row 4, sector column 8)
              08578
              08579 ;*** Initialize current sector and hyperwarp marker column and row numbers *****
B4A4 A948     08580                 LDA #$48                ; Place our starship's current sector at
B4A6 8590     08581                 STA CURRSECTOR          ; ...sector row 4, sector column 8
B4A8 A943     08582                 LDA #$43                ; Init departure & arrival hyperwarp marker column
B4AA 858D     08583                 STA WARPDEPRCOLUMN      ;
B4AC 858F     08584                 STA WARPARRVCOLUMN      ;
B4AE A947     08585                 LDA #$47                ; Init departure & arrival hyperwarp marker row
B4B0 858E     08586                 STA WARPARRVROW         ;
B4B2 858C     08587                 STA WARPDEPRROW         ;
              08588
              08589 ;*** Tweak last entry of MAPTOBCD99 ********************************************
B4B4 A9EA     08590                 LDA #CCS.INF*16+CCS.SPC ; Last entry of MAPTOBCD99: 'INFINITY'+'SPACE' char
B4B6 8DE80F   08591                 STA MAPTOBCD99+255      ;
              08592
              08593 ;*******************************************************************************
              08594 ;*                                                                             *
              08595 ;*                                   DRAWGC                                    *
              08596 ;*                                                                             *
              08597 ;*                             Draw Galactic Chart                             *
              08598 ;*                                                                             *
              08599 ;*******************************************************************************
              08600
              08601 ; DESCRIPTION
              08602 ;
              08603 ; Draws the content of the Galactic Chart memory map in GCMEMMAP ($08C9) to the
              08604 ; Galactic Chart PLAYFIELD memory at GCPFMEM ($0D35). 
              08605 ;
              08606 ; NOTE: CPU register X indexes the Galactic Chart memory map GCMEMMAP ($08C9)
              08607 ; (16 x 8 bytes). CPU register Y indexes the Galactic Chart PLAYFIELD memory
              08608 ; GCPFMEM ($0D35) (20 x 9 bytes).
              08609 ;
              08610 ; NOTE: Sectors with 1 or 2 Zylon ships display the same symbol in the Galactic
              08611 ; Chart.
              08612
    =006A     08613 L.GCMEMMAPIND   = $6A                   ; Saves Galactic Chart memory map index
              08614
B4B9 A000     08615 DRAWGC          LDY #0                  ; Clear Galactic Chart PLAYFIELD memory index
B4BB 846A     08616                 STY L.GCMEMMAPIND       ; Clear Galactic Chart memory map index
              08617
B4BD A66A     08618 LOOP067         LDX L.GCMEMMAPIND       ; Load sector of Galactic Chart memory map
B4BF BDC908   08619                 LDA GCMEMMAP,X          ;
B4C2 1002     08620                 BPL SKIP197             ; Skip if not a starbase sector
B4C4 A905     08621                 LDA #5                  ; Prep sector character index for starbase
              08622
B4C6 AA       08623 SKIP197         TAX                     ; Load sector character index
B4C7 BDD1BE   08624                 LDA SECTORCHARTAB,X     ; Load custom character set code from table...
B4CA 994B0D   08625                 STA GCPFMEM+22,Y        ; ...and store it in Galactic Chart PLAYFIELD memory
B4CD C8       08626                 INY                     ; Increment Galactic Chart PLAYFIELD memory index
B4CE E66A     08627                 INC L.GCMEMMAPIND       ; Increment Galactic Chart memory map index
B4D0 A56A     08628                 LDA L.GCMEMMAPIND       ;
B4D2 290F     08629                 AND #$0F                ;
B4D4 D0E7     08630                 BNE LOOP067             ; Next sector column until right border reached
              08631
B4D6 A919     08632                 LDA #CCS.BORDERW        ; Draw right border
B4D8 994B0D   08633                 STA GCPFMEM+22,Y        ;
              08634
B4DB C8       08635                 INY                     ; Adjust Galactic Chart PLAYFIELD memory index
B4DC C8       08636                 INY                     ;
B4DD C8       08637                 INY                     ;
B4DE C8       08638                 INY                     ;
B4DF C0A0     08639                 CPY #$A0                ;
B4E1 90DA     08640                 BCC LOOP067             ; Next sector until bottom-right sector reached
              08641
B4E3 60       08642                 RTS                     ; Return
              08643
              08644 ;*******************************************************************************
              08645 ;*                                                                             *
              08646 ;*                                FLUSHGAMELOOP                                *
              08647 ;*                                                                             *
              08648 ;*         Handle remaining tasks at the end of a game loop iteration          *
              08649 ;*                                                                             *
              08650 ;*******************************************************************************
              08651
              08652 ; DESCRIPTION
              08653 ;
              08654 ; This subroutine handles at the end of a game loop iteration the following
              08655 ; tasks:
              08656 ;
              08657 ; (1)  Increment counters COUNT256 ($76) and COUNT8 ($72).
              08658 ;
              08659 ; (2)  If our starship's energy has dropped below 1000 units then flash a {PINK}
              08660 ;      alert that changes to {DARK GREY BLUE} and back to {PINK} every 128 game
              08661 ;      loop iterations.
              08662 ;
              08663 ; (3)  Set the Shields color and the Control Panel background color every 8 game
              08664 ;      loop iterations:
              08665 ;
              08666 ;      o   If the Shields are up and OK then set the Shields color to {DARK
              08667 ;          GREEN} and the Control Panel background color to {DARK BLUE}.
              08668 ;
              08669 ;      o   If the Shields are up and damaged there is a probability of 78%
              08670 ;          (200:256) that the Shield color is not changed.
              08671 ;
              08672 ;      o   If the Shields are down, damaged, or destroyed then set the Shields
              08673 ;          color to {BLACK}.
              08674 ;
              08675 ;      o   If the Shields are destroyed then set the Control Panel background
              08676 ;          color to {ORANGE}.
              08677 ;
              08678 ; (4)  Decrement the lifetime of our starship's and Zylon photon torpedoes.
              08679 ;
              08680 ; (5)  Decrement the lifetime of an explosion. If the explosion lifetime is less
              08681 ;      than 112 game loop iterations, clear HITBADNESS ($8A) (thus the explosion
              08682 ;      cannot destroy our starship). If the explosion lifetime is less than 24
              08683 ;      (?) game loops decrement the number of explosion fragments. This makes
              08684 ;      explosion fragments disappear gradually toward the end of an explosion.
              08685 ;
              08686 ; (6)  Increment every 40 game loop iterations the stardate clock of the
              08687 ;      Galactic Chart Panel Display.
              08688 ;
              08689 ; (7)  Move Zylon units in the Galactic Chart.
              08690 ;
              08691 ;      Every 50 game loop iterations (or 100 game loop iterations when a
              08692 ;      starbase is surrounded by Zylon units) decrement the score.
              08693 ;
              08694 ; Code execution continues if the game is not in demo mode with the following
              08695 ; steps:
              08696 ;
              08697 ; (1)  Search the Galactic Chart for starbases surrounded by Zylon units.
              08698 ;      Destroy any such starbase: Replace it with a 2-Zylon sector and subtract
              08699 ;      18 points from the score. If the Subspace Radio was not destroyed, then
              08700 ;      flash the title phrase "STARBASE DESTROYED" and play the beeper sound
              08701 ;      pattern MESSAGE FROM STARBASE in subroutine BEEP ($B3A6).
              08702 ;
              08703 ; (2)  Every 8 game loop iterations the Zylon units decide, which starbase to
              08704 ;      hunt: First, 128 randomly picked sectors are searched for a starbase. If
              08705 ;      no starbase was found in this way, the sectors of the Galactic Chart are
              08706 ;      scanned systematically left-to-right, top-to-bottom. If a starbase was
              08707 ;      found then its sector, sector column, and sector row are saved, otherwise
              08708 ;      code execution returns.
              08709 ;
              08710 ; (3)  Now the Zylon units converge toward the sector of the hunted starbase:
              08711 ;      All sectors of the Galactic Chart are scanned. For any sector with a
              08712 ;      Zylon unit that was not moved yet (its sector does not have the temporary
              08713 ;      "already-moved" bit B5 set) its movement probability value is picked from
              08714 ;      table MOVEPROBTAB ($BFBB):
              08715 ;
              08716 ;      +---------------+-------------+----------------+
              08717 ;      |  Sector Type  |  Movement   |   Movement     | 
              08718 ;      |               | Probability |  Probability   |
              08719 ;      |               |    Value    |                |
              08720 ;      +---------------+-------------+----------------+
              08721 ;      | Empty sector  |       0     |   0% (  0:256) | 
              08722 ;      | 1 Zylon ship  |     255     | 100% (255:256) |
              08723 ;      | 2 Zylon ships |     255     | 100% (255:256) | 
              08724 ;      | 3 Zylon ships |     192     |  75% (192:256) | 
              08725 ;      | 4 Zylon ships |      32     |  13% ( 32:256) |
              08726 ;      +---------------+-------------+----------------+
              08727 ;
              08728 ;      If this value is less or equal than a random number in 0..255 then the
              08729 ;      Zylon unit is moved to another sector. A Zylon unit that currently
              08730 ;      occupies the sector of our starship is not moved.
              08731 ;
              08732 ;      BUG (at $B620): The instruction to check the marker bit B5 of the sector
              08733 ;      is CPY #$0A. This works, as sectors containing Zylon units that need to
              08734 ;      be moved have values of 2..4, see table SECTORTYPETAB ($BBA6). Suggested
              08735 ;      fix: Replace CPY #$0A with CPY #$20, which may make the code clearer.
              08736 ;
              08737 ; (4)  For every Zylon unit that is about to be moved, 9 distances ("block
              08738 ;      distances") between the Zylon unit and the starbase are calculated by
              08739 ;      tentatively moving the Zylon unit into each of its 8 adjacent sectors -
              08740 ;      and by moving it not at all. The sector offsets are taken from table
              08741 ;      COMPASSOFFTAB ($BFC0) which stores direction offsets in the following
              08742 ;      order: NORTH, NORTHWEST, WEST, SOUTHWEST, SOUTH, SOUTHEAST, EAST,
              08743 ;      NORTHEAST, CENTER. All 9 distances are stored in 9 consecutive bytes at
              08744 ;      NEWZYLONDIST ($96).
              08745 ;
              08746 ;      NOTE: The last calculated distance is the current distance between Zylon
              08747 ;      unit and starbase.
              08748 ;
              08749 ;      The Zylon unit moves to the first of the 8 adjacent sectors that matches
              08750 ;      the following conditions: 
              08751 ;
              08752 ;      (1)  It is closer to the starbase than the Zylon unit's current sector.
              08753 ;
              08754 ;      (2)  It is located inside the Galactic Chart.
              08755 ;
              08756 ;      (3)  It is empty.
              08757 ;
              08758 ;      (4)  It is not the sector containing our starship.
              08759 ;
              08760 ;      If a suitable new sector was found then the Zylon unit is moved to this
              08761 ;      sector, which is marked with the "already-moved" marker bit B5 in the
              08762 ;      Galactic Chart memory map. This marker bit prevents a Zylon unit that has
              08763 ;      been already moved from being moved again. The old Zylon unit sector is
              08764 ;      cleared. 
              08765 ;
              08766 ;      If no suitable new sector was found then the above distance calculations
              08767 ;      are repeated once again by adding 1 to the current distance between the
              08768 ;      Zylon unit and the starbase. This may provoke a Zylon unit to move that
              08769 ;      would not have moved in the previous set of distance calculations.
              08770 ;
              08771 ;      After having moved all Zylon units the sectors are stripped of the
              08772 ;      "already-moved" marker bit B5.
              08773 ;
              08774 ; (5)  If a starbase has been surrounded then the Zylon unit movement timer is
              08775 ;      reset to 99, buying our starship some time to destroy one of the
              08776 ;      surrounding Zylon units. If the Subspace Radio is not destroyed, then the
              08777 ;      message "STARBASE SURROUNDED" is flashed in the title line and the beeper
              08778 ;      sound pattern MESSAGE FROM STARBASE is played in subroutine BEEP ($B3A6).
              08779
    =006A     08780 L.ISDESTROYED   = $6A                   ; Flags the destruction of a starbase.
              08781                                         ; Used values are:
              08782                                         ;   $00 -> Starbase not destroyed
              08783                                         ;   $02 -> Starbase has been destroyed
    =006A     08784 L.NEWSECTOR     = $6A                   ; Sector to which the Zylon unit is tentatively moved
    =006B     08785 L.ABSDIFFCOLUMN = $6B                   ; Absolute difference between new Zylon and starbase
              08786                                         ;   column on Galactic Chart in PM pixels
    =006B     08787 L.LOOPCNT2      = $6B                   ; Loop counter. Used values are: 0..1.
    =006A     08788 L.DIRECTIONIND  = $6A                   ; Compass rose direction index.
              08789                                         ; Used values are: 0..7.
              08790
              08791 ;*** Increment counters and flash low-energy alert *****************************
B4E4 E676     08792 FLUSHGAMELOOP   INC COUNT256            ; Increment COUNT256 counter
              08793
B4E6 A290     08794                 LDX #$90                ; Prep DLI background color {DARK GREY BLUE}
B4E8 A576     08795                 LDA COUNT256            ;
B4EA 1009     08796                 BPL SKIP198             ; Skip if counter < 128.
              08797
B4EC AC5509   08798                 LDY ENERGYD1            ; When energy drops below 1000 units...
B4EF C080     08799                 CPY #CCS.COL2!CCS.0     ;
B4F1 D002     08800                 BNE SKIP198             ;
B4F3 A244     08801                 LDX #$44                ; ...prep new DLI background color {PINK}
              08802
B4F5 2903     08803 SKIP198         AND #$03                ; Increment COUNT8
B4F7 8572     08804                 STA COUNT8              ;
B4F9 D01F     08805                 BNE SKIP202             ; Skip setting colors but every 8 game loops
              08806
              08807 ;*** Set Shields and Control Panel background color ****************************
B4FB A47D     08808                 LDY DRAINSHIELDS        ; Skip if Shields are off
B4FD F017     08809                 BEQ SKIP201             ;
              08810
B4FF A0A0     08811                 LDY #$A0                ; Prep Shields color {DARK GREEN}
B501 2C9409   08812                 BIT GCSTATSHL           ; Skip if Shields are OK
B504 100B     08813                 BPL SKIP200             ;
B506 7007     08814                 BVS SKIP199             ; Skip if Shields are destroyed
B508 AD0AD2   08815                 LDA RANDOM              ; If Shields are damaged, Shields colors are...
B50B C9C8     08816                 CMP #200                ; ...unchanged with probability of 78% (200:256)
B50D 9007     08817                 BCC SKIP201             ;
              08818
B50F A000     08819 SKIP199         LDY #$00                ; Prep Shields color {BLACK}
B511 98       08820 SKIP200         TYA                     ;
B512 D002     08821                 BNE SKIP201             ;
              08822
B514 A226     08823                 LDX #$26                ; Prep Control Panel background color {ORANGE}
              08824
B516 8481     08825 SKIP201         STY SHIELDSCOLOR        ; Store Shields color
B518 86FB     08826                 STX BGRCOLORDLI         ; Store Control Panel background color
              08827
              08828 ;*** Decrement lifetime of our starship's and Zylon photon torpedoes ***********
B51A A202     08829 SKIP202         LDX #2                  ; Loop over PLAYER2..4
              08830
B51C BD8E0C   08831 LOOP068         LDA PL2SHAPTYPE,X       ; Next PLAYER if not PHOTON TORPEDO (shape type 0)
B51F D006     08832                 BNE SKIP203             ;
              08833
B521 B5EB     08834                 LDA PL2LIFE,X           ; Next PLAYER if this PLAYER not alive
B523 F002     08835                 BEQ SKIP203             ;
              08836
B525 D6EB     08837                 DEC PL2LIFE,X           ; Decrement photon torpedo PLAYER lifetime
              08838
B527 CA       08839 SKIP203         DEX                     ;
B528 10F2     08840                 BPL LOOP068             ; Next PLAYER
              08841
              08842 ;*** Decrement lifetime of explosion *******************************************
B52A A573     08843                 LDA EXPLLIFE            ; Skip if explosion lifetime expired
B52C F016     08844                 BEQ SKIP206             ;
              08845
B52E C673     08846                 DEC EXPLLIFE            ; Decrement explosion lifetime
B530 D004     08847                 BNE SKIP204             ; Skip if explosion lifetime still counting
              08848
B532 A211     08849                 LDX #NUMSPCOBJ.NORM     ; Explosion finished,...
B534 8679     08850                 STX MAXSPCOBJIND        ; ...restore normal number of space objects
              08851
B536 C970     08852 SKIP204         CMP #112                ; Skip if explosion lifetime >= 112 game loops
B538 B004     08853                 BCS SKIP205             ;
              08854
B53A A200     08855                 LDX #0                  ; HITBADNESS := NO HIT
B53C 868A     08856                 STX HITBADNESS          ;
              08857
B53E C918     08858 SKIP205         CMP #24                 ; Skip if explosion lifetime >= 24 game loops (?)
B540 B002     08859                 BCS SKIP206             ;
              08860
B542 C679     08861                 DEC MAXSPCOBJIND        ; Decrement number of explosion fragment space objs
              08862
              08863 ;*** Increment stardate clock **************************************************
B544 C674     08864 SKIP206         DEC CLOCKTIM            ; Decrement stardate clock timer
B546 1021     08865                 BPL SKIP209             ; Return if timer is still counting
              08866
B548 A928     08867                 LDA #40                 ; Reset stardate clock timer to 40 game loops
B54A 8574     08868                 STA CLOCKTIM            ;
              08869
B54C A204     08870                 LDX #4                  ; Increment stardate clock of Galactic Chart Panel
B54E FEA309   08871 LOOP069         INC GCSTARDAT,X         ;
B551 BDA309   08872                 LDA GCSTARDAT,X         ;
B554 C9DA     08873                 CMP #[CCS.COL3!ROM.9]+1 ;
B556 900D     08874                 BCC SKIP208             ;
B558 A9D0     08875                 LDA #[CCS.COL3!ROM.0]   ;
B55A 9DA309   08876                 STA GCSTARDAT,X         ;
B55D E003     08877                 CPX #3                  ;
B55F D001     08878                 BNE SKIP207             ;
B561 CA       08879                 DEX                     ;
B562 CA       08880 SKIP207         DEX                     ;
B563 10E9     08881                 BPL LOOP069             ;
              08882
              08883 ;*** Decrement Zylon unit movement timer ***************************************
B565 C678     08884 SKIP208         DEC ZYLONUNITTIM        ; Decrement Zylon unit movement timer
B567 3001     08885                 BMI SKIP210             ; If timer < 0 move Zylon units
              08886
B569 60       08887 SKIP209         RTS                     ; Return
              08888
              08889 ;*** Restore Zylon unit movement timer and decrement score *********************
B56A A931     08890 SKIP210         LDA #49                 ; Reset Zylon unit movement timer to 49
B56C 8578     08891                 STA ZYLONUNITTIM        ;
              08892
B56E A5CB     08893                 LDA SCORE               ; SCORE := SCORE - 1
B570 D002     08894                 BNE SKIP211             ;
B572 C6CC     08895                 DEC SCORE+1             ;
B574 C6CB     08896 SKIP211         DEC SCORE               ;
              08897
B576 A664     08898                 LDX ISDEMOMODE          ; Return if in demo mode
B578 D0EF     08899                 BNE SKIP209             ;
              08900
              08901 ;*** Is starbase surrounded? ***************************************************
B57A 866A     08902                 STX L.ISDESTROYED       ; Init L.ISDESTROYED with 0 (starbase not destroyed)
B57C BDC908   08903 LOOP070         LDA GCMEMMAP,X          ; Loop over all sectors, load sector type
B57F 1019     08904                 BPL SKIP212             ; Skip if not a starbase sector
              08905
B581 20F1B7   08906                 JSR ISSURROUNDED        ; Skip if starbase sector not completely surrounded
B584 F014     08907                 BEQ SKIP212             ;
              08908
              08909 ;*** Starbase is surrounded, destroy starbase **********************************
B586 A902     08910                 LDA #2                  ; Replace starbase sector with 2-Zylon sector
B588 9DC908   08911                 STA GCMEMMAP,X          ;
B58B 856A     08912                 STA L.ISDESTROYED       ; Flag destruction of starbase
              08913
B58D 38       08914                 SEC                     ; SCORE := SCORE - 18
B58E A5CB     08915                 LDA SCORE               ;
B590 E912     08916                 SBC #18                 ;
B592 85CB     08917                 STA SCORE               ;
B594 A5CC     08918                 LDA SCORE+1             ;
B596 E900     08919                 SBC #0                  ;
B598 85CC     08920                 STA SCORE+1             ;
              08921
B59A E8       08922 SKIP212         INX                     ;
B59B 10DF     08923                 BPL LOOP070             ; Next sector
              08924
              08925 ;*** Report starbase destruction ***********************************************
B59D A56A     08926                 LDA L.ISDESTROYED       ; Skip if no starbase has been destroyed
B59F F00F     08927                 BEQ SKIP213             ;
              08928
B5A1 2C9709   08929                 BIT GCSTATRAD           ; Skip notification if Subspace Radio destroyed
B5A4 700A     08930                 BVS SKIP213             ;
              08931
B5A6 A015     08932                 LDY #$15                ; Set title phrase "STARBASE DESTROYED"
B5A8 2023B2   08933                 JSR SETTITLE            ;
              08934
B5AB A218     08935                 LDX #$18                ; Play beeper sound pattern MESSAGE FROM STARBASE
B5AD 20A6B3   08936                 JSR BEEP                ;
              08937
              08938 ;*** Pick new starbase to be hunted by Zylon units *****************************
B5B0 C69F     08939 SKIP213         DEC HUNTTIM             ; Decrement hunting timer
B5B2 3007     08940                 BMI SKIP214             ; If timer < 0 decide which starbase to hunt
              08941
B5B4 A693     08942                 LDX HUNTSECTOR          ; Skip if Zylon units already picked starbase to hunt
B5B6 BDC908   08943                 LDA GCMEMMAP,X          ;
B5B9 301F     08944                 BMI SKIP215             ;
              08945
B5BB A907     08946 SKIP214         LDA #7                  ; Reset hunting timer
B5BD 859F     08947                 STA HUNTTIM             ;
              08948
B5BF A07F     08949                 LDY #127                ; Loop over 127(+1) randomly picked sectors
B5C1 AD0AD2   08950 LOOP071         LDA RANDOM              ;
B5C4 297F     08951                 AND #$7F                ;
B5C6 AA       08952                 TAX                     ;
B5C7 BDC908   08953                 LDA GCMEMMAP,X          ; Skip if starbase sector found
B5CA 300E     08954                 BMI SKIP215             ;
B5CC 88       08955                 DEY                     ;
B5CD 10F2     08956                 BPL LOOP071             ; Next sector
              08957
B5CF A27F     08958                 LDX #127                ; Loop over all sectors of the Galactic Chart
B5D1 BDC908   08959 LOOP072         LDA GCMEMMAP,X          ;
B5D4 3004     08960                 BMI SKIP215             ; Skip if starbase sector found
B5D6 CA       08961                 DEX                     ;
B5D7 10F8     08962                 BPL LOOP072             ; Next sector
              08963
B5D9 60       08964                 RTS                     ; Return (no starbase sector found)
              08965
              08966 ;*** Store coordinates of starbase to be hunted ********************************
B5DA 8693     08967 SKIP215         STX HUNTSECTOR          ; Store hunted starbase sector column and row
B5DC 8A       08968                 TXA                     ;
B5DD 290F     08969                 AND #$0F                ;
B5DF 8594     08970                 STA HUNTSECTCOLUMN      ;
B5E1 8A       08971                 TXA                     ;
B5E2 4A       08972                 LSR A                   ;
B5E3 4A       08973                 LSR A                   ;
B5E4 4A       08974                 LSR A                   ;
B5E5 4A       08975                 LSR A                   ;
B5E6 8595     08976                 STA HUNTSECTROW         ;
              08977
              08978 ;*** Move all Zylon units toward hunted starbase *******************************
B5E8 A2FF     08979                 LDX #$FF                ;
B5EA E8       08980 LOOP073         INX                     ; Loop over all sectors to move Zylon units
B5EB 1030     08981                 BPL SKIP218             ; Jump into loop body below
              08982
              08983 ;*** Strip marker bits from moved Zylon units **********************************
B5ED A200     08984                 LDX #0                  ;
B5EF BDC908   08985 LOOP074         LDA GCMEMMAP,X          ; Loop over all sectors
B5F2 29DF     08986                 AND #$DF                ;
B5F4 9DC908   08987                 STA GCMEMMAP,X          ; Strip marker bit B5 from moved Zylon units
B5F7 E8       08988                 INX                     ;
B5F8 10F5     08989                 BPL LOOP074             ; Next sector
              08990
              08991 ;*** Handle surrounded starbase ************************************************
B5FA 2C9709   08992                 BIT GCSTATRAD           ; Return if Subspace Radio is destroyed
B5FD 701D     08993                 BVS SKIP217             ;
              08994
B5FF A200     08995                 LDX #0                  ; Loop over all sectors
B601 BDC908   08996 LOOP075         LDA GCMEMMAP,X          ;
B604 1013     08997                 BPL SKIP216             ; Skip if not a starbase sector
B606 20F1B7   08998                 JSR ISSURROUNDED        ; Skip if starbase not surrounded
B609 F00E     08999                 BEQ SKIP216             ;
              09000
B60B A963     09001                 LDA #99                 ; Yes, starbase surrounded...
B60D 8578     09002                 STA ZYLONUNITTIM        ; ...set Zylon unit movement timer to 99
              09003
B60F A013     09004                 LDY #$13                ; Set title phrase "STARBASE SURROUNDED"
B611 2023B2   09005                 JSR SETTITLE            ;
              09006
B614 A218     09007                 LDX #$18                ; Play beeper sound pattern MESSAGE FROM STARBASE...
B616 4CA6B3   09008                 JMP BEEP                ; ...and return
              09009
B619 E8       09010 SKIP216         INX                     ;
B61A 10E5     09011                 BPL LOOP075             ; Next sector
              09012
B61C 60       09013 SKIP217         RTS                     ; Return
              09014
              09015 ;*** Move single Zylon unit ****************************************************
B61D BCC908   09016 SKIP218         LDY GCMEMMAP,X          ; X contains current sector
B620 C00A     09017                 CPY #$0A                ; Next sector if it has marker bit B5 set (!)
B622 B0C6     09018                 BCS LOOP073             ;
              09019
B624 AD0AD2   09020                 LDA RANDOM              ; Get random number
B627 D9BBBF   09021                 CMP MOVEPROBTAB,Y       ; Get movement probability
B62A B0BE     09022                 BCS LOOP073             ; Next sector if movement probability < random number
              09023
B62C E490     09024                 CPX CURRSECTOR          ; Next sector if this is our starship's sector
B62E F0BA     09025                 BEQ LOOP073             ;
              09026
              09027 ;*** Compute distance to starbase by moving Zylon unit into 9 directions *******
B630 A008     09028                 LDY #8                  ; Loop over 8(+1) possible directions
B632 18       09029 LOOP076         CLC                     ;
B633 8A       09030                 TXA                     ;
B634 79C0BF   09031                 ADC COMPASSOFFTAB,Y     ; Add direction offset to current sector
B637 856A     09032                 STA L.NEWSECTOR         ; Store new sector
              09033
B639 290F     09034                 AND #$0F                ; Calc distance ("block distance") between...
B63B 38       09035                 SEC                     ; ...starbase sector and tentative new Zylon sector
B63C E594     09036                 SBC HUNTSECTCOLUMN      ;
B63E B004     09037                 BCS SKIP219             ;
B640 49FF     09038                 EOR #$FF                ;
B642 6901     09039                 ADC #1                  ;
B644 856B     09040 SKIP219         STA L.ABSDIFFCOLUMN     ;
B646 A56A     09041                 LDA L.NEWSECTOR         ;
B648 4A       09042                 LSR A                   ;
B649 4A       09043                 LSR A                   ;
B64A 4A       09044                 LSR A                   ;
B64B 4A       09045                 LSR A                   ;
B64C 38       09046                 SEC                     ;
B64D E595     09047                 SBC HUNTSECTROW         ;
B64F B004     09048                 BCS SKIP220             ;
B651 49FF     09049                 EOR #$FF                ;
B653 6901     09050                 ADC #1                  ;
B655 18       09051 SKIP220         CLC                     ;
B656 656B     09052                 ADC L.ABSDIFFCOLUMN     ;
              09053
B658 999600   09054                 STA NEWZYLONDIST,Y      ; Store distance in distance array
B65B 88       09055                 DEY                     ;
B65C 10D4     09056                 BPL LOOP076             ; Next direction
              09057
              09058 ;*** Pick the shortest distance to starbase ************************************
B65E A901     09059                 LDA #1                  ; Loop over compass rose directions twice to...
B660 856B     09060                 STA L.LOOPCNT2          ; ...provoke movement regardless of truncation errors
              09061
B662 A007     09062 LOOP077         LDY #7                  ;
B664 B99600   09063 LOOP078         LDA NEWZYLONDIST,Y      ; Loop over all 7(+1) compass rose directions
B667 C59E     09064                 CMP OLDZYLONDIST        ;
B669 B024     09065                 BCS SKIP222             ; Next direction if new distance > current distance
              09066
B66B 18       09067                 CLC                     ; Calc new Galactic Chart sector for Zylon unit
B66C 8A       09068                 TXA                     ;
B66D 79C0BF   09069                 ADC COMPASSOFFTAB,Y     ;
B670 301D     09070                 BMI SKIP222             ; Next direction if new sector outside Galactic Chart
              09071
B672 846A     09072                 STY L.DIRECTIONIND      ; Save compass rose direction index
B674 A8       09073                 TAY                     ;
B675 B9C908   09074                 LDA GCMEMMAP,Y          ;
B678 D013     09075                 BNE SKIP221             ; Next direction if new sector not empty
              09076
B67A BDC908   09077                 LDA GCMEMMAP,X          ; Preload Zylon sector type to be moved
B67D C490     09078                 CPY CURRSECTOR          ;
B67F F00C     09079                 BEQ SKIP221             ; Next direction if sector is our starship's sector
              09080
B681 0920     09081                 ORA #$20                ; New sector for Zylon unit found!
B683 99C908   09082                 STA GCMEMMAP,Y          ; Temporarily mark that sector with marker bit B5
B686 A900     09083                 LDA #0                  ;
B688 9DC908   09084                 STA GCMEMMAP,X          ; Clear old Zylon unit sector
B68B F00B     09085                 BEQ SKIP223             ; Next sector (unconditional branch)
              09086
B68D A46A     09087 SKIP221         LDY L.DIRECTIONIND      ; Restore compass rose direction index
B68F 88       09088 SKIP222         DEY                     ; Next compass rose direction
B690 10D2     09089                 BPL LOOP078             ;
              09090
B692 E69E     09091                 INC OLDZYLONDIST        ; Increment center distance
B694 C66B     09092                 DEC L.LOOPCNT2          ;
B696 10CA     09093                 BPL LOOP077             ; Loop over all compass rose directions one more time
              09094
B698 4CEAB5   09095 SKIP223         JMP LOOP073             ; Next sector
              09096
              09097 ; *******************************************************************************
              09098 ; *                                                                             *
              09099 ; *                                   ROTATE                                    *
              09100 ; *                                                                             *
              09101 ; *        Rotate position vector component (coordinate) by fixed angle         *
              09102 ; *                                                                             *
              09103 ; *******************************************************************************
              09104
              09105 ; DESCRIPTION
              09106 ;
              09107 ; This subroutine rotates a position vector component (coordinate) of a space
              09108 ; object by a fixed angle around the center of the 3D coordinate system, the
              09109 ; location of our starship. This is used in the Front, Aft, and Long-Range Scan
              09110 ; views to rotate space objects in and out of the view. Although the code is
              09111 ; deceptively short, there is some interesting math involved, so a more detailed
              09112 ; discussion is in order.
              09113 ;
              09114 ; ROTATION MATHEMATICS
              09115 ;
              09116 ; The game uses a left-handed 3D coordinate system with the positive x-axis
              09117 ; pointing to the right, the positive y-axis pointing up, and the positive
              09118 ; z-axis pointing into flight direction.
              09119 ;
              09120 ; A rotation in this coordinate system around the y-axis (horizontal rotation)
              09121 ; can be expressed as 
              09122 ;
              09123 ;     x' :=   cos(ry) * x + sin(ry) * z    (1a)
              09124 ;     z' := - sin(ry) * x + cos(ry) * z    (1b)
              09125 ;
              09126 ; where ry is the clockwise rotation angle around the y-axis, x and z are the
              09127 ; coordinates before this rotation, and the primed coordinates x' and z' the
              09128 ; coordinates after this rotation. The y-coordinate is not changed by this
              09129 ; rotation.
              09130 ;
              09131 ; A rotation in this coordinate system around the x-axis (vertical rotation) can
              09132 ; be expressed as 
              09133 ;
              09134 ;     z' :=   cos(rx) * z + sin(rx) * y    (2a)
              09135 ;     y' := - sin(rx) * z + cos(rx) * y    (2b)
              09136 ;
              09137 ; where rx is the clockwise rotation angle around the x-axis, z and y are the
              09138 ; coordinates before this rotation, and the primed coordinates z' and y' the
              09139 ; coordinates after this rotation. The x-coordinate is not changed by this
              09140 ; rotation.
              09141 ;
              09142 ; SUBROUTINE IMPLEMENTATION OVERVIEW
              09143 ;
              09144 ; A single call of this subroutine is able to compute one of the four
              09145 ; expressions (1a)-(2b). To compute all four expressions to get the new set of
              09146 ; coordinates, this subroutine has to be called four times. This is done twice
              09147 ; in pairs in GAMELOOP ($A1F3) at $A391 and $A398, and at $A3AE and $A3B5,
              09148 ; respectively.
              09149 ;
              09150 ; The first pair of calls calculates the new x and z coordinates of a space
              09151 ; object due to a horizontal (left/right) rotation of our starship around the
              09152 ; y-axis following expressions (1a) and (1b).
              09153 ;
              09154 ; The second pair of calls calculates the new y and z coordinates of the same
              09155 ; space object due to a vertical (up/down) rotation of our starship around the
              09156 ; x-axis following expressions (2a) and (2b).
              09157 ;
              09158 ; If you look at the code, you may be wondering how this calculation is actually
              09159 ; executed, as there is neither a sin() nor a cos() function call. What you'll
              09160 ; actually find implemented, however, are the following calculations:
              09161 ;
              09162 ;     Joystick left                        Joystick right
              09163 ;     ---------------------                ---------------------
              09164 ;     x :=  x      + z / 64    (3a)        x :=  x      - z / 64    (4a)
              09165 ;     z := -x / 64 + z         (3b)        z :=  x / 64 + z         (4b)
              09166 ;
              09167 ;     Joystick down                        Joystick up
              09168 ;     ---------------------                ---------------------
              09169 ;     y :=  y      + z / 64    (5a)        y :=  y      - z / 64    (6a)
              09170 ;     z := -y / 64 + z         (5b)        z :=  y / 64 + z         (6b)
              09171 ;
              09172 ; CORDIC ALGORITHM
              09173 ;
              09174 ; When you compare expressions (1a)-(2b) with (3a)-(6b), notice the similarity
              09175 ; between the expressions if you substitute
              09176 ;
              09177 ;     sin(ry) -> 1 / 64, 
              09178 ;     cos(ry) -> 1,
              09179 ;     sin(rx) -> 1 / 64, and
              09180 ;     cos(rx) -> 1.
              09181 ;
              09182 ; From sin(ry) = 1 / 64 and sin(rx) = 1 / 64 you can derive that the rotation
              09183 ; angles ry and rx by which the space object is rotated per game loop iteration
              09184 ; have a constant value of 0.89 degrees, as arcsine(1 / 64) = 0.89 degrees.
              09185 ;
              09186 ; What about cos(ry) and cos(rx)? The substitution does not match our derived
              09187 ; angle exactly, because cos(0.89 degrees) = 0.99988 and is not exactly 1.
              09188 ; However, this value is so close to 1 that substituting cos(0.89 degrees) with
              09189 ; 1 is a very good approximation, simplifying calculations significantly.
              09190 ;
              09191 ; Another significant simplification results from the division by 64, because
              09192 ; the actual division operation can be replaced with a much faster bit shift
              09193 ; operation.
              09194 ;
              09195 ; This calculation-friendly way of computing rotations is known as the "CORDIC
              09196 ; (COordinate Rotation DIgital Computer)" algorithm.
              09197 ;
              09198 ; MINSKY ROTATION
              09199 ;
              09200 ; There is one more interesting mathematical subtlety: Did you notice that
              09201 ; expressions (1a)-(2b) use a new (primed) pair of variables to store the
              09202 ; resulting coordinates, whereas in the implemented expressions (3a)-(6b) the
              09203 ; value of the first coordinate of a coordinate pair is overwritten with its new
              09204 ; value and this value is used in the subsequent calculation of the second
              09205 ; coordinate? For example, when the joystick is pushed left, the first call of
              09206 ; this subroutine calculates the new value of x according to expression (3a),
              09207 ; overwriting the old value of x. During the second call to calculate z
              09208 ; according to expression (3b), the new value of x is used instead of the old
              09209 ; one. Is this to save the memory needed to temporarily store the old value of
              09210 ; x? Is this a bug? If so, why does the rotation calculation actually work?
              09211 ;
              09212 ; Have a look at the expression pair (3a) and (3b) (the other expression pairs
              09213 ; (4a)-(6b) work in a similar fashion):
              09214 ;
              09215 ;     x :=  x      + z / 64
              09216 ;     z := -x / 64 + z
              09217 ;
              09218 ; With the substitution 1 / 64 -> e, we get
              09219 ;
              09220 ;     x :=  x     + e * z
              09221 ;     z := -e * x + z
              09222 ;
              09223 ; Note that x is calculated first and then used in the second expression. When
              09224 ; using primed coordinates for the resulting coordinates after calculating the
              09225 ; two expressions we get
              09226 ;
              09227 ;     x' := x + e * z
              09228 ;     z' := -e * x' + z = -e * (x + e * z) + z = -e * x + (1 - e^2) * z
              09229 ;
              09230 ; or in matrix form
              09231 ;
              09232 ;     |x'| := | 1       e   | * |x|
              09233 ;     |z'|    |-e  (1 - e^2)|   |z|
              09234 ;
              09235 ; Surprisingly, this turns out to be a rotation matrix, because its determinant
              09236 ; is (1 * (1 - e^2) - (e * -e)) = 1.
              09237 ;
              09238 ; (Incidentally, the column vectors of this matrix do not form an orthogonal
              09239 ; basis, as their scalar product is 1 * e + (-e * (1 - e^2)) = -e^2.
              09240 ; Orthogonality holds for e = 0 only.)
              09241 ;
              09242 ; This kind of rotation calculation is described by Marvin Minsky in ["AIM 239
              09243 ; HAKMEM", Item 149, p. 73, MIT AI Lab, February 1972] and is called "Minsky
              09244 ; Rotation".
              09245 ;
              09246 ; SUBROUTINE IMPLEMENTATION DETAILS
              09247 ;
              09248 ; To better understand how the implementation of this subroutine works, have
              09249 ; again a look at expressions (3a)-(6b). If you rearrange the expressions a
              09250 ; little their structure is always of the form
              09251 ;
              09252 ;     TERM1 := TERM1 SIGN TERM2 / 64
              09253 ;
              09254 ;     or shorter
              09255 ;
              09256 ;     TERM1 := TERM1 SIGN TERM3
              09257 ;
              09258 ;     where
              09259 ;
              09260 ;     TERM3 := TERM2 / 64
              09261 ;     SIGN := + or -
              09262 ;
              09263 ; and where TERM1 and TERM2 are position vector components (coordinates). In
              09264 ; fact, this is all this subroutine actually does: It simply adds TERM2 divided
              09265 ; by 64 to TERM1 or subtracts TERM2 divided by 64 from TERM1. 
              09266 ;
              09267 ; When calling this subroutine the correct indices for the appropriate position
              09268 ; vector components (coordinates) TERM1 and TERM2 are passed in the Y and X
              09269 ; registers, respectively.
              09270 ;
              09271 ; What about SIGN between TERM1 and TERM3? Have again a look at expressions
              09272 ; (3a)-(6b). To compute the two new coordinates after a rotation, the SIGN
              09273 ; toggles from plus to minus and vice versa. The SIGN is initialized with
              09274 ; JOYSTICKDELTA ($6D) before calling subroutine ROTATE ($B69B) and is toggled
              09275 ; inside every call of this subroutine before the addition or subtraction of the
              09276 ; terms takes place there. The initial value of SIGN should be positive (+) if
              09277 ; the rotation is clockwise (the joystick is pushed right or up) and negative
              09278 ; (-) if the rotation is counter-clockwise (the joystick is pushed left or
              09279 ; down), respectively. Because SIGN is always toggled inside the subroutine
              09280 ; before the addition or subtraction of the terms actually happens there, you
              09281 ; have to pass the already toggled value with the first call.
              09282 ;
              09283 ; NOTE: Unclear still are three instructions starting at address $B6AD. They
              09284 ; seem to set the two least significant bits of TERM3 in a random fashion. Could
              09285 ; this be some quick hack to avoid messing with exact but potentially lengthy
              09286 ; two-complement's arithmetic here?
              09287 ;
              09288 ; INPUT
              09289 ;
              09290 ;   X = Position vector component index of TERM2. Used values are:
              09291 ;     $00..$30 -> z-component (z-coordinate) of position vector 0..48
              09292 ;     $31..$61 -> x-component (x-coordinate) of position vector 0..48
              09293 ;     $62..$92 -> y-component (y-coordinate) of position vector 0..48
              09294 ;
              09295 ;   Y = Position vector component index of TERM1. Used values are: 
              09296 ;     $00..$30 -> z-component (z-coordinate) of position vector 0..48
              09297 ;     $31..$61 -> x-component (x-coordinate) of position vector 0..48
              09298 ;     $62..$92 -> y-component (y-coordinate) of position vector 0..48
              09299 ;
              09300 ;   JOYSTICKDELTA ($6D) = Initial value of SIGN. Used values are:
              09301 ;     $01 -> (= Positive) Rotate right or up
              09302 ;     $FF -> (= Negative) Rotate left or down
              09303
              09304                                         ; TERM3 is a 24-bit value, represented by 3 bytes as
              09305                                         ; $(sign)(high byte)(low byte)
    =006A     09306 L.TERM3LO       = $6A                   ; TERM3 (high byte), where TERM3 := TERM2 / 64
    =006B     09307 L.TERM3HI       = $6B                   ; TERM3 (low byte),  where TERM3 := TERM2 / 64
    =006C     09308 L.TERM3SIGN     = $6C                   ; TERM3 (sign),      where TERM3 := TERM2 / 64
              09309
B69B BDAD09   09310 ROTATE          LDA ZPOSSIGN,X          ;
B69E 4901     09311                 EOR #$01                ;
B6A0 F002     09312                 BEQ SKIP224             ; Skip if sign of TERM2 is positive
B6A2 A9FF     09313                 LDA #$FF                ;
              09314
B6A4 856B     09315 SKIP224         STA L.TERM3HI           ; If TERM2 pos. -> TERM3 := $0000xx (= TERM2 / 256)
B6A6 856C     09316                 STA L.TERM3SIGN         ; If TERM2 neg. -> TERM3 := $FFFFxx (= TERM2 / 256)
B6A8 BD400A   09317                 LDA ZPOSHI,X            ; where xx := TERM2 (high byte)
B6AB 856A     09318                 STA L.TERM3LO           ;
              09319
B6AD AD0AD2   09320                 LDA RANDOM              ; (?) Hack to avoid messing with two-complement's
B6B0 09BF     09321                 ORA #$BF                ; (?) arithmetic? Provides two least significant
B6B2 5DD30A   09322                 EOR ZPOSLO,X            ; (?) bits B1..0 in TERM3.
              09323
B6B5 0A       09324                 ASL A                   ; TERM3 := TERM3 * 4 (= TERM2 / 256 * 4 = TERM2 / 64)
B6B6 266A     09325                 ROL L.TERM3LO           ;
B6B8 266B     09326                 ROL L.TERM3HI           ;
B6BA 0A       09327                 ASL A                   ;
B6BB 266A     09328                 ROL L.TERM3LO           ;
B6BD 266B     09329                 ROL L.TERM3HI           ;
              09330
B6BF A56D     09331                 LDA JOYSTICKDELTA       ; Toggle SIGN for next call of ROTATE
B6C1 49FF     09332                 EOR #$FF                ;
B6C3 856D     09333                 STA JOYSTICKDELTA       ;
B6C5 301A     09334                 BMI SKIP225             ; If SIGN negative then subtract, else add TERM3
              09335
              09336 ;*** Addition ******************************************************************
B6C7 18       09337                 CLC                     ; TERM1 := TERM1 + TERM3
B6C8 B9D30A   09338                 LDA ZPOSLO,Y            ; (24-bit addition)
B6CB 656A     09339                 ADC L.TERM3LO           ;
B6CD 99D30A   09340                 STA ZPOSLO,Y            ;
              09341
B6D0 B9400A   09342                 LDA ZPOSHI,Y            ;
B6D3 656B     09343                 ADC L.TERM3HI           ;
B6D5 99400A   09344                 STA ZPOSHI,Y            ;
              09345
B6D8 B9AD09   09346                 LDA ZPOSSIGN,Y          ;
B6DB 656C     09347                 ADC L.TERM3SIGN         ;
B6DD 99AD09   09348                 STA ZPOSSIGN,Y          ;
B6E0 60       09349                 RTS                     ;
              09350
              09351 ;*** Subtraction ***************************************************************
B6E1 38       09352 SKIP225         SEC                     ; TERM1 := TERM1 - TERM3
B6E2 B9D30A   09353                 LDA ZPOSLO,Y            ; (24-bit subtraction)
B6E5 E56A     09354                 SBC L.TERM3LO           ;
B6E7 99D30A   09355                 STA ZPOSLO,Y            ;
              09356
B6EA B9400A   09357                 LDA ZPOSHI,Y            ;
B6ED E56B     09358                 SBC L.TERM3HI           ;
B6EF 99400A   09359                 STA ZPOSHI,Y            ;
              09360
B6F2 B9AD09   09361                 LDA ZPOSSIGN,Y          ;
B6F5 E56C     09362                 SBC L.TERM3SIGN         ;
B6F7 99AD09   09363                 STA ZPOSSIGN,Y          ;
B6FA 60       09364                 RTS                     ;
              09365
              09366 ;*******************************************************************************
              09367 ;*                                                                             *
              09368 ;*                                SCREENCOLUMN                                 *
              09369 ;*                                                                             *
              09370 ;*       Calculate pixel column number from centered pixel column number       *
              09371 ;*                                                                             *
              09372 ;*******************************************************************************
              09373
              09374 ; DESCRIPTION
              09375 ;
              09376 ; Converts a pixel column number relative to the horizontal screen center to a
              09377 ; pixel column number relative to the top-left corner of the screen and stores
              09378 ; the result in table PIXELCOLUMN ($0C2A). The passed relative pixel column
              09379 ; number is always positive. The sign is picked from the corresponding
              09380 ; x-component of the position vector (x-coordinate).
              09381 ;
              09382 ; If the passed relative pixel column number is offscreen horizontally the
              09383 ; calculation is skipped and code execution returns. If the position vector
              09384 ; corresponding to this pixel represents a PLAYFIELD space object (star,
              09385 ; explosion fragments) a new position vector is initialized before code
              09386 ; execution returns. If it represents a PLAYER space object the PLAYER is pushed
              09387 ; offscreen before code execution returns.
              09388 ;
              09389 ; NOTE: The horizontal screen center's pixel column number for PLAYFIELD space
              09390 ; objects has a value of 80 = 160 PLAYFIELD pixels / 2. For PLAYER space objects
              09391 ; it has a value of 125 Player/Missile (PM) pixels (from left to right: 128 PM
              09392 ; pixels to the horizontal screen center - 3 PM pixels relative offset of the
              09393 ; PLAYER shape's horizontal center to its left edge = 125 PM pixels).
              09394 ;
              09395 ; INPUT
              09396 ;
              09397 ;   A = Pixel column number relative to the horizontal screen center, always
              09398 ;       positive. Used values are:
              09399 ;     0..80 -> Regular values, pixel is onscreen
              09400 ;     $FF   -> Pixel is offscreen
              09401 ;
              09402 ;   X = Position vector index. Used values are:
              09403 ;     0..4  -> Position vector of a PLAYER space object
              09404 ;     5..48 -> Position vector of a PLAYFIELD space object
              09405
    =006D     09406 L.PIXELCOLUMN   = $6D                   ; Saves relative pixel column number
              09407
B6FB C950     09408 SCREENCOLUMN    CMP #80                 ; If pixel is offscreen (A > 79)...
B6FD B05B     09409                 BCS SKIP233             ; ...return via initializing a new position vector
              09410
B6FF 856D     09411                 STA L.PIXELCOLUMN       ; Save relative pixel column number
B701 A950     09412                 LDA #80                 ; If PLAYFIELD space object -> A := CENTERCOL = 80
B703 E005     09413                 CPX #NUMSPCOBJ.PL       ; If PLAYER space object    -> A := CENTERCOL = 125
B705 B002     09414                 BCS SKIP226             ;
B707 A97D     09415                 LDA #125                ;
              09416
B709 BCDE09   09417 SKIP226         LDY XPOSSIGN,X          ; Skip if x-coordinate positive
B70C D009     09418                 BNE SKIP227             ;
              09419
B70E 38       09420                 SEC                     ; Pixel in left screen half (x-coordinate negative)
B70F E66D     09421                 INC L.PIXELCOLUMN       ;
B711 E56D     09422                 SBC L.PIXELCOLUMN       ;
B713 9D2A0C   09423                 STA PIXELCOLUMN,X       ; Pixel column := CENTERCOL - (rel. pixel column + 1)
B716 60       09424                 RTS                     ; Return
              09425
B717 18       09426 SKIP227         CLC                     ; Pixel in right screen half (x-coordinate positive)
B718 656D     09427                 ADC L.PIXELCOLUMN       ;
B71A 9D2A0C   09428                 STA PIXELCOLUMN,X       ; Pixel column := CENTERCOL + relative pixel column
B71D 60       09429                 RTS                     ; Return
              09430
              09431 ;*******************************************************************************
              09432 ;*                                                                             *
              09433 ;*                                  SCREENROW                                  *
              09434 ;*                                                                             *
              09435 ;*          Calculate pixel row number from centered pixel row number          *
              09436 ;*                                                                             *
              09437 ;*******************************************************************************
              09438
              09439 ; Converts a pixel row number relative to the vertical screen center to a pixel
              09440 ; row number relative to the top-left corner of the screen and stores the result
              09441 ; in table PIXELROWNEW ($0BF9). The passed relative pixel row number is always
              09442 ; positive. The sign is picked from the corresponding y-component of the
              09443 ; position vector (y-coordinate).
              09444 ;
              09445 ; If the passed relative pixel row number is offscreen vertically the
              09446 ; calculation is skipped and code execution returns. If the position vector
              09447 ; corresponding to this pixel represents a PLAYFIELD space object (star,
              09448 ; explosion fragments) a new position vector is initialized in subroutine
              09449 ; INITPOSVEC ($B764) before code execution returns. If it represents a PLAYER
              09450 ; space object the PLAYER is pushed offscreen before code execution returns.
              09451 ;
              09452 ; NOTE: The vertical screen center's pixel row number for PLAYFIELD space
              09453 ; objects has a value of 50 = 100 PLAYFIELD pixels / 2. For PLAYER space objects
              09454 ; it has a value of 122 Player/Missile (PM) pixels (from top to bottom: 8 PM
              09455 ; pixels to start of Display List + 16 PM pixels to begin of PLAYFIELD + 100 PM
              09456 ; pixels to vertical screen center - 2 PM pixels (?) = 122 PM pixels).
              09457 ;
              09458 ; NOTE: If the position vector corresponding to the pixel represents a PLAYER
              09459 ; space object the passed pixel row number is doubled because 1 PLAYFIELD pixel
              09460 ; has the same height as 2 PM pixels at single-line resolution.
              09461 ;
              09462 ; When in Long-Range Scan view the z-coordinate takes the place of the
              09463 ; y-coordinate of the Front or Aft view. If the Long-Range Scan is damaged the
              09464 ; passed pixel row number is treated randomly as a negative or positive value
              09465 ; (mirror effect).
              09466 ;
              09467 ; INPUT
              09468 ;
              09469 ;   A = Pixel row number relative to the vertical screen center, always
              09470 ;       positive. Used values are:
              09471 ;     0..50 -> Regular values, pixel is onscreen
              09472 ;     $FF   -> Pixel is offscreen
              09473 ;
              09474 ;   X = Position vector index. Used values are:
              09475 ;     0..4  -> Position vector of a PLAYER space object
              09476 ;     5..48 -> Position vector of a PLAYFIELD space object
              09477
    =006D     09478 L.PIXELROW      = $6D                   ; Saves relative pixel row number
              09479
B71E C932     09480 SCREENROW       CMP #50                 ; If pixel is offscreen (A > 49)...
B720 B038     09481                 BCS SKIP233             ; ...return via initializing a new position vector
              09482
B722 856D     09483                 STA L.PIXELROW          ; Save relative pixel row number
B724 A932     09484                 LDA #50                 ; If PLAYFIELD space object -> A := CENTERROW = 50
B726 E005     09485                 CPX #NUMSPCOBJ.PL       ;
B728 B004     09486                 BCS SKIP228             ;
B72A 066D     09487                 ASL L.PIXELROW          ; If PLAYER space object -> Double pixel row number
B72C A97A     09488                 LDA #122                ; If PLAYER space object ->    A := CENTERROW = 122
              09489
B72E 24D0     09490 SKIP228         BIT SHIPVIEW            ; Skip if not in Long-Range Scan view
B730 5013     09491                 BVC SKIP230             ;
              09492
B732 2C9609   09493                 BIT GCSTATLRS           ; Skip if Long-Range Scan OK
B735 1007     09494                 BPL SKIP229             ;
              09495
B737 2C0AD2   09496                 BIT RANDOM              ; Long-Range Scan damaged...
B73A 500E     09497                 BVC SKIP231             ; ...branch randomly to pixel row number calculation
B73C 7015     09498                 BVS SKIP232             ; ...(mirror effect)
              09499
B73E BCAD09   09500 SKIP229         LDY ZPOSSIGN,X          ;
B741 D007     09501                 BNE SKIP231             ; Skip if z-coordinate pos. (Long-Range Scan view)
B743 F00E     09502                 BEQ SKIP232             ; Skip if z-coordinate neg. (Long-Range Scan view)
              09503
B745 BC0F0A   09504 SKIP230         LDY YPOSSIGN,X          ;
B748 F009     09505                 BEQ SKIP232             ; Skip if y-coordinate neg. (Front or Aft view)
              09506
B74A 38       09507 SKIP231         SEC                     ; Pixel in upper screen half (z or y coordinate pos.)
B74B E66D     09508                 INC L.PIXELROW          ;
B74D E56D     09509                 SBC L.PIXELROW          ;
B74F 9DF90B   09510                 STA PIXELROWNEW,X       ; Pixel row  := CENTERROW - (rel. pixel row + 1)
B752 60       09511                 RTS                     ; Return
              09512
B753 18       09513 SKIP232         CLC                     ; Pixel in lower screen half (y or z coordinate neg.)
B754 656D     09514                 ADC L.PIXELROW          ;
B756 9DF90B   09515                 STA PIXELROWNEW,X       ; Pixel row := CENTERROW + relative pixel row
B759 60       09516                 RTS                     ; Return
              09517
B75A E005     09518 SKIP233         CPX #NUMSPCOBJ.PL       ; Space object is offscreen. If it is a...
B75C B006     09519                 BCS INITPOSVEC          ; ...PLAYFIELD space object -> New position vector
B75E A9FB     09520                 LDA #251                ; ...PLAYER space object    -> Push PLAYER offscreen
B760 9DF90B   09521                 STA PIXELROWNEW,X       ;                              Why a value of 251 (?)
B763 60       09522 SKIP234         RTS                     ; Return
              09523
              09524 ;*******************************************************************************
              09525 ;*                                                                             *
              09526 ;*                                 INITPOSVEC                                  *
              09527 ;*                                                                             *
              09528 ;*                Initialize position vector of a space object                 *
              09529 ;*                                                                             *
              09530 ;*******************************************************************************
              09531
              09532 ; DESCRIPTION
              09533 ;
              09534 ; Initializes the position vector of a space object.
              09535 ;
              09536 ; This subroutine executes the following steps:
              09537 ;
              09538 ; (1)  Set the pixel row and column number to an offscreen value (= 99).
              09539 ;
              09540 ; (2)  If the position vector represents an explosion fragment space object then
              09541 ;      return code execution immediately. This avoids generating new explosion
              09542 ;      fragment space objects. They are separately initialized in subroutine
              09543 ;      COPYPOSVEC ($ACAF), which is called from subroutine INITEXPL ($AC6B).
              09544 ;
              09545 ; (3)  Assign default values (see below) to the position vector components
              09546 ;      (coordinates) depending on our starship's view.
              09547 ;
              09548 ; Code execution continues into subroutine RNDINVXY ($B7BE) where x and y
              09549 ; coordinates are inverted randomly.
              09550 ;
              09551 ; After passing through this and the next subroutine RNDINVXY ($B7BE) the
              09552 ; components of a position vector (coordinates) are assigned to one of the
              09553 ; following values depending on our starship's view:
              09554 ;
              09555 ; o   FRONT VIEW
              09556 ;
              09557 ;     +------------+---------------------------------------+
              09558 ;     | Coordinate |                 Values                |
              09559 ;     +------------+---------------------------------------+
              09560 ;     |     x      |  -4095..+4095 (-($0***)..+$0***) <KM> |
              09561 ;     |     y      |  -4095..+4095 (-($0***)..+$0***) <KM> | 
              09562 ;     |     z      |  +3840..+4095 (          +$0F**) <KM> |
              09563 ;     +------------+---------------------------------------+
              09564 ;
              09565 ; o   AFT VIEW
              09566 ;
              09567 ;     +------------+---------------------------------------+
              09568 ;     | Coordinate |                 Values                |
              09569 ;     +------------+---------------------------------------+ 
              09570 ;     |     x      |  -3840..+3840 (-($0*00)..+$0*00) <KM> |
              09571 ;     |     y      |  -3840..+3840 (-($0*00)..+$0*00) <KM> |
              09572 ;     |     z      |  -3968.. -128 (-($0*80)        ) <KM> |
              09573 ;     +------------+---------------------------------------+ 
              09574 ;     Values of x, y, and z coordinates change in increments of 256.
              09575 ;     Second digit of z-coordinate is -MAX(RNDY,RNDX), where
              09576 ;     RNDY := RND($00..$0F), RNDX := RND($00..$0F).
              09577 ;
              09578 ; o   LONG-RANGE SCAN VIEW
              09579 ;
              09580 ;     +------------+---------------------------------------+
              09581 ;     | Coordinate |                 Values                |
              09582 ;     +------------+---------------------------------------+
              09583 ;     |     x      | -65535..+65535 (-($****)..$****) <KM> |
              09584 ;     |     y      |  -4095..+4095  (-($0***)..$0***) <KM> |
              09585 ;     |     z      | -65535..+65535 (-($****)..$****) <KM> |
              09586 ;     +------------+---------------------------------------+
              09587 ;
              09588 ; INPUT
              09589 ;
              09590 ;   X = Position vector index. Used values are: 0..48.
              09591
    =006A     09592 L.MAXRNDXY      = $6A                   ; Saves MAX(new y-coordinate (high byte), ...
              09593                                         ;  ...new x-coordinate (high byte))
              09594
B764 A963     09595 INITPOSVEC      LDA #99                 ; Init to offscreen pixel row and column numbers
B766 9DF90B   09596                 STA PIXELROWNEW,X       ;
B769 9D2A0C   09597                 STA PIXELCOLUMN,X       ;
              09598
B76C E011     09599                 CPX #NUMSPCOBJ.NORM     ; Return if pos vector is explosion frag space obj
B76E B0F3     09600                 BCS SKIP234             ; This avoids creating new explosion frag space objs
              09601
B770 AD0AD2   09602                 LDA RANDOM              ; RNDY := RND($00..$0F)
B773 290F     09603                 AND #$0F                ;
B775 856A     09604                 STA L.MAXRNDXY          ; Save RNDY
B777 9DA20A   09605                 STA YPOSHI,X            ; y-coordinate (high byte) := RNDY
              09606
B77A AD0AD2   09607                 LDA RANDOM              ; RNDX := RND($00..$0F)
B77D 290F     09608                 AND #$0F                ;
B77F C56A     09609                 CMP L.MAXRNDXY          ;
B781 9002     09610                 BCC SKIP235             ;
B783 856A     09611                 STA L.MAXRNDXY          ; Save MAX(RNDY,RNDX)
B785 9D710A   09612 SKIP235         STA XPOSHI,X            ; x-coordinate (high byte) := RNDX
              09613
B788 A90F     09614                 LDA #$0F                ; z-coordinate (high byte) := $0F
B78A 9D400A   09615                 STA ZPOSHI,X            ;
              09616
B78D A5D0     09617                 LDA SHIPVIEW            ; z-coordinate (sign) := 1 or 0 (Front or Aft view)
B78F 4901     09618                 EOR #$01                ;
B791 2901     09619                 AND #$01                ;
B793 9DAD09   09620                 STA ZPOSSIGN,X          ;
B796 D011     09621                 BNE SKIP236             ; Skip if in Front or Long-Range Scan view
              09622
              09623                                         ; Aft view only:
B798 9D040B   09624                 STA XPOSLO,X            ; x-coordinate (low byte) := 0
B79B 9D350B   09625                 STA YPOSLO,X            ; y-coordinate (low byte) := 0
B79E 38       09626                 SEC                     ; z-coordinate (high byte) := -MAX(RNDY,RNDX)
B79F E56A     09627                 SBC L.MAXRNDXY          ;
B7A1 9D400A   09628                 STA ZPOSHI,X            ;
B7A4 A980     09629                 LDA #$80                ; z-coordinate (low byte) := $80
B7A6 9DD30A   09630                 STA ZPOSLO,X            ;
              09631
B7A9 24D0     09632 SKIP236         BIT SHIPVIEW            ; If not in Long-Range Scan view skip to RNDINVXY
B7AB 5011     09633                 BVC RNDINVXY            ;
              09634
              09635                                         ; Long-Range Scan view only:
B7AD AD0AD2   09636                 LDA RANDOM              ; x-coordinate (high byte) := RND($00..$FF)
B7B0 9D710A   09637                 STA XPOSHI,X            ;
B7B3 AD0AD2   09638                 LDA RANDOM              ; z-coordinate (high byte) := RND($00..$FF)
B7B6 9D400A   09639                 STA ZPOSHI,X            ;
B7B9 2901     09640                 AND #$01                ; Invert z-coordinate randomly
B7BB 9DAD09   09641                 STA ZPOSSIGN,X          ;
              09642
              09643 ;*******************************************************************************
              09644 ;*                                                                             *
              09645 ;*                                  RNDINVXY                                   *
              09646 ;*                                                                             *
              09647 ;*         Randomly invert the x and y components of a position vector         *
              09648 ;*                                                                             *
              09649 ;*******************************************************************************
              09650
              09651 ; DESCRIPTION
              09652 ;
              09653 ; Randomly inverts the x and y components of a position vector (x and y
              09654 ; coordinates). See also subroutine INITPOSVEC ($B764).
              09655 ;
              09656 ; INPUT
              09657 ;
              09658 ;   X = Position vector index. Used values are: 0..48.
              09659
B7BE AD0AD2   09660 RNDINVXY        LDA RANDOM              ; Set sign of y-coordinate randomly
B7C1 2901     09661                 AND #$01                ;
B7C3 9D0F0A   09662                 STA YPOSSIGN,X          ;
B7C6 D00F     09663                 BNE SKIP237             ; Skip if sign positive
              09664
B7C8 38       09665                 SEC                     ; Sign negative -> Calc negative y-coordinate
B7C9 FD350B   09666                 SBC YPOSLO,X            ; (calculate two's-complement of 16-bit value)
B7CC 9D350B   09667                 STA YPOSLO,X            ;
B7CF A900     09668                 LDA #0                  ;
B7D1 FDA20A   09669                 SBC YPOSHI,X            ;
B7D4 9DA20A   09670                 STA YPOSHI,X            ;
              09671
B7D7 AD0AD2   09672 SKIP237         LDA RANDOM              ; Set sign of x-coordinate randomly
B7DA 2901     09673                 AND #$01                ;
B7DC 9DDE09   09674                 STA XPOSSIGN,X          ;
B7DF D00F     09675                 BNE SKIP238             ; Skip if sign positive
              09676
B7E1 38       09677                 SEC                     ; Sign negative -> Calc negative x-coordinate
B7E2 FD040B   09678                 SBC XPOSLO,X            ; (calculate two's-complement of 16-bit value)
B7E5 9D040B   09679                 STA XPOSLO,X            ;
B7E8 A900     09680                 LDA #0                  ;
B7EA FD710A   09681                 SBC XPOSHI,X            ;
B7ED 9D710A   09682                 STA XPOSHI,X            ;
B7F0 60       09683 SKIP238         RTS                     ; Return
              09684
              09685 ;*******************************************************************************
              09686 ;*                                                                             *
              09687 ;*                                ISSURROUNDED                                 *
              09688 ;*                                                                             *
              09689 ;*               Check if a sector is surrounded by Zylon units                *
              09690 ;*                                                                             *
              09691 ;*******************************************************************************
              09692
              09693 ; DESCRIPTION
              09694 ;
              09695 ; Checks if a sector of the Galactic Chart is surrounded by Zylon units in the
              09696 ; adjacent NORTH, EAST, SOUTH, and WEST sectors.
              09697 ;
              09698 ; INPUT
              09699 ;
              09700 ;   X = Sector of Galactic Chart. Used values are: $00..$7F with, for example,
              09701 ;     $00 -> NORTHWEST corner sector
              09702 ;     $0F -> NORTHEAST corner sector
              09703 ;     $70 -> SOUTHWEST corner sector
              09704 ;     $7F -> SOUTHWEST corner sector
              09705 ;
              09706 ; OUTPUT
              09707 ;
              09708 ;   A = Returns if the sector is surrounded by Zylon units in the adjacent
              09709 ;       NORTH, EAST, SOUTH, and WEST sectors.
              09710 ;       0 -> Sector is not surrounded
              09711 ;     > 0 -> Sector is surrounded
              09712
B7F1 BDC808   09713 ISSURROUNDED    LDA GCMEMMAP-1,X        ; Check WEST sector
B7F4 F00D     09714                 BEQ SKIP239             ;
B7F6 BDCA08   09715                 LDA GCMEMMAP+1,X        ; Check EAST sector
B7F9 F008     09716                 BEQ SKIP239             ;
B7FB BDB908   09717                 LDA GCMEMMAP-16,X       ; Check NORTH sector
B7FE F003     09718                 BEQ SKIP239             ;
B800 BDD908   09719                 LDA GCMEMMAP+16,X       ; Check SOUTH sector
B803 60       09720 SKIP239         RTS                     ; Return
              09721
              09722 ;*******************************************************************************
              09723 ;*                                                                             *
              09724 ;*                                  UPDPANEL                                   *
              09725 ;*                                                                             *
              09726 ;*                        Update Control Panel Display                         *
              09727 ;*                                                                             *
              09728 ;*******************************************************************************
              09729
              09730 ; DESCRIPTION
              09731 ;
              09732 ; This subroutine executes the following steps: 
              09733 ;
              09734 ; (1)  Accelerate or decelerate our starship, update the VELOCITY readout
              09735 ;
              09736 ;      If the new velocity value is different from the current one either
              09737 ;      increment or decrement the current velocity value toward the new one.
              09738 ;
              09739 ;      If the Engines are damaged or destroyed (and hyperwarp is not engaged)
              09740 ;      then store a random value (less or equal than the current velocity) as
              09741 ;      the current velocity.
              09742 ;
              09743 ;      Display the updated velocity by the VELOCITY readout of the Control Panel
              09744 ;      Display.
              09745 ;
              09746 ; (2)  Update THETA, PHI, and RANGE readouts.
              09747 ;
              09748 ;      If the Attack Computer is working then display the x, y, and z
              09749 ;      coordinates of the currently tracked space object as THETA, PHI, and
              09750 ;      RANGE readout values of the Control Panel Display.
              09751 ;
              09752 ; (3)  Calculate overall energy consumption.
              09753 ;
              09754 ;      Add the overall energy consumption per game loop iteration to the energy
              09755 ;      counter. This value is given in energy subunits (256 energy subunits = 1
              09756 ;      energy unit displayed by the 4-digit ENERGY readout of the Console Panel
              09757 ;      Display). It is the total of the following items:
              09758 ;
              09759 ;      (1)  8 energy subunits if the Shields are up
              09760 ;
              09761 ;      (2)  2 energy subunits if the Attack Computer is on
              09762 ;
              09763 ;      (3)  1 energy subunit of the life support system
              09764 ;
              09765 ;      (4)  Our starship's Engines energy drain rate (depending on its velocity)
              09766 ;
              09767 ;      If there is a carryover of the energy counter then decrement the ENERGY
              09768 ;      readout of the Control Panel Display by one energy unit after code
              09769 ;      execution has continued into subroutine DECENERGY ($B86F). 
              09770
              09771 ;*** Accelerate or decelerate our starship *************************************
B804 A670     09772 UPDPANEL        LDX VELOCITYLO          ; Skip if new velocity = current velocity
B806 E471     09773                 CPX NEWVELOCITY         ;
B808 F008     09774                 BEQ SKIP241             ;
              09775
B80A 9004     09776                 BCC SKIP240             ; In/decrement current velocity toward new velocity
B80C C670     09777                 DEC VELOCITYLO          ;
B80E B012     09778                 BCS SKIP242             ;
B810 E670     09779 SKIP240         INC VELOCITYLO          ;
              09780
B812 A5C0     09781 SKIP241         LDA WARPSTATE           ; Skip if hyperwarp engaged
B814 D00C     09782                 BNE SKIP242             ;
              09783
B816 2C9309   09784                 BIT GCSTATENG           ; Skip if Engines are OK
B819 1007     09785                 BPL SKIP242             ;
              09786
B81B A571     09787                 LDA NEWVELOCITY         ; Store RND(0..current velocity) to current velocity
B81D 2D0AD2   09788                 AND RANDOM              ;
B820 8570     09789                 STA VELOCITYLO          ;
              09790
B822 A001     09791 SKIP242         LDY #VELOCD1-PANELTXT-1 ; Update digits of VELOCITY readout
B824 20CDB8   09792                 JSR SHOWDIGITS          ;
              09793
              09794 ;*** Display coordinates of tracked space object of Control Panel Display ******
B827 2C9509   09795                 BIT GCSTATCOM           ; Skip if Attack Computer damaged or destroyed
B82A 3030     09796                 BMI SKIP243             ;
              09797
B82C A931     09798                 LDA #$31                ; Update THETA readout (x-coordinate)
B82E A017     09799                 LDY #THETAC1-PANELTXT   ;
B830 20A7B8   09800                 JSR SHOWCOORD           ;
              09801
B833 A962     09802                 LDA #$62                ; Update PHI readout (y-coordinate)
B835 A01D     09803                 LDY #PHIC1-PANELTXT     ;
B837 20A7B8   09804                 JSR SHOWCOORD           ;
              09805
B83A A900     09806                 LDA #$00                ; Update RANGE readout (z-coordinate)
B83C A023     09807                 LDY #RANGEC1-PANELTXT   ;
B83E 20A7B8   09808                 JSR SHOWCOORD           ;
              09809
B841 AD6E09   09810                 LDA RANGEC1+2           ; Hack to clear RANGE digit 3 when in hyperwarp:
B844 8D6F09   09811                 STA RANGEC1+3           ; Copy RANGE digit 2 to digit 3
B847 C90A     09812                 CMP #CCS.9+1            ; Skip if digit character > '9' (= 'infinity' char)
B849 B011     09813                 BCS SKIP243             ;
              09814
B84B AE5C09   09815                 LDX TRACKDIGIT          ; Get z-coordinate (low byte) of tracked space object
B84E BDD30A   09816                 LDA ZPOSLO,X            ;
B851 4A       09817                 LSR A                   ; ...divide it by 16...
B852 4A       09818                 LSR A                   ;
B853 4A       09819                 LSR A                   ;
B854 4A       09820                 LSR A                   ;
B855 AA       09821                 TAX                     ;
B856 BDE90E   09822                 LDA MAPTOBCD99,X        ; ...map value of $00..$0F to BCD value 0..9
B859 8D6F09   09823                 STA RANGEC1+3           ; ...and store it to RANGE digit 3
              09824
              09825 ;*** Calculate overall energy consumption **************************************
B85C 18       09826 SKIP243         CLC                     ;
B85D A57F     09827                 LDA ENERGYCNT           ; Load energy counter
B85F 657D     09828                 ADC DRAINSHIELDS        ; Add energy drain rate of Shields
B861 6580     09829                 ADC DRAINENGINES        ; Add energy drain rate of our starship's Engines
B863 657E     09830                 ADC DRAINATTCOMP        ; Add energy drain rate of Attack Computer
B865 6901     09831                 ADC #$01                ; Add 1 energy subunit of life support system
B867 C57F     09832                 CMP ENERGYCNT           ;
B869 857F     09833                 STA ENERGYCNT           ;
B86B B039     09834                 BCS SKIP246             ; Return if no energy counter carryover
              09835
B86D A203     09836                 LDX #3                  ; Will decrement third energy digit
              09837
              09838 ;*******************************************************************************
              09839 ;*                                                                             *
              09840 ;*                                  DECENERGY                                  *
              09841 ;*                                                                             *
              09842 ;*                               Decrease energy                               *
              09843 ;*                                                                             *
              09844 ;*******************************************************************************
              09845
              09846 ; DESCRIPTION
              09847 ;
              09848 ; When not in demo mode, subtract energy from the 4-digit ENERGY readout of the
              09849 ; Control Panel Display. If crossing a 100-energy-unit boundary during
              09850 ; subtraction the score is decremented by one unit. If the energy is zero the
              09851 ; game is over.
              09852 ;
              09853 ; INPUT
              09854 ;
              09855 ;   X = ENERGY readout digit to be decremented. Used values are:
              09856 ;     1 -> Subtract 100 units from ENERGY readout
              09857 ;     2 -> Subtract  10 units from ENERGY readout
              09858 ;     3 -> Subtract   1 unit  from ENERGY readout
              09859
              09860 ;*** Display ENERGY readout ****************************************************
B86F 2464     09861 DECENERGY       BIT ISDEMOMODE          ; Return if in demo mode
B871 7033     09862                 BVS SKIP246             ;
              09863
B873 DE5509   09864                 DEC ENERGYD1,X          ; Decrement energy digit character
B876 BD5509   09865                 LDA ENERGYD1,X          ;
B879 C980     09866                 CMP #CCS.COL2!CCS.0     ;
B87B B029     09867                 BCS SKIP246             ; Return if digit character >= '0'
B87D A989     09868                 LDA #CCS.COL2!CCS.9     ;
B87F 9D5509   09869                 STA ENERGYD1,X          ; Store digit character '9'
              09870
              09871 ;*** Decrement score when crossing a 100-energy-unit boundary while subtracting 
B882 E002     09872                 CPX #2                  ; Skip if no crossing of 100-energy-unit boundary
B884 D008     09873                 BNE SKIP245             ;
              09874
B886 A5CB     09875                 LDA SCORE               ; SCORE := SCORE - 1
B888 D002     09876                 BNE SKIP244             ;
B88A C6CC     09877                 DEC SCORE+1             ;
B88C C6CB     09878 SKIP244         DEC SCORE               ;
              09879
B88E CA       09880 SKIP245         DEX                     ;
B88F 10DE     09881                 BPL DECENERGY           ; Next digit
              09882
              09883 ;*** Energy is zero, game over *************************************************
B891 A20A     09884                 LDX #CCS.SPC            ; Clear 4-digit ENERGY readout
B893 8A       09885                 TXA                     ;
B894 A003     09886                 LDY #3                  ;
B896 995509   09887 LOOP079         STA ENERGYD1,Y          ;
B899 88       09888                 DEY                     ;
B89A 10FA     09889                 BPL LOOP079             ;
              09890
B89C 2045B0   09891                 JSR SETVIEW             ; Set Front view
              09892
B89F A031     09893                 LDY #$31                ; Set title phrase "MISSION ABORTED ZERO ENERGY"
B8A1 A204     09894                 LDX #$04                ; Set mission bonus offset
B8A3 200AB1   09895                 JSR GAMEOVER            ; Game over
              09896
B8A6 60       09897 SKIP246         RTS                     ; Return
              09898
              09899 ;*******************************************************************************
              09900 ;*                                                                             *
              09901 ;*                                  SHOWCOORD                                  *
              09902 ;*                                                                             *
              09903 ;*  Display a position vector component (coordinate) in Control Panel Display  *
              09904 ;*                                                                             *
              09905 ;*******************************************************************************
              09906
              09907 ; DESCRIPTION
              09908 ;
              09909 ; Displays a position vector component (coordinate) by one of the THETA, PHI, or
              09910 ; RANGE readouts of the Control Panel Display.
              09911 ;
              09912 ; Write the sign to the Control Panel Display, then map the high byte of the
              09913 ; respective coordinate (x -> THETA, y -> PHI, z -> RANGE) to a BCD-value in
              09914 ; 00..99. Code execution continues into subroutine SHOWDIGITS ($B8CD) where the
              09915 ; digits are actually stored in the Control Panel Display.
              09916 ;
              09917 ; NOTE: If the digits of either the THETA or PHI readout are to be displayed and
              09918 ; the x or y position vector component (high byte) is $FF then tweak the value
              09919 ; to $FE. This avoids accessing table MAPTOBCD99 ($0EE9) with an index of $FF
              09920 ; that would return the special value $EA. This value represents the CCS.INF
              09921 ; ($0E) and CCS.SPC ($0A) characters (see comments in subroutine INITIALIZE
              09922 ; ($B3BA)) that are displayed by the RANGE readout only.
              09923 ;
              09924 ; INPUT
              09925 ;
              09926 ;   A = Position vector component (coordinate) offset. Used values are: 
              09927 ;     $00 -> z-coordinate
              09928 ;     $31 -> x-coordinate
              09929 ;     $62 -> y-coordinate
              09930 ;
              09931 ;   Y = Offset into the Control Panel Display memory map. Used values are:
              09932 ;     $17 -> First character (sign) of THETA readout (x-coordinate of tracked
              09933 ;            space object)
              09934 ;     $1D -> First character (sign) of PHI readout   (y-coordinate of tracked
              09935 ;            space object)
              09936 ;     $23 -> First character (sign) of RANGE readout (z-coordinate of tracked
              09937 ;            space object)
              09938
    =006A     09939 L.SIGNCHAR      = $6A                   ; Saves sign character
              09940
B8A7 18       09941 SHOWCOORD       CLC                     ; Add index of tracked space object...
B8A8 6D5C09   09942                 ADC TRACKDIGIT          ; ...to position vector component offset
B8AB AA       09943                 TAX                     ; Save position vector component index
              09944
              09945 ;*** Display sign in Control Panel Display *************************************
B8AC A910     09946                 LDA #CCS.PLUS           ; Save '+' (CCS.PLUS) to sign character
B8AE 856A     09947                 STA L.SIGNCHAR          ;
              09948
B8B0 BDAD09   09949                 LDA ZPOSSIGN,X          ; Prep sign of coordinate
B8B3 4A       09950                 LSR A                   ;
B8B4 BD400A   09951                 LDA ZPOSHI,X            ; Prep coordinate (high byte)
B8B7 B004     09952                 BCS SKIP247             ; Skip if sign is positive
              09953
B8B9 49FF     09954                 EOR #$FF                ; Invert coordinate (high byte)
B8BB C66A     09955                 DEC L.SIGNCHAR          ; Change saved sign character to '-' (CCS.MINUS)
              09956
B8BD AA       09957 SKIP247         TAX                     ; Save coordinate (high byte)
B8BE A56A     09958                 LDA L.SIGNCHAR          ; Store sign character in Control Panel Display
B8C0 994909   09959                 STA PANELTXT,Y          ;
              09960
              09961 ;*** Get RANGE digits **********************************************************
B8C3 98       09962                 TYA                     ; Skip if RANGE is to be displayed
B8C4 2910     09963                 AND #$10                ;
B8C6 F005     09964                 BEQ SHOWDIGITS          ;
              09965
B8C8 E0FF     09966                 CPX #$FF                ; If coordinate (high byte) = $FF decrement value
B8CA D001     09967                 BNE SHOWDIGITS          ; This avoids output of CCS.INFINITY in...
B8CC CA       09968                 DEX                     ; ...THETA and PHI readouts
              09969
              09970 ;*******************************************************************************
              09971 ;*                                                                             *
              09972 ;*                                 SHOWDIGITS                                  *
              09973 ;*                                                                             *
              09974 ;*          Display a value by a readout of the Control Panel Display          *
              09975 ;*                                                                             *
              09976 ;*******************************************************************************
              09977
              09978 ; DESCRIPTION
              09979 ;
              09980 ; Converts a binary value in $00..$FF to a BCD-value in 0..99 and displays it as
              09981 ; a 2-digit number in the Control Panel Display.
              09982 ;
              09983 ; INPUT
              09984 ;
              09985 ;   X = Value to be displayed as a 2-digit BCD-value. Used values are: $00..$FF.
              09986 ;
              09987 ;   Y = Offset into the Control Panel Display memory map relative to the first
              09988 ;       character of the Control Panel Display (the 'V' of the VELOCITY
              09989 ;       readout). Used values are: 
              09990 ;     $01 -> Character before first digit of VELOCITY readout
              09991 ;     $17 -> First character (sign) of THETA readout (x-coordinate of tracked
              09992 ;            space object)
              09993 ;     $1D -> First character (sign) of PHI readout   (y-coordinate of tracked
              09994 ;            space object)
              09995 ;     $23 -> First character (sign) of RANGE readout (z-coordinate of tracked
              09996 ;            space object)
              09997
B8CD BDE90E   09998 SHOWDIGITS      LDA MAPTOBCD99,X        ; Map binary value to BCD-value
B8D0 AA       09999                 TAX                     ;
B8D1 290F     10000                 AND #$0F                ;
B8D3 994B09   10001                 STA PANELTXT+2,Y        ; Store 'ones' digit in Control Panel Display
B8D6 8A       10002                 TXA                     ;
B8D7 4A       10003                 LSR A                   ;
B8D8 4A       10004                 LSR A                   ;
B8D9 4A       10005                 LSR A                   ;
B8DA 4A       10006                 LSR A                   ;
B8DB 994A09   10007                 STA PANELTXT+1,Y        ; Store 'tens' digit in Control Panel Display
B8DE 60       10008                 RTS                     ; Return
              10009
              10010 ;*******************************************************************************
              10011 ;*                                                                             *
              10012 ;*                G A M E   D A T A   ( P A R T   2   O F   2 )                *
              10013 ;*                                                                             *
              10014 ;*******************************************************************************
              10015
              10016 ;*** Color register offsets of PLAYER0..4 **************************************
B8DF 00       10017 PLCOLOROFFTAB   .BYTE 0                               ; PLAYER0
B8E0 01       10018                 .BYTE 1                               ; PLAYER1
B8E1 02       10019                 .BYTE 2                               ; PLAYER2
B8E2 03       10020                 .BYTE 3                               ; PLAYER3
B8E3 07       10021                 .BYTE 7                               ; PLAYER4
              10022
              10023 ;*** Shape table 1 (PLAYER2..4) ************************************************
B8E4 00       10024 PLSHAP1TAB      .BYTE $00                             ; ........
B8E5 18       10025                 .BYTE $18                             ; ...##...
B8E6 3C       10026                 .BYTE $3C                             ; ..####..
B8E7 7E       10027                 .BYTE $7E                             ; .######.
B8E8 7E       10028                 .BYTE $7E                             ; .######.
B8E9 76       10029                 .BYTE $76                             ; .###.##.
B8EA F7       10030                 .BYTE $F7                             ; ####.###
B8EB DF       10031                 .BYTE $DF                             ; ##.#####
B8EC DF       10032                 .BYTE $DF                             ; ##.#####
B8ED FF       10033                 .BYTE $FF                             ; ########
B8EE FF       10034                 .BYTE $FF                             ; ########
B8EF F7       10035                 .BYTE $F7                             ; ####.###
B8F0 76       10036                 .BYTE $76                             ; .###.##.
B8F1 7E       10037                 .BYTE $7E                             ; .######.
B8F2 7E       10038                 .BYTE $7E                             ; .######.
B8F3 3C       10039                 .BYTE $3C                             ; ..####..
B8F4 18       10040                 .BYTE $18                             ; ...##...
B8F5 10       10041                 .BYTE $10                             ; ...#....
B8F6 38       10042                 .BYTE $38                             ; ..###...
B8F7 7C       10043                 .BYTE $7C                             ; .#####..
B8F8 7C       10044                 .BYTE $7C                             ; .#####..
B8F9 FE       10045                 .BYTE $FE                             ; #######.
B8FA DE       10046                 .BYTE $DE                             ; ##.####.
B8FB DA       10047                 .BYTE $DA                             ; ##.##.#.
B8FC FA       10048                 .BYTE $FA                             ; #####.#.
B8FD EE       10049                 .BYTE $EE                             ; ###.###.
B8FE EE       10050                 .BYTE $EE                             ; ###.###.
B8FF 7C       10051                 .BYTE $7C                             ; .#####..
B900 7C       10052                 .BYTE $7C                             ; .#####..
B901 38       10053                 .BYTE $38                             ; ..###...
B902 10       10054                 .BYTE $10                             ; ...#....
B903 18       10055                 .BYTE $18                             ; ...##...
B904 3C       10056                 .BYTE $3C                             ; ..####..
B905 3C       10057                 .BYTE $3C                             ; ..####..
B906 7E       10058                 .BYTE $7E                             ; .######.
B907 6E       10059                 .BYTE $6E                             ; .##.###.
B908 7A       10060                 .BYTE $7A                             ; .####.#.
B909 7E       10061                 .BYTE $7E                             ; .######.
B90A 76       10062                 .BYTE $76                             ; .###.##.
B90B 7E       10063                 .BYTE $7E                             ; .######.
B90C 3C       10064                 .BYTE $3C                             ; ..####..
B90D 3C       10065                 .BYTE $3C                             ; ..####..
B90E 18       10066                 .BYTE $18                             ; ...##...
B90F 10       10067                 .BYTE $10                             ; ...#....
B910 38       10068                 .BYTE $38                             ; ..###...
B911 38       10069                 .BYTE $38                             ; ..###...
B912 7C       10070                 .BYTE $7C                             ; .#####..
B913 74       10071                 .BYTE $74                             ; .###.#..
B914 7C       10072                 .BYTE $7C                             ; .#####..
B915 6C       10073                 .BYTE $6C                             ; .##.##..
B916 38       10074                 .BYTE $38                             ; ..###...
B917 38       10075                 .BYTE $38                             ; ..###...
B918 10       10076                 .BYTE $10                             ; ...#....
B919 10       10077                 .BYTE $10                             ; ...#....
B91A 18       10078                 .BYTE $18                             ; ...##...
B91B 3C       10079                 .BYTE $3C                             ; ..####..
B91C 2C       10080                 .BYTE $2C                             ; ..#.##..
B91D 3C       10081                 .BYTE $3C                             ; ..####..
B91E 3C       10082                 .BYTE $3C                             ; ..####..
B91F 18       10083                 .BYTE $18                             ; ...##...
B920 08       10084                 .BYTE $08                             ; ....#...
B921 10       10085                 .BYTE $10                             ; ...#....
B922 38       10086                 .BYTE $38                             ; ..###...
B923 38       10087                 .BYTE $38                             ; ..###...
B924 28       10088                 .BYTE $28                             ; ..#.#...
B925 38       10089                 .BYTE $38                             ; ..###...
B926 10       10090                 .BYTE $10                             ; ...#....
B927 3C       10091                 .BYTE $3C                             ; ..####..
B928 3C       10092                 .BYTE $3C                             ; ..####..
B929 24       10093                 .BYTE $24                             ; ..#..#..
B92A 3C       10094                 .BYTE $3C                             ; ..####..
B92B 7E       10095                 .BYTE $7E                             ; .######.
B92C 7E       10096                 .BYTE $7E                             ; .######.
B92D 7E       10097                 .BYTE $7E                             ; .######.
B92E 5A       10098                 .BYTE $5A                             ; .#.##.#.
B92F FF       10099                 .BYTE $FF                             ; ########
B930 FF       10100                 .BYTE $FF                             ; ########
B931 42       10101                 .BYTE $42                             ; .#....#.
B932 42       10102                 .BYTE $42                             ; .#....#.
B933 42       10103                 .BYTE $42                             ; .#....#.
B934 42       10104                 .BYTE $42                             ; .#....#.
B935 42       10105                 .BYTE $42                             ; .#....#.
B936 42       10106                 .BYTE $42                             ; .#....#.
B937 1C       10107                 .BYTE $1C                             ; ...###..
B938 1C       10108                 .BYTE $1C                             ; ...###..
B939 14       10109                 .BYTE $14                             ; ...#.#..
B93A 3E       10110                 .BYTE $3E                             ; ..#####.
B93B 3E       10111                 .BYTE $3E                             ; ..#####.
B93C 3E       10112                 .BYTE $3E                             ; ..#####.
B93D 2A       10113                 .BYTE $2A                             ; ..#.#.#.
B93E 7F       10114                 .BYTE $7F                             ; .#######
B93F 7F       10115                 .BYTE $7F                             ; .#######
B940 22       10116                 .BYTE $22                             ; ..#...#.
B941 22       10117                 .BYTE $22                             ; ..#...#.
B942 22       10118                 .BYTE $22                             ; ..#...#.
B943 22       10119                 .BYTE $22                             ; ..#...#.
B944 22       10120                 .BYTE $22                             ; ..#...#.
B945 18       10121                 .BYTE $18                             ; ...##...
B946 18       10122                 .BYTE $18                             ; ...##...
B947 3C       10123                 .BYTE $3C                             ; ..####..
B948 3C       10124                 .BYTE $3C                             ; ..####..
B949 3C       10125                 .BYTE $3C                             ; ..####..
B94A 3C       10126                 .BYTE $3C                             ; ..####..
B94B 7E       10127                 .BYTE $7E                             ; .######.
B94C 24       10128                 .BYTE $24                             ; ..#..#..
B94D 24       10129                 .BYTE $24                             ; ..#..#..
B94E 24       10130                 .BYTE $24                             ; ..#..#..
B94F 24       10131                 .BYTE $24                             ; ..#..#..
B950 10       10132                 .BYTE $10                             ; ...#....
B951 10       10133                 .BYTE $10                             ; ...#....
B952 38       10134                 .BYTE $38                             ; ..###...
B953 38       10135                 .BYTE $38                             ; ..###...
B954 38       10136                 .BYTE $38                             ; ..###...
B955 7C       10137                 .BYTE $7C                             ; .#####..
B956 28       10138                 .BYTE $28                             ; ..#.#...
B957 28       10139                 .BYTE $28                             ; ..#.#...
B958 28       10140                 .BYTE $28                             ; ..#.#...
B959 18       10141                 .BYTE $18                             ; ...##...
B95A 18       10142                 .BYTE $18                             ; ...##...
B95B 3C       10143                 .BYTE $3C                             ; ..####..
B95C 18       10144                 .BYTE $18                             ; ...##...
B95D 18       10145                 .BYTE $18                             ; ...##...
B95E 10       10146                 .BYTE $10                             ; ...#....
B95F 10       10147                 .BYTE $10                             ; ...#....
B960 38       10148                 .BYTE $38                             ; ..###...
B961 10       10149                 .BYTE $10                             ; ...#....
B962 18       10150                 .BYTE $18                             ; ...##...
B963 7E       10151                 .BYTE $7E                             ; .######.
B964 FF       10152                 .BYTE $FF                             ; ########
B965 FF       10153                 .BYTE $FF                             ; ########
B966 FF       10154                 .BYTE $FF                             ; ########
B967 FF       10155                 .BYTE $FF                             ; ########
B968 FF       10156                 .BYTE $FF                             ; ########
B969 E7       10157                 .BYTE $E7                             ; ###..###
B96A E7       10158                 .BYTE $E7                             ; ###..###
B96B FF       10159                 .BYTE $FF                             ; ########
B96C FF       10160                 .BYTE $FF                             ; ########
B96D FF       10161                 .BYTE $FF                             ; ########
B96E FF       10162                 .BYTE $FF                             ; ########
B96F FF       10163                 .BYTE $FF                             ; ########
B970 7E       10164                 .BYTE $7E                             ; .######.
B971 7E       10165                 .BYTE $7E                             ; .######.
B972 00       10166                 .BYTE $00                             ; ........
B973 18       10167                 .BYTE $18                             ; ...##...
B974 3C       10168                 .BYTE $3C                             ; ..####..
B975 7E       10169                 .BYTE $7E                             ; .######.
B976 FF       10170                 .BYTE $FF                             ; ########
B977 FF       10171                 .BYTE $FF                             ; ########
B978 FF       10172                 .BYTE $FF                             ; ########
B979 E7       10173                 .BYTE $E7                             ; ###..###
B97A 66       10174                 .BYTE $66                             ; .##..##.
B97B FF       10175                 .BYTE $FF                             ; ########
B97C FF       10176                 .BYTE $FF                             ; ########
B97D FF       10177                 .BYTE $FF                             ; ########
B97E FF       10178                 .BYTE $FF                             ; ########
B97F 7E       10179                 .BYTE $7E                             ; .######.
B980 7E       10180                 .BYTE $7E                             ; .######.
B981 00       10181                 .BYTE $00                             ; ........
B982 18       10182                 .BYTE $18                             ; ...##...
B983 3C       10183                 .BYTE $3C                             ; ..####..
B984 7E       10184                 .BYTE $7E                             ; .######.
B985 FF       10185                 .BYTE $FF                             ; ########
B986 FF       10186                 .BYTE $FF                             ; ########
B987 E7       10187                 .BYTE $E7                             ; ###..###
B988 66       10188                 .BYTE $66                             ; .##..##.
B989 FF       10189                 .BYTE $FF                             ; ########
B98A FF       10190                 .BYTE $FF                             ; ########
B98B FF       10191                 .BYTE $FF                             ; ########
B98C FF       10192                 .BYTE $FF                             ; ########
B98D 3C       10193                 .BYTE $3C                             ; ..####..
B98E 18       10194                 .BYTE $18                             ; ...##...
B98F 3C       10195                 .BYTE $3C                             ; ..####..
B990 FF       10196                 .BYTE $FF                             ; ########
B991 FF       10197                 .BYTE $FF                             ; ########
B992 E7       10198                 .BYTE $E7                             ; ###..###
B993 66       10199                 .BYTE $66                             ; .##..##.
B994 FF       10200                 .BYTE $FF                             ; ########
B995 FF       10201                 .BYTE $FF                             ; ########
B996 7E       10202                 .BYTE $7E                             ; .######.
B997 3C       10203                 .BYTE $3C                             ; ..####..
B998 00       10204                 .BYTE $00                             ; ........
B999 18       10205                 .BYTE $18                             ; ...##...
B99A 3C       10206                 .BYTE $3C                             ; ..####..
B99B FF       10207                 .BYTE $FF                             ; ########
B99C FF       10208                 .BYTE $FF                             ; ########
B99D FF       10209                 .BYTE $FF                             ; ########
B99E 3C       10210                 .BYTE $3C                             ; ..####..
B99F 18       10211                 .BYTE $18                             ; ...##...
B9A0 18       10212                 .BYTE $18                             ; ...##...
B9A1 3C       10213                 .BYTE $3C                             ; ..####..
B9A2 FF       10214                 .BYTE $FF                             ; ########
B9A3 3C       10215                 .BYTE $3C                             ; ..####..
B9A4 18       10216                 .BYTE $18                             ; ...##...
B9A5 28       10217                 .BYTE $28                             ; ..#.#...
B9A6 28       10218                 .BYTE $28                             ; ..#.#...
B9A7 28       10219                 .BYTE $28                             ; ..#.#...
B9A8 28       10220                 .BYTE $28                             ; ..#.#...
B9A9 EE       10221                 .BYTE $EE                             ; ###.###.
B9AA 00       10222                 .BYTE $00                             ; ........
B9AB 00       10223                 .BYTE $00                             ; ........
B9AC EE       10224                 .BYTE $EE                             ; ###.###.
B9AD 28       10225                 .BYTE $28                             ; ..#.#...
B9AE 28       10226                 .BYTE $28                             ; ..#.#...
B9AF 28       10227                 .BYTE $28                             ; ..#.#...
B9B0 28       10228                 .BYTE $28                             ; ..#.#...
              10229
              10230 ;*** Shape table 2 (PLAYER0..1) ************************************************
B9B1 00       10231 PLSHAP2TAB      .BYTE $00                             ; ........
B9B2 81       10232                 .BYTE $81                             ; #......#
B9B3 81       10233                 .BYTE $81                             ; #......#
B9B4 81       10234                 .BYTE $81                             ; #......#
B9B5 81       10235                 .BYTE $81                             ; #......#
B9B6 BD       10236                 .BYTE $BD                             ; #.####.#
B9B7 FF       10237                 .BYTE $FF                             ; ########
B9B8 FF       10238                 .BYTE $FF                             ; ########
B9B9 BD       10239                 .BYTE $BD                             ; #.####.#
B9BA 81       10240                 .BYTE $81                             ; #......#
B9BB 81       10241                 .BYTE $81                             ; #......#
B9BC 81       10242                 .BYTE $81                             ; #......#
B9BD 81       10243                 .BYTE $81                             ; #......#
B9BE 82       10244                 .BYTE $82                             ; #.....#.
B9BF 82       10245                 .BYTE $82                             ; #.....#.
B9C0 BA       10246                 .BYTE $BA                             ; #.###.#.
B9C1 FE       10247                 .BYTE $FE                             ; #######.
B9C2 FE       10248                 .BYTE $FE                             ; #######.
B9C3 BA       10249                 .BYTE $BA                             ; #.###.#.
B9C4 82       10250                 .BYTE $82                             ; #.....#.
B9C5 82       10251                 .BYTE $82                             ; #.....#.
B9C6 42       10252                 .BYTE $42                             ; .#....#.
B9C7 5A       10253                 .BYTE $5A                             ; .#.##.#.
B9C8 7E       10254                 .BYTE $7E                             ; .######.
B9C9 7E       10255                 .BYTE $7E                             ; .######.
B9CA 5A       10256                 .BYTE $5A                             ; .#.##.#.
B9CB 42       10257                 .BYTE $42                             ; .#....#.
B9CC 44       10258                 .BYTE $44                             ; .#...#..
B9CD 54       10259                 .BYTE $54                             ; .#.#.#..
B9CE 7C       10260                 .BYTE $7C                             ; .#####..
B9CF 7C       10261                 .BYTE $7C                             ; .#####..
B9D0 54       10262                 .BYTE $54                             ; .#.#.#..
B9D1 44       10263                 .BYTE $44                             ; .#...#..
B9D2 24       10264                 .BYTE $24                             ; ..#..#..
B9D3 3C       10265                 .BYTE $3C                             ; ..####..
B9D4 3C       10266                 .BYTE $3C                             ; ..####..
B9D5 24       10267                 .BYTE $24                             ; ..#..#..
B9D6 28       10268                 .BYTE $28                             ; ..#.#...
B9D7 38       10269                 .BYTE $38                             ; ..###...
B9D8 38       10270                 .BYTE $38                             ; ..###...
B9D9 28       10271                 .BYTE $28                             ; ..#.#...
B9DA 18       10272                 .BYTE $18                             ; ...##...
B9DB 18       10273                 .BYTE $18                             ; ...##...
B9DC 10       10274                 .BYTE $10                             ; ...#....
B9DD 10       10275                 .BYTE $10                             ; ...#....
B9DE E0       10276                 .BYTE $E0                             ; ###.....
B9DF F8       10277                 .BYTE $F8                             ; #####...
B9E0 F8       10278                 .BYTE $F8                             ; #####...
B9E1 FE       10279                 .BYTE $FE                             ; #######.
B9E2 57       10280                 .BYTE $57                             ; .#.#.###
B9E3 FE       10281                 .BYTE $FE                             ; #######.
B9E4 F8       10282                 .BYTE $F8                             ; #####...
B9E5 F8       10283                 .BYTE $F8                             ; #####...
B9E6 C0       10284                 .BYTE $C0                             ; ##......
B9E7 C0       10285                 .BYTE $C0                             ; ##......
B9E8 F0       10286                 .BYTE $F0                             ; ####....
B9E9 C0       10287                 .BYTE $C0                             ; ##......
B9EA F0       10288                 .BYTE $F0                             ; ####....
B9EB F0       10289                 .BYTE $F0                             ; ####....
B9EC FC       10290                 .BYTE $FC                             ; ######..
B9ED BE       10291                 .BYTE $BE                             ; #.#####.
B9EE FC       10292                 .BYTE $FC                             ; ######..
B9EF F0       10293                 .BYTE $F0                             ; ####....
B9F0 80       10294                 .BYTE $80                             ; #.......
B9F1 80       10295                 .BYTE $80                             ; #.......
B9F2 C0       10296                 .BYTE $C0                             ; ##......
B9F3 C0       10297                 .BYTE $C0                             ; ##......
B9F4 F0       10298                 .BYTE $F0                             ; ####....
B9F5 BC       10299                 .BYTE $BC                             ; #.####..
B9F6 F0       10300                 .BYTE $F0                             ; ####....
B9F7 C0       10301                 .BYTE $C0                             ; ##......
B9F8 07       10302                 .BYTE $07                             ; .....###
B9F9 1F       10303                 .BYTE $1F                             ; ...#####
B9FA 1F       10304                 .BYTE $1F                             ; ...#####
B9FB 7F       10305                 .BYTE $7F                             ; .#######
B9FC EA       10306                 .BYTE $EA                             ; ###.#.#.
B9FD 7F       10307                 .BYTE $7F                             ; .#######
B9FE 1F       10308                 .BYTE $1F                             ; ...#####
B9FF 1F       10309                 .BYTE $1F                             ; ...#####
BA00 03       10310                 .BYTE $03                             ; ......##
BA01 03       10311                 .BYTE $03                             ; ......##
BA02 0F       10312                 .BYTE $0F                             ; ....####
BA03 03       10313                 .BYTE $03                             ; ......##
BA04 0F       10314                 .BYTE $0F                             ; ....####
BA05 0F       10315                 .BYTE $0F                             ; ....####
BA06 3F       10316                 .BYTE $3F                             ; ..######
BA07 7D       10317                 .BYTE $7D                             ; .#####.#
BA08 3F       10318                 .BYTE $3F                             ; ..######
BA09 0F       10319                 .BYTE $0F                             ; ....####
BA0A 01       10320                 .BYTE $01                             ; .......#
BA0B 01       10321                 .BYTE $01                             ; .......#
BA0C 03       10322                 .BYTE $03                             ; ......##
BA0D 03       10323                 .BYTE $03                             ; ......##
BA0E 0F       10324                 .BYTE $0F                             ; ....####
BA0F 3D       10325                 .BYTE $3D                             ; ..####.#
BA10 0F       10326                 .BYTE $0F                             ; ....####
BA11 03       10327                 .BYTE $03                             ; ......##
BA12 18       10328                 .BYTE $18                             ; ...##...
BA13 3C       10329                 .BYTE $3C                             ; ..####..
BA14 7E       10330                 .BYTE $7E                             ; .######.
BA15 7E       10331                 .BYTE $7E                             ; .######.
BA16 DB       10332                 .BYTE $DB                             ; ##.##.##
BA17 C3       10333                 .BYTE $C3                             ; ##....##
BA18 81       10334                 .BYTE $81                             ; #......#
BA19 81       10335                 .BYTE $81                             ; #......#
BA1A 81       10336                 .BYTE $81                             ; #......#
BA1B 10       10337                 .BYTE $10                             ; ...#....
BA1C 38       10338                 .BYTE $38                             ; ..###...
BA1D 7C       10339                 .BYTE $7C                             ; .#####..
BA1E 7C       10340                 .BYTE $7C                             ; .#####..
BA1F D6       10341                 .BYTE $D6                             ; ##.#.##.
BA20 C6       10342                 .BYTE $C6                             ; ##...##.
BA21 82       10343                 .BYTE $82                             ; #.....#.
BA22 82       10344                 .BYTE $82                             ; #.....#.
BA23 18       10345                 .BYTE $18                             ; ...##...
BA24 3C       10346                 .BYTE $3C                             ; ..####..
BA25 3C       10347                 .BYTE $3C                             ; ..####..
BA26 66       10348                 .BYTE $66                             ; .##..##.
BA27 66       10349                 .BYTE $66                             ; .##..##.
BA28 42       10350                 .BYTE $42                             ; .#....#.
BA29 42       10351                 .BYTE $42                             ; .#....#.
BA2A 10       10352                 .BYTE $10                             ; ...#....
BA2B 38       10353                 .BYTE $38                             ; ..###...
BA2C 38       10354                 .BYTE $38                             ; ..###...
BA2D 6C       10355                 .BYTE $6C                             ; .##.##..
BA2E 44       10356                 .BYTE $44                             ; .#...#..
BA2F 44       10357                 .BYTE $44                             ; .#...#..
BA30 18       10358                 .BYTE $18                             ; ...##...
BA31 3C       10359                 .BYTE $3C                             ; ..####..
BA32 24       10360                 .BYTE $24                             ; ..#..#..
BA33 24       10361                 .BYTE $24                             ; ..#..#..
BA34 10       10362                 .BYTE $10                             ; ...#....
BA35 38       10363                 .BYTE $38                             ; ..###...
BA36 28       10364                 .BYTE $28                             ; ..#.#...
BA37 18       10365                 .BYTE $18                             ; ...##...
BA38 3C       10366                 .BYTE $3C                             ; ..####..
BA39 7E       10367                 .BYTE $7E                             ; .######.
BA3A FF       10368                 .BYTE $FF                             ; ########
BA3B 18       10369                 .BYTE $18                             ; ...##...
BA3C 18       10370                 .BYTE $18                             ; ...##...
BA3D FF       10371                 .BYTE $FF                             ; ########
BA3E 7E       10372                 .BYTE $7E                             ; .######.
BA3F 3C       10373                 .BYTE $3C                             ; ..####..
BA40 18       10374                 .BYTE $18                             ; ...##...
BA41 10       10375                 .BYTE $10                             ; ...#....
BA42 38       10376                 .BYTE $38                             ; ..###...
BA43 7C       10377                 .BYTE $7C                             ; .#####..
BA44 FE       10378                 .BYTE $FE                             ; #######.
BA45 38       10379                 .BYTE $38                             ; ..###...
BA46 38       10380                 .BYTE $38                             ; ..###...
BA47 FE       10381                 .BYTE $FE                             ; #######.
BA48 7C       10382                 .BYTE $7C                             ; .#####..
BA49 38       10383                 .BYTE $38                             ; ..###...
BA4A 10       10384                 .BYTE $10                             ; ...#....
BA4B 18       10385                 .BYTE $18                             ; ...##...
BA4C 3C       10386                 .BYTE $3C                             ; ..####..
BA4D 7E       10387                 .BYTE $7E                             ; .######.
BA4E 18       10388                 .BYTE $18                             ; ...##...
BA4F 7E       10389                 .BYTE $7E                             ; .######.
BA50 3C       10390                 .BYTE $3C                             ; ..####..
BA51 18       10391                 .BYTE $18                             ; ...##...
BA52 10       10392                 .BYTE $10                             ; ...#....
BA53 38       10393                 .BYTE $38                             ; ..###...
BA54 7C       10394                 .BYTE $7C                             ; .#####..
BA55 10       10395                 .BYTE $10                             ; ...#....
BA56 7C       10396                 .BYTE $7C                             ; .#####..
BA57 38       10397                 .BYTE $38                             ; ..###...
BA58 10       10398                 .BYTE $10                             ; ...#....
BA59 18       10399                 .BYTE $18                             ; ...##...
BA5A 3C       10400                 .BYTE $3C                             ; ..####..
BA5B 18       10401                 .BYTE $18                             ; ...##...
BA5C 3C       10402                 .BYTE $3C                             ; ..####..
BA5D 18       10403                 .BYTE $18                             ; ...##...
BA5E 10       10404                 .BYTE $10                             ; ...#....
BA5F 38       10405                 .BYTE $38                             ; ..###...
BA60 38       10406                 .BYTE $38                             ; ..###...
BA61 10       10407                 .BYTE $10                             ; ...#....
              10408
              10409 ;*** Display List fragments ****************************************************
              10410 ;
              10411 ; LOCAL VARIABLES
    =1000     10412 PFMEM.C0R0      = PFMEM+0*40                          ; Start address of PLAYFIELD row 0
    =10C8     10413 PFMEM.C0R5      = PFMEM+5*40                          ; Start address of PLAYFIELD row 5
    =12A8     10414 PFMEM.C0R17     = PFMEM+17*40                         ; Start address of PLAYFIELD row 17
              10415
              10416 ;*** Display List fragment for Control Panel Display (bottom text window) ******
BA62 8D       10417 DLSTFRAG        .BYTE $8D                             ; GR7 + DLI
BA63 00       10418                 .BYTE $00                             ; BLK1
BA64 464909   10419                 .BYTE $46,<PANELTXT,>PANELTXT         ; GR1 @ PANELTXT
BA67 20       10420                 .BYTE $20                             ; BLK3
BA68 06       10421                 .BYTE $06                             ; GR1
BA69 00       10422                 .BYTE $00                             ; BLK1
              10423
              10424 ;*** Display List fragment for Galactic Chart view *****************************
BA6A 012EA1   10425 DLSTFRAGGC      .BYTE $01,<DLSTGC,>DLSTGC             ; JMP @ DLSTGC
              10426
              10427 ;*** Display List fragment for Long-Range Scan view ****************************
BA6D 00       10428 DLSTFRAGLRS     .BYTE $00                             ; BLK1
BA6E 00       10429                 .BYTE $00                             ; BLK1
BA6F 46F8A0   10430                 .BYTE $46,<LRSHEADER,>LRSHEADER       ; GR1 @ LRSHEADER
BA72 4DC810   10431                 .BYTE $4D,<PFMEM.C0R5,>PFMEM.C0R5     ; GR7 @ PFMEM.C0R5
              10432
              10433 ;*** Display List fragment for Aft view ****************************************
BA75 00       10434 DLSTFRAGAFT     .BYTE $00                             ; BLK1
BA76 00       10435                 .BYTE $00                             ; BLK1
BA77 4609A1   10436                 .BYTE $46,<AFTHEADER,>AFTHEADER       ; GR1 @ AFTHEADER
BA7A 4DC810   10437                 .BYTE $4D,<PFMEM.C0R5,>PFMEM.C0R5     ; GR7 @ PFMEM.C0R5
              10438
              10439 ;*** Display List fragment for Front view and Title text line ******************
BA7D 4D0010   10440 DLSTFRAGFRONT   .BYTE $4D,<PFMEM.C0R0,>PFMEM.C0R0     ; GR7 @ PFMEM.C0R0
BA80 0D       10441                 .BYTE $0D                             ; GR7
BA81 0D       10442                 .BYTE $0D                             ; GR7
BA82 0D       10443                 .BYTE $0D                             ; GR7
BA83 0D       10444                 .BYTE $0D                             ; GR7
BA84 0D       10445                 .BYTE $0D                             ; GR7
BA85 30       10446                 .BYTE $30                             ; BLK4
BA86 461F0D   10447                 .BYTE $46,<TITLETXT,>TITLETXT         ; GR1 @ TITLETXT
BA89 4DA812   10448                 .BYTE $4D,<PFMEM.C0R17,>PFMEM.C0R17   ; GR7 @ PFMEM.C0R17
              10449
              10450 ;*** Display List fragment offsets relative to DLSTFRAG ************************
BA8C 1B       10451 DLSTFRAGOFFTAB  .BYTE DLSTFRAGFRONT-DLSTFRAG          ; Front view
BA8D 13       10452                 .BYTE DLSTFRAGAFT-DLSTFRAG            ; Aft view
BA8E 0B       10453                 .BYTE DLSTFRAGLRS-DLSTFRAG            ; Long-Range Scan view
BA8F 08       10454                 .BYTE DLSTFRAGGC-DLSTFRAG             ; Galactic Chart view
              10455
              10456 ;*** 1-byte bit patterns for 4 pixels of same color for PLAYFIELD space objects 
BA90 FF       10457 FOURCOLORPIXEL  .BYTE $FF                             ; COLOR3
BA91 FF       10458                 .BYTE $FF                             ; COLOR3
BA92 FF       10459                 .BYTE $FF                             ; COLOR3
BA93 FF       10460                 .BYTE $FF                             ; COLOR3
BA94 AA       10461                 .BYTE $AA                             ; COLOR2
BA95 FF       10462                 .BYTE $FF                             ; COLOR3
BA96 AA       10463                 .BYTE $AA                             ; COLOR2
BA97 FF       10464                 .BYTE $FF                             ; COLOR3
BA98 AA       10465                 .BYTE $AA                             ; COLOR2
BA99 AA       10466                 .BYTE $AA                             ; COLOR2
BA9A AA       10467                 .BYTE $AA                             ; COLOR2
BA9B FF       10468                 .BYTE $FF                             ; COLOR3
BA9C AA       10469                 .BYTE $AA                             ; COLOR2
BA9D AA       10470                 .BYTE $AA                             ; COLOR2
BA9E AA       10471                 .BYTE $AA                             ; COLOR2
BA9F AA       10472                 .BYTE $AA                             ; COLOR2
BAA0 AA       10473                 .BYTE $AA                             ; COLOR2
BAA1 AA       10474                 .BYTE $AA                             ; COLOR2
BAA2 AA       10475                 .BYTE $AA                             ; COLOR2
BAA3 55       10476                 .BYTE $55                             ; COLOR1
BAA4 55       10477                 .BYTE $55                             ; COLOR1
BAA5 AA       10478                 .BYTE $AA                             ; COLOR2
BAA6 55       10479                 .BYTE $55                             ; COLOR1
BAA7 AA       10480                 .BYTE $AA                             ; COLOR2
BAA8 55       10481                 .BYTE $55                             ; COLOR1
BAA9 55       10482                 .BYTE $55                             ; COLOR1
BAAA 55       10483                 .BYTE $55                             ; COLOR1
BAAB AA       10484                 .BYTE $AA                             ; COLOR2
BAAC 55       10485                 .BYTE $55                             ; COLOR1
BAAD 55       10486                 .BYTE $55                             ; COLOR1
BAAE 55       10487                 .BYTE $55                             ; COLOR1
BAAF 55       10488                 .BYTE $55                             ; COLOR1
              10489
              10490 ;*** Masks to filter 1 pixel (2 bits) from 4 pixels (1 byte of PLAYFIELD memory)
BAB0 C0       10491 PIXELMASKTAB    .BYTE $C0                             ; ##......
BAB1 30       10492                 .BYTE $30                             ; ..##....
BAB2 0C       10493                 .BYTE $0C                             ; ....##..
BAB3 03       10494                 .BYTE $03                             ; ......##
              10495
              10496 ;*** Velocity table ************************************************************
BAB4 00       10497 VELOCITYTAB     .BYTE 0                               ; Speed 0 =   0 <KM/H>
BAB5 01       10498                 .BYTE 1                               ; Speed 1 =   1 <KM/H>
BAB6 02       10499                 .BYTE 2                               ; Speed 2 =   2 <KM/H>
BAB7 04       10500                 .BYTE 4                               ; Speed 3 =   4 <KM/H>
BAB8 08       10501                 .BYTE 8                               ; Speed 4 =   8 <KM/H>
BAB9 10       10502                 .BYTE 16                              ; Speed 5 =  16 <KM/H>
BABA 20       10503                 .BYTE 32                              ; Speed 6 =  32 <KM/H>
BABB 40       10504                 .BYTE 64                              ; Speed 7 =  64 <KM/H>
BABC 60       10505                 .BYTE 96                              ; Speed 8 =  96 <KM/H>
BABD 70       10506                 .BYTE 112                             ; Speed 9 = 112 <KM/H>
              10507
              10508 ;*** Keyboard code lookup table ************************************************
BABE F2       10509 KEYTAB          .BYTE $F2                             ; '0'   - Speed 0
BABF DF       10510                 .BYTE $DF                             ; '1'   - Speed 1
BAC0 DE       10511                 .BYTE $DE                             ; '2'   - Speed 2
BAC1 DA       10512                 .BYTE $DA                             ; '3'   - Speed 3
BAC2 D8       10513                 .BYTE $D8                             ; '4'   - Speed 4
BAC3 DD       10514                 .BYTE $DD                             ; '5'   - Speed 5
BAC4 DB       10515                 .BYTE $DB                             ; '6'   - Speed 6
BAC5 F3       10516                 .BYTE $F3                             ; '7'   - Speed 7
BAC6 F5       10517                 .BYTE $F5                             ; '8'   - Speed 8
BAC7 F0       10518                 .BYTE $F0                             ; '9'   - Speed 9
BAC8 F8       10519                 .BYTE $F8                             ; 'F'   - Front view
BAC9 FF       10520                 .BYTE $FF                             ; 'A'   - Aft view
BACA C0       10521                 .BYTE $C0                             ; 'L'   - Long-Range Scan view
BACB FD       10522                 .BYTE $FD                             ; 'G'   - Galactic Chart view
BACC ED       10523                 .BYTE $ED                             ; 'T'   - Tracking on/off
BACD FE       10524                 .BYTE $FE                             ; 'S'   - Shields on/off
BACE D2       10525                 .BYTE $D2                             ; 'C'   - Attack Computer on/off
BACF F9       10526                 .BYTE $F9                             ; 'H'   - Hyperwarp
BAD0 E5       10527                 .BYTE $E5                             ; 'M'   - Manual Target Selector
BAD1 CA       10528                 .BYTE $CA                             ; 'P'   - Pause
BAD2 E7       10529                 .BYTE $E7                             ; 'INV' - Abort Mission
              10530
              10531 ;*** Engines energy drain rates per game loop iteration in energy subunits *****
BAD3 00       10532 DRAINRATETAB    .BYTE 0                               ;
BAD4 04       10533                 .BYTE 4                               ;
BAD5 06       10534                 .BYTE 6                               ;
BAD6 08       10535                 .BYTE 8                               ;
BAD7 0A       10536                 .BYTE 10                              ;
BAD8 0C       10537                 .BYTE 12                              ;
BAD9 0E       10538                 .BYTE 14                              ;
BADA 1E       10539                 .BYTE 30                              ;
BADB 2D       10540                 .BYTE 45                              ;
BADC 3C       10541                 .BYTE 60                              ;
              10542
              10543 ;*** Hyperwarp energy depending on distance ************************************
BADD 0A       10544 WARPENERGYTAB   .BYTE 10                              ; =  100 energy units
BADE 0D       10545                 .BYTE 13                              ; =  130 energy units
BADF 10       10546                 .BYTE 16                              ; =  160 energy units
BAE0 14       10547                 .BYTE 20                              ; =  200 energy units
BAE1 17       10548                 .BYTE 23                              ; =  230 energy units
BAE2 32       10549                 .BYTE 50                              ; =  500 energy units
BAE3 46       10550                 .BYTE 70                              ; =  700 energy units
BAE4 50       10551                 .BYTE 80                              ; =  800 energy units
BAE5 5A       10552                 .BYTE 90                              ; =  900 energy units
BAE6 78       10553                 .BYTE 120                             ; = 1200 energy units
BAE7 7D       10554                 .BYTE 125                             ; = 1250 energy units
BAE8 82       10555                 .BYTE 130                             ; = 1300 energy units
BAE9 87       10556                 .BYTE 135                             ; = 1350 energy units
BAEA 8C       10557                 .BYTE 140                             ; = 1400 energy units
BAEB 9B       10558                 .BYTE 155                             ; = 1550 energy units
BAEC AA       10559                 .BYTE 170                             ; = 1700 energy units
BAED B8       10560                 .BYTE 184                             ; = 1840 energy units
BAEE C8       10561                 .BYTE 200                             ; = 2000 energy units
BAEF D0       10562                 .BYTE 208                             ; = 2080 energy units
BAF0 D8       10563                 .BYTE 216                             ; = 2160 energy units
BAF1 DF       10564                 .BYTE 223                             ; = 2230 energy units
BAF2 E8       10565                 .BYTE 232                             ; = 2320 energy units
BAF3 F1       10566                 .BYTE 241                             ; = 2410 energy units
BAF4 FA       10567                 .BYTE 250                             ; = 2500 energy units
              10568
              10569 ;*** Joystick increments *******************************************************
BAF5 00       10570 STICKINCTAB     .BYTE 0                               ; Centered
BAF6 01       10571                 .BYTE 1                               ; Right or up
BAF7 FF       10572                 .BYTE -1                              ; Left or down
BAF8 00       10573                 .BYTE 0                               ; Centered
              10574
              10575 ;*** 3-byte elements to draw cross hairs and Attack Computer Display ***********
              10576 ;   Byte 1 : Pixel column number of line start
              10577 ;   Byte 2 : Pixel row number of line start
              10578 ;   Byte 3 : B7 = 0 -> Draw line to the right
              10579 ;            B7 = 1 -> Draw line down
              10580 ;            B6..0  -> Length of line in pixels. Possible values are: 0..127.
              10581 ;
              10582 ;                   #
              10583 ;                   #                              4
              10584 ;                   #                      ##############################
              10585 ;                   #1                     #             #              #
              10586 ;                   #                      #             #11            #
              10587 ;                   #                      #             #              #
              10588 ;                   #                      #5            #    8         #6
              10589 ;                                          #      ###############       #
              10590 ;                                          #      #             #       #
              10591 ;         15                  16           #   7  #             #   10  #
              10592 ; ###############       ###############    ########             #########
              10593 ;                                          #      #12           #       #
              10594 ;                                          #      #             #13     #
              10595 ;                                          #      ###############       #
              10596 ;                   #                      #         9   #              #
              10597 ;                   #                      #             #              #
              10598 ;                   #                      #             #14            #
              10599 ;                   #                      #       3     #              #
              10600 ;                   #2                     ##############################
              10601 ;                   #
              10602 ;                   #
              10603 ;
              10604 ;         Front/Aft Cross Hairs                Attack Computer Display
              10605 ;
              10606 ; LOCAL VARIABLES
    =0080     10607 DOWN            = $80
    =0000     10608 RIGHT           = $00
              10609
BAF9 502887   10610 DRAWLINESTAB    .BYTE 80,40,DOWN!7                    ; Line 1
BAFC 503687   10611                 .BYTE 80,54,DOWN!7                    ; Line 2
              10612
BAFF 77461E   10613                 .BYTE 119,70,RIGHT!30                 ; Line 3
BB02 77561E   10614                 .BYTE 119,86,RIGHT!30                 ; Line 4
BB05 774691   10615                 .BYTE 119,70,DOWN!17                  ; Line 5
BB08 944691   10616                 .BYTE 148,70,DOWN!17                  ; Line 6
BB0B 784E06   10617                 .BYTE 120,78,RIGHT!6                  ; Line 7
BB0E 7E4B0F   10618                 .BYTE 126,75,RIGHT!15                 ; Line 8
BB11 7E510F   10619                 .BYTE 126,81,RIGHT!15                 ; Line 9
BB14 8D4E07   10620                 .BYTE 141,78,RIGHT!7                  ; Line 10
BB17 854784   10621                 .BYTE 133,71,DOWN!4                   ; Line 11
BB1A 7E4C85   10622                 .BYTE 126,76,DOWN!5                   ; Line 12
BB1D 8C4C85   10623                 .BYTE 140,76,DOWN!5                   ; Line 13
BB20 855284   10624                 .BYTE 133,82,DOWN!4                   ; Line 14
              10625
BB23 3E320F   10626                 .BYTE 62,50,RIGHT!15                  ; Line 15
BB26 54320F   10627                 .BYTE 84,50,RIGHT!15                  ; Line 16
BB29 FE       10628                 .BYTE $FE                             ; End marker
              10629
              10630 ;*** 3-byte elements to draw our starship's shape in Long-Range Scan view ******
              10631 ;
              10632 ;   Line  17 18 19 20 21
              10633 ;               ##
              10634 ;               ##
              10635 ;            ## ## ##
              10636 ;         ## ## ## ## ##
              10637 ;         ##    ##    ##
              10638
BB2A 4E3582   10639                 .BYTE 78,53,DOWN!2                    ; Line 17
BB2D 4F3482   10640                 .BYTE 79,52,DOWN!2                    ; Line 18
BB30 503285   10641                 .BYTE 80,50,DOWN!5                    ; Line 19
BB33 513482   10642                 .BYTE 81,52,DOWN!2                    ; Line 20
BB36 523582   10643                 .BYTE 82,53,DOWN!2                    ; Line 21
BB39 FE       10644                 .BYTE $FE                             ; End marker
              10645
              10646 ;*** Initial x and y coordinates of a star during hyperwarp ********************
              10647 ; The following two tables are used to determine the initial x and y coordinates
              10648 ; (high byte) of a star during hyperwarp. An index in 0..3 picks both the x and
              10649 ; y coordinate, thus 4 pairs of coordinates are possible:
              10650 ;
              10651 ; Y           +-------+----------------------------+----------------------------+
              10652 ; ^           | Index |        x-coordinate        |        y-coordinate        |
              10653 ; |           +-------+----------------------------+----------------------------+
              10654 ; |.32.       |   0   | +1024..+1279 (+$04**) <KM> |  +512..+767  (+$02**) <KM> |
              10655 ; |...1       |   1   | +1024..+1279 (+$04**) <KM> |  +768..+1023 (+$03**) <KM> |
              10656 ; |...0       |   2   |  +768..+1023 (+$03**) <KM> | +1024..+1279 (+$04**) <KM> |
              10657 ; |....       |   3   |  +512..+767  (+$02**) <KM> | +1024..+1279 (+$04**) <KM> |
              10658 ; 0----->X    +-------+----------------------------+----------------------------+
              10659
              10660 ;*** Initial x-coordinate (high byte) of star in hyperwarp *********************
BB3A 04       10661 WARPSTARXTAB    .BYTE $04                             ; +1024..+1279 (+$04**) <KM>
BB3B 04       10662                 .BYTE $04                             ; +1024..+1279 (+$04**) <KM>
BB3C 03       10663                 .BYTE $03                             ;  +768..+1023 (+$03**) <KM>
BB3D 02       10664                 .BYTE $02                             ;  +512..+767  (+$02**) <KM>
              10665
              10666 ;*** Initial y-coordinate (high byte) of star in hyperwarp *********************
BB3E 02       10667 WARPSTARYTAB    .BYTE $02                             ;  +512..+767  (+$02**) <KM>
BB3F 03       10668                 .BYTE $03                             ;  +768..+1023 (+$03**) <KM>
BB40 04       10669                 .BYTE $04                             ; +1024..+1279 (+$04**) <KM>
BB41 04       10670                 .BYTE $04                             ; +1024..+1279 (+$04**) <KM>
              10671
              10672 ;*** Text of Control Panel Display (encoded in custom character set) ***********
              10673 ; Row 1: "V:00 K:00 E:9999 T:0"
              10674 ; Row 2: " O:-00 O:-00 R:-000 "
              10675
BB42 12       10676 PANELTXTTAB     .BYTE CCS.V
BB43 0B       10677                 .BYTE CCS.COLON
BB44 00       10678                 .BYTE CCS.0
BB45 00       10679                 .BYTE CCS.0
BB46 0A       10680                 .BYTE CCS.SPC
BB47 55       10681                 .BYTE CCS.COL1!CCS.K
BB48 4B       10682                 .BYTE CCS.COL1!CCS.COLON
BB49 40       10683                 .BYTE CCS.COL1!CCS.0
BB4A 40       10684                 .BYTE CCS.COL1!CCS.0
BB4B 0A       10685                 .BYTE CCS.SPC
BB4C 8D       10686                 .BYTE CCS.COL2!CCS.E
BB4D 8B       10687                 .BYTE CCS.COL2!CCS.COLON
BB4E 89       10688                 .BYTE CCS.COL2!CCS.9
BB4F 89       10689                 .BYTE CCS.COL2!CCS.9
BB50 89       10690                 .BYTE CCS.COL2!CCS.9
BB51 89       10691                 .BYTE CCS.COL2!CCS.9
BB52 0A       10692                 .BYTE CCS.SPC
BB53 16       10693                 .BYTE CCS.T
BB54 0B       10694                 .BYTE CCS.COLON
BB55 00       10695                 .BYTE CCS.0
              10696
BB56 0A       10697                 .BYTE CCS.SPC
BB57 14       10698                 .BYTE CCS.THETA
BB58 0B       10699                 .BYTE CCS.COLON
BB59 0F       10700                 .BYTE CCS.MINUS
BB5A 00       10701                 .BYTE CCS.0
BB5B 00       10702                 .BYTE CCS.0
BB5C 0A       10703                 .BYTE CCS.SPC
BB5D 51       10704                 .BYTE CCS.COL1!CCS.PHI
BB5E 4B       10705                 .BYTE CCS.COL1!CCS.COLON
BB5F 0F       10706                 .BYTE CCS.MINUS
BB60 00       10707                 .BYTE CCS.0
BB61 00       10708                 .BYTE CCS.0
BB62 0A       10709                 .BYTE CCS.SPC
BB63 93       10710                 .BYTE CCS.COL2!CCS.R
BB64 8B       10711                 .BYTE CCS.COL2!CCS.COLON
BB65 0F       10712                 .BYTE CCS.MINUS
BB66 00       10713                 .BYTE CCS.0
BB67 00       10714                 .BYTE CCS.0
BB68 00       10715                 .BYTE CCS.0
BB69 0A       10716                 .BYTE CCS.SPC
              10717
              10718 ;*** Text of Galactic Chart Panel Display **************************************
              10719 ; Row 1: "WARP ENERGY:   0    "
              10720 ; Row 2: "TARGETS:  DC:PESCLR "
              10721 ; Row 3: "STAR DATE:00.00     "
              10722
BB6A 37       10723                 .BYTE ROM.W
BB6B 21       10724                 .BYTE ROM.A
BB6C 32       10725                 .BYTE ROM.R
BB6D 30       10726                 .BYTE ROM.P
BB6E 00       10727                 .BYTE ROM.SPC
BB6F 25       10728                 .BYTE ROM.E
BB70 2E       10729                 .BYTE ROM.N
BB71 25       10730                 .BYTE ROM.E
BB72 32       10731                 .BYTE ROM.R
BB73 27       10732                 .BYTE ROM.G
BB74 39       10733                 .BYTE ROM.Y
BB75 1A       10734                 .BYTE ROM.COLON
BB76 00       10735                 .BYTE ROM.SPC
BB77 00       10736                 .BYTE ROM.SPC
BB78 00       10737                 .BYTE ROM.SPC
BB79 10       10738                 .BYTE ROM.0
BB7A 00       10739                 .BYTE ROM.SPC
BB7B 00       10740                 .BYTE ROM.SPC
BB7C 00       10741                 .BYTE ROM.SPC
BB7D 00       10742                 .BYTE ROM.SPC
              10743
BB7E B4       10744                 .BYTE CCS.COL2!ROM.T
BB7F A1       10745                 .BYTE CCS.COL2!ROM.A
BB80 B2       10746                 .BYTE CCS.COL2!ROM.R
BB81 A7       10747                 .BYTE CCS.COL2!ROM.G
BB82 A5       10748                 .BYTE CCS.COL2!ROM.E
BB83 B4       10749                 .BYTE CCS.COL2!ROM.T
BB84 B3       10750                 .BYTE CCS.COL2!ROM.S
BB85 9A       10751                 .BYTE CCS.COL2!ROM.COLON
BB86 00       10752                 .BYTE ROM.SPC
BB87 00       10753                 .BYTE ROM.SPC
BB88 24       10754                 .BYTE ROM.D
BB89 23       10755                 .BYTE ROM.C
BB8A 1A       10756                 .BYTE ROM.COLON
BB8B 30       10757                 .BYTE ROM.P
BB8C 25       10758                 .BYTE ROM.E
BB8D 33       10759                 .BYTE ROM.S
BB8E 23       10760                 .BYTE ROM.C
BB8F 2C       10761                 .BYTE ROM.L
BB90 32       10762                 .BYTE ROM.R
BB91 00       10763                 .BYTE ROM.SPC
              10764
BB92 F3       10765                 .BYTE CCS.COL3!ROM.S
BB93 F4       10766                 .BYTE CCS.COL3!ROM.T
BB94 E1       10767                 .BYTE CCS.COL3!ROM.A
BB95 F2       10768                 .BYTE CCS.COL3!ROM.R
BB96 00       10769                 .BYTE ROM.SPC
BB97 E4       10770                 .BYTE CCS.COL3!ROM.D
BB98 E1       10771                 .BYTE CCS.COL3!ROM.A
BB99 F4       10772                 .BYTE CCS.COL3!ROM.T
BB9A E5       10773                 .BYTE CCS.COL3!ROM.E
BB9B DA       10774                 .BYTE CCS.COL3!ROM.COLON
BB9C D0       10775                 .BYTE CCS.COL3!ROM.0
BB9D D0       10776                 .BYTE CCS.COL3!ROM.0
BB9E CE       10777                 .BYTE CCS.COL3!ROM.DOT
BB9F D0       10778                 .BYTE CCS.COL3!ROM.0
BBA0 D0       10779                 .BYTE CCS.COL3!ROM.0
BBA1 00       10780                 .BYTE ROM.SPC
BBA2 00       10781                 .BYTE ROM.SPC
BBA3 00       10782                 .BYTE ROM.SPC
BBA4 00       10783                 .BYTE ROM.SPC
BBA5 00       10784                 .BYTE ROM.SPC
              10785
              10786 ;*** Galactic Chart sector type table ******************************************
BBA6 CF       10787 SECTORTYPETAB   .BYTE $CF                             ; Starbase
BBA7 04       10788                 .BYTE $04                             ; 4 Zylon ships
BBA8 03       10789                 .BYTE $03                             ; 3 Zylon ships
BBA9 02       10790                 .BYTE $02                             ; 1 or 2 Zylon ships
              10791
              10792 ;*** Phrase table **************************************************************
              10793 ; Phrases consist of phrase tokens. These are bytes that encode words, segments
              10794 ; (multiple words that fit into a single line of text), and how they are displayed.
              10795 ;
              10796 ; LOCAL VARIABLES
    =0040     10797 EOP             = $40                                 ; End of phrase
    =0080     10798 EOS             = $80                                 ; End of segment
    =00C0     10799 LONG            = $C0                                 ; Display title phrase for a long time
              10800
              10801                                                       ; Title Phrase Offset, Text
BBAA 00       10802 PHRASETAB       .BYTE $00                             ; (unused)
BBAB 050642   10803                 .BYTE $05,$06,$02!EOP                 ; $01  "ATTACK COMPUTER ON"
BBAE 050643   10804                 .BYTE $05,$06,$03!EOP                 ; $04  "ATTACK COMPUTER OFF"
BBB1 0442     10805                 .BYTE $04,$02!EOP                     ; $07  "SHIELDS ON"
BBB3 0443     10806                 .BYTE $04,$03!EOP                     ; $09  "SHIELDS OFF"
BBB5 060742   10807                 .BYTE $06,$07,$02!EOP                 ; $0B  "COMPUTER TRACKING ON"
BBB8 0743     10808                 .BYTE $07,$03!EOP                     ; $0E  "TRACKING OFF"
BBBA 48       10809                 .BYTE $08!EOP                         ; $10  "WHATS WRONG?"
BBBB 094A     10810                 .BYTE $09,$0A!EOP                     ; $11  "HYPERWARP ENGAGED"
BBBD 0BCD     10811                 .BYTE $0B,$0D!LONG                    ; $13  "STARBASE SURROUNDED"
BBBF 0BCC     10812                 .BYTE $0B,$0C!LONG                    ; $15  "STARBASE DESTROYED"
BBC1 094E     10813                 .BYTE $09,$0E!EOP                     ; $17  "HYPERWARP ABORTED"
BBC3 094F     10814                 .BYTE $09,$0F!EOP                     ; $19  "HYPERWARP COMPLETE"
BBC5 D0       10815                 .BYTE $10!LONG                        ; $1B  "HYPERSPACE"
BBC6 1192     10816                 .BYTE $11,$12!EOS                     ; $1C  "ORBIT ESTABLISHED"
BBC8 56       10817                 .BYTE $16!EOP                         ; $1E  "STANDBY"
BBC9 134E     10818                 .BYTE $13,$0E!EOP                     ; $1F  "DOCKING ABORTED"
BBCB 154F     10819                 .BYTE $15,$0F!EOP                     ; $21  "TRANSFER COMPLETE"
BBCD B8       10820                 .BYTE $38!EOS                         ; $23  " "
BBCE 97       10821                 .BYTE $17!EOS                         ; $24  "STAR FLEET TO"
BBCF 99       10822                 .BYTE $19!EOS                         ; $25  "ALL UNITS"
BBD0 98       10823                 .BYTE $18!EOS                         ; $26  "STAR CRUISER 7"
BBD1 8C       10824                 .BYTE $0C!EOS                         ; $27  "DESTROYED"
BBD2 9D       10825                 .BYTE $1D!EOS                         ; $28  "BY ZYLON FIRE"
BBD3 1E9F     10826                 .BYTE $1E,$1F!EOS                     ; $29  "POSTHUMOUS RANK IS:"
BBD5 FD       10827                 .BYTE $FD                             ; $2B  "<PLACEHOLDER FOR RANK>"
BBD6 25FC     10828                 .BYTE $25,$FC                         ; $2C  "CLASS <PLACEHOLDER FOR CLASS>"
BBD8 78       10829                 .BYTE $38!EOP                         ; $2E  " "
BBD9 9B       10830                 .BYTE $1B!EOS                         ; $2F  "STAR RAIDERS"
BBDA 60       10831                 .BYTE $20!EOP                         ; $30  "COPYRIGHT ATARI 1979"
BBDB B8       10832                 .BYTE $38!EOS                         ; $31  " "
BBDC 97       10833                 .BYTE $17!EOS                         ; $32  "STAR FLEET TO"
BBDD 98       10834                 .BYTE $18!EOS                         ; $33  "STAR CRUISER 7"
BBDE 1A8E     10835                 .BYTE $1A,$0E!EOS                     ; $34  "MISSION ABORTED"
BBE0 1C94     10836                 .BYTE $1C,$14!EOS                     ; $36  "ZERO ENERGY"
BBE2 249F     10837                 .BYTE $24,$1F!EOS                     ; $38  "NEW RANK IS"
BBE4 FD       10838                 .BYTE $FD                             ; $3A  "<PLACEHOLDER FOR RANK>"
BBE5 25FC     10839                 .BYTE $25,$FC                         ; $3B  "CLASS <PLACEHOLDER FOR CLASS>"
BBE7 A7       10840                 .BYTE $27!EOS                         ; $3D  "REPORT TO BASE"
BBE8 68       10841                 .BYTE $28!EOP                         ; $3E  "FOR TRAINING"
BBE9 B8       10842                 .BYTE $38!EOS                         ; $3F  " "
BBEA 97       10843                 .BYTE $17!EOS                         ; $40  "STAR FLEET TO"
BBEB 98       10844                 .BYTE $18!EOS                         ; $41  "STAR CRUISER 7"
BBEC 1A8F     10845                 .BYTE $1A,$0F!EOS                     ; $42  "MISSION COMPLETE"
BBEE 249F     10846                 .BYTE $24,$1F!EOS                     ; $44  "NEW RANK IS:"
BBF0 FD       10847                 .BYTE $FD                             ; $46  "<PLACEHOLDER FOR RANK>"
BBF1 25FC     10848                 .BYTE $25,$FC                         ; $47  "CLASS <PLACEHOLDER FOR CLASS>"
BBF3 66       10849                 .BYTE $26!EOP                         ; $49  "CONGRATULATIONS"
BBF4 2C5A     10850                 .BYTE $2C,$1A!EOP                     ; $4A  "NOVICE MISSION"
BBF6 2E5A     10851                 .BYTE $2E,$1A!EOP                     ; $4C  "PILOT MISSION"
BBF8 315A     10852                 .BYTE $31,$1A!EOP                     ; $4E  "WARRIOR MISSION"
BBFA 335A     10853                 .BYTE $33,$1A!EOP                     ; $50  "COMMANDER MISSION"
BBFC B8       10854                 .BYTE $38!EOS                         ; $52  " "
BBFD 3476     10855                 .BYTE $34,$36!EOP                     ; $53  "DAMAGE CONTROL"
BBFF 37B5     10856                 .BYTE $37,$35!EOS                     ; $55  "PHOTONS DAMAGED"
BC01 78       10857                 .BYTE $38!EOP                         ; $57  " "
BC02 378C     10858                 .BYTE $37,$0C!EOS                     ; $58  "PHOTONS DESTROYED"
BC04 78       10859                 .BYTE $38!EOP                         ; $5A  " "
BC05 23B5     10860                 .BYTE $23,$35!EOS                     ; $5B  "ENGINES DAMAGED"
BC07 78       10861                 .BYTE $38!EOP                         ; $5D  " "
BC08 238C     10862                 .BYTE $23,$0C!EOS                     ; $5E  "ENGINES DESTROYED"
BC0A 78       10863                 .BYTE $38!EOP                         ; $60  " "
BC0B 04B5     10864                 .BYTE $04,$35!EOS                     ; $61  "SHIELDS DAMAGED"
BC0D 78       10865                 .BYTE $38!EOP                         ; $63  " "
BC0E 048C     10866                 .BYTE $04,$0C!EOS                     ; $64  "SHIELDS DESTROYED"
BC10 78       10867                 .BYTE $38!EOP                         ; $66  " "
BC11 06B5     10868                 .BYTE $06,$35!EOS                     ; $67  "COMPUTER DAMAGED"
BC13 78       10869                 .BYTE $38!EOP                         ; $69  " "
BC14 068C     10870                 .BYTE $06,$0C!EOS                     ; $6A  "COMPUTER DESTROYED"
BC16 78       10871                 .BYTE $38!EOP                         ; $6C  " "
BC17 A2       10872                 .BYTE $22!EOS                         ; $6D  "SECTOR SCAN"
BC18 75       10873                 .BYTE $35!EOP                         ; $6E  "DAMAGED"
BC19 A2       10874                 .BYTE $22!EOS                         ; $6F  "SECTOR SCAN"
BC1A 4C       10875                 .BYTE $0C!EOP                         ; $70  "DESTROYED"
BC1B A1       10876                 .BYTE $21!EOS                         ; $71  "SUB-SPACE RADIO"
BC1C 75       10877                 .BYTE $35!EOP                         ; $72  "DAMAGED"
BC1D A1       10878                 .BYTE $21!EOS                         ; $73  "SUB-SPACE RADIO"
BC1E 4C       10879                 .BYTE $0C!EOP                         ; $74  "DESTROYED"
BC1F C1       10880                 .BYTE $01!LONG                        ; $75  "RED ALERT"
BC20 B8       10881                 .BYTE $38!EOS                         ; $76  " "
BC21 97       10882                 .BYTE $17!EOS                         ; $77  "STAR FLEET TO"
BC22 98       10883                 .BYTE $18!EOS                         ; $78  "STAR CRUISER 7"
BC23 1A8E     10884                 .BYTE $1A,$0E!EOS                     ; $79  "MISSION ABORTED"
BC25 249F     10885                 .BYTE $24,$1F!EOS                     ; $7B  "NEW RANK IS:"
BC27 FD       10886                 .BYTE $FD                             ; $7D  "<PLACEHOLDER FOR RANK>"
BC28 25FC     10887                 .BYTE $25,$FC                         ; $7E  "CLASS <PLACEHOLDER FOR CLASS>"
BC2A 66       10888                 .BYTE $26!EOP                         ; $80  "CONGRATULATIONS"
              10889
              10890 ;*** Word table ****************************************************************
              10891 ; Bit B7 of the first byte of a word is the end-of-word marker of the preceding
              10892 ; word
              10893 ;
              10894 ; LOCAL VARIABLES
    =0080     10895 EOW             = $80                                 ; End of word
              10896
BC2B A0202020 10897 WORDTAB         .BYTE EOW!$20,"    RED ALERT"         ; Word $01
BC2F 20524544
BC33 20414C45
BC37 5254    
BC39 CF4E     10898                 .BYTE EOW!'O,"N"                      ; Word $02
BC3B CF4646   10899                 .BYTE EOW!'O,"FF"                     ; Word $03
BC3E D3484945 10900                 .BYTE EOW!'S,"HIELDS"                 ; Word $04
BC42 4C4453  
BC45 C1545441 10901                 .BYTE EOW!'A,"TTACK"                  ; Word $05
BC49 434B    
BC4B C34F4D50 10902                 .BYTE EOW!'C,"OMPUTER"                ; Word $06
BC4F 55544552
BC53 D4524143 10903                 .BYTE EOW!'T,"RACKING"                ; Word $07
BC57 4B494E47
BC5B D7484154 10904                 .BYTE EOW!'W,"HATS WRONG?"            ; Word $08
BC5F 53205752
BC63 4F4E473F
BC67 C8595045 10905                 .BYTE EOW!'H,"YPERWARP"               ; Word $09
BC6B 52574152
BC6F 50      
BC70 C54E4741 10906                 .BYTE EOW!'E,"NGAGED"                 ; Word $0A
BC74 474544  
BC77 D3544152 10907                 .BYTE EOW!'S,"TARBASE"                ; Word $0B
BC7B 42415345
BC7F C4455354 10908                 .BYTE EOW!'D,"ESTROYED"               ; Word $0C
BC83 524F5945
BC87 44      
BC88 D3555252 10909                 .BYTE EOW!'S,"URROUNDED"              ; Word $0D
BC8C 4F554E44
BC90 4544    
BC92 C1424F52 10910                 .BYTE EOW!'A,"BORTED"                 ; Word $0E
BC96 544544  
BC99 C34F4D50 10911                 .BYTE EOW!'C,"OMPLETE"                ; Word $0F
BC9D 4C455445
BCA1 C8595045 10912                 .BYTE EOW!'H,"YPERSPACE"              ; Word $10
BCA5 52535041
BCA9 4345    
BCAB CF524249 10913                 .BYTE EOW!'O,"RBIT"                   ; Word $11
BCAF 54      
BCB0 C5535441 10914                 .BYTE EOW!'E,"STABLISHED"             ; Word $12
BCB4 424C4953
BCB8 484544  
BCBB C44F434B 10915                 .BYTE EOW!'D,"OCKING"                 ; Word $13
BCBF 494E47  
BCC2 C54E4552 10916                 .BYTE EOW!'E,"NERGY"                  ; Word $14
BCC6 4759    
BCC8 D452414E 10917                 .BYTE EOW!'T,"RANSFER"                ; Word $15
BCCC 53464552
BCD0 D354414E 10918                 .BYTE EOW!'S,"TANDBY"                 ; Word $16
BCD4 444259  
BCD7 D3544152 10919                 .BYTE EOW!'S,"TAR FLEET TO"           ; Word $17
BCDB 20464C45
BCDF 45542054
BCE3 4F      
BCE4 D3544152 10920                 .BYTE EOW!'S,"TAR CRUISER 7"          ; Word $18
BCE8 20435255
BCEC 49534552
BCF0 2037    
BCF2 C14C4C20 10921                 .BYTE EOW!'A,"LL UNITS"               ; Word $19
BCF6 554E4954
BCFA 53      
BCFB CD495353 10922                 .BYTE EOW!'M,"ISSION"                 ; Word $1A
BCFF 494F4E  
BD02 A0202020 10923                 .BYTE EOW!$20,"   STAR RAIDERS"       ; Word $1B
BD06 53544152
BD0A 20524149
BD0E 44455253
BD12 DA45524F 10924                 .BYTE EOW!'Z,"ERO"                    ; Word $1C
BD16 C259205A 10925                 .BYTE EOW!'B,"Y ZYLON FIRE"           ; Word $1D
BD1A 594C4F4E
BD1E 20464952
BD22 45      
BD23 D04F5354 10926                 .BYTE EOW!'P,"OSTHUMOUS"              ; Word $1E
BD27 48554D4F
BD2B 5553    
BD2D D2414E4B 10927                 .BYTE EOW!'R,"ANK IS:"                ; Word $1F
BD31 2049533A
BD35 C34F5059 10928                 .BYTE EOW!'C,"OPYRIGHT ATARI 1979"    ; Word $20
BD39 52494748
BD3D 54204154
BD41 41524920
BD45 31393739
BD49 D355422D 10929                 .BYTE EOW!'S,"UB-SPACE RADIO"         ; Word $21
BD4D 53504143
BD51 45205241
BD55 44494F  
BD58 D3454354 10930                 .BYTE EOW!'S,"ECTOR SCAN"             ; Word $22
BD5C 4F522053
BD60 43414E  
BD63 C54E4749 10931                 .BYTE EOW!'E,"NGINES"                 ; Word $23
BD67 4E4553  
BD6A CE4557   10932                 .BYTE EOW!'N,"EW"                     ; Word $24
BD6D C34C4153 10933                 .BYTE EOW!'C,"LASS"                   ; Word $25
BD71 53      
BD72 C34F4E47 10934                 .BYTE EOW!'C,"ONGRATULATIONS"         ; Word $26
BD76 52415455
BD7A 4C415449
BD7E 4F4E53  
BD81 D245504F 10935                 .BYTE EOW!'R,"EPORT TO BASE"          ; Word $27
BD85 52542054
BD89 4F204241
BD8D 5345    
BD8F C64F5220 10936                 .BYTE EOW!'F,"OR TRAINING"            ; Word $28
BD93 54524149
BD97 4E494E47
BD9B C7414C41 10937                 .BYTE EOW!'G,"ALACTIC COOK"           ; Word $29
BD9F 43544943
BDA3 20434F4F
BDA7 4B      
BDA8 C7415242 10938                 .BYTE EOW!'G,"ARBAGE SCOW CAPTAIN"    ; Word $2A
BDAC 41474520
BDB0 53434F57
BDB4 20434150
BDB8 5441494E
BDBC D24F4F4B 10939                 .BYTE EOW!'R,"OOKIE"                  ; Word $2B
BDC0 4945    
BDC2 CE4F5649 10940                 .BYTE EOW!'N,"OVICE"                  ; Word $2C
BDC6 4345    
BDC8 C54E5349 10941                 .BYTE EOW!'E,"NSIGN"                  ; Word $2D
BDCC 474E    
BDCE D0494C4F 10942                 .BYTE EOW!'P,"ILOT"                   ; Word $2E
BDD2 54      
BDD3 C14345   10943                 .BYTE EOW!'A,"CE"                     ; Word $2F
BDD6 CC494555 10944                 .BYTE EOW!'L,"IEUTENANT"              ; Word $30
BDDA 54454E41
BDDE 4E54    
BDE0 D7415252 10945                 .BYTE EOW!'W,"ARRIOR"                 ; Word $31
BDE4 494F52  
BDE7 C3415054 10946                 .BYTE EOW!'C,"APTAIN"                 ; Word $32
BDEB 41494E  
BDEE C34F4D4D 10947                 .BYTE EOW!'C,"OMMANDER"               ; Word $33
BDF2 414E4445
BDF6 52      
BDF7 C4414D41 10948                 .BYTE EOW!'D,"AMAGE"                  ; Word $34
BDFB 4745    
BDFD C4414D41 10949                 .BYTE EOW!'D,"AMAGED"                 ; Word $35
BE01 474544  
BE04 C34F4E54 10950                 .BYTE EOW!'C,"ONTROL"                 ; Word $36
BE08 524F4C  
BE0B D0484F54 10951                 .BYTE EOW!'P,"HOTONS"                 ; Word $37
BE0F 4F4E53  
BE12 A0       10952                 .BYTE EOW!$20                         ; Word $38
BE13 D3544152 10953                 .BYTE EOW!'S,"TAR COMMANDER"          ; Word $39
BE17 20434F4D
BE1B 4D414E44
BE1F 4552    
BE21 80       10954                 .BYTE EOW!$00                         ;
              10955
              10956 ;*** View modes ****************************************************************
BE22 00       10957 VIEWMODETAB     .BYTE $00                             ; Front view
BE23 01       10958                 .BYTE $01                             ; Aft view
BE24 40       10959                 .BYTE $40                             ; Long-Range Scan view
BE25 80       10960                 .BYTE $80                             ; Galactic Chart view
              10961
              10962 ;*** Title phrase offsets of "TRACKING OFF", "SHIELDS OFF", "COMPUTER OFF" *****
BE26 0E       10963 MSGOFFTAB       .BYTE $0E                             ; "TRACKING OFF"
BE27 09       10964                 .BYTE $09                             ; "SHIELDS OFF"
BE28 04       10965                 .BYTE $04                             ; "COMPUTER OFF"
              10966
              10967 ;*** Masks to test if Tracking Computer, Shields, or Attack Computer are on ****
BE29 FF       10968 MSGBITTAB       .BYTE $FF                             ; Mask Tracking Computer
BE2A 08       10969                 .BYTE $08                             ; Mask Shields
BE2B 02       10970                 .BYTE $02                             ; Mask Attack Computer
              10971
              10972 ;*** Title phrase offsets of "COMPUTER TRACKING ON", "SHIELDS ON", "COMPUTER ON"
BE2C 0B       10973 MSGONTAB        .BYTE $0B                             ; "COMPUTER TRACKING ON"
BE2D 07       10974                 .BYTE $07                             ; "SHIELDS ON"
BE2E 01       10975                 .BYTE $01                             ; "COMPUTER ON"
              10976
              10977 ;*** The following two tables encode the PLAYER shapes *************************
              10978 ;
              10979 ; PHOTON TORPEDO (shape type 0, data in shape table PLSHAP1TAB)
              10980 ; Numbers at top indicate the shape table offset of the first and last shape row
              10981 ;
              10982 ; $01..$10  $11..$1E  $1F..$2A  $2B..$34  $35..$3C  $3D..$42  $75..$76  $7A..$7B
              10983 ; ...##...  ...#....  ...##...  ...#....  ...#....  ...#....  ...##...  ...#....
              10984 ; ..####..  ..###...  ..####..  ..###...  ...##...  ..###...  ...##...  ...#....
              10985 ; .######.  .#####..  ..####..  ..###...  ..####..  ..###...
              10986 ; .######.  .#####..  .######.  .#####..  ..#.##..  ..#.#...
              10987 ; .###.##.  #######.  .##.###.  .###.#..  ..####..  ..###...
              10988 ; ####.###  ##.####.  .####.#.  .#####..  ..####..  ...#....
              10989 ; ##.#####  ##.##.#.  .######.  .##.##..  ...##...
              10990 ; ##.#####  #####.#.  .###.##.  ..###...  ....#...
              10991 ; ########  ###.###.  .######.  ..###...
              10992 ; ########  ###.###.  ..####..  ...#....
              10993 ; ####.###  .#####..  ..####..
              10994 ; .###.##.  .#####..  ...##...
              10995 ; .######.  ..###...
              10996 ; .######.  ...#....
              10997 ; ..####..
              10998 ; ...##...
              10999 ;
              11000 ; ZYLON FIGHTER (shape type 1, data in shape table PLSHAP2TAB)
              11001 ; Numbers at top indicate the shape table offset of the first and last shape row
              11002 ;
              11003 ; $01..$0C  $0D..$14  $15..$1A  $1B..$20  $21..$24  $25..$28  $29..$2A  $2B..$2C
              11004 ; #......#  #.....#.  .#....#.  .#...#..  ..#..#..  ..#.#...  ...##...  ...#....
              11005 ; #......#  #.....#.  .#.##.#.  .#.#.#..  ..####..  ..###...  ...##...  ...#....
              11006 ; #......#  #.###.#.  .######.  .#####..  ..####..  ..###...
              11007 ; #......#  #######.  .######.  .#####..  ..#..#..  ..#.#...
              11008 ; #.####.#  #######.  .#.##.#.  .#.#.#..
              11009 ; ########  #.###.#.  .#....#.  .#...#..
              11010 ; ########  #.....#.
              11011 ; #.####.#  #.....#.
              11012 ; #......#
              11013 ; #......#
              11014 ; #......#
              11015 ; #......#
              11016 ;
              11017 ; STARBASE RIGHT (shape type 2, data in shape table PLSHAP2TAB)
              11018 ; Numbers at top indicate the shape table offset of the first and last shape row
              11019 ;
              11020 ; $2D..$36  $38..$40  $41..$46  $36..$38  $36       $00       $00       $00
              11021 ; ###.....  ##......  ##......  ##......  ##......  ........  ........  ........
              11022 ; #####...  ####....  ##......  ####....
              11023 ; #####...  ####....  ####....  ##......
              11024 ; #######.  ######..  #.####..
              11025 ;  #.#.###  #.#####.  ####....
              11026 ; #######.  ######..  ##......
              11027 ; #####...  ####....
              11028 ; #####...  #.......
              11029 ; ##......  #.......
              11030 ; ##......
              11031 ;
              11032 ; STARBASE CENTER (shape type 3, data in shape table PLSHAP1TAB)
              11033 ; Numbers at top indicate the shape table offset of the first and last shape row
              11034 ;
              11035 ; $7E..$8D  $8E..$9C  $9D..$A9  $AA..$B3  $B4..$BB  $BC..$C0  $7B..$7D  $7A..$7B
              11036 ; ...##...  ........  ........  ...##...  ........  ...##...  ...#....  ...#....
              11037 ; .######.  ...##...  ...##...  ..####..  ...##...  ..####..  ..###...  ...#....
              11038 ; ########  ..####..  ..####..  ########  ..####..  ########  ...#....
              11039 ; ########  .######.  .######.  ########  ########  ..####..
              11040 ; ########  ########  ########  ###..###  ########  ...##...
              11041 ; ########  ########  ########  .##..##.  ########
              11042 ; ########  ########  ###..###  ########  ..####..
              11043 ; ###..###  ###..###  .##..##.  ########  ...##...
              11044 ; ###..###  .##..##.  ########  .######.
              11045 ; ########  ########  ########  ..####..
              11046 ; ########  ########  ########
              11047 ; ########  ########  ########
              11048 ; ########  ########  ..####..
              11049 ; ########  .######.
              11050 ; .######.  .######.
              11051 ; .######.
              11052 ;
              11053 ; STARBASE LEFT (shape type 4, data in shape table PLSHAP2TAB)
              11054 ; Numbers at top indicate the shape table offset of the first and last shape row
              11055 ;
              11056 ; $47..$50  $52..$5A  $5B..$60  $50..$52  $50       $00       $00       $00
              11057 ; .....###  ......##  ......##  ......##  ......##  ........  ........  ........
              11058 ; ...#####  ....####  ......##  ....####
              11059 ; ...#####  ....####  ....####  ......##
              11060 ; .#######  ..######  ..####.#
              11061 ; ###.#.#.  .#####.#  ....####
              11062 ; .#######  ..######  ......##
              11063 ; ...#####  ....####
              11064 ; ...#####  .......#
              11065 ; ......##  .......#
              11066 ; ......##
              11067 ;
              11068 ; TRANSFER VESSEL (shape type 5, data in shape table PLSHAP1TAB)
              11069 ; Numbers at top indicate the shape table offset of the first and last shape row
              11070 ;
              11071 ; $43..$52  $53..$60  $61..$6B  $6C..$74  $75..$79  $7A..$7D  $75..$76  $7A..$7B
              11072 ; ..####..  ...###..  ...##...  ...#....  ...##...  ...#....  ...##...  ...#....
              11073 ; ..####..  ...###..  ...##...  ...#....  ...##...  ...#....  ...##...  ...#....
              11074 ; ..#..#..  ...#.#..  ..####..  ..###...  ..####..  ..###...
              11075 ; ..####..  ..#####.  ..####..  ..###...  ...##...  ...#....
              11076 ; .######.  ..#####.  ..####..  ..###...  ...##...
              11077 ; .######.  ..#####.  ..####..  .#####..
              11078 ; .######.  ..#.#.#.  .######.  ..#.#...
              11079 ; .#.##.#.  .#######  ..#..#..  ..#.#...
              11080 ; ########  .#######  ..#..#..  ..#.#...
              11081 ; ########  ..#...#.  ..#..#..
              11082 ; .#....#.  ..#...#.  ..#..#..
              11083 ; .#....#.  ..#...#.
              11084 ; .#....#.  ..#...#.
              11085 ; .#....#.  ..#...#.
              11086 ; .#....#.
              11087 ; .#....#.
              11088 ;
              11089 ; METEOR (shape type 6, data in shape table PLSHAP1TAB)
              11090 ; Numbers at top indicate the shape table offset of the first and last shape row
              11091 ;
              11092 ; $01..$10  $11..$1E  $1F..$2A  $2B..$34  $35..$3C  $3D..$42  $75..$76  $7A..$7B
              11093 ; ...##...  ...#....  ...##...  ...#....  ...#....  ...#....  ...##...  ...#....
              11094 ; ..####..  ..###...  ..####..  ..###...  ...##...  ..###...  ...##...  ...#....
              11095 ; .######.  .#####..  ..####..  ..###...  ..####..  ..###...
              11096 ; .######.  .#####..  .######.  .#####..  ..#.##..  ..#.#...
              11097 ; .###.##.  #######.  .##.###.  .###.#..  ..####..  ..###...
              11098 ; ####.###  ##.####.  .####.#.  .#####..  ..####..  ...#....
              11099 ; ##.#####  ##.##.#.  .######.  .##.##..  ...##...
              11100 ; ##.#####  #####.#.  .###.##.  ..###...  ....#...
              11101 ; ########  ###.###.  .######.  ..###...
              11102 ; ########  ###.###.  ..####..  ...#....
              11103 ; ####.###  .#####..  ..####..
              11104 ; .###.##.  .#####..  ...##...
              11105 ; .######.  ..###...
              11106 ; .######.  ...#....
              11107 ; ..####..
              11108 ; ...##...
              11109 ;
              11110 ; ZYLON CRUISER (shape type 7, data in shape table PLSHAP2TAB)
              11111 ; Numbers at top indicate the shape table offset of the first and last shape row
              11112 ;
              11113 ; $61..$69  $6A..$71  $72..$78  $79..$7E  $7F..$82  $83..$85  $29..$2A  $2B..$2C
              11114 ; ...##...  ...#....  ...##...  ...#....  ...##...  ...#....  ...##...  ...#....
              11115 ; ..####..  ..###...  ..####..  ..###...  ..####..  ..###...  ...##...  ...#....
              11116 ; .######.  .#####..  ..####..  ..###...  ..#..#..  ..#.#...
              11117 ; .######.  .#####..  .##..##.  .##.##..  ..#..#..
              11118 ; ##.##.##  ##.#.##.  .##..##.  .#...#..
              11119 ; ##....##  ##...##.  .#....#.  .#...#..
              11120 ; #......#  #.....#.  .#....#.
              11121 ; #......#  #.....#.
              11122 ; #......#
              11123 ;
              11124 ; ZYLON BASESTAR (shape type 8, data in shape table PLSHAP2TAB)
              11125 ; Numbers at top indicate the shape table offset of the first and last shape row
              11126 ;
              11127 ; $86..$8F  $90..$99  $9A..$A0  $A1..$A7  $A8..$AC  $AD..$B0  $29..$2A  $2B..$2C
              11128 ; ...##...  ...#....  ...##...  ...#....  ...##...  ...#....  ...##...  ...#....
              11129 ; ..####..  ..###...  ..####..  ..###...  ..####..  ..###...  ...##...  ...#....
              11130 ; .######.  .#####..  .######.  .#####..  ...##...  ..###...
              11131 ; ########  #######.  ...##...  ...#....  ..####..  ...#....
              11132 ; ...##...  ..###...  .######.  .#####..  ...##...
              11133 ; ...##...  ..###...  ..####..  ..###...
              11134 ; ########  #######.  ...##...  ...#....
              11135 ; .######.  .#####..
              11136 ; ..####..  ..###...
              11137 ; ...##...  ...#....
              11138 ;
              11139 ; HYPERWARP TARGET MARKER (shape type 9, data in shape table PLSHAP1TAB)
              11140 ; Numbers at top indicate the shape table offset of the first and last shape row
              11141 ;
              11142 ; $C1..$CC  $C1..$CC  $C1..$CC  $C1..$CC  $C1..$CC  $C1..$CC  $75..$76  $C1..$CC
              11143 ; ..#.#...  ..#.#...  ..#.#...  ..#.#...  ..#.#...  ..#.#...  ...##...  ..#.#...
              11144 ; ..#.#...  ..#.#...  ..#.#...  ..#.#...  ..#.#...  ..#.#...  ...##...  ..#.#...
              11145 ; ..#.#...  ..#.#...  ..#.#...  ..#.#...  ..#.#...  ..#.#...            ..#.#...
              11146 ; ..#.#...  ..#.#...  ..#.#...  ..#.#...  ..#.#...  ..#.#...            ..#.#...
              11147 ; ###.###.  ###.###.  ###.###.  ###.###.  ###.###.  ###.###.            ###.###.
              11148 ; ........  ........  ........  ........  ........  ........            ........
              11149 ; ........  ........  ........  ........  ........  ........            ........
              11150 ; ###.###.  ###.###.  ###.###.  ###.###.  ###.###.  ###.###.            ###.###.
              11151 ; ..#.#...  ..#.#...  ..#.#...  ..#.#...  ..#.#...  ..#.#...            ..#.#...
              11152 ; ..#.#...  ..#.#...  ..#.#...  ..#.#...  ..#.#...  ..#.#...            ..#.#...
              11153 ; ..#.#...  ..#.#...  ..#.#...  ..#.#...  ..#.#...  ..#.#...            ..#.#...
              11154 ; ..#.#...  ..#.#...  ..#.#...  ..#.#...  ..#.#...  ..#.#...            ..#.#...
              11155
              11156 ;*** Shape type 0..9 offset table (10 shape cell offsets of shape type...) *****
BE2F 01111F2B 11157 PLSHAPOFFTAB    .BYTE $01,$11,$1F,$2B,$35,$3D,$75,$7A ; ...0 into PLSHAP1TAB
BE33 353D757A
BE37 010D151B 11158                 .BYTE $01,$0D,$15,$1B,$21,$25,$29,$2B ; ...1 into PLSHAP2TAB
BE3B 2125292B
BE3F 2D384136 11159                 .BYTE $2D,$38,$41,$36,$36,$00,$00,$00 ; ...2 into PLSHAP2TAB
BE43 36000000
BE47 7E8E9DAA 11160                 .BYTE $7E,$8E,$9D,$AA,$B4,$BC,$7B,$7A ; ...3 into PLSHAP1TAB
BE4B B4BC7B7A
BE4F 47525B50 11161                 .BYTE $47,$52,$5B,$50,$50,$00,$00,$00 ; ...4 into PLSHAP2TAB
BE53 50000000
BE57 4353616C 11162                 .BYTE $43,$53,$61,$6C,$75,$7A,$75,$7A ; ...5 into PLSHAP1TAB
BE5B 757A757A
BE5F 01111F2B 11163                 .BYTE $01,$11,$1F,$2B,$35,$3D,$75,$7A ; ...6 into PLSHAP1TAB
BE63 353D757A
BE67 616A7279 11164                 .BYTE $61,$6A,$72,$79,$7F,$83,$29,$2B ; ...7 into PLSHAP2TAB
BE6B 7F83292B
BE6F 86909AA1 11165                 .BYTE $86,$90,$9A,$A1,$A8,$AD,$29,$2B ; ...8 into PLSHAP2TAB
BE73 A8AD292B
BE77 C1C1C1C1 11166                 .BYTE $C1,$C1,$C1,$C1,$C1,$C1,$75,$C1 ; ...9 into PLSHAP1TAB
BE7B C1C175C1
              11167
              11168 ;*** Shape type 0..9 height table (10 shape cell heights of shape type...) *****
BE7F 0F0D0B09 11169 PLSHAPHEIGHTTAB .BYTE $0F,$0D,$0B,$09,$07,$05,$01,$01 ; ...0
BE83 07050101
BE87 0B070505 11170                 .BYTE $0B,$07,$05,$05,$03,$03,$01,$01 ; ...1
BE8B 03030101
BE8F 09080502 11171                 .BYTE $09,$08,$05,$02,$00,$00,$00,$00 ; ...2
BE93 00000000
BE97 0F0E0C09 11172                 .BYTE $0F,$0E,$0C,$09,$07,$04,$02,$01 ; ...3
BE9B 07040201
BE9F 09080502 11173                 .BYTE $09,$08,$05,$02,$00,$00,$00,$00 ; ...4
BEA3 00000000
BEA7 0F0D0A08 11174                 .BYTE $0F,$0D,$0A,$08,$04,$03,$01,$01 ; ...5
BEAB 04030101
BEAF 0F0D0B09 11175                 .BYTE $0F,$0D,$0B,$09,$07,$05,$01,$01 ; ...6
BEB3 07050101
BEB7 08070605 11176                 .BYTE $08,$07,$06,$05,$03,$02,$01,$01 ; ...7
BEBB 03020101
BEBF 09090606 11177                 .BYTE $09,$09,$06,$06,$04,$03,$01,$01 ; ...8
BEC3 04030101
BEC7 0B0B0B0B 11178                 .BYTE $0B,$0B,$0B,$0B,$0B,$0B,$01,$0B ; ...9
BECB 0B0B010B
              11179
              11180 ;*** Keyboard codes to switch to Front or Aft view when Tracking Computer is on 
BECF F8       11181 TRACKKEYSTAB    .BYTE $F8                             ; 'F' - Front view
BED0 FF       11182                 .BYTE $FF                             ; 'A' - Aft view
              11183
              11184 ;*** Galactic Chart sector character codes (encoded in custom character set) ***
BED1 0C       11185 SECTORCHARTAB   .BYTE CCS.BORDERSW                    ; Empty sector
BED2 1E       11186                 .BYTE CCS.2ZYLONS                     ; Sector contains 1 Zylon ship
BED3 1E       11187                 .BYTE CCS.2ZYLONS                     ; Sector contains 2 Zylon ships
BED4 1D       11188                 .BYTE CCS.3ZYLONS                     ; Sector contains 3 Zylon ships
BED5 1C       11189                 .BYTE CCS.4ZYLONS                     ; Sector contains 4 Zylon ships
BED6 1B       11190                 .BYTE CCS.STARBASE                    ; Sector contains starbase
              11191
              11192 ;*** Mask to limit veer-off velocity of Hyperwarp Target Marker in hyperwarp ***
BED7 9F       11193 VEERMASKTAB     .BYTE NEG!31                          ;  -31..+31  <KM/H> (unused)
BED8 BF       11194                 .BYTE NEG!63                          ;  -63..+63  <KM/H> PILOT mission
BED9 DF       11195                 .BYTE NEG!95                          ;  -95..+95  <KM/H> WARRIOR mission
BEDA FF       11196                 .BYTE NEG!127                         ; -127..+127 <KM/H> COMMANDER mission
              11197
              11198 ;*** Horizontal PLAYER offsets for PLAYER0..1 (STARBASE LEFT, STARBASE RIGHT) **
BEDB F8       11199 PLSTARBAOFFTAB  .BYTE -8                              ; -8 Player/Missile pixels
BEDC 08       11200                 .BYTE 8                               ; +8 Player/Missile pixels
              11201
              11202 ;*** Mission bonus table *******************************************************
BEDD 50       11203 BONUSTAB        .BYTE 80                              ; Mission complete   NOVICE mission
BEDE 4C       11204                 .BYTE 76                              ; Mission complete   PILOT mission
BEDF 3C       11205                 .BYTE 60                              ; Mission complete   WARRIOR mission
BEE0 6F       11206                 .BYTE 111                             ; Mission complete   COMMANDER mission
              11207
BEE1 3C       11208                 .BYTE 60                              ; Mission aborted    NOVICE mission
BEE2 3C       11209                 .BYTE 60                              ; Mission aborted    PILOT mission
BEE3 32       11210                 .BYTE 50                              ; Mission aborted    WARRIOR mission
BEE4 64       11211                 .BYTE 100                             ; Mission aborted    COMMANDER mission
              11212
BEE5 28       11213                 .BYTE 40                              ; Starship destroyed NOVICE mission
BEE6 32       11214                 .BYTE 50                              ; Starship destroyed PILOT mission
BEE7 28       11215                 .BYTE 40                              ; Starship destroyed WARRIOR mission
BEE8 5A       11216                 .BYTE 90                              ; Starship destroyed COMMANDER mission
              11217
              11218 ;*** Title phrase offsets of scored class rank *********************************
BEE9 A9       11219 RANKTAB         .BYTE $29!EOS                         ; "GALACTIC COOK"
BEEA AA       11220                 .BYTE $2A!EOS                         ; "GARBAGE SCOW CAPTAIN"
BEEB AA       11221                 .BYTE $2A!EOS                         ; "GARBAGE SCOW CAPTAIN"
BEEC AB       11222                 .BYTE $2B!EOS                         ; "ROOKIE"
BEED AB       11223                 .BYTE $2B!EOS                         ; "ROOKIE"
BEEE AC       11224                 .BYTE $2C!EOS                         ; "NOVICE"
BEEF AC       11225                 .BYTE $2C!EOS                         ; "NOVICE"
BEF0 AD       11226                 .BYTE $2D!EOS                         ; "ENSIGN"
BEF1 AD       11227                 .BYTE $2D!EOS                         ; "ENSIGN"
BEF2 AE       11228                 .BYTE $2E!EOS                         ; "PILOT"
BEF3 AE       11229                 .BYTE $2E!EOS                         ; "PILOT"
BEF4 AF       11230                 .BYTE $2F!EOS                         ; "ACE"
BEF5 B0       11231                 .BYTE $30!EOS                         ; "LIEUTENANT"
BEF6 B1       11232                 .BYTE $31!EOS                         ; "WARRIOR"
BEF7 B2       11233                 .BYTE $32!EOS                         ; "CAPTAIN"
BEF8 B3       11234                 .BYTE $33!EOS                         ; "COMMANDER"
BEF9 B3       11235                 .BYTE $33!EOS                         ; "COMMANDER"
BEFA B9       11236                 .BYTE $39!EOS                         ; "STAR COMMANDER"
BEFB B9       11237                 .BYTE $39!EOS                         ; "STAR COMMANDER"
              11238
              11239 ;*** Scored class number table *************************************************
BEFC 95       11240 CLASSTAB        .BYTE CCS.COL2!ROM.5                  ; Class 5
BEFD 95       11241                 .BYTE CCS.COL2!ROM.5                  ; Class 5
BEFE 95       11242                 .BYTE CCS.COL2!ROM.5                  ; Class 5
BEFF 94       11243                 .BYTE CCS.COL2!ROM.4                  ; Class 4
BF00 94       11244                 .BYTE CCS.COL2!ROM.4                  ; Class 4
BF01 94       11245                 .BYTE CCS.COL2!ROM.4                  ; Class 4
BF02 94       11246                 .BYTE CCS.COL2!ROM.4                  ; Class 4
BF03 93       11247                 .BYTE CCS.COL2!ROM.3                  ; Class 3
BF04 93       11248                 .BYTE CCS.COL2!ROM.3                  ; Class 3
BF05 93       11249                 .BYTE CCS.COL2!ROM.3                  ; Class 3
BF06 92       11250                 .BYTE CCS.COL2!ROM.2                  ; Class 2
BF07 92       11251                 .BYTE CCS.COL2!ROM.2                  ; Class 2
BF08 92       11252                 .BYTE CCS.COL2!ROM.2                  ; Class 2
BF09 91       11253                 .BYTE CCS.COL2!ROM.1                  ; Class 1
BF0A 91       11254                 .BYTE CCS.COL2!ROM.1                  ; Class 1
BF0B 91       11255                 .BYTE CCS.COL2!ROM.1                  ; Class 1
              11256
              11257 ;*** Title phrase offsets of mission level *************************************
BF0C 4A       11258 MISSIONPHRTAB   .BYTE $4A                             ; "NOVICE MISSION"
BF0D 4C       11259                 .BYTE $4C                             ; "PILOT MISSION"
BF0E 4E       11260                 .BYTE $4E                             ; "WARRIOR MISSION"
BF0F 50       11261                 .BYTE $50                             ; "COMMANDER MISSION"
              11262
              11263 ;*** Damage probability of subsystems depending on mission level ***************
BF10 00       11264 DAMAGEPROBTAB   .BYTE 0                               ;  0% (  0:256) NOVICE mission
BF11 50       11265                 .BYTE 80                              ; 31% ( 80:256) PILOT mission
BF12 B4       11266                 .BYTE 180                             ; 70% (180:256) WARRIOR mission
BF13 FE       11267                 .BYTE 254                             ; 99% (254:256) COMMANDER mission
              11268
              11269 ;*** Title phrase offsets of damaged subsystems ********************************
BF14 55       11270 DAMAGEPHRTAB    .BYTE $55                             ; "PHOTON TORPEDOS DAMAGED"
BF15 5B       11271                 .BYTE $5B                             ; "ENGINES DAMAGED"
BF16 61       11272                 .BYTE $61                             ; "SHIELDS DAMAGED"
BF17 67       11273                 .BYTE $67                             ; "COMPUTER DAMAGED"
BF18 6D       11274                 .BYTE $6D                             ; "LONG RANGE SCAN DAMAGED"
BF19 71       11275                 .BYTE $71                             ; "SUB-SPACE RADIO DAMAGED"
              11276
              11277 ;*** Title phrase offsets of destroyed subsystems ******************************
BF1A 58       11278 DESTROYPHRTAB   .BYTE $58                             ; "PHOTON TORPEDOS DESTROYED"
BF1B 5E       11279                 .BYTE $5E                             ; "ENGINES DESTROYED"
BF1C 64       11280                 .BYTE $64                             ; "SHIELDS DESTROYED"
BF1D 6A       11281                 .BYTE $6A                             ; "COMPUTER DESTROYED"
BF1E 6F       11282                 .BYTE $6F                             ; "LONG RANGE SCAN DESTROYED"
BF1F 73       11283                 .BYTE $73                             ; "SUB-SPACE RADIO DESTROYED"
              11284
              11285 ;*** 3 x 10-byte noise sound patterns (bytes 0..7 stored in reverse order) *****
              11286 ;
              11287 ; (9) AUDCTL        ($D208) POKEY: Audio control
              11288 ; (8) AUDF3         ($D204) POKEY: Audio channel 3 frequency
              11289 ; (7) NOISETORPTIM  ($DA)   Timer for PHOTON TORPEDO LAUNCHED noise sound patterns
              11290 ; (6) NOISEEXPLTIM  ($DB)   Timer for SHIELD and ZYLON EXPLOSION noise sound patterns
              11291 ; (5) NOISEAUDC2    ($DC)   Audio channel 1/2 control shadow register
              11292 ; (4) NOISEAUDC3    ($DD)   Audio channel 3   control shadow register
              11293 ; (3) NOISEAUDF1    ($DE)   Audio channel 1 frequency shadow register
              11294 ; (2) NOISEAUDF2    ($DF)   Audio channel 2 frequency shadow register
              11295 ; (1) NOISEFRQINC   ($E0)   Audio channel 1/2 frequency increment
              11296 ; (0) NOISELIFE     ($E1)   Noise sound pattern lifetime
              11297 ;
              11298 ;                     (0),(1),(2),(3),(4),(5),(6),(7),(8),(9)
BF20 18FF0200 11299 NOISEPATTAB     .BYTE $18,$FF,$02,$00,$8A,$A0,$00,$08,$50,$00; PHOTON TORPEDO LAUNCHED
BF24 8AA00008
BF28 5000    
BF2A 40400103 11300                 .BYTE $40,$40,$01,$03,$88,$AF,$08,$00,$50,$04; SHIELD EXPLOSION
BF2E 88AF0800
BF32 5004    
BF34 30400103 11301                 .BYTE $30,$40,$01,$03,$84,$A8,$04,$00,$50,$04; ZYLON EXPLOSION
BF38 84A80400
BF3C 5004    
              11302
              11303 ;*** 5 x 6-byte beeper sound patterns (bytes 0..5 stored in reverse order) *****
              11304 ;
              11305 ; (5) BEEPFRQIND    ($D2) Running index into frequency table BEEPFRQTAB ($BF5C)
              11306 ; (4) BEEPREPEAT    ($D3) Number of times the beeper sound pattern sequence is repeated - 1
              11307 ; (3) BEEPTONELIFE  ($D4) Lifetime of tone in TICKs - 1
              11308 ; (2) BEEPPAUSELIFE ($D5) Lifetime of pause in TICKs - 1 ($FF -> No pause)
              11309 ; (1) BEEPPRIORITY  ($D6) Beeper sound pattern priority. A playing beeper sound pattern is
              11310 ;                         stopped if a beeper sound pattern of higher priority is about to be
              11311 ;                         played. A value of 0 indicates that no beeper sound pattern is
              11312 ;                         playing at the moment.
              11313 ; (0) BEEPFRQSTART  ($D7) Index to first byte of the beeper sound pattern frequency in table
              11314 ;                         BEEPFRQTAB ($BF5C)
              11315 ;
              11316 ; Frequency-over-TICKs diagrams for all beeper sound patterns:
              11317 ;
              11318 ; HYPERWARP TRANSIT
              11319 ;
              11320 ;      FRQ
              11321 ;       |
              11322 ;   $18 |-4--
              11323 ;       |
              11324 ;   $00 |    -3-
              11325 ;       +-------> TICKS
              11326 ;        <13 x >
              11327 ;
              11328 ; RED ALERT
              11329 ;
              11330 ;      FRQ
              11331 ;       |
              11332 ;   $60 |                 --------17-------
              11333 ;       |
              11334 ;   $40 |--------17-------
              11335 ;       |
              11336 ;       +----------------------------------> TICKS
              11337 ;        <-------------- 8 x ------------->
              11338 ;
              11339 ; ACKNOWLEDGE
              11340 ;
              11341 ;      FRQ
              11342 ;       |
              11343 ;   $10 |-3-   -3-   -3-
              11344 ;       |
              11345 ;   $00 |   -3-   -3-   -3-
              11346 ;       +------------------> TICKS
              11347 ;        <------ 1 x ----->
              11348 ;
              11349 ; DAMAGE REPORT (not to scale)
              11350 ;
              11351 ;      FRQ
              11352 ;       |
              11353 ;   $40 |------------33-------------
              11354 ;       |
              11355 ;   $20 |                           ------------33-------------
              11356 ;       |
              11357 ;       +------------------------------------------------------> TICKS
              11358 ;        <------------------------ 3 x ----------------------->
              11359 ;
              11360 ; MESSAGE FROM STARBASE (not to scale)
              11361 ;
              11362 ;      FRQ
              11363 ;       |
              11364 ;   $51 |                                  -----33-----
              11365 ;   $48 |-----33-----
              11366 ;   $40 |                 -----33-----
              11367 ;       |
              11368 ;   $00 |            --9--            --9--            --9--
              11369 ;       +----------------------------------------------------> TICKS
              11370 ;        <---------------------- 1 x ---------------------->
              11371 ;
              11372 ;                     (0),(1),(2),(3),(4),(5)
BF3E 02020203 11373 BEEPPATTAB      .BYTE $02,$02,$02,$03,$0C,$02         ; HYPERWARP TRANSIT
BF42 0C02    
BF44 0403FF10 11374                 .BYTE $04,$03,$FF,$10,$07,$04         ; RED ALERT
BF48 0704    
BF4A 07040202 11375                 .BYTE $07,$04,$02,$02,$00,$07         ; ACKNOWLEDGE
BF4E 0007    
BF50 0B05FF20 11376                 .BYTE $0B,$05,$FF,$20,$02,$0B         ; DAMAGE REPORT
BF54 020B    
BF56 0E060820 11377                 .BYTE $0E,$06,$08,$20,$00,$0E         ; MESSAGE FROM STARBASE
BF5A 000E    
              11378
              11379 ;*** Beeper sound pattern frequency table **************************************
BF5C 10FF     11380 BEEPFRQTAB      .BYTE $10,$FF                         ; (unused) (!)
BF5E 18FF     11381                 .BYTE $18,$FF                         ; HYPERWARP TRANSIT
BF60 4060FF   11382                 .BYTE $40,$60,$FF                     ; RED ALERT
BF63 101010FF 11383                 .BYTE $10,$10,$10,$FF                 ; ACKNOWLEDGE
BF67 4020FF   11384                 .BYTE $40,$20,$FF                     ; DAMAGE REPORT
BF6A 484051FF 11385                 .BYTE $48,$40,$51,$FF                 ; MESSAGE FROM STARBASE
              11386
              11387 ;*** Shape of blip in Attack Computer Display **********************************
BF6E 84       11388 BLIPSHAPTAB     .BYTE $84                             ; #....#..
BF6F B4       11389                 .BYTE $B4                             ; #.##.#..
BF70 FC       11390                 .BYTE $FC                             ; ######..
BF71 B4       11391                 .BYTE $B4                             ; #.##.#..
BF72 84       11392                 .BYTE $84                             ; #....#..
              11393
              11394 ;*** Initial x-coordinate (high byte) of our starship's photon torpedo *********
BF73 FF       11395 BARRELXTAB      .BYTE $FF                             ; Left barrel  = -256 (-$FF00) <KM>
BF74 01       11396                 .BYTE $01                             ; Right barrel = +256 (+$0100) <KM>
              11397
              11398 ;*** Maximum photon torpedo hit z-coordinate (high byte) ***********************
BF75 0C       11399 HITMAXZTAB      .BYTE $0C                             ; < 3328 ($0C**) <KM>
BF76 0C       11400                 .BYTE $0C                             ; < 3328 ($0C**) <KM>
BF77 0C       11401                 .BYTE $0C                             ; < 3328 ($0C**) <KM>
BF78 0C       11402                 .BYTE $0C                             ; < 3328 ($0C**) <KM>
BF79 0E       11403                 .BYTE $0E                             ; < 3840 ($0E**) <KM>
BF7A 0E       11404                 .BYTE $0E                             ; < 3840 ($0E**) <KM>
BF7B 0E       11405                 .BYTE $0E                             ; < 3840 ($0E**) <KM>
BF7C 20       11406                 .BYTE $20                             ; < 8448 ($20**) <KM>
              11407
              11408 ;*** Minimum photon torpedo hit z-coordinate (high byte) ***********************
BF7D 00       11409 HITMINZTAB      .BYTE $00                             ; >=    0 ($00**) <KM>
BF7E 00       11410                 .BYTE $00                             ; >=    0 ($00**) <KM>
BF7F 00       11411                 .BYTE $00                             ; >=    0 ($00**) <KM>
BF80 02       11412                 .BYTE $02                             ; >=  512 ($02**) <KM>
BF81 04       11413                 .BYTE $04                             ; >= 1024 ($04**) <KM>
BF82 06       11414                 .BYTE $06                             ; >= 1536 ($06**) <KM>
BF83 08       11415                 .BYTE $08                             ; >= 2048 ($08**) <KM>
BF84 0C       11416                 .BYTE $0C                             ; >= 3072 ($0C**) <KM>
              11417
              11418 ;*** Velocity of homing Zylon photon torpedo ***********************************
BF85 81       11419 ZYLONHOMVELTAB  .BYTE NEG!1                           ;  -1 <KM/H> NOVICE mission
BF86 84       11420                 .BYTE NEG!4                           ;  -4 <KM/H> PILOT mission
BF87 88       11421                 .BYTE NEG!8                           ;  -8 <KM/H> WARRIOR mission
BF88 94       11422                 .BYTE NEG!20                          ; -20 <KM/H> COMMANDER mission
              11423
              11424 ;*** Zylon shape type table ****************************************************
BF89 80       11425 ZYLONSHAPTAB    .BYTE SHAP.ZBASESTAR                  ; ZYLON BASESTAR
BF8A 10       11426                 .BYTE SHAP.ZFIGHTER                   ; ZYLON FIGHTER
BF8B 10       11427                 .BYTE SHAP.ZFIGHTER                   ; ZYLON FIGHTER
BF8C 10       11428                 .BYTE SHAP.ZFIGHTER                   ; ZYLON FIGHTER
BF8D 70       11429                 .BYTE SHAP.ZCRUISER                   ; ZYLON CRUISER
BF8E 70       11430                 .BYTE SHAP.ZCRUISER                   ; ZYLON CRUISER
BF8F 70       11431                 .BYTE SHAP.ZCRUISER                   ; ZYLON CRUISER
BF90 10       11432                 .BYTE SHAP.ZFIGHTER                   ; ZYLON FIGHTER
              11433
              11434 ;*** Zylon flight pattern table ************************************************
BF91 04       11435 ZYLONFLPATTAB   .BYTE 4                               ; Flight pattern 4
BF92 04       11436                 .BYTE 4                               ; Flight pattern 4
BF93 00       11437                 .BYTE 0                               ; Attack Flight Pattern 0
BF94 00       11438                 .BYTE 0                               ; Attack Flight Pattern 0
BF95 00       11439                 .BYTE 0                               ; Attack Flight Pattern 0
BF96 01       11440                 .BYTE 1                               ; Flight pattern 1
BF97 00       11441                 .BYTE 0                               ; Attack Flight Pattern 0
BF98 00       11442                 .BYTE 0                               ; Attack Flight Pattern 0
              11443
              11444 ;*** Zylon velocity table ******************************************************
BF99 3E       11445 ZYLONVELTAB     .BYTE 62                              ; +62 <KM/H>
BF9A 1E       11446                 .BYTE 30                              ; +30 <KM/H>
BF9B 10       11447                 .BYTE 16                              ; +16 <KM/H>
BF9C 08       11448                 .BYTE 8                               ;  +8 <KM/H>
BF9D 04       11449                 .BYTE 4                               ;  +4 <KM/H>
BF9E 02       11450                 .BYTE 2                               ;  +2 <KM/H>
BF9F 01       11451                 .BYTE 1                               ;  +1 <KM/H>
BFA0 00       11452                 .BYTE 0                               ;   0 <KM/H>
BFA1 00       11453                 .BYTE 0                               ;   0 <KM/H>
BFA2 81       11454                 .BYTE NEG!1                           ;  -1 <KM/H>
BFA3 82       11455                 .BYTE NEG!2                           ;  -2 <KM/H>
BFA4 84       11456                 .BYTE NEG!4                           ;  -4 <KM/H>
BFA5 88       11457                 .BYTE NEG!8                           ;  -8 <KM/H>
BFA6 90       11458                 .BYTE NEG!16                          ; -16 <KM/H>
BFA7 9E       11459                 .BYTE NEG!30                          ; -30 <KM/H>
BFA8 BE       11460                 .BYTE NEG!62                          ; -62 <KM/H>
              11461
              11462 ;*** PLAYFIELD colors (including PLAYFIELD colors during DLI) ******************
BFA9 A6       11463 PFCOLORTAB      .BYTE $A6                             ; PF0COLOR    = {GREEN}
BFAA AA       11464                 .BYTE $AA                             ; PF1COLOR    = {LIGHT GREEN}
BFAB AF       11465                 .BYTE $AF                             ; PF2COLOR    = {VERY LIGHT GREEN}
BFAC 00       11466                 .BYTE $00                             ; PF3COLOR    = {BLACK}
BFAD 00       11467                 .BYTE $00                             ; BGRCOLOR    = {BLACK}
BFAE B8       11468                 .BYTE $B8                             ; PF0COLORDLI = {LIGHT MINT}
BFAF 5A       11469                 .BYTE $5A                             ; PF1COLORDLI = {MEDIUM PINK}
BFB0 FC       11470                 .BYTE $FC                             ; PF2COLORDLI = {LIGHT ORANGE}
BFB1 5E       11471                 .BYTE $5E                             ; PF3COLORDLI = {LIGHT PINK}
BFB2 90       11472                 .BYTE $90                             ; BGRCOLORDLI = {DARK BLUE}
              11473
              11474 ;*** Vicinity mask table. Confines coordinates of space objects in sector ******
BFB3 FF       11475 VICINITYMASKTAB .BYTE $FF                             ; <= 65535 ($FF**) <KM>
BFB4 FF       11476                 .BYTE $FF                             ; <= 65535 ($FF**) <KM>
BFB5 3F       11477                 .BYTE $3F                             ; <= 16383 ($3F**) <KM>
BFB6 0F       11478                 .BYTE $0F                             ; <=  4095 ($0F**) <KM>
BFB7 3F       11479                 .BYTE $3F                             ; <= 16383 ($3F**) <KM>
BFB8 7F       11480                 .BYTE $7F                             ; <= 32767 ($7F**) <KM>
BFB9 FF       11481                 .BYTE $FF                             ; <= 65535 ($FF**) <KM>
BFBA FF       11482                 .BYTE $FF                             ; <= 65535 ($FF**) <KM>
              11483
              11484 ;*** Movement probability of sector types in Galactic Chart ********************
BFBB 00       11485 MOVEPROBTAB     .BYTE 0                               ; Empty sector    0% (  0:256)
BFBC FF       11486                 .BYTE 255                             ; 1 Zylon ship  100% (255:256)
BFBD FF       11487                 .BYTE 255                             ; 2 Zylon ships 100% (255:256)
BFBE C0       11488                 .BYTE 192                             ; 3 Zylon ships  75% (192:256)
BFBF 20       11489                 .BYTE 32                              ; 4 Zylon ships  13% ( 32:256)
              11490
              11491 ;*** Galactic Chart sector offset to adjacent sector ***************************
BFC0 F0       11492 COMPASSOFFTAB   .BYTE -16                             ; NORTH
BFC1 EF       11493                 .BYTE -17                             ; NORTHWEST
BFC2 FF       11494                 .BYTE -1                              ; WEST
BFC3 0F       11495                 .BYTE 15                              ; SOUTHWEST
BFC4 10       11496                 .BYTE 16                              ; SOUTH
BFC5 11       11497                 .BYTE 17                              ; SOUTHEAST
BFC6 01       11498                 .BYTE 1                               ; EAST
BFC7 F1       11499                 .BYTE -15                             ; NORTHEAST
BFC8 00       11500                 .BYTE 0                               ; CENTER
              11501
              11502 ;*** Homing velocities of photon torpedoes 0..1 depending on distance to target 
BFC9 00       11503 HOMVELTAB       .BYTE 0                               ;  +0 <KM/H>
BFCA 08       11504                 .BYTE 8                               ;  +8 <KM/H>
BFCB 10       11505                 .BYTE 16                              ; +16 <KM/H>
BFCC 18       11506                 .BYTE 24                              ; +24 <KM/H>
BFCD 28       11507                 .BYTE 40                              ; +40 <KM/H>
BFCE 30       11508                 .BYTE 48                              ; +48 <KM/H>
BFCF 38       11509                 .BYTE 56                              ; +56 <KM/H>
BFD0 40       11510                 .BYTE 64                              ; +64 <KM/H>
              11511
              11512 ;*** PLAYER shape color table (bits B7..4 of color/brightness) *****************
BFD1 50       11513 PLSHAPCOLORTAB  .BYTE $50                             ; PHOTON TORPEDO          = {PURPLE}
BFD2 00       11514                 .BYTE $00                             ; ZYLON FIGHTER           = {GRAY}
BFD3 20       11515                 .BYTE $20                             ; STARBASE RIGHT          = {ORANGE}
BFD4 20       11516                 .BYTE $20                             ; STARBASE CENTER         = {ORANGE}
BFD5 20       11517                 .BYTE $20                             ; STARBASE LEFT           = {ORANGE}
BFD6 00       11518                 .BYTE $00                             ; TRANSFER VESSEL         = {GRAY}
BFD7 A0       11519                 .BYTE $A0                             ; METEOR                  = {GREEN}
BFD8 00       11520                 .BYTE $00                             ; ZYLON CRUISER           = {GRAY}
BFD9 00       11521                 .BYTE $00                             ; ZYLON BASESTAR          = {GRAY}
BFDA 9F       11522                 .BYTE $9F                             ; HYPERWARP TARGET MARKER = {SKY BLUE}
              11523
              11524 ;*** PLAYER shape brightness table (bits B3..0 of color/brightness) ************
BFDB 0E       11525 PLSHAPBRITTAB   .BYTE $0E                             ; ##############..
BFDC 0E       11526                 .BYTE $0E                             ; ##############..
BFDD 0E       11527                 .BYTE $0E                             ; ##############..
BFDE 0C       11528                 .BYTE $0C                             ; ############....
BFDF 0C       11529                 .BYTE $0C                             ; ############....
BFE0 0C       11530                 .BYTE $0C                             ; ############....
BFE1 0A       11531                 .BYTE $0A                             ; ##########......
BFE2 0A       11532                 .BYTE $0A                             ; ##########......
BFE3 0A       11533                 .BYTE $0A                             ; ##########......
BFE4 08       11534                 .BYTE $08                             ; ########........
BFE5 08       11535                 .BYTE $08                             ; ########........
BFE6 08       11536                 .BYTE $08                             ; ########........
BFE7 06       11537                 .BYTE $06                             ; ######..........
BFE8 06       11538                 .BYTE $06                             ; ######..........
BFE9 04       11539                 .BYTE $04                             ; ####............
BFEA 04       11540                 .BYTE $04                             ; ####............
              11541
              11542 ;*** PHOTON TORPEDO LAUNCHED noise bit and volume (stored in reverse order) ****
BFEB 8A       11543 NOISETORPVOLTAB .BYTE $8A                             ; ##########.....
BFEC 8F       11544                 .BYTE $8F                             ; ###############
BFED 8D       11545                 .BYTE $8D                             ; #############..
BFEE 8B       11546                 .BYTE $8B                             ; ###########....
BFEF 89       11547                 .BYTE $89                             ; #########......
BFF0 87       11548                 .BYTE $87                             ; #######........
BFF1 85       11549                 .BYTE $85                             ; ######.........
BFF2 83       11550                 .BYTE $83                             ; ###............
              11551
              11552 ;*** PHOTON TORPEDO LAUNCHED noise frequency table (stored in reverse order) ***
BFF3 00       11553 NOISETORPFRQTAB .BYTE $00                             ;
BFF4 04       11554                 .BYTE $04                             ;
BFF5 01       11555                 .BYTE $01                             ;
BFF6 04       11556                 .BYTE $04                             ;
BFF7 01       11557                 .BYTE $01                             ;
BFF8 04       11558                 .BYTE $04                             ;
BFF9 01       11559                 .BYTE $01                             ;
BFFA 04       11560                 .BYTE $04                             ;
              11561
BFFB 07       11562                 .BYTE $07                             ; (unused)
              11563
BFFC 00       11564                 .BYTE $00                             ; Always 0 for cartridges
BFFD 80       11565                 .BYTE $80                             ; On SYSTEM RESET jump to INITCOLD via
BFFE 4AA1     11566                 .WORD INITCOLD                        ; Cartridge Initialization Address

SYMBOLS (SORTED BY NAME): 898

 A980  ABORTWARP
 A109  AFTHEADER
=0092  ARRVSECTOR
=D203  AUDC2
=D205  AUDC3
=D207  AUDC4
=D208  AUDCTL
=D200  AUDF1
=D202  AUDF2
=D204  AUDF3
=D206  AUDF4
=0087  BARRELNR
 BF73  BARRELXTAB
 B3A6  BEEP
=00D2  BEEPFRQIND
=00D7  BEEPFRQSTART
 BF5C  BEEPFRQTAB
=00D8  BEEPLIFE
 BF3E  BEEPPATTAB
=00D5  BEEPPAUSELIFE
=00D6  BEEPPRIORITY
=00D3  BEEPREPEAT
=00D9  BEEPTOGGLE
=00D4  BEEPTONELIFE
=00F6  BGRCOLOR
=00FB  BGRCOLORDLI
=00A0  BLIPCOLUMN
=00A2  BLIPCYCLECNT
=00A1  BLIPROW
 BF6E  BLIPSHAPTAB
 BEDD  BONUSTAB
 B1A7  CALCWARP
=0000  CCS.0
=0001 ?CCS.1
=0002 ?CCS.2
=001E  CCS.2ZYLONS
=0003 ?CCS.3
=001D  CCS.3ZYLONS
=0004 ?CCS.4
=001C  CCS.4ZYLONS
=0005 ?CCS.5
=0006 ?CCS.6
=0007 ?CCS.7
=0008 ?CCS.8
=0009  CCS.9
=0018  CCS.BORDERS
=000C  CCS.BORDERSW
=0019  CCS.BORDERW
=0017 ?CCS.C
=0040  CCS.COL1
=0080  CCS.COL2
=00C0  CCS.COL3
=000B  CCS.COLON
=001A  CCS.CORNERSW
=000D  CCS.E
=000E  CCS.INF
=0015  CCS.K
=000F  CCS.MINUS
=0011  CCS.PHI
=0010  CCS.PLUS
=0013  CCS.R
=000A  CCS.SPC
=001B  CCS.STARBASE
=0016  CCS.T
=0014  CCS.THETA
=0012  CCS.V
 A000  CHARSET
=D409  CHBASE
 BEFC  CLASSTAB
 A98D  CLEANUPWARP
=0074  CLOCKTIM
 AE0F  CLRMEM
 AE0D  CLRPLAYFIELD
 AF3D  COLLISION
=D016  COLPF0
=D012  COLPM0
 BFC0  COMPASSOFFTAB
=D01F  CONSOL
 ACAF  COPYPOSVEC
 ACC1  COPYPOSXY
=0076  COUNT256
=0072  COUNT8
=00A7  CTRLDZYLON
=0090  CURRSECTOR
 AEE1  DAMAGE
 BF14  DAMAGEPHRTAB
 BF10  DAMAGEPROBTAB
 B86F  DECENERGY
 BF1A  DESTROYPHRTAB
=00A4  DIRLEN
=006A  DIVIDEND
=D402  DLIST
 BA62  DLSTFRAG
 BA75  DLSTFRAGAFT
 BA7D  DLSTFRAGFRONT
 BA6A  DLSTFRAGGC
 BA6D  DLSTFRAGLRS
 BA8C  DLSTFRAGOFFTAB
 A12E  DLSTGC
 A718  DLSTHNDLR
=D400  DMACTL
 ACE6  DOCKING
=0075  DOCKSTATE
=0080  DOWN
=007E  DRAINATTCOMP
=0080  DRAINENGINES
 BAD3  DRAINRATETAB
=007D  DRAINSHIELDS
 B4B9  DRAWGC
 A782  DRAWLINE
 A784  DRAWLINE2
 A76F  DRAWLINES
 BAF9  DRAWLINESTAB
=0280  DSPLST
 A987  ENDWARP
=007F  ENERGYCNT
=0955  ENERGYD1
=0040  EOP
=0080  EOS
=0080  EOW
=0073  EXPLLIFE
=0063  FKEYCODE
 B4E4  FLUSHGAMELOOP
 BA90  FOURCOLORPIXEL
 A1F3  GAMELOOP
 B10A  GAMEOVER
 B121  GAMEOVER2
 A11A  GCHEADER
=08C9  GCMEMMAP
=0D35  GCPFMEM
=09A3  GCSTARDAT
=0995  GCSTATCOM
=0993  GCSTATENG
=0996  GCSTATLRS
=0992  GCSTATPHO
=0997  GCSTATRAD
=0994  GCSTATSHL
=098D  GCTRGCNT
=0971  GCTXT
=097D  GCWARPD1
=D01D  GRACTL
=008A  HITBADNESS
=D01E  HITCLR
 BF75  HITMAXZTAB
 BF7D  HITMINZTAB
 AECA  HOMINGVEL
 BFC9  HOMVELTAB
=D004  HPOSM0
=D005  HPOSM1
=D006  HPOSM2
=D007  HPOSM3
=D000  HPOSP0
=D001  HPOSP1
=D002  HPOSP2
=D003  HPOSP3
=0094  HUNTSECTCOLUMN
=0093  HUNTSECTOR
=0095  HUNTSECTROW
=009F  HUNTTIM
 A89B  HYPERWARP
=0066  IDLECNTHI
=0077  IDLECNTLO
 A14A  INITCOLD
 A15C  INITDEMO
 AC6B  INITEXPL
 B3BA  INITIALIZE
 B764  INITPOSVEC
 A15A  INITSELECT
 A15E  INITSTART
 A9B4  INITTRAIL
=D20E  IRQEN
 A751  IRQHNDLR
=00B8  ISBACKATTACK0
=00B9 ?ISBACKATTACK1
=0064  ISDEMOMODE
=00A3  ISINLOCKON
=007B  ISSTARBASESECT
 B7F1  ISSURROUNDED
=007C  ISTRACKCOMPON
=0086  ISTRACKING
=0067  ISVBISYNC
=006D  JOYSTICKDELTA
=00C8  JOYSTICKX
=00C9  JOYSTICKY
 A47D  JUMP001
 A4A4  JUMP002
 A579  JUMP003
 A74B  JUMP004
=D209  KBCODE
 AFFE  KEYBOARD
=00CA  KEYCODE
 BABE  KEYTAB
=0950  KILLCNTD1
=006B  L.ABSDIFFCOLUMN
=006B  L.BITPAT
=006B  L.COLORMASK
=006B  L.COLUMNPOS
=006A  L.CTRLDZYLON
=006A  L.DELTAC
=006A  L.DIRECTIONIND
=006E  L.DIRSAV
=0068  L.DIVISOR
=006A  L.FOURCOLORPIX
=006A  L.GCMEMMAPIND
=006A  L.HEIGHTCNT
=006A  L.ISDESTROYED
=006A  L.KEYCODE
=006E  L.LOOPCNT
=006B  L.LOOPCNT2
=006A  L.MAXRNDXY
=0068  L.MEMPTR1
=006A  L.MEMPTR2
=006A  L.NEWSECTOR
=006A  L.NUMBYTES
=006A  L.PIXELBYTEOFF
=006D  L.PIXELCOLUMN
=006D  L.PIXELROW
=006B  L.PLHIT
=006D  L.QUOTIENT
=0068  L.RANGE
=006A  L.RANGEINDEX
=006B  L.SECTORCNT
=006A  L.SECTORTYPE
=006C  L.SHIFTSHAP
=006A  L.SIGNCHAR
=006B  L.TERM3HI
=006A  L.TERM3LO
=006C  L.TERM3SIGN
=006C  L.TOKEN
=006E  L.TRAILCNT
=006A  L.VECCOMPIND
=006B  L.VELOCITYHI
=006A  L.VELSIGN
=006C  L.VIEWDIR
=006A  L.WARPARRVCOL
=006A  L.WORD
=006E  L.ZPOSOFF
=0088  LOCKONLIFE
=00C0  LONG
 A165  LOOP001
 A201  LOOP002
 A227  LOOP003
 A26A  LOOP004
 A277  LOOP005
 A284  LOOP006
 A291  LOOP007
 A29E  LOOP008
 A2BA  LOOP009
 A2E0  LOOP010
 A306  LOOP011
 A327  LOOP012
 A343  LOOP013
 A389  LOOP014
 A3A6  LOOP015
 A3BD  LOOP016
 A3E4  LOOP017
 A3EB  LOOP018
 A422  LOOP019
 A428  LOOP020
 A453  LOOP021
 A4C0  LOOP022
 A4E7  LOOP023
 A4FC  LOOP024
 A593  LOOP025
 A6F6  LOOP026
 A730  LOOP027
 A765  LOOP028
 A78E  LOOP029
 A7CF  LOOP030
 A83A  LOOP031
 A83C  LOOP032
 A947  LOOP033
 A9E5  LOOP034
 AA52  LOOP035
 AAB5  LOOP036
 ABB3  LOOP037
 ABCA  LOOP038
 ABFC  LOOP039
 AC73  LOOP040
 ADCA  LOOP041
 ADD7  LOOP042
 ADF4  LOOP043
 ADFB  LOOP044
 AE1A  LOOP045
 AEB3  LOOP046
 AEE7  LOOP047
 AF3F  LOOP048
 AFD5  LOOP049
 AFEC  LOOP050
 B011  LOOP051
 B056  LOOP052
 B1FE  LOOP053
 B200  LOOP054
 B234  LOOP055
 B276  LOOP056
 B286  LOOP057
 B2C1  LOOP058
 B3AF  LOOP059
 B3BC  LOOP060
 B3EE  LOOP061
 B41B  LOOP062
 B441  LOOP063
 B44C  LOOP064
 B488  LOOP065
 B492  LOOP066
 B4BD  LOOP067
 B51C  LOOP068
 B54E  LOOP069
 B57C  LOOP070
 B5C1  LOOP071
 B5D1  LOOP072
 B5EA  LOOP073
 B5EF  LOOP074
 B601  LOOP075
 B632  LOOP076
 B662  LOOP077
 B664  LOOP078
 B896  LOOP079
 A0F8  LRSHEADER
=D008  M0PL
=D009  M1PL
=D00A  M2PL
=D00B  M3PL
 AA79  MANEUVER
=0DE9  MAPTO80
=0EE9  MAPTOBCD99
=0079  MAXSPCOBJIND
=0068  MEMPTR
=00AA  MILESTTIM0
=00AB ?MILESTTIM1
=00AE ?MILESTVELINDX0
=00AF ?MILESTVELINDX1
=00B0 ?MILESTVELINDY0
=00B1 ?MILESTVELINDY1
=00AC  MILESTVELINDZ0
=00AD ?MILESTVELINDZ1
=0062  MISSIONLEVEL
 BF0C  MISSIONPHRTAB
 ADF1  MODDLST
 BFBB  MOVEPROBTAB
 BE29  MSGBITTAB
 BE26  MSGOFFTAB
 BE2C  MSGONTAB
=0080  NEG
=0065  NEWTITLEPHR
=0071  NEWVELOCITY
=0096  NEWZYLONDIST
=D40E  NMIEN
 AEA8  NOISE
=00DC  NOISEAUDC2
=00DD  NOISEAUDC3
=00DE  NOISEAUDF1
=00DF  NOISEAUDF2
=00DB  NOISEEXPLTIM
=00E0  NOISEFRQINC
=00E3  NOISEHITLIFE
=00E1  NOISELIFE
 BF20  NOISEPATTAB
 BFF3  NOISETORPFRQTAB
=00DA  NOISETORPTIM
 BFEB  NOISETORPVOLTAB
=00E2  NOISEZYLONTIM
=0031  NUMSPCOBJ.ALL
=0011  NUMSPCOBJ.NORM
=0005  NUMSPCOBJ.PL
=000C  NUMSPCOBJ.STARS
=007A  OLDMAXSPCOBJIND
=0084  OLDTRIG0
=009E  OLDZYLONDIST
=D00F  P3PL
=D302  PACTL
=0949  PANELTXT
 BB42  PANELTXTTAB
=00A6  PENCOLUMN
=00A5  PENROW
=00F2  PF0COLOR
=00F7  PF0COLORDLI
=00F3 ?PF1COLOR
=00F8 ?PF1COLORDLI
=00F4  PF2COLOR
=00F9 ?PF2COLORDLI
=00F5 ?PF3COLOR
=00FA ?PF3COLORDLI
 BFA9  PFCOLORTAB
=1000  PFMEM
=1000  PFMEM.C0R0
=12A8  PFMEM.C0R17
=10C8  PFMEM.C0R5
=1B36  PFMEM.C120R71
=1BFE  PFMEM.C120R76
=1C9E  PFMEM.C120R80
=1D40  PFMEM.C128R84
=1D68  PFMEM.C128R85
=1D42  PFMEM.C136R84
=1D6A  PFMEM.C136R85
=1C04  PFMEM.C144R76
=1CA4  PFMEM.C144R80
=17BB  PFMEM.C76R49
=17E3  PFMEM.C76R50
=17BC  PFMEM.C80R49
=17E4  PFMEM.C80R50
=0864  PFMEMROWHI
=0800  PFMEMROWLO
=0966  PHIC1
 BBAA  PHRASETAB
=0CEE  PIXELBYTE
=0C8C  PIXELBYTEOFF
=0C2A  PIXELCOLUMN
 BAB0  PIXELMASKTAB
=0C5B  PIXELROW
=0BF9  PIXELROWNEW
=0CBD  PIXELSAVE
=00EE  PL0COLOR
=0C2A  PL0COLUMN
=0400  PL0DATA
=0CBD  PL0HEIGHT
=0CEE  PL0HEIGHTNEW
=00E9  PL0LIFE
=0C5B  PL0ROW
=0BF9  PL0ROWNEW
=00E4  PL0SHAPOFF
=0C8C  PL0SHAPTYPE
=0B97 ?PL0XVEL
=0BC8 ?PL0YVEL
=0A40  PL0ZPOSHI
=0B66 ?PL0ZVEL
=00EF ?PL1COLOR
=0C2B  PL1COLUMN
=0500  PL1DATA
=0CBE  PL1HEIGHT
=0CEF  PL1HEIGHTNEW
=00EA  PL1LIFE
=0C5C  PL1ROW
=0BFA  PL1ROWNEW
=00E5  PL1SHAPOFF
=0C8D  PL1SHAPTYPE
=0B98 ?PL1XVEL
=0BC9 ?PL1YVEL
=0B67 ?PL1ZVEL
=00F0 ?PL2COLOR
=0C2C  PL2COLUMN
=0600  PL2DATA
=0CBF  PL2HEIGHT
=0CF0  PL2HEIGHTNEW
=00EB  PL2LIFE
=0C5D  PL2ROW
=0BFB  PL2ROWNEW
=00E6  PL2SHAPOFF
=0C8E  PL2SHAPTYPE
=0A73  PL2XPOSHI
=0B06 ?PL2XPOSLO
=09E0 ?PL2XPOSSIGN
=0B99  PL2XVEL
=0AA4  PL2YPOSHI
=0B37 ?PL2YPOSLO
=0A11  PL2YPOSSIGN
=0BCA  PL2YVEL
=0A42  PL2ZPOSHI
=0AD5  PL2ZPOSLO
=09AF  PL2ZPOSSIGN
=0B68  PL2ZVEL
=00F1 ?PL3COLOR
=0C2D  PL3COLUMN
=0700  PL3DATA
=0CC0  PL3HEIGHT
=0CF1  PL3HEIGHTNEW
=0082  PL3HIT
=00EC  PL3LIFE
=0C5E  PL3ROW
=0BFC  PL3ROWNEW
=00E7  PL3SHAPOFF
=0C8F  PL3SHAPTYPE
=0A74  PL3XPOSHI
=0B07  PL3XPOSLO
=09E1  PL3XPOSSIGN
=0B9A  PL3XVEL
=0AA5  PL3YPOSHI
=0B38  PL3YPOSLO
=0A12  PL3YPOSSIGN
=0BCB  PL3YVEL
=0A43  PL3ZPOSHI
=0AD6  PL3ZPOSLO
=09B0  PL3ZPOSSIGN
=0B69  PL3ZVEL
=0C2E  PL4COLUMN
=0300  PL4DATA
=0CC1  PL4HEIGHT
=0CF2  PL4HEIGHTNEW
=0083  PL4HIT
=00ED  PL4LIFE
=0C5F  PL4ROW
=0BFD  PL4ROWNEW
=00E8  PL4SHAPOFF
=0C90  PL4SHAPTYPE
=0A75  PL4XPOSHI
=0B08 ?PL4XPOSLO
=09E2  PL4XPOSSIGN
=0B9B  PL4XVEL
=0AA6  PL4YPOSHI
=0B39 ?PL4YPOSLO
=0A13  PL4YPOSSIGN
=0BCC  PL4YVEL
=0A44  PL4ZPOSHI
=0AD7 ?PL4ZPOSLO
=09B1  PL4ZPOSSIGN
=0B6A  PL4ZVEL
 B8DF  PLCOLOROFFTAB
 B8E4  PLSHAP1TAB
 B9B1  PLSHAP2TAB
 BFDB  PLSHAPBRITTAB
 BFD1  PLSHAPCOLORTAB
 BE7F  PLSHAPHEIGHTTAB
 BE2F  PLSHAPOFFTAB
 BEDB  PLSTARBAOFFTAB
=0089  PLTRACKED
=D407  PMBASE
=D300  PORTA
=D01B  PRIOR
 AA21  PROJECTION
=D20A  RANDOM
=096C  RANGEC1
 BEE9  RANKTAB
=008B  REDALERTLIFE
=0000  RIGHT
 B7BE  RNDINVXY
=0010  ROM.0
=0011  ROM.1
=0012  ROM.2
=0013  ROM.3
=0014  ROM.4
=0015  ROM.5
=0019  ROM.9
=0021  ROM.A
=0023  ROM.C
=001A  ROM.COLON
=0024  ROM.D
=000E  ROM.DOT
=0025  ROM.E
=0027  ROM.G
=002C  ROM.L
=002E  ROM.N
=0030  ROM.P
=0032  ROM.R
=0033  ROM.S
=0000  ROM.SPC
=0034  ROM.T
=0037  ROM.W
=0039  ROM.Y
=E000  ROMCHARSET
 B69B  ROTATE
=00CB  SCORE
=00CE  SCOREDCLASSIND
=00CD  SCOREDRANKIND
 B6FB  SCREENCOLUMN
 B71E  SCREENROW
 BED1  SECTORCHARTAB
 BBA6  SECTORTYPETAB
 B162  SELECTWARP
 B223  SETTITLE
 B045  SETVIEW
=0090  SHAP.HYPERWARP
=0060  SHAP.METEOR
=0030  SHAP.STARBASEC
=0020  SHAP.STARBASEL
=0040  SHAP.STARBASER
=0000 ?SHAP.TORPEDO
=0050  SHAP.TRANSVSSL
=0080  SHAP.ZBASESTAR
=0070  SHAP.ZCRUISER
=0010  SHAP.ZFIGHTER
=0081  SHIELDSCOLOR
=00D0  SHIPVIEW
 B8A7  SHOWCOORD
 B8CD  SHOWDIGITS
=D20F  SKCTL
 A172  SKIP001
 A21F  SKIP002
 A250  SKIP003
 A262  SKIP004
 A2C2  SKIP005
 A2E8  SKIP006
 A30E  SKIP007
 A39E  SKIP008
 A3BB  SKIP009
 A3C6  SKIP010
 A3DF  SKIP011
 A3EA  SKIP012
 A3FE  SKIP013
 A43C  SKIP014
 A43F  SKIP015
 A473  SKIP016
 A49A  SKIP017
 A4A7  SKIP018
 A4AD  SKIP019
 A4CA  SKIP020
 A4DB  SKIP021
 A4E5  SKIP022
 A4ED  SKIP023
 A503  SKIP024
 A52A  SKIP025
 A52E  SKIP026
 A53E  SKIP027
 A548  SKIP028
 A569  SKIP029
 A58D  SKIP030
 A5A3  SKIP031
 A5A5  SKIP032
 A5AB  SKIP033
 A5D0  SKIP034
 A600  SKIP035
 A60C  SKIP036
 A61B  SKIP037
 A635  SKIP038
 A687  SKIP039
 A69B  SKIP040
 A6B7  SKIP041
 A6C2  SKIP042
 A6E9  SKIP043
 A6EA  SKIP044
 A6F2  SKIP045
 A715  SKIP046
 A728  SKIP047
 A77A  SKIP048
 A781  SKIP049
 A7B8  SKIP050
 A7BA  SKIP051
 A7E1  SKIP052
 A7E9  SKIP053
 A7EC  SKIP054
 A804  SKIP055
 A80A  SKIP056
 A821  SKIP057
 A827  SKIP058
 A830  SKIP059
 A850  SKIP060
 A85F  SKIP061
 A898  SKIP062
 A8AC  SKIP063
 A8E8  SKIP064
 A8EC  SKIP065
 A900  SKIP066
 A901  SKIP067
 A915  SKIP068
 A91E  SKIP069
 A96F  SKIP070
 A97F  SKIP071
 A9A6  SKIP072
 AA1A  SKIP073
 AA20  SKIP074
 AA40  SKIP075
 AA66  SKIP076
 AA6F  SKIP077
 AA78  SKIP078
 AA90  SKIP079
 AAB3  SKIP080
 AAC8  SKIP081
 AACF  SKIP082
 AAD5  SKIP083
 AADD  SKIP084
 AAE0  SKIP085
 AAF4  SKIP086
 AB00  SKIP087
 AB03  SKIP088
 AB09  SKIP089
 AB11  SKIP090
 AB36  SKIP091
 AB37  SKIP092
 AB66  SKIP093
 AB84  SKIP094
 AB98  SKIP095
 AB9C  SKIP096
 ABAE  SKIP097
 ABBA  SKIP098
 ABC4  SKIP099
 ABDD  SKIP100
 ABE1  SKIP101
 ABE5  SKIP102
 ABE9  SKIP103
 ABEB  SKIP104
 ABFA  SKIP105
 AC08  SKIP106
 AC0A  SKIP107
 AC31  SKIP108
 AC32  SKIP109
 AC4F  SKIP110
 ACE5  SKIP111
 ACF3  SKIP112
 AD12  SKIP113
 AD26  SKIP114
 AD35  SKIP115
 AD61  SKIP116
 AD6C  SKIP117
 AD70  SKIP118
 AD71  SKIP119
 AD82  SKIP120
 ADB8  SKIP121
 ADB9  SKIP122
 AE03  SKIP123
 AE40  SKIP124
 AE41  SKIP125
 AE56  SKIP126
 AE58  SKIP127
 AE66  SKIP128
 AEB1  SKIP129
 AEC9  SKIP130
 AED2  SKIP131
 AEDA  SKIP132
 AF10  SKIP133
 AF19  SKIP134
 AF1E  SKIP135
 AF32  SKIP136
 AF3C  SKIP137
 AF43  SKIP138
 AF58  SKIP139
 AF64  SKIP140
 AF6F  SKIP141
 AF94  SKIP142
 AFC6  SKIP143
 AFE7  SKIP144
 AFF3  SKIP145
 AFFD  SKIP146
 B020  SKIP147
 B02B  SKIP148
 B036  SKIP149
 B040  SKIP150
 B041  SKIP151
 B060  SKIP152
 B073  SKIP153
 B082  SKIP154
 B096  SKIP155
 B099  SKIP156
 B0E6  SKIP157
 B0ED  SKIP158
 B0FB  SKIP159
 B0FC  SKIP160
 B106  SKIP161
 B14A  SKIP162
 B15A  SKIP163
 B15D  SKIP164
 B161  SKIP165
 B16A  SKIP166
 B16B  SKIP167
 B173  SKIP168
 B1BE  SKIP169
 B1C8  SKIP170
 B1D3  SKIP171
 B1E0  SKIP172
 B212  SKIP173
 B21E  SKIP174
 B21F  SKIP175
 B22E  SKIP176
 B23A  SKIP177
 B249  SKIP178
 B25F  SKIP179
 B268  SKIP180
 B27C  SKIP181
 B2A2  SKIP182
 B2A8  SKIP183
 B2E1  SKIP184
 B2E6  SKIP185
 B2F3  SKIP186
 B32B  SKIP187
 B337  SKIP188
 B349  SKIP189
 B357  SKIP190
 B369  SKIP191
 B397  SKIP192
 B39F  SKIP193
 B3B9  SKIP194
 B3CA  SKIP195
 B47C  SKIP196
 B4C6  SKIP197
 B4F5  SKIP198
 B50F  SKIP199
 B511  SKIP200
 B516  SKIP201
 B51A  SKIP202
 B527  SKIP203
 B536  SKIP204
 B53E  SKIP205
 B544  SKIP206
 B562  SKIP207
 B565  SKIP208
 B569  SKIP209
 B56A  SKIP210
 B574  SKIP211
 B59A  SKIP212
 B5B0  SKIP213
 B5BB  SKIP214
 B5DA  SKIP215
 B619  SKIP216
 B61C  SKIP217
 B61D  SKIP218
 B644  SKIP219
 B655  SKIP220
 B68D  SKIP221
 B68F  SKIP222
 B698  SKIP223
 B6A4  SKIP224
 B6E1  SKIP225
 B709  SKIP226
 B717  SKIP227
 B72E  SKIP228
 B73E  SKIP229
 B745  SKIP230
 B74A  SKIP231
 B753  SKIP232
 B75A  SKIP233
 B763  SKIP234
 B785  SKIP235
 B7A9  SKIP236
 B7D7  SKIP237
 B7F0  SKIP238
 B803  SKIP239
 B810  SKIP240
 B812  SKIP241
 B822  SKIP242
 B85C  SKIP243
 B88C  SKIP244
 B88E  SKIP245
 B8A6  SKIP246
 B8BD  SKIP247
 B2AB  SOUND
 BAF5  STICKINCTAB
=D209  STIMER
=0960  THETAC1
=00CF  TITLELIFE
=00D1  TITLEPHR
=0D1F  TITLETXT
=00BE  TORPEDODELAY
=095A  TRACKC1
=095C  TRACKDIGIT
 BECF  TRACKKEYSTAB
=00C2  TRAILDELAY
=00C3  TRAILIND
=D010  TRIG0
 AE29  TRIGGER
 A7BF  UPDATTCOMP
 B804  UPDPANEL
 B07B  UPDSCREEN
 B216  UPDTITLE
 A6D1  VBIHNDLR
=D40B  VCOUNT
=0200  VDSLST
=00C6  VEERMASK
 BED7  VEERMASKTAB
=094B  VELOCD1
=00C1  VELOCITYHI
=0070  VELOCITYLO
 BAB4  VELOCITYTAB
=00C7  VICINITYMASK
 BFB3  VICINITYMASKTAB
 BE22  VIEWMODETAB
=0216  VIMIRQ
=0222  VVBLKI
=008F  WARPARRVCOLUMN
=008E  WARPARRVROW
=008D  WARPDEPRCOLUMN
=008C  WARPDEPRROW
=0091  WARPENERGY
 BADD  WARPENERGYTAB
 BB3A  WARPSTARXTAB
 BB3E  WARPSTARYTAB
=00C0  WARPSTATE
=00C4  WARPTEMPCOLUMN
=00C5  WARPTEMPROW
 BC2B  WORDTAB
=D40A  WSYNC
=0A71  XPOSHI
=0B04  XPOSLO
=09DE  XPOSSIGN
=0B97  XVEL
=0AA2  YPOSHI
=0B35  YPOSLO
=0A0F  YPOSSIGN
=0BC8  YVEL
=0A40  ZPOSHI
=0AD3  ZPOSLO
=09AD  ZPOSSIGN
=0B66  ZVEL
=00BF  ZYLONATTACKER
=00A8  ZYLONFLPAT0
=00A9 ?ZYLONFLPAT1
 BF91  ZYLONFLPATTAB
 BF85  ZYLONHOMVELTAB
 BF89  ZYLONSHAPTAB
=00BA  ZYLONTIMX0
=00BB ?ZYLONTIMX1
=00BC ?ZYLONTIMY0
=00BD ?ZYLONTIMY1
=0078  ZYLONUNITTIM
=00B4  ZYLONVELINDX0
=00B5 ?ZYLONVELINDX1
=00B6 ?ZYLONVELINDY0
=00B7 ?ZYLONVELINDY1
=00B2  ZYLONVELINDZ0
=00B3 ?ZYLONVELINDZ1
 BF99  ZYLONVELTAB

SYMBOLS (SORTED BY VALUE): 898

=0000  CCS.0
=0000  RIGHT
=0000  ROM.SPC
=0000 ?SHAP.TORPEDO
=0001 ?CCS.1
=0002 ?CCS.2
=0003 ?CCS.3
=0004 ?CCS.4
=0005 ?CCS.5
=0005  NUMSPCOBJ.PL
=0006 ?CCS.6
=0007 ?CCS.7
=0008 ?CCS.8
=0009  CCS.9
=000A  CCS.SPC
=000B  CCS.COLON
=000C  CCS.BORDERSW
=000C  NUMSPCOBJ.STARS
=000D  CCS.E
=000E  CCS.INF
=000E  ROM.DOT
=000F  CCS.MINUS
=0010  CCS.PLUS
=0010  ROM.0
=0010  SHAP.ZFIGHTER
=0011  CCS.PHI
=0011  NUMSPCOBJ.NORM
=0011  ROM.1
=0012  CCS.V
=0012  ROM.2
=0013  CCS.R
=0013  ROM.3
=0014  CCS.THETA
=0014  ROM.4
=0015  CCS.K
=0015  ROM.5
=0016  CCS.T
=0017 ?CCS.C
=0018  CCS.BORDERS
=0019  CCS.BORDERW
=0019  ROM.9
=001A  CCS.CORNERSW
=001A  ROM.COLON
=001B  CCS.STARBASE
=001C  CCS.4ZYLONS
=001D  CCS.3ZYLONS
=001E  CCS.2ZYLONS
=0020  SHAP.STARBASEL
=0021  ROM.A
=0023  ROM.C
=0024  ROM.D
=0025  ROM.E
=0027  ROM.G
=002C  ROM.L
=002E  ROM.N
=0030  ROM.P
=0030  SHAP.STARBASEC
=0031  NUMSPCOBJ.ALL
=0032  ROM.R
=0033  ROM.S
=0034  ROM.T
=0037  ROM.W
=0039  ROM.Y
=0040  CCS.COL1
=0040  EOP
=0040  SHAP.STARBASER
=0050  SHAP.TRANSVSSL
=0060  SHAP.METEOR
=0062  MISSIONLEVEL
=0063  FKEYCODE
=0064  ISDEMOMODE
=0065  NEWTITLEPHR
=0066  IDLECNTHI
=0067  ISVBISYNC
=0068  L.DIVISOR
=0068  L.MEMPTR1
=0068  L.RANGE
=0068  MEMPTR
=006A  DIVIDEND
=006A  L.CTRLDZYLON
=006A  L.DELTAC
=006A  L.DIRECTIONIND
=006A  L.FOURCOLORPIX
=006A  L.GCMEMMAPIND
=006A  L.HEIGHTCNT
=006A  L.ISDESTROYED
=006A  L.KEYCODE
=006A  L.MAXRNDXY
=006A  L.MEMPTR2
=006A  L.NEWSECTOR
=006A  L.NUMBYTES
=006A  L.PIXELBYTEOFF
=006A  L.RANGEINDEX
=006A  L.SECTORTYPE
=006A  L.SIGNCHAR
=006A  L.TERM3LO
=006A  L.VECCOMPIND
=006A  L.VELSIGN
=006A  L.WARPARRVCOL
=006A  L.WORD
=006B  L.ABSDIFFCOLUMN
=006B  L.BITPAT
=006B  L.COLORMASK
=006B  L.COLUMNPOS
=006B  L.LOOPCNT2
=006B  L.PLHIT
=006B  L.SECTORCNT
=006B  L.TERM3HI
=006B  L.VELOCITYHI
=006C  L.SHIFTSHAP
=006C  L.TERM3SIGN
=006C  L.TOKEN
=006C  L.VIEWDIR
=006D  JOYSTICKDELTA
=006D  L.PIXELCOLUMN
=006D  L.PIXELROW
=006D  L.QUOTIENT
=006E  L.DIRSAV
=006E  L.LOOPCNT
=006E  L.TRAILCNT
=006E  L.ZPOSOFF
=0070  SHAP.ZCRUISER
=0070  VELOCITYLO
=0071  NEWVELOCITY
=0072  COUNT8
=0073  EXPLLIFE
=0074  CLOCKTIM
=0075  DOCKSTATE
=0076  COUNT256
=0077  IDLECNTLO
=0078  ZYLONUNITTIM
=0079  MAXSPCOBJIND
=007A  OLDMAXSPCOBJIND
=007B  ISSTARBASESECT
=007C  ISTRACKCOMPON
=007D  DRAINSHIELDS
=007E  DRAINATTCOMP
=007F  ENERGYCNT
=0080  CCS.COL2
=0080  DOWN
=0080  DRAINENGINES
=0080  EOS
=0080  EOW
=0080  NEG
=0080  SHAP.ZBASESTAR
=0081  SHIELDSCOLOR
=0082  PL3HIT
=0083  PL4HIT
=0084  OLDTRIG0
=0086  ISTRACKING
=0087  BARRELNR
=0088  LOCKONLIFE
=0089  PLTRACKED
=008A  HITBADNESS
=008B  REDALERTLIFE
=008C  WARPDEPRROW
=008D  WARPDEPRCOLUMN
=008E  WARPARRVROW
=008F  WARPARRVCOLUMN
=0090  CURRSECTOR
=0090  SHAP.HYPERWARP
=0091  WARPENERGY
=0092  ARRVSECTOR
=0093  HUNTSECTOR
=0094  HUNTSECTCOLUMN
=0095  HUNTSECTROW
=0096  NEWZYLONDIST
=009E  OLDZYLONDIST
=009F  HUNTTIM
=00A0  BLIPCOLUMN
=00A1  BLIPROW
=00A2  BLIPCYCLECNT
=00A3  ISINLOCKON
=00A4  DIRLEN
=00A5  PENROW
=00A6  PENCOLUMN
=00A7  CTRLDZYLON
=00A8  ZYLONFLPAT0
=00A9 ?ZYLONFLPAT1
=00AA  MILESTTIM0
=00AB ?MILESTTIM1
=00AC  MILESTVELINDZ0
=00AD ?MILESTVELINDZ1
=00AE ?MILESTVELINDX0
=00AF ?MILESTVELINDX1
=00B0 ?MILESTVELINDY0
=00B1 ?MILESTVELINDY1
=00B2  ZYLONVELINDZ0
=00B3 ?ZYLONVELINDZ1
=00B4  ZYLONVELINDX0
=00B5 ?ZYLONVELINDX1
=00B6 ?ZYLONVELINDY0
=00B7 ?ZYLONVELINDY1
=00B8  ISBACKATTACK0
=00B9 ?ISBACKATTACK1
=00BA  ZYLONTIMX0
=00BB ?ZYLONTIMX1
=00BC ?ZYLONTIMY0
=00BD ?ZYLONTIMY1
=00BE  TORPEDODELAY
=00BF  ZYLONATTACKER
=00C0  CCS.COL3
=00C0  LONG
=00C0  WARPSTATE
=00C1  VELOCITYHI
=00C2  TRAILDELAY
=00C3  TRAILIND
=00C4  WARPTEMPCOLUMN
=00C5  WARPTEMPROW
=00C6  VEERMASK
=00C7  VICINITYMASK
=00C8  JOYSTICKX
=00C9  JOYSTICKY
=00CA  KEYCODE
=00CB  SCORE
=00CD  SCOREDRANKIND
=00CE  SCOREDCLASSIND
=00CF  TITLELIFE
=00D0  SHIPVIEW
=00D1  TITLEPHR
=00D2  BEEPFRQIND
=00D3  BEEPREPEAT
=00D4  BEEPTONELIFE
=00D5  BEEPPAUSELIFE
=00D6  BEEPPRIORITY
=00D7  BEEPFRQSTART
=00D8  BEEPLIFE
=00D9  BEEPTOGGLE
=00DA  NOISETORPTIM
=00DB  NOISEEXPLTIM
=00DC  NOISEAUDC2
=00DD  NOISEAUDC3
=00DE  NOISEAUDF1
=00DF  NOISEAUDF2
=00E0  NOISEFRQINC
=00E1  NOISELIFE
=00E2  NOISEZYLONTIM
=00E3  NOISEHITLIFE
=00E4  PL0SHAPOFF
=00E5  PL1SHAPOFF
=00E6  PL2SHAPOFF
=00E7  PL3SHAPOFF
=00E8  PL4SHAPOFF
=00E9  PL0LIFE
=00EA  PL1LIFE
=00EB  PL2LIFE
=00EC  PL3LIFE
=00ED  PL4LIFE
=00EE  PL0COLOR
=00EF ?PL1COLOR
=00F0 ?PL2COLOR
=00F1 ?PL3COLOR
=00F2  PF0COLOR
=00F3 ?PF1COLOR
=00F4  PF2COLOR
=00F5 ?PF3COLOR
=00F6  BGRCOLOR
=00F7  PF0COLORDLI
=00F8 ?PF1COLORDLI
=00F9 ?PF2COLORDLI
=00FA ?PF3COLORDLI
=00FB  BGRCOLORDLI
=0200  VDSLST
=0216  VIMIRQ
=0222  VVBLKI
=0280  DSPLST
=0300  PL4DATA
=0400  PL0DATA
=0500  PL1DATA
=0600  PL2DATA
=0700  PL3DATA
=0800  PFMEMROWLO
=0864  PFMEMROWHI
=08C9  GCMEMMAP
=0949  PANELTXT
=094B  VELOCD1
=0950  KILLCNTD1
=0955  ENERGYD1
=095A  TRACKC1
=095C  TRACKDIGIT
=0960  THETAC1
=0966  PHIC1
=096C  RANGEC1
=0971  GCTXT
=097D  GCWARPD1
=098D  GCTRGCNT
=0992  GCSTATPHO
=0993  GCSTATENG
=0994  GCSTATSHL
=0995  GCSTATCOM
=0996  GCSTATLRS
=0997  GCSTATRAD
=09A3  GCSTARDAT
=09AD  ZPOSSIGN
=09AF  PL2ZPOSSIGN
=09B0  PL3ZPOSSIGN
=09B1  PL4ZPOSSIGN
=09DE  XPOSSIGN
=09E0 ?PL2XPOSSIGN
=09E1  PL3XPOSSIGN
=09E2  PL4XPOSSIGN
=0A0F  YPOSSIGN
=0A11  PL2YPOSSIGN
=0A12  PL3YPOSSIGN
=0A13  PL4YPOSSIGN
=0A40  PL0ZPOSHI
=0A40  ZPOSHI
=0A42  PL2ZPOSHI
=0A43  PL3ZPOSHI
=0A44  PL4ZPOSHI
=0A71  XPOSHI
=0A73  PL2XPOSHI
=0A74  PL3XPOSHI
=0A75  PL4XPOSHI
=0AA2  YPOSHI
=0AA4  PL2YPOSHI
=0AA5  PL3YPOSHI
=0AA6  PL4YPOSHI
=0AD3  ZPOSLO
=0AD5  PL2ZPOSLO
=0AD6  PL3ZPOSLO
=0AD7 ?PL4ZPOSLO
=0B04  XPOSLO
=0B06 ?PL2XPOSLO
=0B07  PL3XPOSLO
=0B08 ?PL4XPOSLO
=0B35  YPOSLO
=0B37 ?PL2YPOSLO
=0B38  PL3YPOSLO
=0B39 ?PL4YPOSLO
=0B66 ?PL0ZVEL
=0B66  ZVEL
=0B67 ?PL1ZVEL
=0B68  PL2ZVEL
=0B69  PL3ZVEL
=0B6A  PL4ZVEL
=0B97 ?PL0XVEL
=0B97  XVEL
=0B98 ?PL1XVEL
=0B99  PL2XVEL
=0B9A  PL3XVEL
=0B9B  PL4XVEL
=0BC8 ?PL0YVEL
=0BC8  YVEL
=0BC9 ?PL1YVEL
=0BCA  PL2YVEL
=0BCB  PL3YVEL
=0BCC  PL4YVEL
=0BF9  PIXELROWNEW
=0BF9  PL0ROWNEW
=0BFA  PL1ROWNEW
=0BFB  PL2ROWNEW
=0BFC  PL3ROWNEW
=0BFD  PL4ROWNEW
=0C2A  PIXELCOLUMN
=0C2A  PL0COLUMN
=0C2B  PL1COLUMN
=0C2C  PL2COLUMN
=0C2D  PL3COLUMN
=0C2E  PL4COLUMN
=0C5B  PIXELROW
=0C5B  PL0ROW
=0C5C  PL1ROW
=0C5D  PL2ROW
=0C5E  PL3ROW
=0C5F  PL4ROW
=0C8C  PIXELBYTEOFF
=0C8C  PL0SHAPTYPE
=0C8D  PL1SHAPTYPE
=0C8E  PL2SHAPTYPE
=0C8F  PL3SHAPTYPE
=0C90  PL4SHAPTYPE
=0CBD  PIXELSAVE
=0CBD  PL0HEIGHT
=0CBE  PL1HEIGHT
=0CBF  PL2HEIGHT
=0CC0  PL3HEIGHT
=0CC1  PL4HEIGHT
=0CEE  PIXELBYTE
=0CEE  PL0HEIGHTNEW
=0CEF  PL1HEIGHTNEW
=0CF0  PL2HEIGHTNEW
=0CF1  PL3HEIGHTNEW
=0CF2  PL4HEIGHTNEW
=0D1F  TITLETXT
=0D35  GCPFMEM
=0DE9  MAPTO80
=0EE9  MAPTOBCD99
=1000  PFMEM
=1000  PFMEM.C0R0
=10C8  PFMEM.C0R5
=12A8  PFMEM.C0R17
=17BB  PFMEM.C76R49
=17BC  PFMEM.C80R49
=17E3  PFMEM.C76R50
=17E4  PFMEM.C80R50
=1B36  PFMEM.C120R71
=1BFE  PFMEM.C120R76
=1C04  PFMEM.C144R76
=1C9E  PFMEM.C120R80
=1CA4  PFMEM.C144R80
=1D40  PFMEM.C128R84
=1D42  PFMEM.C136R84
=1D68  PFMEM.C128R85
=1D6A  PFMEM.C136R85
 A000  CHARSET
 A0F8  LRSHEADER
 A109  AFTHEADER
 A11A  GCHEADER
 A12E  DLSTGC
 A14A  INITCOLD
 A15A  INITSELECT
 A15C  INITDEMO
 A15E  INITSTART
 A165  LOOP001
 A172  SKIP001
 A1F3  GAMELOOP
 A201  LOOP002
 A21F  SKIP002
 A227  LOOP003
 A250  SKIP003
 A262  SKIP004
 A26A  LOOP004
 A277  LOOP005
 A284  LOOP006
 A291  LOOP007
 A29E  LOOP008
 A2BA  LOOP009
 A2C2  SKIP005
 A2E0  LOOP010
 A2E8  SKIP006
 A306  LOOP011
 A30E  SKIP007
 A327  LOOP012
 A343  LOOP013
 A389  LOOP014
 A39E  SKIP008
 A3A6  LOOP015
 A3BB  SKIP009
 A3BD  LOOP016
 A3C6  SKIP010
 A3DF  SKIP011
 A3E4  LOOP017
 A3EA  SKIP012
 A3EB  LOOP018
 A3FE  SKIP013
 A422  LOOP019
 A428  LOOP020
 A43C  SKIP014
 A43F  SKIP015
 A453  LOOP021
 A473  SKIP016
 A47D  JUMP001
 A49A  SKIP017
 A4A4  JUMP002
 A4A7  SKIP018
 A4AD  SKIP019
 A4C0  LOOP022
 A4CA  SKIP020
 A4DB  SKIP021
 A4E5  SKIP022
 A4E7  LOOP023
 A4ED  SKIP023
 A4FC  LOOP024
 A503  SKIP024
 A52A  SKIP025
 A52E  SKIP026
 A53E  SKIP027
 A548  SKIP028
 A569  SKIP029
 A579  JUMP003
 A58D  SKIP030
 A593  LOOP025
 A5A3  SKIP031
 A5A5  SKIP032
 A5AB  SKIP033
 A5D0  SKIP034
 A600  SKIP035
 A60C  SKIP036
 A61B  SKIP037
 A635  SKIP038
 A687  SKIP039
 A69B  SKIP040
 A6B7  SKIP041
 A6C2  SKIP042
 A6D1  VBIHNDLR
 A6E9  SKIP043
 A6EA  SKIP044
 A6F2  SKIP045
 A6F6  LOOP026
 A715  SKIP046
 A718  DLSTHNDLR
 A728  SKIP047
 A730  LOOP027
 A74B  JUMP004
 A751  IRQHNDLR
 A765  LOOP028
 A76F  DRAWLINES
 A77A  SKIP048
 A781  SKIP049
 A782  DRAWLINE
 A784  DRAWLINE2
 A78E  LOOP029
 A7B8  SKIP050
 A7BA  SKIP051
 A7BF  UPDATTCOMP
 A7CF  LOOP030
 A7E1  SKIP052
 A7E9  SKIP053
 A7EC  SKIP054
 A804  SKIP055
 A80A  SKIP056
 A821  SKIP057
 A827  SKIP058
 A830  SKIP059
 A83A  LOOP031
 A83C  LOOP032
 A850  SKIP060
 A85F  SKIP061
 A898  SKIP062
 A89B  HYPERWARP
 A8AC  SKIP063
 A8E8  SKIP064
 A8EC  SKIP065
 A900  SKIP066
 A901  SKIP067
 A915  SKIP068
 A91E  SKIP069
 A947  LOOP033
 A96F  SKIP070
 A97F  SKIP071
 A980  ABORTWARP
 A987  ENDWARP
 A98D  CLEANUPWARP
 A9A6  SKIP072
 A9B4  INITTRAIL
 A9E5  LOOP034
 AA1A  SKIP073
 AA20  SKIP074
 AA21  PROJECTION
 AA40  SKIP075
 AA52  LOOP035
 AA66  SKIP076
 AA6F  SKIP077
 AA78  SKIP078
 AA79  MANEUVER
 AA90  SKIP079
 AAB3  SKIP080
 AAB5  LOOP036
 AAC8  SKIP081
 AACF  SKIP082
 AAD5  SKIP083
 AADD  SKIP084
 AAE0  SKIP085
 AAF4  SKIP086
 AB00  SKIP087
 AB03  SKIP088
 AB09  SKIP089
 AB11  SKIP090
 AB36  SKIP091
 AB37  SKIP092
 AB66  SKIP093
 AB84  SKIP094
 AB98  SKIP095
 AB9C  SKIP096
 ABAE  SKIP097
 ABB3  LOOP037
 ABBA  SKIP098
 ABC4  SKIP099
 ABCA  LOOP038
 ABDD  SKIP100
 ABE1  SKIP101
 ABE5  SKIP102
 ABE9  SKIP103
 ABEB  SKIP104
 ABFA  SKIP105
 ABFC  LOOP039
 AC08  SKIP106
 AC0A  SKIP107
 AC31  SKIP108
 AC32  SKIP109
 AC4F  SKIP110
 AC6B  INITEXPL
 AC73  LOOP040
 ACAF  COPYPOSVEC
 ACC1  COPYPOSXY
 ACE5  SKIP111
 ACE6  DOCKING
 ACF3  SKIP112
 AD12  SKIP113
 AD26  SKIP114
 AD35  SKIP115
 AD61  SKIP116
 AD6C  SKIP117
 AD70  SKIP118
 AD71  SKIP119
 AD82  SKIP120
 ADB8  SKIP121
 ADB9  SKIP122
 ADCA  LOOP041
 ADD7  LOOP042
 ADF1  MODDLST
 ADF4  LOOP043
 ADFB  LOOP044
 AE03  SKIP123
 AE0D  CLRPLAYFIELD
 AE0F  CLRMEM
 AE1A  LOOP045
 AE29  TRIGGER
 AE40  SKIP124
 AE41  SKIP125
 AE56  SKIP126
 AE58  SKIP127
 AE66  SKIP128
 AEA8  NOISE
 AEB1  SKIP129
 AEB3  LOOP046
 AEC9  SKIP130
 AECA  HOMINGVEL
 AED2  SKIP131
 AEDA  SKIP132
 AEE1  DAMAGE
 AEE7  LOOP047
 AF10  SKIP133
 AF19  SKIP134
 AF1E  SKIP135
 AF32  SKIP136
 AF3C  SKIP137
 AF3D  COLLISION
 AF3F  LOOP048
 AF43  SKIP138
 AF58  SKIP139
 AF64  SKIP140
 AF6F  SKIP141
 AF94  SKIP142
 AFC6  SKIP143
 AFD5  LOOP049
 AFE7  SKIP144
 AFEC  LOOP050
 AFF3  SKIP145
 AFFD  SKIP146
 AFFE  KEYBOARD
 B011  LOOP051
 B020  SKIP147
 B02B  SKIP148
 B036  SKIP149
 B040  SKIP150
 B041  SKIP151
 B045  SETVIEW
 B056  LOOP052
 B060  SKIP152
 B073  SKIP153
 B07B  UPDSCREEN
 B082  SKIP154
 B096  SKIP155
 B099  SKIP156
 B0E6  SKIP157
 B0ED  SKIP158
 B0FB  SKIP159
 B0FC  SKIP160
 B106  SKIP161
 B10A  GAMEOVER
 B121  GAMEOVER2
 B14A  SKIP162
 B15A  SKIP163
 B15D  SKIP164
 B161  SKIP165
 B162  SELECTWARP
 B16A  SKIP166
 B16B  SKIP167
 B173  SKIP168
 B1A7  CALCWARP
 B1BE  SKIP169
 B1C8  SKIP170
 B1D3  SKIP171
 B1E0  SKIP172
 B1FE  LOOP053
 B200  LOOP054
 B212  SKIP173
 B216  UPDTITLE
 B21E  SKIP174
 B21F  SKIP175
 B223  SETTITLE
 B22E  SKIP176
 B234  LOOP055
 B23A  SKIP177
 B249  SKIP178
 B25F  SKIP179
 B268  SKIP180
 B276  LOOP056
 B27C  SKIP181
 B286  LOOP057
 B2A2  SKIP182
 B2A8  SKIP183
 B2AB  SOUND
 B2C1  LOOP058
 B2E1  SKIP184
 B2E6  SKIP185
 B2F3  SKIP186
 B32B  SKIP187
 B337  SKIP188
 B349  SKIP189
 B357  SKIP190
 B369  SKIP191
 B397  SKIP192
 B39F  SKIP193
 B3A6  BEEP
 B3AF  LOOP059
 B3B9  SKIP194
 B3BA  INITIALIZE
 B3BC  LOOP060
 B3CA  SKIP195
 B3EE  LOOP061
 B41B  LOOP062
 B441  LOOP063
 B44C  LOOP064
 B47C  SKIP196
 B488  LOOP065
 B492  LOOP066
 B4B9  DRAWGC
 B4BD  LOOP067
 B4C6  SKIP197
 B4E4  FLUSHGAMELOOP
 B4F5  SKIP198
 B50F  SKIP199
 B511  SKIP200
 B516  SKIP201
 B51A  SKIP202
 B51C  LOOP068
 B527  SKIP203
 B536  SKIP204
 B53E  SKIP205
 B544  SKIP206
 B54E  LOOP069
 B562  SKIP207
 B565  SKIP208
 B569  SKIP209
 B56A  SKIP210
 B574  SKIP211
 B57C  LOOP070
 B59A  SKIP212
 B5B0  SKIP213
 B5BB  SKIP214
 B5C1  LOOP071
 B5D1  LOOP072
 B5DA  SKIP215
 B5EA  LOOP073
 B5EF  LOOP074
 B601  LOOP075
 B619  SKIP216
 B61C  SKIP217
 B61D  SKIP218
 B632  LOOP076
 B644  SKIP219
 B655  SKIP220
 B662  LOOP077
 B664  LOOP078
 B68D  SKIP221
 B68F  SKIP222
 B698  SKIP223
 B69B  ROTATE
 B6A4  SKIP224
 B6E1  SKIP225
 B6FB  SCREENCOLUMN
 B709  SKIP226
 B717  SKIP227
 B71E  SCREENROW
 B72E  SKIP228
 B73E  SKIP229
 B745  SKIP230
 B74A  SKIP231
 B753  SKIP232
 B75A  SKIP233
 B763  SKIP234
 B764  INITPOSVEC
 B785  SKIP235
 B7A9  SKIP236
 B7BE  RNDINVXY
 B7D7  SKIP237
 B7F0  SKIP238
 B7F1  ISSURROUNDED
 B803  SKIP239
 B804  UPDPANEL
 B810  SKIP240
 B812  SKIP241
 B822  SKIP242
 B85C  SKIP243
 B86F  DECENERGY
 B88C  SKIP244
 B88E  SKIP245
 B896  LOOP079
 B8A6  SKIP246
 B8A7  SHOWCOORD
 B8BD  SKIP247
 B8CD  SHOWDIGITS
 B8DF  PLCOLOROFFTAB
 B8E4  PLSHAP1TAB
 B9B1  PLSHAP2TAB
 BA62  DLSTFRAG
 BA6A  DLSTFRAGGC
 BA6D  DLSTFRAGLRS
 BA75  DLSTFRAGAFT
 BA7D  DLSTFRAGFRONT
 BA8C  DLSTFRAGOFFTAB
 BA90  FOURCOLORPIXEL
 BAB0  PIXELMASKTAB
 BAB4  VELOCITYTAB
 BABE  KEYTAB
 BAD3  DRAINRATETAB
 BADD  WARPENERGYTAB
 BAF5  STICKINCTAB
 BAF9  DRAWLINESTAB
 BB3A  WARPSTARXTAB
 BB3E  WARPSTARYTAB
 BB42  PANELTXTTAB
 BBA6  SECTORTYPETAB
 BBAA  PHRASETAB
 BC2B  WORDTAB
 BE22  VIEWMODETAB
 BE26  MSGOFFTAB
 BE29  MSGBITTAB
 BE2C  MSGONTAB
 BE2F  PLSHAPOFFTAB
 BE7F  PLSHAPHEIGHTTAB
 BECF  TRACKKEYSTAB
 BED1  SECTORCHARTAB
 BED7  VEERMASKTAB
 BEDB  PLSTARBAOFFTAB
 BEDD  BONUSTAB
 BEE9  RANKTAB
 BEFC  CLASSTAB
 BF0C  MISSIONPHRTAB
 BF10  DAMAGEPROBTAB
 BF14  DAMAGEPHRTAB
 BF1A  DESTROYPHRTAB
 BF20  NOISEPATTAB
 BF3E  BEEPPATTAB
 BF5C  BEEPFRQTAB
 BF6E  BLIPSHAPTAB
 BF73  BARRELXTAB
 BF75  HITMAXZTAB
 BF7D  HITMINZTAB
 BF85  ZYLONHOMVELTAB
 BF89  ZYLONSHAPTAB
 BF91  ZYLONFLPATTAB
 BF99  ZYLONVELTAB
 BFA9  PFCOLORTAB
 BFB3  VICINITYMASKTAB
 BFBB  MOVEPROBTAB
 BFC0  COMPASSOFFTAB
 BFC9  HOMVELTAB
 BFD1  PLSHAPCOLORTAB
 BFDB  PLSHAPBRITTAB
 BFEB  NOISETORPVOLTAB
 BFF3  NOISETORPFRQTAB
=D000  HPOSP0
=D001  HPOSP1
=D002  HPOSP2
=D003  HPOSP3
=D004  HPOSM0
=D005  HPOSM1
=D006  HPOSM2
=D007  HPOSM3
=D008  M0PL
=D009  M1PL
=D00A  M2PL
=D00B  M3PL
=D00F  P3PL
=D010  TRIG0
=D012  COLPM0
=D016  COLPF0
=D01B  PRIOR
=D01D  GRACTL
=D01E  HITCLR
=D01F  CONSOL
=D200  AUDF1
=D202  AUDF2
=D203  AUDC2
=D204  AUDF3
=D205  AUDC3
=D206  AUDF4
=D207  AUDC4
=D208  AUDCTL
=D209  KBCODE
=D209  STIMER
=D20A  RANDOM
=D20E  IRQEN
=D20F  SKCTL
=D300  PORTA
=D302  PACTL
=D400  DMACTL
=D402  DLIST
=D407  PMBASE
=D409  CHBASE
=D40A  WSYNC
=D40B  VCOUNT
=D40E  NMIEN
=E000  ROMCHARSET

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ColorSheets.pdf 250.3 kB 1 24-Nov-2017 20:50 Roland B. Wassenberg ColorSheets.pdf
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DisplayListSheets.pdf 237.2 kB 1 24-Nov-2017 20:50 Roland B. Wassenberg DisplayListSheets.pdf
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GenomeSequence.png 10.5 kB 1 24-Nov-2017 20:50 Roland B. Wassenberg GenomeSequence.png
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StarRaiders.source.asm.txt 2,820.0 kB 1 24-Nov-2017 20:49 Roland B. Wassenberg StarRaiders.source.asm.txt
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StarRaiders.source.txt 839.9 kB 3 24-Nov-2017 20:49 Roland B. Wassenberg StarRaiders.source.txt
« This page (revision-10) was last changed on 24-Nov-2017 21:29 by Roland B. Wassenberg