SynAssembler#

SYNASSEMBLER

SynAssembler by SYNAPSE SOFTWARE

An Adaptation by Steve Hales of the S.C. Assembler II - Version 4.0

SynAssembler (c) 1982 SYNAPSE SOFTWARE

Introduction#

SYNASSEMBLER is a convenient and powerful tool for software development on the Atari computer system. The assembler uses standard 6502 mnemonics and syntax, and includes many useful features for creating, editing, assembling and testing your assembly language programs. Now assembly language programming is almost as easy as programming in BASIC.

Here is a summary of the most exciting features:

  • Full use of the standard Atari Screen Editor
  • Tab stops for opcode, operand, and comment fields
  • Fast parameterized renumber and delete command
  • Uses BASIC like commands for files (eg. LOAD, SAVE, BLOAD etc.)
  • Labels up to 32 characters long (lowercase letters and . accepted)
  • English ERROR messages
  • Ability to append source programs from tape or disk
  • Display of memory usage
  • Multiple source files, using .IN directive
  • Store object code directly to disk file, using the .TF directive
  • Listing to screen option using .LI ON and .LI OFF
  • Assembles 6500 lines/minute
  • Local labels
  • Offending line is listed after an ERROR occurs
  • Value of .EQ and address of .BS are printed on listing
  • ASSEMBLER, DOS, HARDWARE, and OS locations protected during assembly
  • ATASCII literals in address expressions
  • Symbol table printed in alphabetical order

Synassembler requires 48K of RAM and one disk drive to operate. Very large programs can now be developed, using the "INCLUDE" and "TARGET FILE" capabilities. These allow the assembly of multiple source files, and direct storage of object code on binary files.


Manual#

We have included several sample programs to illustrate the use of the SYNASSEMBLER as well as being useful routines. These include:

  1. HARSH SCROLL :A Utility to coarse scroll the Atari screen display
  2. FINE SCROLL :A utility to fine scroll the Atari screen display
  3. PM MOVER :A utility to move players and missiles on the screen
  4. BELL :Ring the bell using Atari sound generators.

Blanks are compressed in source files to conserve memory and save space on disks. The compression algorithm replaces any string of consecutive blanks with a single code byte. Also, Atari assembler files are compatible and only require minor modification to assemble correctly. (See APPENDIX for further detail). Synassembler uses a memory-efficient method of storing the symbol table, with variable length entries. The symbol table is maintained in alphabetical order, using a high speed hashing scheme. The symbol table is maintained in memory until a new assembly is started or the NEW command is typed. This allows the RUN and VAL commands to be more useful and effective.

Assembler error messages are printed on the Screen and accompanied by a pleasant bell like tone on the speaker. (At least as pleasant as an ERROR message can be). After an assembly error is detected the offending line is listed to the screen automatically, in a position for easy editing.

EDITING FEATURES#

Any time the cursor is at the beginning of a line, typing [TAB] will cause the next line number to be generated. Immediately after loading, the "next line number" will be 10. The number will be displayed as five digits and a trailing blank. The cursor will be in a position for the first character of a label, or the asterisk for a comment line, or a semi-colon.

The "next line number" is always the value of the previously entered line number plus the current "increment". The increment is normally 10, but you can set it to any reasonable value with the INCREMENT command.

If you type the [TAB] in any other position than the beginning of a line, it will cause a "tab" to the next tab stop.

TAB STOPS#

The standard tab stops have been changed to allow for a nine character label before the opcode. Of course, you may use any length label from 1 to 32 characters followed by a blank and an opcode; but the use of the tab stops make for nicer looking programs. (Longer labels look nicer, if left on a line by themselves.)

CURSOR CONTROL#

SYNASSMBLER allows continued use of the ATARI cursor controls by pressing the CTRL key plus one of the four arrow keys on the right side of the keyboard. In addition, SynAssembler makes full use of the ATARI screen editor.

MEMORY USAGE#

The SYNASSEMBLER program is about 8000 bytes long, and occupies $9C00 through $BC1F in memory. The screen begins at $BC1F and goes through $BFFF, while the source program begins at the top of DOS and goes to $9C00.

During source program entry or editing, memory usage is monitored so that the source program does not grow so large as to overlap the symbol table. Overlapping will cause the "MEMORY FULL" error. message to print. During assembly, memory required by the symbol table is monitored to prevent the symbol table from overlapping the source program. Overlapping will generate the "MEMORY FULL" error message and abort the assembly.

In addition, memory usage by the object program is monitored, so that it will not destroy the source program, DOS, the Operating System, and hardware. Therefore, if the object program bytes are directed at any memory protected addresses the "MEMORY PROTECT" error message will be printed and assembly.

There are three types of commands in the SYNASSEMBLER: EDITING commands DOS commands and MONITOR commands. The EDITING commands are used to control the Editor and the assembler. Commands are typed immediately after the prompt symbol, which looks like this Ok..

EDITING COMMANDS#

There are seventeen editing commands in the SYNASSEMBLER. All editing commands may be abbreviated to the first three letters if you so desire.

command description
ASM Assemble source program, put object program into memory, and produce assembly listing.
COPy Duplicates specified lines in the source.
DELete Delete specified line.
FINd List all lines containing the specified string.
HIDe Changes the HIMEM pointer to 'hide' current source code prior to a MERge command.
INCrement Set the line # increment for automatic line numbering.
LISt List the source program or specified lines of source code.
MEMory Display the beginning and ending address.
MERge Use with HIDe to join source programs.
MOVe Moves a line of source code from one specified location to another.
NEW Delete the entire source program.
RENumber Renumber all or specified lines of source code.
REPlace Replace a specified string with another specified string.
REStore Restores HIMEM pointer after HIDe and MERge.
RUN Begins execution of your object program.
VAL Evaluates an operand expression and prints the value in hexadecimal.
MON Exit the editor and enter the monitor.

EDITING COMMAND DETAIL#

The SYNASSEMBLER editor, combines the powerful Atari screen editing features with a BASIC-like line editor, Source programs are entered and edited in almost exactly the same way you would enter and edit an Atari BASIC program.

ASM command:

SYNASSEMBLER is a two pass assembler. The ASM command initiates assembly of your source program. During the first pass it builds a symbol table with the definition of every label that is used in your program. During the second pass the assembler stores the object code into memory or disk and produces an assembly listing. At the end of the second pass a list, in alphabetical order, of all the labels and their definitions is produced.

If any errors are detected during either pass, an error message will be printed as well as the offending line. The error message will briefly explain the type of error encountered and the line will be positioned for easy editing. All of these messages abort the assembly process so that as soon as you correct the error condition you may immediately restart the assembly.

If you are listing the assembly to the screen you may use the [CTRL]+[1] control to start and stop your listing. You may abort the assembly process by hitting the [BREAK] key in pass two of the SYNASSEMBLER.

COPY L1 L2

This command places a copy of line L2 just before L1 in the source. The new line is assigned line number L1. The old line L2 remains in the source. This command should be followed by a renumber command if there are multiple lines with the same line number in the source.

COPY L1 L2 L3

This command places a copy of lines L2 through L3 just before line L1 in the source. The old lines are assigned line number L1. The old line L2 through L3 remain in the source. This command should be followed by a renumber command if there are any multiple lines with the same line number in the source.

DELete command:

Deletes a line or a range of lines from your source program. Another way to delete a single line is to type it's line #, followed immediately by a carriage return.

HIDe AND MERge

These two commands, when used with the LOAD command allow you to join a program from disk or tape to a program that is already in memory.

HIDe temporarily changes the HIMEM pointer so that it appears as if there were no source proaram in memory. To remind you that you are HIDe-ing, the prompt symbol changes to [H] ok. After HIDe-ing a program, you can load another one from disk or tape. Then you type MERge to join the two programs together.

After this sequence of commands the program which was already in memory will follow after the program just LOADed. If the line numbers are not already as you wish them to be, you can use the RENUMBER command to assign new ones.

For example, suppose that we have 2 source programs on the disk named "PART1" and "PART2". We want to join them together so that "PART1" precedes "PART2".

        Ok.
        LOAD "D:PART1"
        Ok.
        LIST
        00010 *       PROGPAM NUMBER ONE
        00020 MAIN    JSR SUBROUTINE
        00030         RTS
        Ok.
        LOAD "D:PART2"
        Ok.
        LIST
        00010 *       PROGRAM NUMBER TWO
        00020 SUBROUTINE
        00030         LDA BOAT.LOC
        00040         ASL
        00050         ASL
        00060         RTS
        Ok.
        HIDE
        [H] Ok.
        LOAD "D:PART1"
        [H] Ok.
        LIST
        00010 *       PROGRAM NUMBER ONE
        00020 MAIN    JSR SUBROUTINE
        00030         RTS
        [H] Ok.
        MERGE
        Ok.

INCrement

Sets the increment used for automatic line number generation. The increment is normally 10, but you may set it to any value between 0 and 9999. INC 5

FINd

The FINd command allows you to search through your source program for a given text string, and list all the lines that contain that string. The correct procedure for use of this command is as follows: Type FINd, followed by a space and then the string for which you are searching. Every character you type between the space and the carriage return is part of the search key. (NOTE: you may append or prefix spaces to any string to perform label searches.)

LIST L1 L2

Lists a single line, a range of lines or your entire program. It works just like the list command in BASIC. While a program or range of lines is listing you can use the standard Atari pause control [CTRL1], to start and stop the listing to the screen. You may abort the listing by pressing the [BREAK] key.

MEMory

Displays the beginning and ending memory address of the source program and of the symbol table.

 Source program: $9B99-9C1F
  Source length: $0086
   Symbol table: $1F00-1F00
Memory between the top of the symbol table and the bottom of the source program is free to be used without clobbering anything.

MERge; SEE "HIDe and MERge"

MOVe L1 L2

This command places a copy of line L2 just before L1 in the source. The new line is assigned line number L1. The old line L2 is removed from the source . This command should be followed by a renumber command if there are multiple lines with the same line number in the source.

MOVe L1 L2 L3

This command places a copy of lines L2 through L3 just before line L1 in the source. The new lines are assigned line number L1. The old lines L2 through L3 are removed from the source. This command should be followed by a renumber command if there are multiple lines with the same line number in the source.

NEW

This command acts just like it's BASIC counterpart. It deletes the current source program from memory and restarts SYNASSEMBLER just as though you were to reboot the program.

NOTE: A source program must, of course, be assembled into memory before it can be executed with the RUN command.

RENumber

Renumbers all or part of the lines in your source program with the specified starting line number and increment. There are three optional parameters for specyifying the line number to assign the first renumbered line (base), the increment, and the place in your program to begin renumbering (start). There are four possible forms of the command:

        REN             Renumber the whole source program:
                        BASE=1000, INC=10, START=0

        REN #           Renumber the whole source program:
                        BASE=#, INC=10, START=0

        REN #1,#2       Renumber the whole source program:
                        BASE=#1, INC=#2, START=0

        REN #1,#2,#3    Renumber all lines from #3 through the end.
                        BASE=#1, INC=#2, START=#3

        The last form above is useful for opening up a "hole" in the line
        numbers	for entering a new section of code.

        OK.
        LIST
        00000 * A RENUMBER EXAMPLE
        00003 START     LDA #100
        00013           STA $95
        00058           LDA #99
        00103           STA $A0
        00110           RTS
        Ok.
        REN
        Ok.
        LIST
        00010 * A RENUMBER EXAMPLE
        00020 START     LDA #100
        00030           STA $95
        00040           LDA #90
        00050           STA $A0
        00060           RTS
        Ok.
        REN 100
        Ok.
        LIST
        00100 * A RENUMBER EXAMPLE
        00110 START     LOA #100
        00120           STA $95
        00130           LDA #90
        00140           STA $A0
        00150           RTS
        Ok.

        REN 2000,4
        Ok.
        LIST
        02000 * A RENUMBER EXAMPLE
        02004 START     LDA #100
        02008           STA $95
        02012           LDA #90
        02016           STA $A0
        02020           RTS
        OK.
        REN 3000,10,2008
        OK.
        LIST
        02000 * A RENUMBER EXAMPLE
        02004 START     LDA #100
        03000           STA $95
        03010           LDA #90
        03020           STA $A0
        03030           RTS

REPlace dS1dS2d

This command replaces all occurences of string S1 with string S2 in the source. d is a delimiter and must be a non-space printable character that does not appear in either, S1 or S2.

REPlace dSidS2dtP

This command causes a search to be made for string S1. The search starts at the beginning of the source. Whenever S1 is found, the line containing it is listed and the user is prompted for 1 of 3 actions:

       Y or [RETURN]-relace S1 with S2 and continue.
       N do not replace S1 with S2 and continue search.
       X do not replace S1 with S2 and stop search.

       d is a delimiter and must be a non-space, printable
         character not appearing in either SI or S2.

REStore

Restores the root source program if an assembly is aborted while inside an "included" module.

The 'root source program" is the source program that is in memory at the time the "ASM" command is issued. If this source program uses the ".IN" directive to include additional source files, it is possible that assembly might be aborted either manually by typing a [BREAK] key during the listing phase, or automatically due to an error in the source program.

If the assembly is aborted during the time that the root program is hidden, the prompt character changes from "Ok" to "I Ok". The RESTORE command will reset the memory pointers so that the root program is no longer hidden, and change the prompt character back to "Ok".

You do not have to use the REStore command after an abort unless you wish to get back to the root source program for editing purposes. If you type the ASM command, the assembler automatically restores before starting the assembly.

If an assembly aborts due to an error in a source line, you may correct the source line, SAVE the module on the appropriate file, and type ASM to restart the assembly.

RUN

Begins execution of your object program. An expression MUST follow the RUN command to define the place to begin execution of the program. For example, "RUN BEGIN" will cause execution to begin at the point in your program where the label BEGIN is defined. Your program will return to SYNASSEMBLER by using an RTS instruction in your program. You may abort your program by hitting the RESET key. Or, you may use the [BREAK] key to break and fall back to the monitor.

VALue

The VAL command will evaluate any legal operand expression, and print the value in hexadecimal. It may be used to quickly convert decimal numbers to hexadecimal, to determine the ASCII code for a character or to find the value of a label from the last assembled program.

	EXAMPLE:

        VAL 'T
        $0054         00084
        OK.
        VAL 3493 + $3493
        $4238         16952
        OK.
        VAL START + S12
        $4200         16896
        OK.

DOS commands:#

LOAD and SAVE commands:

These commands are used to store your source files onto Disk or Tape in the internal compressed form. This saves disk space and speed.

EXAMPLE: LOAd "D:GAME1.TXT" or SAVE "D:MISC.SRC" 

BLOad and BSAve commands:

These commands are used to load and save BINARY files to disk.

NOTE: BLOad and BSAve function in the same manner as the L and K options in Atari DOS II.

EXAMPLE: BLOad "D:GAME.OBJ".
                 (This will load the binary file called GAME.OBJ
                 into memory at the address where it was saved.)

         BLOad "D:GAME.OBJ",$2000
                 (this will load GAME.OBJ starting at HEX 2000,
                 not at the address where i t was saved.)

EXAMPLE: BSAve "D:GAME.OBJ",$2000,$4000
                 (This saves a binary file called GAME.OBJ from
                 Hex location $2000 to $4000.
NOTE: the $ always must precede a hexadecimal number. SYMASSEMBLER assumes a decimal number if the $ sign is not present.

ENTer

This command allows you to enter ASCII text directly from tape or disk. It functions like the ENTER command in Atari BASIC. You can use this command to ENTER Atari assembler source files and then convert them to SYNASSEMBLER format.

EXAMPLE: ENTer "D:ATARIFIL.SRC" or ENTer"C:". 

TYPe

The TYPE command is used to save your source to any device in full ASCII format.

  EXAMPLE: TYPe "D:MYSOURCE.TXT"
                  (This comand saves the full ASCII source under
                   the MYSOURCE.TXT file, to disk drive 1)
           TYPe "P:" ... sends the source file to the printer.

DIRectory

The directory command is used to examine the contents of your diskettes.

  EXAMPLE: DIR by itself will show you the catalog for disk drive 1
           DIR "D:*.OBJ" will show anything in the catalog on drive 1
               with an OBJ extender.
           DIR "D2:*.TXT" will show anything in the catalog on drive 2
               with an OBJ extender.

DOS

The DOS command jumps from SYNASSEMBLER into the resident DOS in your system.

OUTput

The OUTput command is used to redirect the output of SYNASSEMBLER to another device; eg. printer, disk, screen etc.

EXAMPLE: OUT "P:" 

After changing the output you may use the ASM command to send assembled listings to the device specified. To cancel the redirection simply type OUTput without a filespec.

EXAMPLE: OUTput. 

ZYNAPSE MONITOR#

The ZYNAPSE monitor in SYNASSEMBLER allows you to examine, change, move, and verify memory. You may read and write to disk and cassette, dis-assemble machine-language programs; execute programs; perform hexadecimal arithmetic; read and write sectors directly to and from disk; and monitor program execution for debugging purposes.

MONITOR COMMANDS #

DISPLAY MEMORY: adrs1.adrs2 RETURN This command allows you to display the memory from address1 to address2.

EXAMPLE: 2000.4000 and [RETURN] 

CHANGE MEMORY: adrs;data data .....

In order to change data at a particular address enter the address (in HEX of course), and then a semi-colon(;) after which you may enter as much data as you wish making sure that each byte is separated by exactly one space.

  EXAMPLE: 2000;4C 00 9D
After having entered an address, you may just use a semi-colon to indicate the next location for your next data entry.
  EXAMPLE: 2000;4C
               ;00
               ;9D
This example has the same effect as the previous example.

DIS-ASSEMBLING MEMORY: adrsL

This command allows you to dis-assemble 20 instructions starting at the specified address. By typing L again the next 20 instructions will be dis-assembled.

ADDITION AND SUBTRACTION (HEX): data+data or data-data

You may add or subtract data (in HEX) simply by entering data and pressing RETURN.

MOVING MEMORY: adrs1&ltadrs2.adrs3M

You may easily move data from one part memory to another. You first specify the address into which you wish to move, and then the range of memory that is to be moved.

  EXAMPLE:   2000<3FF0.4000M

VERIFY MEMORY: adrs1&ltadrs2.adrs3V

If you wish to compare two blocks of memory, you can easily do so by specifying the starting address of the block you wish to compare and then the range that you wish it compared to.

  EXAMPLE:   2000<3FF0.4000V
DISK (READ and WRITE): adrs>sec1.sec2r (READ); adrs>sec1.sec2w (WRITE)

This unique feature of the ZYNAPSE monitor allows you to access the disk directly. The first parameter is the starting address of the buffer in which you wish to store the contents of the sec1 through sec2. Note:The READ and WRITE commands are lowercase. (CAUTION: BE EXTREMELY CAREFUL WHEN ACCESSING THE DISK DIRECTLY. YOU CAN EASILY OVERWRITE THE CONTENTS OF YOUR DISK.)

  EXAMPLE: 2000<1.4r (reads sector 1 through 4 into
                      buffer starting at 2000)
           2000<1.4w (wites the contents of buffer starting
                      at 2000 to sectors 1 through 4.)

RESTORING NORMAL MODE: N

This command tells the assembler to restore the original screen color and tab stops to the power-up specifications.

OTHER COMMANDS #

These commands are mainly used for execution and debugging assembly language programs.

EXECUTE: G

The G command is used to execute a program from the monitor, by typing the program address and the G command.

[*] Ok.
4000G

This will execute a program at 4000

EXAMINE and MODIFY registers: R

The R command allows you to examine and modify the 6502 registers (A,X,Y,P,S).

[*] Ok.
R
A=05 X=10 Y=50 P=30 S=F7
They can now be modified with the ";" command

STEP and TRACE: S, T (see also DEBUGGING)

The S and T commands are for single stepping your assembly language program but the T repeats the S command indefinitely. The S command will execute one instruction:

[*] Ok
4000S
4000: A9 03    LDA   #$03
A=03 X=00 Y=00 P=90 S=F0

At this point you may modify the register.

The T command will do the same thing as the S command except it will just repeat it forever. To get out of this mode, just tap the [BREAK] key.

QUIT: Q

The Q command will return you to the assembler.


Help File#


00010 *
00020 *  SYNASSEMBLER DIRECTIVES
00030 *
00040  .AS      ASCII STRING
00050     .AS "TEST"
00060  .AT      ATASCII STRING
00070     .AT "SCORE:"
00080  .BS      BLOCK STORAGE
00090     .BS 5  SKIPS 5 BYTES
00100  .DA      WORD
00110     .DA HELLO
00120  .EN     END OF SOURCE (OPTIONAL)
00130     .EN
00140  .EQ     EQUATE
00150     TEST .EQ 5
00160  .HS     HEX STRING
00170     .HS 0001AA5500339944344
00180  .IN      INCLUDE FILE WITH ASM
00190     .IN "D:FILE NAME"
00200  .LI      LIST ON OR OFF
00210     .LI OFF
00220  .OR      SET ORG
00230     .OR $6000
00240  .TA      SET TARGET FOR OBJECT
00250     .TA $9000
00260  .TF      SEND OBJECT TO DISK
00270     .TF "D:FILE NAME"
00280 *
00290 *  SYNASSEMBLER COMMAND
00300 *
00310 LOAD "D:FILE NAME"
00320 SAVE "D:FILE NAME"
00330 BLOAD "D:FILE NAME",<START>
00340 BSAVE "D:FILE NAME",<START>,<END>
00350 ENTER "D:FILE NAME"
00360 DIR       DIRECTORY DRIVE 1
00370 DIR "D4:*.*  DIRECTORY DRIVE 4
00380 DOS
00390 MEM   MEMORY STATUS
00400 LIST L1,L2
00410 NEW
00420 REN L1,L2
00430  RENUMBER L1 USING INC OF L2
00440 REN L1,L2,L3
00450  RENUMBER  L1 USING INC OF L2
00460  STARTING AT L3
00470 COPY L1,L2
00480  COPY L1 AT L2
00490 COPY L1,L2,L3
00500  COPY L1 TO L2 AT L3
00510 MOVE L1,L2
00520  MOVE L1 TO L2
00530 MOVE L1,L2,L3
00540  MOVE L1 TO L2 AT L3
00550 FIND STRING
00560 ASM
00570 DEL L1,L2
00580 HID
00590  HID CURRENT SOURCE PROGRAM
00600 MER
00610  COMBINE HIDDEN SOURCE WITH
00620  CURRENT SOURCE
00630 RUN EXPRESSION
00640 RESTORE
00650  RETURN FROM AN INCLUDE FILE
00660  OR TO UN-HIDE A HIDDEN FILE
00670 SYM
00680  PRINT SYMBOL TABLE
00690 VAL EXPRESSION
00700 REP /.BYTE/.HS/,P
00710  REPLACE WITH PROMPT
00720  PRESS 'Y' TO CHANGE
00730  PRESS 'N' FOR NO CHANGE
00740  PRESS 'X' TO CANCEL REPLACE
00750 REP /.BYTE/.HS/
00760  REPLACE ALL
00770 OUT "P:"
00780  PRINT OUTPUT TO DEVICE
00790 TYPE "P:"
00800  LIST TO DEVICE
00810 LOMEM $4000   OR   LOM $4000
00820  LOMEM OF SYMBOL TABLE
00830 HIMEM $8000   OR   HIM $8000
00840  HIMEM OF SOURCE  CAUTION
00850             DESTROYS SOURCE
00860 MON
00870  JUMP TO MONITOR
00880 Q
00890  JUMP BACK TO ASSEMBLER
00900 ************************
00910 * MONITOR INSTRUCTIONS *
00920 ************************
00930 EXAMINE MEMORY
00940 *
00950 adrs         C0F2
00960 adrs1.adrs2  1024.1048
00970 (RETURN)     DISPLAY NEXT 8 LOC
00980 .adrs        .4096
00990 *
01000 CHANGE MEMORY
01010 *
01020 adrs;data data     A256;EF 20 43
01030 ;data data data    ;F0 A2 12
01040 *
01050 MOVE MEMORY
01060 *
01070 adrs1<adrs2.adrs3M 100<B010.B410M
01080      FROM adrs2 TO adrs3 STARTING            AT adrs1
01090 *
01100 VERIFY MEMORY
01110 *
01120 adrs1<adrs2.adrs3V 100<B010.B410V
01130 *
01140 * READ SECTOR(S)
01150 *
01160 adrs<sec1.sec2r   2000<1.AFr
01170   READ SECTORS 1 TO AF
01180   AND PUT THEM INTO BUFFER
01190   AT 2000
01200 *
01210 * WRITE SECTOR(S)
01220 adrs<sec1.sec2w   2000<1.AFw
01230   WRITE SECTORS 1 TO AF
01240   AND GET THEM FROM BUFFER
01250   AT 2000
01260 *
01270 *
01280 adrsL    C080L
01290 L        NEXT 20 INSTRUCTIONS
01300 *
01310 DEBUGGING
01320 *
01330 adrsG    300G   RUN
01340 adrsT    800T   TRACE
01350 adrsS    C050S  SINGLE STEP
01360 R        DISPLAY REGISTERS
01370          TO CHANGE REGISTERS
01380          TYPE ; THEN DATA
01390          FOR EACH ONE