!!!Atari Assembler Editor
Copyright (C) 1980 Atari, Inc. & Kathleen Ann O'Brien

[{TableOfContents }]


Atari hired Shepardson Microsystems to write [Atari BASIC] for the 8-bit line. Shepardson developed it using a cross-compiler, but took the opportunity to begin writing their own assembler for the Atari platform as well. This was released by Atari in ROM cartridge form in 1980.

Atari Assembler Editor shared many components with Atari BASIC, notably the screen editor which used the same line-number based system as BASIC. However, it added several editing commands, including a RENumber and DELete, which, perhaps surprisingly, could also be used to edit BASIC programs.

The system ran entirely in RAM, meaning that both the source code and resulting machine code had to be able to fit in memory at the same time. This could be a significant limitation in many situations. Additionally, it did not include the ability to link multiple files together into a single larger program, which put further limits on the sort of programs that could be developed with it. [Eastern Front 1941], which was about 12 to 16k of machine code, required the source to be broken into six modules and then linked together by hand using DOS. Significant effort was needed to ensure that the memory references in the six files were correct, as they referred to code in other modules who's position changed as they were recompiled.

For larger programs, Atari also sold the [Atari Macro Assembler and Program-Text Editor CX8121|Atari Macro Assembler], which used a separate full-screen editor, saved files to disk, and included a linker. This was, however, both slow and expensive. As a result, many programmers were left wanting something more powerful than Assembler Editor (notably with macro support, which it lacked) but faster and less expensive than Macro Assembler. This led to a thriving market for 3rd party assemblers on the Atari platform.

The Atari Assembler Editor cartridge was a program used to edit, compile and debug assembly language programs for the Atari 8-bit computers. It was programmed by Kathleen Ann O'Brien of Shepardson Microsystems, Inc., later founding member of OSS, Inc.. It was the first commercially available assembler for the Atari 8-bit computers ever. And yes, it was programmed by a woman. Showing once more, how far ahead of time SMI and OSS were. The program was a two-pass 6502 assembler, in an 8 KB cartridge. With the command __SIZE__, the user gets the info, how much space is free and the command __DOS__, exits the cartridge and jumps into the Disk Operating System (DOS).

!!Assembler Editor - revision A & B cartridges, outlook for revision C and maybe D
There are two different versions of the cartridge which could be verified very easy, please see the md5 checksums below. AtariWiki dares to define them as revision A and B in analogy to the Atari Basic cartridge, which was delivered in three different versions. It is easy to find out, which version one has, just type in ASM and hit RETURN. If you have a revision A cartridge, no error message is shown, in case you have a revision B cartridge, the amount of errors are shown. Please see the two pictures below for an example:

[{Image src='Assembler Editor - Revision A.jpg' width=183 height=187 }]
Assembler Editor - revision A cartridge test result\\
[{Image src='Assembler Editor - Revision B.jpg' width=286 height=307 }]
Assembler Editor - revision B cartridge test result\\
__A binary compare of both cartridges did show, that there is much more different than that! Future investigations have to show, what else is different and how the user can profit of it.__\\
__Revision C:__\\
In the future all bugs shoud be collected and if they can be fixed, a revision C is thinkable. Of course, this requires the source code of the program, which we sadly do not have, nor a license for. Maybe there will be a good soul out there, who will give it to us in the future? At least, the [source code chapter|https://atariwiki.org/wiki/Wiki.jsp?page=Articles#section-Articles-SourceCode] has shown, that there is always hope, unless we never give up. :-)\\
__Revision D:__\\
If we go far ahead of this, then even an interbreed with the [TURBO-BASIC XL source code|https://atariwiki.org/wiki/Wiki.jsp?page=TURBO-BASIC%20XL#section-TURBO-BASIC+XL-SourceCode] is thinkable. In 1985 this was done for the Atari Basic cartridge by Frank Ostrowski and because many code routines are similar, there is a great chance to achieve this. Of course, even a renaming of the cartrige is possible, AtariWiki suggest to call it: 'Atari Turbo-Assembler Editor'. ;-)

!!CAR images
* [Assembler Editor - Revision A.car]
* [Assembler Editor - Revision B.car]

!!ROM images
* [Assembler Editor - Revision A.rom] ; md5 checksum: 13b6dfbcad3ee35f511209b790e04675
* [Assembler Editor - Revision B.rom] ; md5 checksum: aaf134cca657e21e2ad692b03a3233e0

!!BIN images
* [Assembler Editor - Revision A.bin]
* [Assembler Editor - Revision B.bin]

!!ATR images
* [Atari Assembler Editor with DOS 2.0S.atr] ; Assembler Editor - Revision A & B with Atari DOS 2.0S
* [Atari Assembler Editor with OSS DOS XL 2.30p Color.atr] ; Assembler Editor - Revision A & B with OSS DOS XL 2.30p Color
* [Hello_World_Source_Code_Atari_Assembler-Editor_with_DOS_2.0S_SD.atr]
* [Hello_World_Source_Code_Atari_Assembler-Editor_with_DOS_2.75_SD.atr]

!!XEX files
* [Assembler Editor - Revision A.xex] ; Assembler Editor - Revision A execution file
* [Assembler Editor - Revision B.xex] ; Assembler Editor - Revision B execution file

* [ATARI Assembler Editor User's Manual with OCR|ATARI Assembler Editor User-s Manual-OCR.pdf] ; size: 5.8 MB ; good quality
* [ATARI Assembler Editor User's Manual|ATARI Assembler Editor Users Manual.pdf]
* [ATARI Assembler Editor User's Manual Update|ATARI Assembler Editor Users Manual Update.pdf]
* [ATARI Assembler Editor User's Manual Errata 1|Atari_Assembler_Editor_User_s_Manual_Errata.pdf] ; size: 20.6 MB ; Many thanks to Atarimania!
* [ATARI Assembler Editor User's Manual Errata 2|Atari_Assembler_Editor_cartridge_manual_errata.pdf] ; size: 238 KB
* [ATARI Assembler Editor Reference Card|ATARI Assembler Editor Reference Card.pdf]
* [ATARI Assembler Editor Command Summary|ATARI Assembler Editor short.zip]
* [The Atari Assembler Editor Reference.rtf] ; The Atari Assembler Editor Reference by Matthew J. W. Ratcliff
* [The Atari Assembler Editor bug list.rtf] ; List of known bugs in the program, with description, solution, work around and source
[{Image src='The_Atari_Assembler.jpg' width=200 height=306 }]
* [The Atari Atari Assembler Editor-Don Inman, Kurt Inman|http://www.atarimania.com/documents-atari-400-800-xl-xe-books_1_8.html] ; Mega-Thanks to Atarimania for hosting!!!
[{Image src='Der Atari Assembler.jpg' width=200 height=293 }]
* [Der Atari Atari Assembler Editor-Don Inman, Kurt Inman|http://www.atarimania.com/documents-atari-400-800-xl-xe-books_1_8.html] ; Mega-Thanks to Atarimania for hosting!!!

If the user intends to resize the used memory, the command: 'LOMEM xxxx' must be the very first command after booting. Please see page 7 in the manual for further info. Otherwise the user will get an error:\\

[{Image src='LOMEM-SIZE-2.png' width=606 height=317 }]
LOMEM command - correct use\\
[{Image src='LOMEM-SIZE-1.png' width=611 height=296 }]
LOMEM command - incorrect use\\
Thanks to Sijmen Schouten for the hint. :-)

[{Image src='Der Atari Assembler Cover.jpg' width=390 height=520 }]
Atari Assembler Editor Box Cover - front\\
[{Image src='assembler_editor_cart_2.jpg' width=390 height=494 }]
Atari Assembler Editor Box Cover - back\\
[{Image src='assembler_editor_cart_3.jpg' width=200 height=241 }]
Assembler Editor Cartridge - Revision A\\
[{Image src='Assembler Editor Brown front.jpg' width=200 height=236 }]
Assembler Editor Cartridge - Revision B\\
[{Image src='assembler_editor_d_cart_1.jpg' width=300 height=425 }]
Atari Assembler Editor Box Cover - front German version\\
[{Image src='assembler_editor_d_cart_2.jpg' width=300 height=429 }]
Atari Assembler Editor Box Cover - back German version

* [http://ataripodcast.libsyn.com/antic-interview-21-the-atari-8-bit-podcast-kathleen-obrien-oss] ; ANTIC Interview 22 - The Atari 8-bit Podcast - with Kathleen Ann O'Brien from OSS, Inc.

* [https://computingpioneers.com/index.php/Kathleen_O%27Brien] ; transcript of the interview above 

* [http://a8preservation.com/#/software/title/%2Fapi%2Ftitles%2F587] ; Atari Assembler Editor on [a8preservation.com|http://a8preservation.com]

* [http://www.atarimagazines.com/hi-res/v1n1/advanceduser.php] ; Atari Assembler Editor in comparison to other assemblers by Russ Wetmore

* [http://open-source.ma.web.id/IT/1634-1523/Atari-Assembler-Editor_5818_open-source-ma.html] ; good info page about the Atari Assembler Editor including the Hello World! source code

* [Atari Assembler Editor discussion on AtariAge|http://atariage.com/forums/topic/193906-atari-assembler-editor-cartridge-and-inline-comments/?hl=atari+assembler+editor#entry2463276] ; discussion on AtariAge about the Atari Assembler Editor

!!Changing the editors color and background
[{Image src='Change Editor Color.jpg' width=234 height=554 }]
Assembler Editor Cartridge - changing the editor's color and background to user desired colors for better editing

!!Hello World! Source Code for the Atari Assembler Editor

This is the Hello World! source code:

20 ; ---------
30 ;
70 ;
0110 ; ===========
0120     *=  $0340   ;START OF IOCB
0130 IOCB
0140 ;
0150 ICHID *= *+1    ;DEVICE HANDLER
0160 ICDNO *= *+1    ;DEVICE NUMBER
0170 ICCOM *= *+1    ;I/O COMMAND
0180 ICSTA *= *+1    ;I/O STATUS
0190 ICBAL *= *+1    ;LSB BUFFER ADDR
0200 ICBAH *= *+1    ;MSB BUFFER ADDR
0210 ICPTL *= *+1    ;LSB PUT ROUTINE
0220 ICPTH *= *+1    ;MSB PUT ROUTINE
0230 ICBLL *= *+1    ;LSB BUFFER LEN
0240 ICBLH *= *+1    ;MSB BUFFER LEN
0250 ICAX1 *= *+1    ;AUX BYTE 1
0260 ICAX2 *= *+1    ;AUX BYTE 1
0270 ;
0300 ;
0310 CIOV =  $E456   ;CIO ENTRY VECTOR
0320 RUNAD = $02E0   ;RUN ADDRESS
0330 EOL   = $9B     ;END OF LINE
0340 ;
0360 ; -------------
0370     *= $0600
0380 START LDX #0    ;IOCB 0
0410     LDA #MSG&255 ;LOW BYTE OF MSG
0430     LDA #MSG/256 ;HIGH BYTE
0450     LDA #0      ;LENGTH OF MSG
0470     LDA #$FF    ;255 CHAR LENGTH
0490 ;
0510 ; -----------------
0520     JSR CIOV    ;CALL CIO
0530     RTS         ;EXIT TO DOS
0540 ;
0560 ; -----------
0580 ;
0600 ; ----------------
0610     *=  RUNAD
0620     .WORD START
0630     .END

This is the Hello World! source code in assembled form:

            10 ; HELLO.ASM
            20 ; ---------
            30 ;
            50 ; WILL PRINT THE "HELLO WORLD"
            60 ; MESSAGE TO THE SCREEN
            70 ;
            0100 ; CIO EQUATES
            0110 ; ===========
0000        0120        *=   $0340     ;START OF IOCB
            0130 IOCB
            0140 ;
0340        0150 ICHID  *=   *+1       ;DEVICE HANDLER
0341        0160 ICDNO  *=   *+1       ;DEVICE NUMBER
0342        0170 ICCOM  *=   *+1       ;I/O COMMAND
0343        0180 ICSTA  *=   *+1       ;I/O STATUS
0344        0190 ICBAL  *=   *+1       ;LSB BUFFER ADDR
0345        0200 ICBAH  *=   *+1       ;MSB BUFFER ADDR
0346        0210 ICPTL  *=   *+1       ;LSB PUT ROUTINE
0347        0220 ICPTH  *=   *+1       ;MSB PUT ROUTINE
0348        0230 ICBLL  *=   *+1       ;LSB BUFFER LEN
0349        0240 ICBLH  *=   *+1       ;MSB BUFFER LEN
034A        0250 ICAX1  *=   *+1       ;AUX BYTE 1
034B        0260 ICAX2  *=   *+1       ;AUX BYTE 1
            0270 ;
0005        0280 GETREC =    5         ;GET TEXT RECORD
0009        0290 PUTREC =    9         ;PUT TEXT RECORD
            0300 ;
E456        0310 CIOV   =    $E456     ;CIO ENTRY VECTOR
02E0        0320 RUNAD  =    $02E0     ;RUN ADDRESS
009B        0330 EOL    =    $9B       ;END OF LINE
            0340 ;
            0350 ; SETUP FOR CIO
            0360 ; -------------
034C        0370        *=   $0600     
0600 A200   0380 START  LDX  #0        ;IOCB 0
0602 A909   0390        LDA  #PUTREC   ;WANT OUTPUT
0604 9D4203 0400        STA  ICCOM,X   ;ISSUE CMD
0607 A91F   0410        LDA  #MSG&255  ;LOW BYTE OF MSG
0609 9D4403 0420        STA  ICBAL,X   ; INTO ICBAL
060C A906   0430        LDA  #MSG/256  ;HIGH BYTE
060E 9D4503 0440        STA  ICBAH,X   ; INTO ICBAH
0611 A900   0450        LDA  #0        ;LENGTH OF MSG
0613 9D4903 0460        STA  ICBLH,X   ; HIGH BYTE
0616 A9FF   0470        LDA  #$FF      ;255 CHAR LENGTH
0618 9D4803 0480        STA  ICBLL,X   ; LOW BYTE
            0490 ;
            0500 ; CALL CIO TO PRINT
            0510 ; -----------------
061B 2056E4 0520        JSR  CIOV      ;CALL CIO
061E 60     0530        RTS            ;EXIT TO DOS
            0540 ;
            0550 ; OUR MESSAGE
            0560 ; -----------
061F 48     0570 MSG    .BYTE "HELLO WORLD!",EOL
0620 45
0621 4C
0622 4C
0623 4F
0624 20
0625 57
0626 4F
0627 52
0628 4C
0629 44
062A 21
062B 9B
            0580 ;
            0590 ; INIT RUN ADDRESS
            0600 ; ----------------
062C        0610        *=   RUNAD     
02E0 0006   0620        .WORD START    
02E2        0630        .END           

!!Atari Assembler Editor Mnemonics

ADC Add Memory to Accumulator with Carry
AND AND Accumulator with Memory
ASL Shift Left (Accumulator or Memory)
BCC Branch if Carry Clear
BCS Branch if Carry Set
BEQ Branch if Result = Zero
BIT Test Memory Against Accumulator
BMI Branch if Minus Result
BNE Branch if Result ≠ Zero
BPL Branch on Plus Result
BRK Break
BVC Branch if V Flag Clear
BVS Branch if V Flag Set
CLC Clear Carry Flag
CLD Clear Decimal Mode Flag
CLI Clear Interrupt Disable flag (Enable Interrupt)
CLV Clear V Flag
CMP Compare Accumulator and Memory
CPX Compare Register X and Memory
CPY Compare Register Y and Memory
DEC Decrement Memory
DEX Decrement Register X
DEY Decrement Register Y
EOR Exclusive-OR Accumulator with Memory
INC Increment Memory
INX Increment Register X
INY Increment Register Y
JMP Jump to New Location
JSR Jump to Subroutine
LDA Load Accumulator
LDX Load Register X
LDY Load Register Y
LSR Shift Right (Accumulator or Memory)
NOP No Operation
ORA OR Accumulator with Memory
PHA Push Accumulator on Stack
PHP Push Processor Status Register (P) onto Stack
PLA Pull Accumulator from Stack
PLP Pull Processor Status Register (P) from Stack
ROL Rotate Left (Accumulator or Memory)
ROR Rotate Right (Accumulator or Memory)
RTI Return from Interrupt
RTS Return from Subroutine
SBC Subtract Memory from Accumulator with Borrow
SEC Set Carry Flag
SED Set Decimal Mode Flag
SEI Set Interrupt Disable Flag (Disable Interrupt)
STA Store Accumulator
STX Store Register X
STY Store Register Y
TAX Transfer Accumulator to Register X
TAY Transfer Accumulator to Register Y
TSX Transfer Register SP to Register X
TXA Transfer Register X to Accumulator
TXS Transfer Register X to Register SP
TYA Transfer Register Y to Accumulator

!!Instruction Set (Operation Codes)
[{Image src='Instruction Set (Operation Codes)-1.png' width=1089 height=824 }]
[{Image src='Instruction Set (Operation Codes)-2.png' width=1134 height=686 }]
Instruction Set (Operation Codes)

!!Commands and error codes
[{Image src='Editor.jpg' width=818 height=755 }]
Atari Assembler Editor - Editor commands\\
[{Image src='Assembler.jpg' width=733 height=853 }]
Atari Assembler Editor - Assembler commands\\
[{Image src='Debugger.jpg' width=841 height=669 }]
Atari Assembler Editor - Debugger commands\\
[{Image src='Assembler Editor Error Codes 001-139.jpg' width=847 height=949 }]
Atari Assembler Editor - Error Codes 001-139\\
[{Image src='Assembler Editor Error Codes 140-165.jpg' width=681 height=237 }]
Atari Assembler Editor - Error Codes 140-165\\
[{Image src='Error Codes 2-171.jpg' width=782 height=895 }]
Atari Assembler Editor - Error Codes 2-171