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Atari Mega Archive 2
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disasm.doc
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1995-04-22
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DISASM.DOC Don Lebow 70717,720
THE STRING INDEXING ROUTINES IN THIS
PROGRAM ARE BY RICHARD MANSFIELD. MY
THANKS FOR HIS PERMISSION TO SHARE
THEM IN MY OWN PROGRAM.
ONCE THE STRINGS ARE INITIALIZED, YOU
CAN RE-ENTER THE PROGRAM BY TYPING
GOTO 70 IN IMMEDIATE MODE.
DISASSEMBLER CONVERTS OBJECT CODE
INTO 6502 SOURCE CODE. THIS IS MOST
USEFUL FOR US ROOKIES WHEN PRESENTED
WITH A USEFUL ROUTINE THAT HAS NO
SOURCE LISTING AND NO CLUES.
SINCE DISASM ONLY DISASSEMBLES OBJECT
CODE THAT IS PRESENT IN MEMORY (ROM
INCLUDED), THE FIRST MENU ALLOWS YOU
TO LOAD THE CODE FROM SOME EXTERNAL
SOURCES. SELECT THE OPTION BY PRESSING
THE NUMBER KEY.
EXCEPT FOR BINARY DISK FILES, WHICH
CONTAIN THEIR OWN LOAD ADDRESSES, ALL
LOAD OPTIONS REQUIRE THAT YOU SPECIFY
A STARTING ADDRESS FOR THE LOAD. THE
PROGRAM ASKS IF YOU WISH TO USE A
STRING. IF YOU DON'T, THEN JUST PRESS
RETURN, AND INPUT THE ADDRESS. ANY
FREE RAM, INCLUDING PAGE SIX, CAN
BE USED. IF YOU NEED TO RESERVE LOW
MEMORY, DO THAT BEFORE LOADING THE
BASIC PROGRAM.
THE 'D:' DEVICE SPEC IS OPTIONAL.
DISASM USES D1: AS A DEFAULT.
DISK FILES MAY BE EITHER DATA FILES
(HANDY FOR THOSE WEIRD CHARACTER
STRINGS) OR REGULAR BINARY FILES.
MULTI-STAGE BINARY LOADS WILL ASK
FOR PERMISSION TO POKE THE BYTES.
WHEN THE ENTIRE FILE HAS BEEN READ,
INPUT THE STARTING ADDRESS FOR
DISASSEMBLY.
DATA READS DATA STATEMENTS, WHICH
SHOULD BE ENTERED AFTER DISASM HAS
BEEN LOADED. MAKE SURE THE LINE
NUMBERS ARE ABOVE 1540. THE PROGRAM
WILL READ THE WHOLE BLOCK, POKEING
BYTES STARTING AT THE FIRST ADDRESS
SPECIFIED.
KEYBOARD LETS YOU TYPE IN PROGRAMS
DIRECTLY. TYPING 999 BACKS UP FIVE
BYTES, TO CORRECT TYPOS. ANY MINUS
NUMBER STARTS THE DISASSEMBLY.
ONCE THE SCREEN IS FULL, SELECT AN
OPTION FROM THE MENU BY PRESSING THE
APPROPRIATE LETTER KEY. C (OR RETURN)
CONTINUES DISASSEMBLY INLINE. N SHIFTS
TO A NEW ADDRESS (EG. TO CHECK A JMP
INSTRUCTION). P DUMPS THE CURRENT
SCREEN TO THE PRINTER (THE SCREEN
IS TURNED OFF FOR THIS AND ALL OTHER
I/O TO SPEED THINGS UP.) E GOES
TO THE EXIT MENU.
FROM THIS MENU, R STARTS OVER FROM
THE ORIGINAL STARTING ADDRESS. M
GOES BACK TO THE TOP MENU. Q ENDS
THE PROGRAM. S WRITES A SOURCE FILE!
FIRST CHOICE IS WHETHER TO WRITE A
REGULAR SOURCE FILE, OR A .BYTE FILE,
WHICH IS USED FOR TEXT, TABLES, AND
SUCH.
FILES MAY BE WRITTEN TO THE PRINTER.
INPUT P OR P: FOR A FILENAME. A
LINECOUNT OPTION IS PROVIDED FOR THOSE
WITH SINGLE SHEET PRINTERS. IF USING
CONTINUOUS FEED, INPUT SOMETHING LIKE
10000 AT THE PROMPT. WHEN THE COUNT
IS REACHED, THE PROGRAM WILL HALT
AND BEEP TO SIGNAL THAT IT'S WAITING
FOR A KEY PRESS TO CONTINUE.
DISK FILES ARE IN LISTED FORMAT, SO
THEY CAN BE ENTERED INTO ASM/ED,
MAC/65, OR ANY OTHER LINE ORIENTED
ASSEMBLER WHICH USES STANDARD OPCODES.
LINE NUMBERS CORRESPOND TO ADDRESSES,
SO IF YOU SEE A 'JMP 1608', YOU CAN
'LIST 1608' TO SEE WHAT'S THERE. NO
.ORG ADDRESS IS INCLUDED IN THE FILE.
ONCE YOU HAVE THE FILE, DON'T
RENUMBER IT UNTIL YOU'VE PROVIDED
LABELS FOR ALL THE APPROPRIATE
REFERENCES. BUT ONCE YOU DO SO, YOU'LL
FIND THAT YOU CAN STUDY AND MODIFY
TO YOUR HEART'S CONTENT. HAVE FUN!