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Assembly Source File | 1986-07-21 | 30KB | 1,075 lines

.XALL PAGE ,132 TITLE DASM80 - 14 SEP 1985 ; **************************************************************** ; ** ** ; ** MS-DOS 8080/8085 DISASSEMBLER ** ; ** ** ; **............................................................** ; ** ** ; ** DASM80 DISASSEMBLES 8080/8085 INTEL HEX FILES. ** ; ** ** ; **************************************************************** ; ..... MODULE CONNECTION POINTS ..... EXTRN MNEM:NEAR ; MNEMONIC TABLE EXTRN BYTES:NEAR ; BYTES TABLE ; ..... MACROS ..... DISKRD MACRO NUMBYTE ; READ SPECIFIED NUMBER OF BYTES FROM DISK LOCAL OK ; OK IS A LOCAL SYMBOL MOV AH,READ ; LOAD READ COMMAND MOV BX,RDHAND ; LOAD READ FILE HANDLE MOV CX,NUMBYTE ; LOAD NUMBER OF CHARACTERS TO BE READ MOV DX,OFFSET DSKBUF; POINT TO DISK BUFFER INT DOSFUNC ; READ FROM INPUT FILE - ERROR? JNC OK ; NO - DONE JMP DSKERR ; YES - DISPLAY ERROR OK: ENDM ; DISKWR MACRO NUMBYTE ; WRITE SPECIFIED NUMBER OF BYTES TO DISK LOCAL OK ; OK IS A LOCAL SYMBOL MOV AH,WRITE ; LOAD WRITE COMMAND MOV BX,WRHAND ; LOAD WRITE FILE HANDLE MOV CX,NUMBYTE ; LOAD NUMBER OF CHARACTERS TO WRITE MOV DX,OFFSET DSKBUF; POINT TO DISK BUFFER INT DOSFUNC ; WRITE TO OUTPUT - ERROR? JNC OK ; NO - DONE JMP DSKERR ; YES - DISPLAY ERROR OK: ENDM ; PAGE ; ..... DOS COMMANDS ..... DOSFUNC EQU 21H ; DOS FUNCTION INTERRUPT PR_STR EQU 09H ; DOS FUNCTION PRINT STRING COMMAND CREATE EQU 3CH ; CREATE FILE COMMAND OPEN EQU 3DH ; OPEN FILE COMMAND CLOSE EQU 3EH ; CLOSE FILE COMMAND READ EQU 3FH ; READ FILE COMMAND WRITE EQU 40H ; WRITE FILE COMMAND RDACC EQU 0 ; READ FILE ACCESS CODE WRACC EQU 1 ; WRITE FILE ACCESS CODE WRATT EQU 0 ; WRITE FILE ATTRIBUTE CODE ; ..... CONSTANTS ..... MEMLEN EQU 2000H ; LENGTH OF MEMORY BUFFER MAXLEN EQU 80 ; MAXIMUM FILE NAME LENGTH CR EQU 0DH ; ASCII <CR> LF EQU 0AH ; ASCII LINE FEED RS EQU 1EH ; ASCII RECORD SEPARATOR TAB EQU 09H ; ASCII TAB DATIND EQU 00H ; HEX FILE DATA RECORD INDICATOR EOFIND EQU 01H ; HEX FILE END OF FILE INDICATOR PAGE STACK SEGMENT STACK ; STACK SEGMENT DW 1024 DUP (?) ; 1024 LEVELS OF STACK STACK ENDS DATA SEGMENT PUBLIC ; DATA SEGMENT ; **************************************************************** ; ** ** ; ** MISCELLANEOUS STRINGS ** ; ** ** ; **************************************************************** MSGORG DB ';',CR,LF,TAB,'ORG',TAB,'0' LENORG EQU $-MSGORG MSGEND DB ';',CR,LF,TAB,'END',CR,LF LENEND EQU $-MSGEND ; **************************************************************** ; ** ** ; ** ERROR STRINGS ** ; ** ** ; **************************************************************** MBCOM DB CR,LF,'COMMAND LINE ERROR',CR,LF,LF,'$' MBHEX DB CR,LF,'BAD HEX DATA',CR,LF,LF,'$' MDISK0 DB CR,LF,'ERROR 0 - DISK FULL',CR,LF,LF,'$' MDISK1 DB CR,LF,'ERROR 1 - INVALID FUNCTION',CR,LF,LF,'$' MDISK2 DB CR,LF,'ERROR 2 - FILE NOT FOUND',CR,LF,LF,'$' MDISK3 DB CR,LF,'ERROR 3 - PATH NOT FOUND',CR,LF,LF,'$' MDISK4 DB CR,LF,'ERROR 4 - TOO MANY OPEN FILES',CR,LF,LF,'$' MDISK5 DB CR,LF,'ERROR 5 - ACCESS DENIED',CR,LF,LF,'$' MDISK6 DB CR,LF,'ERROR 6 - INVALID FILE HANDLE',CR,LF,LF,'$' MUKNOW DB CR,LF,'UNKNOWN DISK ERROR',CR,LF,LF,'$' PAGE ; **************************************************************** ; ** ** ; ** PROGRESS MESSAGE STRINGS ** ; ** ** ; **************************************************************** MRCOM DB CR,LF,'READING COMMAND LINE',CR,LF,'$' MOPENR DB 'OPENING READ FILE',CR,LF,'$' MCHEX DB 'CONVERTING HEX FILE',CR,LF,'$' MOPENW DB 'CLOSING READ AND OPENING WRITE FILE',CR,LF,'$' MDISS DB 'DISASSEMBLING CONVERTED DATA',CR,LF,'$' MCLOSW DB 'CLOSING WRITE FILE',CR,LF,'$' MEXIT DB 'EXITING TO DOS',CR,LF,LF,'$' PAGE ; **************************************************************** ; ** ** ; ** MEMORY ASSIGNMENTS ** ; ** ** ; **************************************************************** DSKBUF DB 80 DUP (?) ; DISK I/O BUFFER DSKCNT DW (?) ; DISK BUFFER COUNTER RDFILE DB MAXLEN+1 DUP (0); INPUT FILE NAME BUFFER WRFILE DB MAXLEN+1 DUP (0); OUTPUT FILE NAME BUFFER RDHAND DW (?) ; READ FILE HANDLE WRHAND DW (?) ; WRITE FILE HANDLE CHKACC DB (?) ; CHECKSUM ACCUMULATOR DSKPTR DW (?) ; DISK BUFFER POINTER MEMPTR DW (?) ; MEMORY POINTER MEMCNT DW (?) ; MEMORY COUNTER NUMREC DW (?) ; NUMBER OF RECORDS IN CURRENT LINE RECNUM DW (?) ; NUMBER OF BYTES FOR NUMREC RECORDS CURADD DW (?) ; CURRENT ADDRESS DB (0) ; DUMMY START OF MEMBUF MEMBUF DB MEMLEN DUP (0) ; MEMORY BUFFER DATA ENDS PAGE CODE SEGMENT ; CODE SEGMENT ASSUME CS:CODE,DS:DATA,ES:DATA,SS:STACK ; **************************************************************** ; ** ** ; ** MAIN PROGRAM ** ; ** ** ; **************************************************************** DASM80 PROC FAR ; PUSH DS ; MOV AX,0 ; PUSH AX ; SET UP FOR A FAR RETURN TO DOS MOV AX,DATA ; MOV DS,AX ; SET UP DATA SEGMENT REGISTER MOV DX,OFFSET MRCOM ; POINT TO READING COMMAND LINE MESSAGE CALL MSGCO ; WRITE MESSAGE TO STANDARD OUTPUT CALL RCMD ; READ COMMAND LINE MOV DX,OFFSET MOPENR; POINT TO OPENING INPUT FILE MESSAGE CALL MSGCO ; WRITE MESSAGE TO STANDARD OUTPUT CALL OPENRD ; OPEN INPUT FILE FOR READ MOV DX,OFFSET MCHEX ; POINT TO CONVERTING HEX FILE MESSAGE CALL MSGCO ; WRITE MESSAGE TO STANDARD OUTPUT CALL CHEX ; CONVERT INPUT FILE MOV DX,OFFSET MOPENW; POINT TO OPENING OUTPUT FILE MESSAGE CALL MSGCO ; WRITE MESSAGE TO STANDARD OUTPUT CALL OPENWR ; OPEN OUTPUT FILE FOR WRITE MOV DX,OFFSET MDISS ; POINT TO DISASSEMBLING MESSAGE CALL MSGCO ; WRITE MESSAGE TO STANDARD OUTPUT CALL DISS ; DISASSEMBLE FILE MOV DX,OFFSET MCLOSW; POINT TO CLOSING WRITE FILE MESSAGE CALL MSGCO ; WRITE MESSAGE TO STANDARD OUTPUT CALL CLOSWR ; DISASSEMBLE FILE MOV DX,OFFSET MEXIT ; POINT TO EXITING MESSAGE CALL MSGCO ; WRITE MESSAGE TO STANDARD OUTPUT RET ; RETURN TO DOS DASM80 ENDP ; PAGE ; **************************************************************** ; ** ** ; ** READ COMMAND LINE ** ; ** ** ; **************************************************************** RCMD PROC NEAR ; MOV BX,80H ; POINT TO NUMBER OF RECEIVED CHARACTERS MOV CH,ES:[BX] ; LOAD NUMBER OF RECEIVED CHARACTERS OR CH,CH ; ZERO CHARACTERS? JZ RCMD25 ; YES - DISPLAY ERROR INC BX ; NO - POINT TO CHARACTERS MOV DI,OFFSET RDFILE; POINT TO INPUT FILE NAME BUFFER MOV CL,MAXLEN ; LOAD MAXIMUM FILE NAME LENGTH MOV AL,ES:[BX] ; READ NEXT CHARACTER INC BX ; ADVANCE POINTER DEC CH ; RETARD CHARACTER COUNTER - END? JZ RCMD25 ; YES - DISPLAY ERROR CMP AL,' ' ; NO - SPACE? JNZ RCMD25 ; NO - DISPLAY ERROR RCMD05: MOV AL,ES:[BX] ; YES - READ NEXT CHARACTER MOV [DI],AL ; WRITE TO INPUT FILE NAME BUFFER CMP AL,' ' ; SPACE? JZ RCMD10 ; YES - LOAD OUTPUT FILE NAME INC BX ; NO - INC DI ; - ADVANCE POINTERS DEC CH ; RETARD CHARACTER COUNTER - END? JZ RCMD25 ; YES - DISPLAY ERROR DEC CL ; NO - RETARD FILE NAME COUNTER - TOO LONG? JZ RCMD25 ; YES - DISPLAY ERROR JMP RCMD05 ; NO - CONTINUE RCMD10: INC BX ; ADVANCE COMMAND LINE POINTER DEC CH ; DECREMENT CHARACTER COUNTER - END? JZ RCMD25 ; YES - DISPLAY ERROR MOV DI,OFFSET WRFILE; NO - POINT TO OUTPUT FILE NAME BUFFER MOV CL,MAXLEN ; LOAD MAXIMUM FILE NAME LENGTH RCMD20: MOV AL,ES:[BX] ; READ NEXT CHARACTER CMP AL,' ' ; SPACE? JZ RCMD25 ; YES - DISPLAY ERROR MOV [DI],AL ; NO - WRITE TO OUTPUT FILE NAME BUFFER INC BX ; INC DI ; ADVANCE POINTERS DEC CH ; RETARD COUNTER - LAST CHARACTER? JZ RCMD30 ; YES - DONE DEC CL ; NO - RETARD COUNTER - FILE NAME TOO LONG? JZ RCMD25 ; YES - DISPLAY ERROR JMP RCMD20 ; NO - CONTINUE RCMD25: MOV DX,OFFSET MBCOM ; POINT TO BAD COMMAND LINE MESSAGE JMP MISERR ; DISPLAY ERROR MESSAGE AND EXIT TO DOS RCMD30: RET ; RCMD ENDP ; ; **************************************************************** ; ** ** ; ** OPEN INPUT FILE FOR READ ** ; ** ** ; **************************************************************** OPENRD PROC NEAR ; MOV AH,OPEN ; LOAD OPEN FILE COMMAND MOV AL,RDACC ; LOAD READ ACCESS CODE MOV DX,OFFSET RDFILE; POINT TO INPUT FILE NAME INT DOSFUNC ; OPEN INPUT FILE - ERROR? JNC OPRD05 ; NO - STORE READ FILE HANDLE JMP DSKERR ; YES - DISPLAY ERROR OPRD05: MOV RDHAND,AX ; NO - STORE READ FILE HANDLE RET ; DONE OPENRD ENDP ; PAGE ; **************************************************************** ; ** ** ; ** CONVERT INPUT FILE ** ; ** ** ; **************************************************************** CHEX PROC NEAR ; CHEX10: DISKRD 1 ; READ ONE BYTE FROM DISK FILE - ERROR? CMP AX,01 ; NO - 1 CHARACTER? JZ CHEX11 ; YES - TEST FOR RECORD MARK JMP CHEX25 ; NO - DISPLAY ERROR CHEX11: MOV BX,OFFSET DSKBUF; POINT TO DISK BUFFER MOV AL,[BX] ; LOAD RECEIVED CHARACTER CMP AL,':' ; RECORD MARK? JNZ CHEX10 ; NO - TRY AGAIN DISKRD 8 ; YES - READ EIGHT BYTES FROM DISK FILE - ERROR? MOV CHKACC,0 ; NO - INITIALIZE CHECKSUM ACCUMULATOR CMP AX,08 ; RECEIVE 8 CHARACTERS? JZ CHEX12 ; YES - CONVERT NUMBER OF BYTES IN RECORD JMP CHEX25 ; NO - DISPLAY ERROR CHEX12: MOV BX,OFFSET DSKBUF; POINT TO DISK BUFFER CALL PACK ; CONVERT NUMBER OF BYTES IN RECORD MOV AH,0 ; MOV NUMREC,AX ; STORE CALL PACK ; CONVERT HIGH START ADDRESS MOV DH,AL ; STORE CALL PACK ; CONVERT LOW START ADDRESS MOV DL,AL ; STORE CALL PACK ; CONVERT RECORD INDICATOR CMP AL,DATIND ; DATA INDICATOR? JNZ CHEX20 ; NO - TEST FOR END OF FILE INDICATOR MOV BX,OFFSET MEMBUF; YES - POINT TO MEMBUF ADD BX,DX ; COMPUTE MEMBUF ADDRESS FOR THIS RECORD MOV MEMPTR,BX ; STORE MOV AX,NUMREC ; LOAD NUMBER OF RECORDS ADD AX,AX ; COMPUTE NUMBER OF DATA CHARACTERS ADD AX,4 ; ADD CHECKSUM AND TERMINATOR CHARACTER COUNT MOV RECNUM,AX ; STORE DISKRD RECNUM ; YES - READ RECNUM BYTES FROM DISK FILE - ERROR? MOV BX,OFFSET DSKBUF; NO - POINT TO DISK BUFFER MOV DSKPTR,BX ; INITITIALIZE DISK BUFFER POINTER CMP RECNUM,CX ; RECEIVED CORRECT NUMBER OF CHARACTERS? JZ CHEX14 ; YES - CONVERT RECORD JMP CHEX25 ; NO - DISPLAY ERROR CHEX14: MOV CX,NUMREC ; LOAD COUNTER JCXZ CHEX21 ; ZERO BYTES? - YES - LOAD AND TEST ; CHECKSUM AND TERMINATOR CHEX15: MOV BX,DSKPTR ; NO - LOAD DISK BUFFER POINTER CALL PACK ; CONVERT DATA MOV DSKPTR,BX ; STORE DISK BUFFER POINTER MOV BX,MEMPTR ; LOAD MEMORY BUFFER POINTER MOV [BX],AL ; STORE DATA INC MEMPTR ; ADVANCE MEMORY BUFFER POINTER DEC CX ; RETARD COUNTER - DONE? JNZ CHEX15 ; NO - CONTINUE MOV BX,DSKPTR ; YES - LOAD DISK BUFFER POINTER CALL PACK ; CONVERT CHECKSUM MOV CL,AL ; STORE CHECKSUM MOV AL,CHKACC ; LOAD CHECKSUM ACCUMULATOR SUB AL,CL ; ADJUST CHECKSUM NOT AL ; INC AL ; COMPUTE 2'S COMPLEMENT OF CHECKSUM CMP AL,CL ; CHECKSUMS MATCH? JNZ CHEX25 ; NO - DISPLAY ERROR CMP BYTE PTR[BX],CR ; YES - TERMINATED WITH <CR>? JNZ CHEX25 ; NO - DISPLAY ERROR INC BX ; YES - POINT TO LINE FEED CMP BYTE PTR[BX],LF ; LINE FEED? JNZ CHEX25 ; NO - DISPLAY ERROR JMP CHEX10 ; YES - CONTINUE CHEX20: CMP AL,EOFIND ; END OF FILE INDICATOR? JNZ CHEX25 ; NO - DISPLAY ERROR DISKRD 4 ; YES - READ 4 BYTES FROM DISK FILE - ERROR? CMP AX,4 ; NO - 4 CHARACTERS? JNZ CHEX25 ; NO - DISPLAY ERROR CHEX21: MOV BX,OFFSET DSKBUF; YES - POINT TO DISK BUFFER CALL PACK ; CONVERT CHECKSUM MOV CL,AL ; STORE CHECKSUM MOV AL,CHKACC ; LOAD CHECKSUM ACCUMULATOR SUB AL,CL ; ADJUST CHECKSUM NOT AL ; INC AL ; COMPUTE 2'S COMPLEMENT OF CHECKSUM CMP AL,CL ; CHECKSUMS MATCH? JNZ CHEX25 ; NO - DISPLAY ERROR CMP BYTE PTR[BX],CR ; YES - TERMINATED WITH <CR>? JNZ CHEX25 ; NO - DISPLAY ERROR INC BX ; YES - POINT TO LINE FEED CMP BYTE PTR[BX],LF ; LINE FEED? JNZ CHEX25 ; NO - DISPLAY ERROR RET ; YES - DONE CHEX25: MOV DX,OFFSET MBHEX ; POINT TO BAD HEX DATA MESSAGE JMP MISERR ; DISPLAY ERROR MESSAGE AND EXIT TO DOS CHEX ENDP ; PAGE ; **************************************************************** ; ** ** ; ** OPEN OUTPUT FILE FOR WRITE ** ; ** ** ; **************************************************************** OPENWR PROC NEAR ; MOV AH,CLOSE ; LOAD CLOSE FILE COMMAND MOV BX,RDHAND ; LOAD INPUT FILE HANDLE INT DOSFUNC ; CLOSE THE INPUT FILE - ERROR? JNC OPWR05 ; NO - OPEN WRITE FILE JMP DSKERR ; YES - DISPLAY ERROR OPWR05: MOV AH,CREATE ; LOAD CREATE FILE COMMAND MOV CX,WRATT ; LOAD WRITE FILE ATTRIBUTE MOV DX,OFFSET WRFILE; POINT TO OUTPUT FILE NAME INT DOSFUNC ; OPEN OUTPUT FILE - ERROR? JNC OPWR10 ; NO - STORE WRITE FILE HANDLE JMP DSKERR ; YES - DISPLAY ERROR OPWR10: MOV WRHAND,AX ; STORE WRITE FILE HANDLE RET ; DONE OPENWR ENDP ; PAGE ; **************************************************************** ; ** ** ; ** DISASSEMBLE MEMORY BUFFER ** ; ** ** ; **************************************************************** DISS PROC NEAR ; MOV BX,OFFSET MEMBUF-1; POINT TO MEMORY BUFFER MOV MEMPTR,BX ; INITIALIZE MEMORY POINTER MOV BX,MEMLEN+2 ; LOAD NUMBER OF BYTES TO DISSASEMBLE MOV MEMCNT,BX ; STORE DISS05: MOV BX,OFFSET DSKBUF; POINT TO DISK BUFFER MOV DSKPTR,BX ; INITIALIZE DISK BUFFER POINTER MOV BX,0 ; MOV DSKCNT,BX ; CLEAR DISK BUFFER COUNTER MOV BX,MEMCNT ; LOAD MEMORY BUFFER COUNTER DEC BX ; RETARD MEMORY BUFFER COUNTER - END OF FILE? MOV MEMCNT,BX ; (STORE) JZ DISS10 ; YES - WRITE "END" TO OUTPUT FILE MOV BX,MEMPTR ; NO - LOAD MEMORY BUFFER POINTER MOV AL,[BX] ; LOAD NEXT OPCODE OR AL,AL ; ZERO? JNZ DISS15 ; NO - FIND IT'S MNEMONIC DISS10: PUSH BX ; YES - SAVE MEMORY BUFFER POINTER MOV BX,MEMCNT ; LOAD MEMORY BUFFER COUNTER DEC BX ; END OF FILE? MOV MEMCNT,BX ; (STORE) POP BX ; (RESTORE MEMORY POINTER) JNZ DISS11 ; NO - POINT TO NEXT BYTE JMP DISS60 ; YES - WRITE "END" TO DISK DISS11: INC BX ; POINT TO NEXT BYTE MOV AL,[BX] ; LOAD IT OR AL,AL ; ZERO? JZ DISS10 ; YES - CONTINUE MOV MEMPTR,BX ; NO - STORE MEMORY BUFFER POINTER CALL ORGWR ; WRITE ORG LINE TO DISK JMP DISS05 ; CONTINUE DISS15: MOV DX,BX ; LOAD CURRENT MEMORY BUFFER LOCATION SUB DX,OFFSET MEMBUF; COMPUTE CURRENT ADDRESS MOV CURADD,DX ; STORE MOV CL,[BX] ; MOV CH,0 ; LOAD OPCODE INC CX ; ADJUST MOV BX,OFFSET MNEM ; POINT TO MNEMONIC TABLE DISS20: DEC CX ; RETARD OPCODE - DONE? JZ DISS30 ; YES - WRITE TAB TO DISK BUFFER DISS25: MOV AL,[BX] ; NO - LOAD NEXT CHARACTER INC BX ; ADVANCE MNEMONIC TABLE POINTER CMP AL,RS ; RS? JZ DISS20 ; YES - RETARD OPCODE AND TEST FOR DONE JMP DISS25 ; NO - TEST NEXT CHARACTER FOR RS DISS30: PUSH BX ; SAVE MNEMONIC POINTER MOV BX,DSKPTR ; LOAD DISK BUFFER POINTER MOV BYTE PTR[BX],TAB; WRITE TAB TO DISK BUFFER INC BX ; ADVANCE DISK BUFFER POINTER MOV AX,DSKCNT ; LOAD DISK BUFFER COUNTER INC AX ; ADVANCE MOV DSKCNT,AX ; STORE PUSH BX ; POP DI ; LOAD DISK BUFFER POINTER IN DX POP BX ; RESTORE MNEMONIC POINTER DISS35: MOV AL,[BX] ; LOAD MNEMONIC CHARACTER CMP AL,RS ; RS? JZ DISS40 ; YES - STORE DISK BUFFER POINTER MOV [DI],AL ; NO - WRITE CHARACTER TO DISK BUFFER INC DI ; ADVANCE DISK BUFFER POINTER INC BX ; ADVANCE MNEMONIC POINTER MOV AX,DSKCNT ; LOAD DISK BUFFER COUNTER INC AX ; ADVANCE MOV DSKCNT,AX ; STORE JMP DISS35 ; TEST NEXT CHARACTER FOR RS DISS40: XCHG BX,DI ; LOAD DISK BUFFER POINTER IN BX MOV DSKPTR,BX ; STORE DISK BUFFER POINTER MOV BX,MEMPTR ; LOAD MEMORY BUFFER POINTER MOV CH,0 ; MOV CL,[BX] ; LOAD OP-CODE INC BX ; ADVANCE MEMORY BUFFER POINTER MOV MEMPTR,BX ; STORE CALL OPBYTE ; COMPUTE NUMBER OF BYTES FOR THIS OPCODE MOV AL,CL ; LOAD NUMBER OF BYTES OR AL,AL ; ZERO BYTES? JNZ DISS41 ; NO - TEST FOR ONE BYTE MOV BX,MEMPTR ; YES - LOAD MEMORY BUFFER POINTER DEC BX ; ADJUST MOV AL,[BX] ; LOAD "OP-CODE" MOV BX,DSKPTR ; LOAD DISK POINTER MOV BYTE PTR[BX],'0'; WRITE LEADING ZERO TO DISK BUFFER INC BX ; ADVANCE DISK BUFFER POINTER MOV DSKPTR,BX ; STORE CALL EXPAND ; WRITE "OP-CODE" TO DISK BUFFER MOV BX,DSKPTR ; LOAD DISK POINTER MOV BYTE PTR[BX],'H'; WRITE "H" TO DISK BUFFER INC BX ; ADVANCE DISK BUFFER POINTER MOV DSKPTR,BX ; STORE ADD DSKCNT,2 ; ADVANCE DISK COUNTER JMP DISS55 ; WRITE "TAB,;,CR,LF" TO OUTPUT FILE DISS41: DEC AL ; ONE BYTE? JNZ DISS42 ; NO - TEST FOR TWO BYTES JMP DISS55 ; YES - WRITE "TAB,;,CR,LF" TO OUTPUT FILE DISS42: DEC AL ; TWO BYTES? JNZ DISS45 ; NO - JUMP TO THREE BYTE HANDLER MOV BX,MEMCNT ; YES - LOAD MEMORY BUFFER COUNTER DEC BX ; RETARD MEMORY BUFFER COUNTER - LAST BYTE? MOV MEMCNT,BX ; (STORE) JNZ DISS43 ; NO - WRITE ADDRESS TO DISK BUFFER JMP DISS60 ; YES - WRITE "END" TO OUTPUT FILE DISS43: MOV BX,DSKPTR ; LOAD DISK BUFFER POINTER MOV BYTE PTR[BX],'0'; LOAD LEADING ZERO INC BX ; ADVANCE DISK BUFFER POINTER MOV DSKPTR,BX ; STORE MOV AX,DSKCNT ; LOAD DISK BUFFER COUNTER INC AX ; ADVANCE MOV DSKCNT,AX ; STORE MOV BX,MEMPTR ; LOAD MEMORY BUFFER POINTER MOV AL,[BX] ; LOAD NEXT BYTE INC BX ; ADVANCE POINTER MOV MEMPTR,BX ; STORE CALL EXPAND ; CONVERT TO ASCII IN DISK BUFFER JMP DISS50 ; WRITE "H" TO DISK BUFFER DISS45: MOV BX,MEMCNT ; LOAD MEMORY BUFFER COUNTER DEC BX ; RETARD MEMORY BUFFER COUNTER - LAST BYTE? JNZ DISS46 ; NO - RETARD AGAIN JMP DISS60 ; YES - WRITE "END" TO OUTPUT FILE DISS46: DEC BX ; RETARD MEMORY BUFFER COUNTER - LAST BYTE? MOV MEMCNT,BX ; (STORE) JNZ DISS47 ; NO - WRITE ADDRESS TO DISK BUFFER JMP DISS60 ; YES - WRITE "END" TO OUTPUT FILE DISS47: MOV BX,DSKPTR ; LOAD DISK BUFFER POINTER MOV BYTE PTR[BX],'0'; LOAD LEADING ZERO INC BX ; ADVANCE DISK BUFFER POINTER MOV DSKPTR,BX ; STORE MOV AX,DSKCNT ; LOAD DISK BUFFER COUNTER INC AX ; ADVANCE MOV DSKCNT,AX ; STORE MOV BX,MEMPTR ; LOAD MEMORY BUFFER POINTER MOV AL,[BX] ; LOAD LOW ADDRESS BYTE PUSH AX ; STORE INC BX ; ADVANCE MEMORY BUFFER POINTER MOV AL,[BX] ; LOAD HIGH ADDRESS BYTE INC BX ; ADVANCE MEMORY BUFFER POINTER MOV MEMPTR,BX ; STORE CALL EXPAND ; CONVERT TO ASCII IN DISK BUFFER POP AX ; RESTORE LOW ADDRESS BYTE CALL EXPAND ; CONVERT TO ASCII DISS50: MOV BX,DSKPTR ; NO - LOAD DISK BUFFER POINTER MOV BYTE PTR[BX],'H'; WRITE HEX INDICATOR INC BX ; ADVANCE DISK BUFFER POINTER MOV DSKPTR,BX ; STORE MOV AX,DSKCNT ; LOAD DISK BUFFER COUNTER INC AX ; ADVANCE MOV DSKCNT,AX ; STORE DISS55: MOV CX,DSKCNT ; LOAD DISK BUFFER COUNTER MOV BX,OFFSET DSKBUF; POINT TO DISK BUFFER DISS56: MOV CH,0 ; CLEAR CHARACTER COUNTER DISS57: MOV AL,[BX] ; LOAD NEXT CHARACTER INC BX ; ADVANCE DISK BUFFER POINTER INC CH ; ADVANCE CHARACTER COUNTER DEC CL ; LAST CHARACTER? JZ DISS58 ; YES - DECIDE WHETHER ONE OR TWO TABS CMP AL,TAB ; NO - TAB? JZ DISS56 ; YES - CLEAR CHARACTER COUNTER JMP DISS57 ; NO - TEST NEXT CHARACTER DISS58: MOV BX,DSKPTR ; LOAD DISK BUFFER POINTER MOV AL,8 ; CMP AL,CH ; LESS THAN EIGHT CHARACTERS SINCE LAST TAB? JBE DISS61 ; NO - WRITE ONE TAB TO DISK BUFFER MOV BYTE PTR[BX],TAB; WRITE TAB TO DISK BUFFER INC BX ; ADVANCE DISK BUFFER POINTER INC DSKCNT ; ADVANCE DISK BUFFER COUNTER DISS61: MOV BYTE PTR[BX],TAB; WRITE TAB TO DISK BUFFER INC BX ; ADVANCE DISK BUFFER POINTER MOV BYTE PTR[BX],';'; WRITE ";" TO DISK BUFFER INC BX ; ADVANCE DISK BUFFER POINTER MOV BYTE PTR[BX],' '; WRITE " " TO DISK BUFFER INC BX ; ADVANCE DISK BUFFER POINTER MOV DSKPTR,BX ; STORE MOV DX,CURADD ; LOAD CURRENT ADDRESS MOV AL,DH ; LOAD HIGH ADDRESS CALL EXPAND ; WRITE TO DISK BUFFER MOV AL,DL ; LOAD LOW ADDRESS CALL EXPAND ; WRITE TO DISK BUFFER MOV BYTE PTR[BX],CR ; WRITE <CR> TO DISK BUFFER INC BX ; ADVANCE DISK BUFFER POINTER MOV BYTE PTR[BX],LF ; WRITE LINE FEED TO DISK BUFFER ADD DSKCNT,5 ; ADD TAB AND TERMINATOR COUNT DISKWR DSKCNT ; WRITE TO DISK FILE - ERROR? CMP AX,DSKCNT ; NO - ALL BYTES WRITTEN? JZ DISS59 ; YES - CONTINUE MOV AX,0 ; NO - LOAD ERROR NUMBER JMP DSKERR ; DISPLAY ERROR DISS59: JMP DISS05 ; CONTINUE DISS60: MOV BX,OFFSET MSGEND; POINT TO "END" STRING MOV DI,OFFSET DSKBUF; POINT TO DISK BUFFER MOV CX,LENEND ; LOAD MESSAGE LENGTH DISS65: MOV AL,[BX] ; LOAD FROM STRING MOV [DI],AL ; WRITE TO DISK BUFFER INC BX ; ADVANCE STRING POINTER INC DI ; ADVANCE DISK BUFFER POINTER DEC CX ; RETARD COUNTER - DONE? JNZ DISS65 ; NO - CONTINUE DISKWR LENEND ; YES - WRITE TO DISK - ERROR? CMP AX,LENEND ; NO - ALL BYTES WRITTEN? JZ DISS70 ; YES - DONE MOV AX,0 ; NO - LOAD ERROR NUMBER JMP DSKERR ; NO - DISPLAY ERROR DISS70: RET ; DONE DISS ENDP ; PAGE ; **************************************************************** ; ** ** ; ** CLOSE OUTPUT FILE ** ; ** ** ; **************************************************************** CLOSWR PROC NEAR ; MOV AH,CLOSE ; LOAD CLOSE FILE COMMAND MOV BX,WRHAND ; LOAD OUTPUT FILE HANDLE INT DOSFUNC ; CLOSE THE OUTPUT FILE - ERROR? JNC CLOS05 ; NO - DONE JMP DSKERR ; YES - DISPLAY ERROR CLOS05: RET ; CLOSWR ENDP PAGE SBRS PROC NEAR ; ; **************************************************************** ; ** ** ; ** SUBROUTINES ** ; ** ** ; **************************************************************** ; **************************************************************** ; ** FUNCTION: CONVERT ASCII TO HEXADECIMAL ** ; ** ENTRY: ASCII REPRESENTATION OF VALID HEX NUMBER IN AL ** ; ** USES: AL ** ; ** EXIT: HEX NUMBER IN AL ** ; ** CALLS: NONE ** ; **************************************************************** ASCHEX: CMP AL,'9'+1 ; IS IT LESS THAN OR EQUAL TO 9? JLE ASC05 ; YES - JUMP PAST HEX CONVERSION ADD AL,9 ; NO - ADD HEX OFFSET ASC05: AND AL,0FH ; STRIP ASCII BIAS RET ; PAGE ; **************************************************************** ; ** FUNCTION: CONVERT 8 BIT VALUE TO TWO ASCII CHARACTERS ** ; ** AND WRITE THEM TO MEMORY POINTED TO BY DSKPTR ** ; ** ENTRY: A=8 BIT VALUE TO BE CONVERTED ** ; ** USES: BX ** ; ** EXIT: BX=END VALUE OF DSKPTR ** ; ** CALLS: HEXASC ** ; **************************************************************** EXPAND: PUSHF ; PUSH AX ; PUSH CX ; PUSH AX ; SAVE BYTE TO BE EXPANDED MOV CL,4 ; ROL AL,CL ; EXCHANGE NIBBLES CALL HEXASC ; CONVERT HEX TO ASCII MOV BX,DSKPTR ; LOAD DISK BUFFER POINTER MOV [BX],AL ; WRITE TO MEMORY INC BX ; ADVANCE MEMORY POINTER POP AX ; RESTORE ORIGINAL BYTE CALL HEXASC ; CONVERT HEX TO ASCII MOV [BX],AL ; WRITE TO MEMORY INC BX ; ADVANCE MEMORY POINTER MOV DSKPTR,BX ; STORE NEW DISK BUFFER POINTER MOV AX,DSKCNT ; LOAD DISK BUFFER COUNTER INC AX ; INC AX ; ADVANCE MOV DSKCNT,AX ; STORE POP CX ; POP AX ; POPF ; RET ; ; **************************************************************** ; ** FUNCTION: CONVERT 4 BIT VALUE TO ASCII ** ; ** ENTRY: LOWER NIBBLE OF A=VALUE TO BE CONVERTED ** ; ** USES: AL ** ; ** EXIT: A=ASCII CHARACTER ** ; ** CALLS: NONE ** ; **************************************************************** HEXASC: AND AL,0FH ; ISOLATE LOWER NIBBLE CMP AL,9+1 ; IS IT LESS THAN OR EQUAL TO 9? JL HXAS05 ; YES - JUMP PAST HEX CONVERSION SUB AL,9 ; NO - SUBTRACT HEX OFFSET OR AL,40H ; COMBINE WITH HEX ASCII BIAS RET ; HXAS05: OR AL,30H ; COMBINE WITH DECIMAL ASCII BIAS RET ; PAGE ; **************************************************************** ; ** FUNCTION: WRITE MESSAGE TO STANDARD OUTPUT ** ; ** ENTRY: DX=START ADDRESS OF MESSAGE STRING ** ; ** USES: ??? ** ; ** EXIT: NONE ** ; ** CALLS: NONE ** ; **************************************************************** MSGCO: MOV AH,PR_STR ; LOAD PRINT STRING COMMAND INT DOSFUNC ; PRINT STRING RET ; DONE PAGE ; **************************************************************** ; ** FUNCTION: COMPUTE NUMBER OF BYTES FOR OP-CODES ** ; ** ENTRY: CX=OPCODE ** ; ** USES: CL ** ; ** EXIT: NUMBER OF BYTES IN CL ** ; ** CALLS: NONE ** ; **************************************************************** OPBYTE: PUSHF ; SAVE FLAGS PUSH AX ; SAVE AX PUSH CX ; SAVE CX PUSH BX ; SAVE BX MOV AL,CL ; LOAD OP-CODE CMP AL,40H ; LESS THAN 40H? JC OPB10 ; YES - LOOK UP NUMBER OF BYTES CMP AL,0C0H ; NO - GREATER THAN OR EQUAL TO C0H? JNC OPB05 ; YES - ADJUST OP-CODE MOV AL,01 ; NO - NUMBER OF BYTES IS 1 JMP OPB25 ; DONE OPB05: MOV AL,80H ; ADD AL,CL ; ADJUST OP-CODE MOV CL,AL ; STORE OPB10: AND AL,03H ; ROL AL,1 ; COMPUTE NUMBER OF SHIFTS PUSH AX ; STORE MOV AL,CL ; LOAD OP-CODE AND AL,0FCH ; ROR AL,1 ; ROR AL,1 ; DIVIDE BY 4 MOV CL,AL ; STORE MOV BX,OFFSET BYTES ; POINT TO BYTES TABLE ADD BX,CX ; ADD OFFSET MOV CL,[BX] ; LOAD NUMBER OF BYTES POP AX ; LOAD NUMBER OF SHIFTS MOV CH,AL ; STORE INC CH ; ADJUST MOV AL,CL ; LOAD NUMBER OF BYTES OPB15: DEC CH ; DONE? JZ OPB20 ; YES - ISOLATE NUMBER OF BYTES ROR AL,1 ; NO - SHIFT JMP OPB15 ; CONTINUE OPB20: AND AL,03H ; ISOLATE NUMBER OF BYTES OPB25: POP BX ; RESTORE BX POP CX ; RESTORE CX MOV CL,AL ; LOAD NUMBER OF BYTES IN C POP AX ; RESTORE A POPF ; RESTORE FLAGS RET ; ; **************************************************************** ; ** FUNCTION: WRITE ORG STRING TO DISK ** ; ** ENTRY: NONE ** ; ** USES: ALL ** ; ** EXIT: ORG STRING WRITTEN TO DISK ** ; ** CALLS: EXPAND ** ; **************************************************************** ORGWR: MOV DSKCNT,0 ; CLEAR DISK BUFFER COUNTER MOV CX,LENORG ; LOAD "ORG" MESSAGE LENGTH MOV DI,OFFSET MSGORG; POINT TO "ORG" STRING MOV BX,OFFSET DSKBUF; POINT TO DISK BUFFER ORGW05: MOV AL,[DI] ; LOAD NEXT CHARACTER OF "ORG" STRING MOV [BX],AL ; WRITE IT TO DISK BUFFER INC DI ; INC BX ; ADVANCE POINTERS INC DSKCNT ; ADVANCE DISK BUFFER COUNTER DEC CX ; DECREMENT COUNTER - DONE? JNZ ORGW05 ; NO - CONTINUE MOV DSKPTR,BX ; YES - STORE DISK BUFFER POINTER MOV DX,OFFSET MEMBUF; LOAD MEMORY BUFFER ADDRESS MOV BX,MEMPTR ; LOAD MEMORY BUFFER POINTER MOV AL,BL ; LOAD LOW MEMORY BUFFER POINTER SUB AL,DL ; COMPUTE LOW ORG ADDRESS PUSH AX ; STORE MOV AL,BH ; LOAD HIGH MEMORY BUFFER POINTER SBB AL,DH ; COMPUTE HIGH ORG ADDRESS CALL EXPAND ; WRITE TO DISK BUFFER POP AX ; LOAD LOW ORG ADDRESS CALL EXPAND ; WRITE TO DISK BUFFER MOV BYTE PTR[BX],'H'; WRITE HEX INDICATOR TO DISK BUFFER INC BX ; ADVANCE POINTER MOV BYTE PTR[BX],CR ; WRITE <CR> TO DISK BUFFER INC BX ; ADVANCE POINTER MOV BYTE PTR[BX],LF ; WRITE LINE FEED TO DISK BUFFER ADD DSKCNT,3 ; ADJUST DISK BUFFER COUNTER DISKWR DSKCNT ; WRITE DKSCNT BYTES TO DISK - ERROR? CMP AX,DSKCNT ; NO - ALL BYTES WRITTEN? JZ ORGW10 ; YES - DONE POP AX ; NO - RESTORE STACK MOV AX,0 ; LOAD ERROR NUMBER JMP DSKERR ; DISPLAY ERROR ORGW10: RET ; DONE ; **************************************************************** ; ** FUNCTION: CONVERT TWO ASCII CHARACTERS TO 8 BIT NUMBER ** ; ** ENTRY: BX=START ADDRESS OF VALID ASCII HEX CHARACTERS ** ; ** USES: AL, BX ** ; ** EXIT: A;=8 BIT NUMBER, BX=BX+2 ** ; ** CALLS: ASCHEX ** ; **************************************************************** PACK: PUSH CX ; SAVE CX MOV AL,[BX] ; LOAD CHARACTER CALL ASCHEX ; CONVERT ASCII CHARACTER TO HEX MOV CL,4 ; ROL AL,CL ; EXCHANGE NIBBLES MOV CH,AL ; STORE INC BX ; POINT TO NEXT CHARACTER MOV AL,[BX] ; LOAD NEXT CHARACTER CALL ASCHEX ; CONVERT ASCII CHARACTER TO HEX OR AL,CH ; COMBINE NIBBLES INC BX ; POINT TO NEXT CHARACTER ADD CHKACC,AL ; UPDATE CHECKSUM ACCUMULATOR POP CX ; RESTORE CX RET ; SBRS ENDP ; PAGE ERRHAN PROC FAR ; **************************************************************** ; ** ** ; ** DISK ERROR HANDLER ** ; ** ** ; **************************************************************** DSKERR: MOV DX,OFFSET MDISK0; POINT TO DISK ERROR MESSAGE 0 OR AX,AX ; ERROR 0? JZ MISERR ; YES - DISPLAY ERROR MESSAGE MOV DX,OFFSET MDISK1; NO - POINT TO DISK ERROR MESSAGE 1 DEC AX ; ERROR 1? JZ MISERR ; YES - DISPLAY ERROR MESSAGE MOV DX,OFFSET MDISK2; NO - POINT TO DISK ERROR MESSAGE 2 DEC AX ; ERROR 2? JZ MISERR ; YES - DISPLAY ERROR MESSAGE MOV DX,OFFSET MDISK3; NO - POINT TO DISK ERROR MESSAGE 3 DEC AX ; ERROR 3? JZ MISERR ; YES - DISPLAY ERROR MESSAGE MOV DX,OFFSET MDISK4; NO - POINT TO DISK ERROR MESSAGE 4 DEC AX ; ERROR 4? JZ MISERR ; YES - DISPLAY ERROR MESSAGE MOV DX,OFFSET MDISK5; NO - POINT TO DISK ERROR MESSAGE 5 DEC AX ; ERROR 5? JZ MISERR ; YES - DISPLAY ERROR MESSAGE MOV DX,OFFSET MDISK6; NO - POINT TO DISK ERROR MESSAGE 6 DEC AX ; ERROR 6? JZ MISERR ; YES - DISPLAY ERROR MESSAGE MOV DX,OFFSET MUKNOW; NO - POINT TO UNKNOWN DISK ERROR MESSAGE JMP MISERR ; DISPLAY ERROR MESSAGE ; **************************************************************** ; ** ** ; ** MISCELANEOUS ERROR HANDLER ** ; ** ** ; **************************************************************** MISERR: CALL MSGCO ; WRITE MESSAGE TO STANDARD OUTPUT POP AX ; RESTORE STACK RET ; RETURN TO DOS ERRHAN ENDP ; CODE ENDS ; END DASM80 ;