TITLE DEBUGger for MS-DOS
; DEBUG-86 8086 debugger runs under 86-DOS version 2.30
;
; Modified 5/4/82 by AaronR to do all I/O direct to devices
; Runs on MS-DOS 1.28 and above
; REV 1.20
; Tab expansion
; New device interface (1.29 and above)
; REV 2.0
; line by line assembler added by C. Peters
; REV 2.1
; Uses EXEC system call
; REV 2.2
; Ztrace mode by zibo.
; Fix dump display to indent properly
; Parity nonsense by zibo
;
; REV 2.3
; Split into seperate modules to allow for
; assembly on an IBM PC
;
.xlist
.xcref
INCLUDE DEBEQU.ASM
INCLUDE DOSSYM.ASM
.cref
.list
IF SYSVER
; Structure for system call 72
SYSINITVAR STRUC
DPBHEAD DD ? ; Pointer to head of DPB-FAT list
sft_addr DD ? ; Pointer to first FCB table
; The following address points to the CLOCK device
BCLOCK DD ?
; The following address is used by DISKSTATCHK it is always
; points to the console input device header
BCON DD ? ; Console device entry points
NUMIO DB 0 ; Number of disk tables
MAXSEC DW 0 ; Maximum allowed sector size
BUFFHEAD DD ?
DEVHEAD DD ?
SYSINITVAR ENDS
ENDIF
CODE SEGMENT PUBLIC 'CODE'
CODE ENDS
CONST SEGMENT PUBLIC BYTE
EXTRN USER_PROC_PDB:WORD,STACK:BYTE,CSSAVE:WORD,DSSAVE:WORD
EXTRN SPSAVE:WORD,IPSAVE:WORD,LINEBUF:BYTE,QFLAG:BYTE
EXTRN NEWEXEC:BYTE,HEADSAVE:WORD,LBUFSIZ:BYTE,BACMES:BYTE
EXTRN BADVER:BYTE,ENDMES:BYTE,CARRET:BYTE,ParityMes:BYTE
IF IBMVER
EXTRN DSIZ:BYTE,NOREGL:BYTE,DISPB:WORD
ENDIF
IF SYSVER
EXTRN CONFCB:BYTE,POUT:DWORD,COUT:DWORD,CIN:DWORD,IOBUFF:BYTE
EXTRN IOADDR:DWORD,IOCALL:BYTE,IOCOM:BYTE,IOSTAT:WORD,IOCNT:WORD
EXTRN IOSEG:WORD,COLPOS:BYTE,BADDEV:BYTE,BADLSTMES:BYTE
EXTRN LBUFFCNT:BYTE,PFLAG:BYTE
ENDIF
CONST ENDS
DATA SEGMENT PUBLIC BYTE
EXTRN PARSERR:BYTE,DATAEND:WORD,ParityFlag:BYTE,DISADD:BYTE
EXTRN ASMADD:BYTE,DEFDUMP:BYTE,BYTEBUF:BYTE
DATA ENDS
DG GROUP CODE,CONST,DATA
CODE SEGMENT PUBLIC 'CODE'
ASSUME CS:DG,DS:DG,ES:DG,SS:DG
PUBLIC RESTART,SET_TERMINATE_VECTOR,DABORT,TERMINATE,COMMAND
PUBLIC FIND_DEBUG,CRLF,BLANK,TAB,OUT,INBUF,SCANB,SCANP
PUBLIC PRINTMES,RPRBUF,HEX,OUTSI,OUTDI,OUT16,DIGIT,BACKUP,RBUFIN
IF SYSVER
PUBLIC SETUDEV,DEVIOCALL
EXTRN DISPREG:NEAR,IN:NEAR
ENDIF
EXTRN PERR:NEAR,COMPARE:NEAR,DUMP:NEAR,ENTER:NEAR,FILL:NEAR
EXTRN GO:NEAR,INPUT:NEAR,LOAD:NEAR,MOVE:NEAR,NAME:NEAR
EXTRN REG:NEAR,SEARCH:NEAR,DWRITE:NEAR,UNASSEM:NEAR,ASSEM:NEAR
EXTRN OUTPUT:NEAR,ZTRACE:NEAR,TRACE:NEAR,GETHEX:NEAR,GETEOL:NEAR
EXTRN PREPNAME:NEAR,DEFIO:NEAR,SKIP_FILE:NEAR,DEBUG_FOUND:NEAR
EXTRN TrapParity:NEAR,ReleaseParity:NEAR
ORG 100H
START:
DEBUG:
JMP SHORT DSTRT
HEADER DB "Vers 2.30"
DSTRT:
DOSVER_HIGH EQU 0200H ; 2.00 in hex
MOV AH,GET_VERSION
INT 21H
XCHG AH,AL ; Turn it around to AH.AL
CMP AX,DOSVER_HIGH
JAE OKDOS
GOTBADDOS:
MOV DX,OFFSET DG:BADVER
MOV AH,STD_CON_STRING_OUTPUT
INT 21H
INT 20H
OKDOS:
CALL TrapParity ; scarf up those parity guys
MOV AH,GET_CURRENT_PDB
INT 21H
MOV [USER_PROC_PDB],BX ; Initially set to DEBUG
IF SYSVER
MOV [IOSEG],CS
ENDIF
MOV SP,OFFSET DG:STACK
MOV [PARSERR],AL
MOV AH,GET_IN_VARS
INT 21H
IF SYSVER
LDS SI,ES:[BX.BCON]
MOV WORD PTR CS:[CIN+2],DS
MOV WORD PTR CS:[CIN],SI
MOV WORD PTR CS:[COUT+2],DS
MOV WORD PTR CS:[COUT],SI
PUSH CS
POP DS
MOV DX,OFFSET DG:CONFCB
MOV AH,FCB_OPEN
INT 21H
OR AL,AL
JZ GOTLIST
MOV DX,OFFSET DG:BADLSTMES
CALL RPRBUF
CALL RBUFIN
CALL CRLF
MOV CL,[LBUFFCNT]
OR CL,CL
JZ NOLIST1 ; User didn't specify one
XOR CH,CH
MOV DI,OFFSET DG:(CONFCB + 1)
MOV SI,OFFSET DG:LINEBUF
REP MOVSB
MOV DX,OFFSET DG:CONFCB
MOV AH,FCB_OPEN
INT 21H
OR AL,AL
JZ GOTLIST ; GOOD
MOV DX,OFFSET DG:BADDEV
CALL RPRBUF
NOLIST1:
MOV WORD PTR [POUT+2],CS
MOV WORD PTR [POUT],OFFSET DG:LONGRET
JMP NOLIST
XXX PROC FAR
LONGRET:RET
XXX ENDP
ENDIF
GOTLIST:
IF SYSVER
MOV SI,DX
LDS SI,DWORD PTR DS:[SI.fcb_FIRCLUS]
MOV WORD PTR CS:[POUT+2],DS
MOV WORD PTR CS:[POUT],SI
ENDIF
NOLIST:
MOV AX,CS
MOV DS,AX
MOV ES,AX
; Code to print header
; MOV DX,OFFSET DG:HEADER
; CALL RPRBUF
CALL SET_TERMINATE_VECTOR
IF SETCNTC
MOV AL,23H ; Set vector 23H
MOV DX,OFFSET DG:DABORT
INT 21H
ENDIF
MOV DX,CS ; Get DEBUG's segment
MOV AX,OFFSET DG:DATAEND + 15 ; End of debug
SHR AX,1 ; Convert to segments
SHR AX,1
SHR AX,1
SHR AX,1
ADD DX,AX ; Add siz of debug in paragraphs
MOV AH,CREATE_PROCESS_DATA_BLOCK ; create program segment just after DEBUG
INT 21H
MOV AX,DX
MOV DI,OFFSET DG:DSSAVE
CLD
STOSW
STOSW
STOSW
STOSW
MOV WORD PTR [DISADD+2],AX
MOV WORD PTR [ASMADD+2],AX
MOV WORD PTR [DEFDUMP+2],AX
MOV AX,100H
MOV WORD PTR[DISADD],AX
MOV WORD PTR[ASMADD],AX
MOV WORD PTR [DEFDUMP],AX
MOV DS,DX
MOV ES,DX
MOV DX,80H
MOV AH,SET_DMA
INT 21H ; Set default DMA address to 80H
MOV AX,WORD PTR DS:[6]
MOV BX,AX
CMP AX,0FFF0H
PUSH CS
POP DS
JAE SAVSTK
MOV AX,WORD PTR DS:[6]
PUSH BX
MOV BX,OFFSET DG:DATAEND + 15
AND BX,0FFF0H ; Size of DEBUG in bytes (rounded up to PARA)
SUB AX,BX
POP BX
SAVSTK:
PUSH BX
DEC AX
DEC AX
MOV BX,AX
MOV WORD PTR [BX],0
POP BX
MOV SPSAVE,AX
DEC AH
MOV ES:WORD PTR [6],AX
SUB BX,AX
MOV CL,4
SHR BX,CL
ADD ES:WORD PTR [8],BX
IF IBMVER
; Get screen size and initialize display related variables
MOV AH,15
INT 10H
CMP AH,40
JNZ PARSCHK
MOV BYTE PTR DSIZ,7
MOV BYTE PTR NOREGL,4
MOV DISPB,64
ENDIF
PARSCHK:
; Copy rest of command line to test program's parameter area
MOV DI,FCB
MOV SI,81H
MOV AX,(PARSE_FILE_DESCRIPTOR SHL 8) OR 01H
INT 21H
CALL SKIP_FILE ; Make sure si points to delimiter
CALL PREPNAME
PUSH CS
POP ES
FILECHK:
MOV DI,80H
CMP BYTE PTR ES:[DI],0 ; ANY STUFF FOUND?
JZ COMMAND ; NOPE
FILOOP: INC DI
CMP BYTE PTR ES:[DI],13 ; COMMAND LINE JUST SPACES?
JZ COMMAND
CMP BYTE PTR ES:[DI]," "
JZ FILOOP
CMP BYTE PTR ES:[DI],9
JZ FILOOP
CALL DEFIO ; WELL READ IT IN
MOV AX,CSSAVE
MOV WORD PTR DISADD+2,AX
MOV WORD PTR ASMADD+2,AX
MOV AX,IPSAVE
MOV WORD PTR DISADD,AX
MOV WORD PTR ASMADD,AX
COMMAND:
CLD
MOV AX,CS
MOV DS,AX
MOV ES,AX
MOV SS,AX
MOV SP,OFFSET DG:STACK
STI
CMP [ParityFlag],0 ; did we detect a parity error?
JZ GoPrompt ; nope, go prompt
MOV [ParityFlag],0 ; reset flag
MOV DX,OFFSET DG:ParityMes ; message to print
MOV AH,STD_CON_STRING_OUTPUT; easy way out
INT 21h ; blam
GoPrompt:
MOV AL,PROMPT
CALL OUT
CALL INBUF ; Get command line
; From now and throughout command line processing, DI points
; to next character in command line to be processed.
CALL SCANB ; Scan off leading blanks
JZ COMMAND ; Null command?
LODSB ; AL=first non-blank character
; Prepare command letter for table lookup
SUB AL,"A" ; Low end range check
JB ERR1
CMP AL,"Z"-"A" ; Upper end range check
JA ERR1
SHL AL,1 ; Times two
CBW ; Now a 16-bit quantity
XCHG BX,AX ; In BX we can address with it
CALL CS:[BX+COMTAB] ; Execute command
JMP SHORT COMMAND ; Get next command
ERR1: JMP PERR
SET_TERMINATE_VECTOR:
MOV AX,(SET_INTERRUPT_VECTOR SHL 8) OR 22H ; Set vector 22H
MOV DX,OFFSET DG:TERMINATE
INT 21H
RET
TERMINATE:
CMP BYTE PTR CS:[QFLAG],0
JNZ QUITING
MOV CS:[USER_PROC_PDB],CS
CMP BYTE PTR CS:[NEWEXEC],0
JZ NORMTERM
MOV AX,CS
MOV DS,AX
MOV SS,AX
MOV SP,OFFSET DG:STACK
MOV AX,[HEADSAVE]
JMP DEBUG_FOUND
NORMTERM:
MOV DX,OFFSET DG:ENDMES
JMP SHORT RESTART
QUITING:
MOV AX,(EXIT SHL 8)
INT 21H
DABORT:
MOV DX,OFFSET DG:CARRET
RESTART:
MOV AX,CS
MOV DS,AX
MOV SS,AX
MOV SP,OFFSET DG:STACK
CALL RPRBUF
JMP COMMAND
IF SYSVER
SETUDEV:
MOV DI,OFFSET DG:CONFCB
MOV AX,(PARSE_FILE_DESCRIPTOR SHL 8) OR 01H
INT 21H
CALL USERDEV
JMP DISPREG
USERDEV:
MOV DX,OFFSET DG:CONFCB
MOV AH,FCB_OPEN
INT 21H
OR AL,AL
JNZ OPENERR
MOV SI,DX
TEST BYTE PTR [SI.fcb_DEVID],080H ; Device?
JZ OPENERR ; NO
LDS SI,DWORD PTR [CONFCB.fcb_FIRCLUS]
MOV WORD PTR CS:[CIN],SI
MOV WORD PTR CS:[CIN+2],DS
MOV WORD PTR CS:[COUT],SI
MOV WORD PTR CS:[COUT+2],DS
PUSH CS
POP DS
RET
OPENERR:
MOV DX,OFFSET DG:BADDEV
CALL RPRBUF
RET
ENDIF
; Get input line. Convert all characters NOT in quotes to upper case.
INBUF:
CALL RBUFIN
MOV SI,OFFSET DG:LINEBUF
MOV DI,OFFSET DG:BYTEBUF
CASECHK:
LODSB
CMP AL,'a'
JB NOCONV
CMP AL,'z'
JA NOCONV
ADD AL,"A"-"a" ; Convert to upper case
NOCONV:
STOSB
CMP AL,13
JZ INDONE
CMP AL,'"'
JZ QUOTSCAN
CMP AL,"'"
JNZ CASECHK
QUOTSCAN:
MOV AH,AL
KILLSTR:
LODSB
STOSB
CMP AL,13
JZ INDONE
CMP AL,AH
JNZ KILLSTR
JMP SHORT CASECHK
INDONE:
MOV SI,OFFSET DG:BYTEBUF
; Output CR/LF sequence
CRLF:
MOV AL,13
CALL OUT
MOV AL,10
JMP OUT
; Physical backspace - blank, backspace, blank
BACKUP:
MOV SI,OFFSET DG:BACMES
; Print ASCII message. Last char has bit 7 set
PRINTMES:
LODS CS:BYTE PTR [SI] ; Get char to print
CALL OUT
SHL AL,1 ; High bit set?
JNC PRINTMES
RET
; Scan for parameters of a command
SCANP:
CALL SCANB ; Get first non-blank
CMP BYTE PTR [SI],"," ; One comma between params OK
JNE EOLCHK ; If not comma, we found param
INC SI ; Skip over comma
; Scan command line for next non-blank character
SCANB:
PUSH AX
SCANNEXT:
LODSB
CMP AL," "
JZ SCANNEXT
CMP AL,9
JZ SCANNEXT
DEC SI ; Back to first non-blank
POP AX
EOLCHK:
CMP BYTE PTR [SI],13
RET
; Hex addition and subtraction
HEXADD:
MOV CX,4
CALL GETHEX
MOV DI,DX
MOV CX,4
CALL GETHEX
CALL GETEOL
PUSH DX
ADD DX,DI
CALL OUT16
CALL BLANK
CALL BLANK
POP DX
SUB DI,DX
MOV DX,DI
CALL OUT16
JMP SHORT CRLF
; Print the hex address of DS:SI
OUTSI:
MOV DX,DS ; Put DS where we can work with it
CALL OUT16 ; Display segment
MOV AL,":"
CALL OUT
MOV DX,SI
JMP SHORT OUT16 ; Output displacement
; Print hex address of ES:DI
; Same as OUTSI above
OUTDI:
MOV DX,ES
CALL OUT16
MOV AL,":"
CALL OUT
MOV DX,DI
; Print out 16-bit value in DX in hex
OUT16:
MOV AL,DH ; High-order byte first
CALL HEX
MOV AL,DL ; Then low-order byte
; Output byte in AL as two hex digits
HEX:
MOV AH,AL ; Save for second digit
; Shift high digit into low 4 bits
PUSH CX
MOV CL,4
SHR AL,CL
POP CX
CALL DIGIT ; Output first digit
MOV AL,AH ; Now do digit saved in AH
DIGIT:
AND AL,0FH ; Mask to 4 bits
; Trick 6-byte hex conversion works on 8086 too.
ADD AL,90H
DAA
ADC AL,40H
DAA
; Console output of character in AL. No registers affected but bit 7
; is reset before output.
IF SYSVER
OUT:
PUSH AX
AND AL,7FH
CMP AL,7FH
JNZ NOTDEL
MOV AL,8 ; DELETE same as backspace
NOTDEL:
CMP AL,9
JZ TABDO
CALL DOCONOUT
CMP AL,0DH
JZ ZEROPOS
CMP AL,0AH
JZ ZEROPOS
CMP AL,8
JNZ OOKRET
MOV AL," "
CALL DOCONOUT
MOV AL,8
CALL DOCONOUT
CMP BYTE PTR CS:[COLPOS],0
JZ NOTINC
DEC BYTE PTR CS:[COLPOS]
JMP NOTINC
ZEROPOS:
MOV BYTE PTR CS:[COLPOS],0FFH
OOKRET:
INC BYTE PTR CS:[COLPOS]
NOTINC:
TEST BYTE PTR CS:[PFLAG],1
JZ POPRET
CALL LISTOUT
POPRET:
POP AX
RET
TABDO:
MOV AL,CS:[COLPOS]
OR AL,0F8H
NEG AL
PUSH CX
MOV CL,AL
XOR CH,CH
JCXZ POPTAB
TABLP:
MOV AL," "
CALL OUT
LOOP TABLP
POPTAB:
POP CX
POP AX
RET
DOCONOUT:
PUSH DS
PUSH SI
PUSH AX
CONOWAIT:
LDS SI,CS:[COUT]
MOV AH,10
CALL DEVIOCALL
MOV AX,CS:[IOSTAT]
AND AX,200H
JNZ CONOWAIT
POP AX
PUSH AX
MOV AH,8
CALL DEVIOCALL
POP AX
POP SI
POP DS
RET
LISTOUT:
PUSH DS
PUSH SI
PUSH AX
LISTWAIT:
LDS SI,CS:[POUT]
MOV AH,10
CALL DEVIOCALL
MOV AX,CS:[IOSTAT]
AND AX,200H
JNZ LISTWAIT
POP AX
PUSH AX
MOV AH,8
CALL DEVIOCALL
POP AX
POP SI
POP DS
RET
DEVIOCALL:
PUSH ES
PUSH BX
PUSH CS
POP ES
MOV BX,OFFSET DG:IOCALL
MOV CS:[IOCOM],AH
MOV WORD PTR CS:[IOSTAT],0
MOV WORD PTR CS:[IOCNT],1
MOV CS:[IOBUFF],AL
MOV WORD PTR CS:[IOADDR+2],DS
MOV AX,[SI+6]
MOV WORD PTR CS:[IOADDR],AX
CALL DWORD PTR CS:[IOADDR]
MOV AX,[SI+8]
MOV WORD PTR CS:[IOADDR],AX
CALL DWORD PTR CS:[IOADDR]
MOV AL,CS:[IOBUFF]
POP BX
POP ES
RET
ELSE
OUT:
PUSH DX
PUSH AX
AND AL,7FH
MOV DL,AL
MOV AH,2
INT 21H
POP AX
POP DX
RET
ENDIF
IF SYSVER
RBUFIN:
PUSH AX
PUSH ES
PUSH DI
PUSH CS
POP ES
MOV BYTE PTR [LBUFFCNT],0
MOV DI,OFFSET DG:LINEBUF
FILLBUF:
CALL IN
CMP AL,0DH
JZ BDONE
CMP AL,8
JZ ECHR
CMP AL,7FH
JZ ECHR
CMP BYTE PTR [LBUFFCNT],BUFLEN
JAE BFULL
STOSB
INC BYTE PTR [LBUFFCNT]
JMP SHORT FILLBUF
BDONE:
STOSB
POP DI
POP ES
POP AX
RET
BFULL:
MOV AL,8
CALL OUT
MOV AL,7
CALL OUT
JMP SHORT FILLBUF
ECHR:
CMP DI,OFFSET DG:LINEBUF
JZ FILLBUF
DEC DI
DEC BYTE PTR [LBUFFCNT]
JMP SHORT FILLBUF
ELSE
RBUFIN:
PUSH AX
PUSH DX
MOV AH,10
MOV DX,OFFSET DG:LBUFSIZ
INT 21H
POP DX
POP AX
RET
ENDIF
IF SYSVER
RPRBUF:
PUSHF
PUSH AX
PUSH SI
MOV SI,DX
PLOOP:
LODSB
CMP AL,"$"
JZ PRTDONE
CALL OUT
JMP SHORT PLOOP
PRTDONE:
POP SI
POP AX
POPF
RET
ELSE
RPRBUF:
MOV AH,9
INT 21H
RET
ENDIF
; Output one space
BLANK:
MOV AL," "
JMP OUT
; Output the number of blanks in CX
TAB:
CALL BLANK
LOOP TAB
RET
; Command Table. Command letter indexes into table to get
; address of command. PERR prints error for no such command.
COMTAB DW ASSEM ; A
DW PERR ; B
DW COMPARE ; C
DW DUMP ; D
DW ENTER ; E
DW FILL ; F
DW GO ; G
DW HEXADD ; H
DW INPUT ; I
DW PERR ; J
DW PERR ; K
DW LOAD ; L
DW MOVE ; M
DW NAME ; N
DW OUTPUT ; O
IF ZIBO
DW ZTRACE
ELSE
DW PERR ; P
ENDIF
DW QUIT ; Q (QUIT)
DW REG ; R
DW SEARCH ; S
DW TRACE ; T
DW UNASSEM ; U
DW PERR ; V
DW DWRITE ; W
IF SYSVER
DW SETUDEV ; X
ELSE
DW PERR
ENDIF
DW PERR ; Y
DW PERR ; Z
QUIT:
INC BYTE PTR [QFLAG]
MOV BX,[USER_PROC_PDB]
FIND_DEBUG:
IF NOT SYSVER
MOV AH,SET_CURRENT_PDB
INT 21H
ENDIF
CALL ReleaseParity ; let system do normal parity stuff
MOV AX,(EXIT SHL 8)
INT 21H
CODE ENDS
END START
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