Programmer 7500

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Assembly Source File | 1984-03-04 | 21.4 KB | 485 lines

PAGE ,132 TITLE LOOK - LOOK AT MEMORY SUBTTL LOOK AT MEMORY IN ANY SEGMENT ; ; ;*****************************************************************************; ; ; ; JOHN R. PULLIAM VERSION 2/21/84 ; ; ; ; FOR COLUMBIA DATA PRODUCT COMPUTERS AND COMPATIBLES ; ; RELEASED TO PUBLIC DOMAIN ; ; ; ;*****************************************************************************; ; ; ; ; DOS CALL INT 21H FUNCTIONS USED ; ; ; AH = 01H => INPUT ONE CHARACTER FROM KEYBOARD ; AL = ASCII CHARACTER RECEIVED ; ; AH = 02H => DISPLAY ONE CHARACTER ON CRT ; DL = ASCII CHARACTER TO DISPLAY ; ; AH = 09H => DISPLAY MESSAGE ON CRT ; DS = SEGMENT OF MESSAGE ; DX = OFFSET ADDRESS OF MESSAGE ; ; AH = 0CH & ; AL = 0AH => CLEAR THEN FETCH KEYBOARD BUFFER ; DI = BUFFER FIRST WORD ADDRESS ; [DI] = NUMBER OF CHARACTERS WANTED TO INPUT ; [DI+1] = NUMBER OF CHARACTERS ACTUALLY RECEIVED ; [DI+2] = FIRST CHARACTER RECEIVED ; ; ; DOS INT 20H = TERMINATE PROGRAM AND RETURN TO DOS ; ; TO ASSEMBLE THIS PROGRAM: ; ; 1. PLACE THE SOURCE FILE, LOOK.ASM, IN DRIVE B ; ; 2. MASM B:LOOK,B:LOOK,B:LOOK,NUL.CRF ; ; 3. LINK B:LOOK,B:LOOK,NUL.MAP,NUL.LIB ; (THERE SHOULD BE 1 WARNING ERROR MESSAGE AFTER LINKING) ; ; 4. EXE2BIN B:LOOK,B:LOOK.COM ; ; 5. B:LOOK.OBJ AND B:LOOK.LST MAY BE DELETED IF DESIRED. ; ;*****************************************************************************; ; CSEG SEGMENT PARA PUBLIC ASSUME CS:CSEG,DS:CSEG,ES:CSEG ORG 100H ; DEFINE THE CONSTANTS CR EQU 13 ; CARRIAGE RETURN CODE LF EQU 10 ; LINE FEED CODE QT EQU 34 ; QUOTE MARK BYT EQU 16 ; NUMBER OF BYTES PER LINE LINES EQU 8 ; NUMBER OF LINES TO DISPLAY ; SET UP THE SEGMENT REGISTERS LOOK: MOV AX,CS ; GET CURRENT SEGMENT MOV DS,AX ; SET DS TO THIS SEG MOV ES,AX ; SET ES TO THIS SEG MOV WORD PTR SEGADD,AX ; INITIALIZE DISPLAY SEGMENT ; ASK IF ANOTHER SEGMENT IS DESIRED ASKSEG: MOV DX,OFFSET SEGMSG ;ADDRESS OF MESSAGE MOV AH,9 ; DISPLAY STRING FUNCTION INT 21H ; CALL DOS ; READ REPLY MOV AH,1 ; REQUEST "Y" OR "N" INT 21H ; GET KEY INPUT AND AL,0DFH ; ALLOW EITHER UPPER OR LOWER CASE CMP AL,'N' ; BRANCH TO GET STARTING ADD IF "N" JE DISPSEG CMP AL,'Y' ; REPEAT QUERY IF NOT "Y" JNE ASKSEG ; GET THE SEGMENT TO DISPLAY MEMORY FROM GETSEG: MOV DX,OFFSET SEGMSG2 ; ADDRESS OF MESSAGE MOV AH,9 ; DISPLAY STRING FUNCTION INT 21H ; CALL DOS ; READ DESIRED SEGMENT MOV AH,4 ; MAX NUMBER OF CHARACTERS WANTED MOV DI,OFFSET KBUFSZ ; KEYBOARD BUFFER CALL KYBD ; INPUT REPLY CMP AH,4 ; WANT 4 CHARS EXCLUDING THE CR JE CV1 ; SKIP IF NO LEADING ZEROS CALL INSERT ; INSERT LEADING ZEROS CV1: CALL CRLF ; OUTPUT CR AND LF ; CONVERT FOUR ASCII CODES INTO TWO HEX BYTES (FOUR HEX DIGITS) MOV AX,WORD PTR KBUF ; FIRST TWO ASCII CODES CALL ASC_HEX ; RETURNS ONE HEX BYTE JC GETSEG ; REPEAT QUERY IF ILLEGAL INPUT MOV SEGADD+1,AL ; STORE HIGH SEGMENT BYTE MOV AX,WORD PTR KBUF+2 ; THIRD AND FOURTH ASCII CODES CALL ASC_HEX ; RETURNS ONE HEX BYTE JC GETSEG ; REPEAT QUERY IF ILLEGAL INPUT MOV SEGADD,AL ; STORE LOW SEGMENT BYTE ; DISPLAY THE SEGMENT FROM WHICH DATA IS TO BE DISPLAYED DISPSEG: MOV AL,SEGADD+1 ; GET THE FIRST SEGMENT BYTE CALL HEX_ASC ; CONVERT TO ASCII MOV ASCSEG,AX ; SAVE FOR OUTPUT TO CRT MOV AL,SEGADD ; GET THE SECOND SEGMENT BYTE CALL HEX_ASC ; CONVERT IT TO ASCII TOO MOV ASCSEG+2,AX ; AND SAVE IT ALSO MOV DX,OFFSET SEGMSG3 ; ADDRESS OF MESSAGE MOV AH,9 ; DISPLAY STRING FUNCTION INT 21H ; CALL DOS MOV DX,OFFSET ASCSEG ; ADDRESS OF MESSAGE MOV AH,9 ; DISPLAY STRING FUNCTION INT 21H ; CALL DOS ; ASK FOR THE STARTING ADDRESS ASKADD: MOV DX,OFFSET STMSG ; ADDRESS OF MESSAGE MOV AH,9 ; DISPLAY STRING FUNCTION INT 21H ; CALL DOS ; READ REPLY MOV AH,4 ; MAX NUMBER OF CHARACTERS WANTED MOV DI,OFFSET KBUFSZ ; KEYBOARD BUFFER CALL KYBD ; INPUT REPLY CMP AH,4 ; WANT 4 CHARS EXCLUDING THE CR JE CV2 ; SKIP IF NO LEADING ZEROS CALL INSERT ; INSERT LEADING ZEROS CV2: CALL CRLF ; OUTPUT CR AND LF CALL CRLF ; OUTPUT CR AND LF ; CONVERT FOUR ASCII CODES INTO TWO HEX BYTES (FOUR HEX DIGITS) MOV AX,WORD PTR KBUF ; FIRST AND SECOND ASCII CODES CALL ASC_HEX ; RETURNS ONE HEX BYTE JC ASKADD ; REPEAT QUERY IF ILLEGAL INPUT MOV STADD+1,AL ; STORE HIGH ADDRESS BYTE MOV AX,WORD PTR KBUF+2 ; THIRD AND FOURTH ASCII CODES CALL ASC_HEX ; RETURNS ONE HEX BYTE JC ASKADD ; REPEAT QUERY IF ILLEGAL INPUT MOV STADD,AL ; STORE LOW ADDRESS BYTE MOV AX,WORD PTR STADD ; GET STARTING ADDRESS MOV SI,AX ; STARTING ADDRESS IN SI REGISTER CALL DISPLA ; DISPLAY MEMORY (AT LAST) ; ASK IF WE SHOULD REPEAT EMSG: MOV DX,OFFSET ENDMSG ; ADDRESS OF MESSAGE MOV AH,9 ; DISPLAY STRING FUNCTION INT 21H ; CALL DOS MOV AH,1 ; REQUEST "Y" OR "N" INT 21H ; GET KEY INPUT AND AL,0DFH ; ALLOW EITHER UPPER OR LOWER CASE CMP AL,'N' ; EXIT IF "N" JE EXIT CMP AL,'Y' ; REPEAT QUERY IF NOT "Y" JNE EMSG JMP ASKSEG ; LOOP TO START OVER EXIT: INT 20H ; RETURN TO DOS .XLIST SUBTTL MISCELLANEOUS CALLABLE ROUTINES PAGE + .LIST ; ; ; INSERT LEADING ZEROS INTO KEYBOARD INPUT BUFFER ; INSERT: MOV AL,4 ; NUMBER OF DIGITS IN NUMBER SUB AL,AH ; NUMBER OF LEADING ZEROS INS1: MOV DI,OFFSET KBUF+3 ; DESTINATION ADDRESS MOV SI,OFFSET KBUF+2 ; SOURCE ADDRESS MOV CX,3 ; LOOP COUNT INS2: MOV AH,[SI] ; MOVE ONE MOV [DI],AH ; CHARACTER DEC DI ; DEC POINTERS DEC SI LOOP INS2 ; SHIFT ALL DIGITS MOV AH,'0' ; ASCII ZERO MOV [DI],AH ; ADD LEADING ZERO DEC AL JNZ INS1 ; LOOP FOR EACH ZERO TO ADD ; ; WRITE CR LF TO CRT ; CRLF: MOV DX,OFFSET CRLFM ; ADDRESS OF 'CR,LF' MOV AH,9 INT 21H ; WRITE CR LF RET ; RETURN TO CONTINUE CRLFM DB CR,LF,'$' ; ; ; DISPLAY MEMORY ; ; SI REG = STARTING ADDRESS TO DISPLAY ; SEGADD = SEGMENT TO DISPLAY FROM ; STADD = OFFSET TO DISPLAY FROM ; ASCSEG = ASCII CODE OF SEGMENT ; ASCADD = ASCII CODE OF OFFSET ; ALL REGISTERS ARE ALTERED ; DISPLA: MOV DX,OFFSET SPACE ; SPACE CODES MOV AH,9 ; DISPLAY STRING FUNCTION INT 21H ; OUTPUT SPACES ; ; OUTPUT THE TOP LINE ; MOV CX,BYT ; NUMBER OF BYTES PER LINE MOV AL,STADD ; GET THE LOW ADDRESS BYTE LUP1: PUSH AX ; SAVE FOR NEXT OUTPUT CALL HEX_ASC ; CONVERT TO ASCII MOV ASCTOP,AH ; SAVE FOR OUTPUT MOV AH,9 ; OUTPUT STRING FUNCTION MOV DX,OFFSET ASCTOP ; ADDRESS OF STRING INT 21H ; OUTPUT ONE DIGIT ON TOP LINE POP AX ; GET PREVIOUS DIGIT INC AL ; INCREMENT FOR NEXT DIGIT LOOP LUP1 ; REPEAT FOR THE REST CALL CRLF ; CR AND LF ; MOV BX,LINES ; NUMBER OF LINES TO DISPLAY MOV AX,WORD PTR SEGADD ; FETCH SEGMENT TO DISPLAY MOV ES,AX ; PUT DESIRED SEGMENT IN ES REGISTER ; ; OUTPUT ADDRESS AT START OF LINE ; LUP3: PUSH BX ; SAVE LINE COUNTER MOV AL,STADD+1 ; GET THE FIRST ADDRESS BYTE CALL HEX_ASC ; CONVERT TO ASCII MOV ASCADD,AX ; SAVE FOR OUTPUT TO CRT MOV AL,STADD ; GET THE SECOND ADDRESS BYTE CALL HEX_ASC ; CONVERT IT TO ASCII TOO MOV ASCADD+2,AX ; AND SAVE IT ALSO ; MOV AH,9 ; DISPLAY STRING FUNCTION MOV DX,OFFSET ASCADD ; ADDRESS OF MESSAGE INT 21H ; CALL DOS MOV AL,STADD ; INCREMENT STARTING ADDRESS ADD AL,BYT ; BY NUMBER OF BYTES IN A LINE MOV STADD,AL JNC DLINES INC STADD+1 ; INCREMENT HIGH BYTE IF NECESSARY ; ; OUTPUT ONE LINE ; DLINES: MOV CX,BYT ; NUMBER OF BYTES TO DISPLAY IN A LINE MOV DI,OFFSET ASCCHAR ; ADDRESS OF ASCII BUFFER ; LUP4: MOV AL,ES:[SI] ; PICK UP NEXT MEMORY BYTE PUSH AX ; SAVE IT CMP AL,7FH ; SEE IF IT CAN BE DISPLAYED ON CRT JGE DASC1 ; BRANCH IF NOT CMP AL,20H JGE DASC2 ; BRANCH IF YES DASC1: MOV AL,'.' ; SUBSTITUTE PERIOD DASC2: MOV [DI],AL ; STORE FOR LATER DISPLAY INC DI ; INCREMENT BUFFER POINTER POP AX ; RETRIEVE MEMORY BYTE CALL HEX_ASC ; CONVERT IT TO TWO ASCII CODES MOV CHARS,AX ; STORE THEM PUSH SI ; SAVE POINTER PUSH CX ; SAVE BYTE COUNTER MOV DX,OFFSET CHARS ; ADDRESS OF STRING MOV AH,9 ; DISPLAY STRING FUNCTION INT 21H ; CALL DOS TO DISPLAY THIS BYTE POP CX ; RESTORE BYTE COUNTER POP SI ; RESTORE POINTER INC SI ; INCREMENT SOURCE POINTER LOOP LUP4 ; REPEAT UNTIL DONE ; MOV CX,BYT+2 ; NUMBER OF TOTAL SYMBOLS MOV DI,OFFSET ASCSYM ; ADDRESS OF STRING LUP5: MOV DL,[DI] ; NEXT CHARACTER TO DISPLAY PUSH DI ; SAVE REGISTERS PUSH CX MOV AH,2 ; DISPLAY CHARACTER FUNCTION INT 21H ; CALL DOS TO DISPLAY SYMBOLS POP CX ; RESTORE REGISTERS POP DI INC DI ; INCREMENT SYMBOL ADDRESS LOOP LUP5 ; REPEAT UNTIL FINISHED ; CALL CRLF ; OUTPUT CR AND LF POP BX ; RESTORE LINE COUNTER DEC BX ; DECREMENT LINE COUNTER JNZ LUP3 ; REPEAT FOR ALL LINES ; MOV AX,DS MOV ES,AX ; RESTORE ES REGISTER RET ; RETURN TO CALLING ROUTINE PAGE ; ; ;*****************************************************************************; ; ; ; KEYBOARD INPUT SUBROUTINE VERSION 2/19/84 ; ; ; ; THIS ROUTINE READS ASCII CODES FROM THE KEYBOARD INTO A BUFFER ; ; ; ; ENTRY: AH = MAX NUMBER OF CHARACTERS TO READ EXCLUDING ANY CR CODE ; ; DI = FWA OF THE BUFFER IN WHICH TO STORE THE CHARACTERS ; ; ; ; EXIT: AL = THE LAST CHARACTER READ EXCLUDING ANY CR CODE ; ; AH = THE NUMBER OF CHARACTERS READ EXCLUDING BS OR CR CODES ; ; DI = ADDRESS OF THE LAST CHARACTER READ ; ; ONE LESS THAN BUFFER FWA IF ONLY CR IS RECEIVED ; ; ; ; BACKSPACE AND CARRIAGE RETURN CODES ARE PROCESSED BY DOS ; ; ; ; THE BUFFER MUST HAVE THE FIRST TWO BYTES AVAILABLE FOR STORAGE OF ; ; THE MAX NUMBER OF CHARACTERS TO READ AND NUMBER OF CHARACTERS READ ; ; INCLUDING THE CARRAIGE RETURN CODE ; ; ; ; ALTERS: ALL REGISTERS EXCEPT BX ARE ALTERED ; ; ; ;*****************************************************************************; ; ; KYBD: PUSH BX ; SAVE REGISTER PUSH DI ; SAVE BUFFER ADDRESS INC AH ; ALLOW FOR THE CR CODE MOV [DI],AH ; STORE MAX NUMBER OF WORDS TO READ MOV AX,0C0AH ; CLEAR AND READ KEYBOARD BUFFER MOV DX,DI ; BUFFER ADDRESS IN DX INT 21H ; CALL DOS POP DI ; GET BUFFER ADDRESS INC DI MOV AH,[DI] ; GET NUMBER OF CHARACTERS READ MOV BL,AH ; PUT IN BASE REGISTER XOR BH,BH ADD DI,BX ; SET DI TO LAST CHARACTER POSITION MOV AL,[DI] ; GET LAST CHARACTER READ POP BX ; RESTORE REGISTER RET ; RETURN TO CALLING ROUTINE PAGE ; ; ;*****************************************************************************; ; ; ; CONVERT ASCII TO HEX VERSION 2/21/84 ; ; ; ; CONVERT TWO ASCII CODES IN AX TO ONE HEX NUMBER IN AL ; ; ; ; ENTRY: AL = UPPER ASCII CODE ; ; AH = LOWER ASCII CODE ; ; ; ; EXIT: AL = ONE HEX NUMBER (TWO HEX DIGITS) ; ; CARRY FLAG IS SET IF AN ILLEGAL HEX DIGIT IS IN THE INPUT ; ; ; ; ALTERS: REGISTERS AL AND AH ARE ALTERED ; ; ; ; NOTE: VALID FOR ALL HEX NUMBERS 00 TO FF ; ; ; ;*****************************************************************************; ; ; ASC_HEX:PUSH BX ; SAVE REGISTERS MOV BX,AX ; SAVE THE ASCII CODES CALL CNVRT1 ; RETURNS UPPER DIGIT IN LOWER AL SHL AL,1 ; PUT IT IN UPPER AL SHL AL,1 SHL AL,1 SHL AL,1 XCHG AL,BH ; SAVE IN BH & GET LOWER DIGIT CALL CNVRT1 ; RETURNS LOWER DIGIT IN LOWER AL OR AL,BH ; COMBINE BOTH HEX DIGITS INTO AL POP BX ; RESTORE REGISTERS CLC ; CLEAR CARRY/ERROR FLAG RET ; RETURN TO CALLING ROUTINE ; CNVRT1: SUB AL,30H ; PARTIAL CONVERSION JL CERR ; AL < 0 => ILLEGAL HEX CODE CMP AL,9 ; CHECK FOR 0 - 9 JLE CEND ; AL <= 9 => 0 - 9 CMP AL,11H ; CHECK FOR A - F JL CERR ; AL < 11H => ILLEGAL (BETWEEN '9' AND 'A') SUB AL,7 ; CONVERT A - F CMP AL,0FH ; AL > 0FH => ILLEGAL JG CERR ; ERROR EXIT CEND: RET ; RETURN TO CONTINUE ; CERR: POP AX ; ERASE FIRST RETURN ADDRESS SUB AX,AX ; SET RESULT TO ZERO POP BX ; ADJUST STACK STC ; SET CARRY/ERROR FLAG RET ; RETURN TO CALLING ROUTINE PAGE ; ; ;*****************************************************************************; ; ; ; CONVERT HEX TO ASCII ; ; ; ; CONVERT FROM TWO HEX DIGITS IN AL TO TWO ASCII CODES IN AX ; ; ; ; ENTRY: AL = HEX NUMBER 00H TO FFH ; ; ; ; EXIT: AL = UPPER ASCII CODE ; ; AH = LOWER ASCII CODE ; ; ; ; ALTERS: REGISTERS AL AND AH ARE ALTERED ; ; ; ; NOTE: THIS CONVERSION IS VALID FOR ALL HEX CODES ; ; ; ;*****************************************************************************; ; ; HEX_ASC: MOV AH,AL ; SAVE UPPER HEX DIGIT CALL CVRT2 ; CONVERT HEX LOWER DIGIT XCHG AH,AL ; SAVE IT IN AH / GET UPPER DIGIT TO CONVERT SHR AL,1 ; SHIFT INTO LOW NIBBLE SHR AL,1 SHR AL,1 SHR AL,1 CALL CVRT2 ; CONVERT UPPER HEX DIGIT RET ; RETURN TO CALLING ROUTINE ; ; CONVERT ONE HEX DIGIT IN LOWER NIBBLE OF AL INTO ONE ASCII CODE IN AL ; CVRT2: AND AL,0FH ; SEPARATE OUT ONE HEX DIGIT OR AL,30H ; CONVERT 0 - 9 CMP AL,'9' ; CHECK FOR A - F JLE CVRT4 ; SKIP IF 0 - 9 ADD AL,07H ; CONVERT A - F CVRT4: RET ; RETURN TO CALLING ROUTINE .XLIST SUBTTL MESSAGES AND DATA STORAGE PAGE + .LIST ; ; MESSAGES AND DATA STORAGE ; SEGMSG DB CR,LF,LF,'DO YOU WANT TO DISPLAY A DIFFERENT SEGMENT ? (Y/N) $' ; SEGMSG2 DB CR,LF,LF,'ENTER THE SEGMENT IN HEX $' ; SEGMSG3 DB CR,LF,LF,'DISPLAYING FROM SEGMENT NUMBER $' ; STMSG DB CR,LF,LF,'ENTER THE HEX STARTING ADDRESS $' ; ENDMSG DB CR,LF,'REPEAT TO LOOK AT MORE ? (Y/N) $' ; CHARS DW ' ' DB ' $' ; SPACE DB ' $' ASCTOP DB ' $' ; ASCSYM DB ' ' ASCCHAR DB 16 DUP(' ') ; SEGADD DB 0,0,0,0 ASCSEG DW 0,0 DB ' $' ; STADD DB 0,0,0,0 ASCADD DW 0,0 DB ' $' KBUFSZ DB 0,0 KBUF DB ' $' ; CSEG ENDS END LOOK