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Assembly Source File | 1989-02-27 | 25.9 KB | 1,004 lines

page 60,132 ; SNIPPER is a resident utility which allows cutting out a portion ; of the screen. The selected portion may be printed, written ; to disk or entered in the keyboard buffer. Activate SNIPPER by ; pressing ALT-W, then position the cursor in the upper left corner of ; the window using the arrow keys. Press CR to fix the first corner, ; then expand the window with arrow keys. Finally, type "P" to print, ; "F" for disk file, "G" to retrieve or CR for a help menu. Press ESC ; any time to exit SNIPPER. When installing SNIPPER, use the optional ; parameters to expand it's internal buffer for displays (such as the ; EGA) containing more than the standard 25 rows and 80 columns. ; SNIPPER [rows,columns] ; ------------------------------------; ; BIOS_SEG IS THE ROM-BIOS DATA AREA ; ; ------------------------------------; BIOS_SEG SEGMENT AT 0040H ORG 004AH CRT_COLS DB ? ; CURRENT NUMBER OF COLUMNS ORG 0050H CURSOR_POSN DW 8 DUP(?) ; CURRENT CURSOR LOCATION ORG 0062H ACTIVE_PAGE DB ? ; ACTIVE PAGE FOR CGA AND EGA ORG 0084H ROWS DB ? ; LAST ROW NUMBER FOR EGA BIOS_SEG ENDS CSEG SEGMENT ASSUME CS:CSEG,DS:NOTHING ORG 0100H ; BEGINNING FOR .COM PROGRAMS START: JMP INITIALIZE ; INITIALIZATION CODE IS AT END ; --------------------------------; ; DATA AREA USED BY THIS PROGRAM ; ; --------------------------------; HOTKEY EQU 11H ; SCAN CODE FOR "W" KEY SHIFT_MASK EQU 00001000B ; MASK FOR ALT KEY COPYRIGHT DB "SNIPPER 1.0 (c) 1987 Ziff Communications Co." DB 13,10,"Hotkey is ALT-W",13,10,"$",1AH PROGRAMMER DB "Tom Kihlken" INSTALLED_MSG DB "Already Installed",13,10,"$" BAD_DOS_MSG DB "Requires DOS 2.0+",13,10,"$" OLDINT09 DD ? ; OLD KEYBOARD BREAK INTERRUPT VECTOR OLDINT13 DD ? ; OLD BIOS DISK IO INTERRUPT VECTOR OLDINT16 DD ? ; OLD KEYBOARD INTERRUPT VECTOR OLDINT21 DD ? ; OLD DOS FUNCTION INTERRUPT VECTOR ERR_STAT DB ? ; ERROR STATUS DURING FILE OUTPUT FILE_PROMPT DB "Enter Filename: " FILENAME DB "SCREEN.CUT" ; THE DEFAULT FILENAME DB 15 DUP (0) ; LEAVE ROOM FOR DRIVE AND PATH BUFF_NEXT DW BUFF_START ; POINTER TO NEXT KEY IN BUFFER BUFF_LAST DW BUFF_START ; POINTER TO LAST KEY IN BUFFER BUFF_START EQU OFFSET INITIALIZE BUFF_SIZE EQU 25*(80+2) ; ROOM FOR 25 ROWS OF 80 COLUMNS BUFF_END DW BUFF_START+BUFF_SIZE TOP_LEFT LABEL WORD ; FIRST CORNER OF WINDOW LEFT_SIDE DB 0 ; COLUMN NUMBER OF LEFT SIDE TOP_ROW DB 0 ; ROW NUMBER OF TOP SIDE BOT_RIGHT LABEL WORD ; SECOND CORNER OF WINDOW RIGHT_SIDE DB ? ; COLUMN NUMBER OR RIGHT SIDE BOT_ROW DB ? ; ROW NUMBER OF BOTTOM SEND_CHAR DW ? ; POINTER TO CHARACTER HANDLER SEND_KEYS DB 0 ; IF=1, USE KEYSTROKES FROM BUFFER WRIT_FILE DB 0 ; IF=1, NEED TO WRITE TO DISK BUSY_FLAGS DB 0 ; BIT MASKED AS FOLLOWS: ; 1 - DOS IS ACTIVE ; 2 - BIOS IO IS ACTIVE ; 4 - SNIPPER IS ACTIVE DOS_STAT DB 0 ; CURRENT DOS FUNCTION HELP_MENU DB 201,10 DUP(205),187 DB 186," F - File ",186 DB 186," P - Print",186 DB 186," S - Save ",186 DB 186," G - Get ",186 DB 186,"Esc- Quit ",186 DB 200,10 DUP(205),188 ; ------------------------------------------------------------------; ; SNIPPER BUILDS THE WINDOW AND ACCEPTS COMMANDS FROM THE KEYBOARD ; ; ------------------------------------------------------------------; SNIPPER PROC NEAR ASSUME DS:CSEG, ES:BIOS_SEG XOR BX,BX ; BX IS INCREMENT FOR ROW/COLUMN GET_KB_KEY1: MOV DX,TOP_LEFT ; GET LOCATION OF FIRST CORNER ADD DH,BH ; ADD IN THE ROW INCREMENT ADD DL,BL ; ADD IN THE COLUMN INCREMENT CMP DL,0 ; AT LEFT EDGE OF SCREEN? JGE NOT_LEFT_EDGE MOV DL,CRT_COLS ; JUMP TO THE RIGHT EDGE DEC DL NOT_LEFT_EDGE: CMP DL,CRT_COLS ; AT RIGHT EDGE OF SCREEN YET? JB NOT_RIGHT_EDGE ; IF NOT, KEEP MOVING RIGHT XOR DL,DL ; IF YES, WRAP TO LEFT EDGE NOT_RIGHT_EDGE: CMP DH,0 ; AT TOP OF SCREEN YET? JGE NOT_AT_TOP MOV DH,ROWS ; JUMP DOWN TO THE BOTTOM NOT_AT_TOP: CMP DH,ROWS ; AT BOTTOM OF SCREEN? JLE NOT_AT_BOTTOM XOR DH,DH ; JUMP BACK TO THE TOP NOT_AT_BOTTOM: MOV TOP_LEFT,DX ; SAVE NEW CORNER LOCATION CALL REV_VIDEO ; CHANGE IT TO REVERSE VIDEO XOR AH,AH ; BIOS KEYBOARD INPUT INT 16H ; GET A KEYSTROKE PUSH AX CALL REV_VIDEO ; PUT ATTRIBUTE BACK TO NORMAL POP AX CMP AH,1 ; IS IT ESCAPE? JNE NOT_ESC RET ; JUST RETURN TO EXIT NOT_ESC: MOV BX,0FF00H ; INCREMENT TO SUBTRACT ONE ROW CMP AH,48H ; IS IT UP ARROW? JE GET_KB_KEY1 MOV BX,0100H ; INCREMENT TO ADD ONE ROW CMP AH,50H ; IS IT DOWN ARROW? JE GET_KB_KEY1 MOV BX,0001H ; INCREMENT TO ADD ONE COLUMN CMP AH,4DH ; IS IT RIGHT ARROW? JE GET_KB_KEY1 MOV BX,00FFH ; INCREMENT TO SUBTRACT ONE COLUMN CMP AH,4BH ; IS IT LEFT ARROW? JE GET_KB_KEY1 XOR BX,BX CMP AL,13 ; IS IT A CARRIAGE RETURN? JNE NOT_CR MOV DX,TOP_LEFT ; A CARRIAGE RETURN WAS PRESSED MOV BOT_RIGHT,DX ; INITIALIZE THE SECOND CORNER CALL REV_VIDEO ; CHANGE IT BACK TO REVERSE VIDEO JMP SHORT GET_KB_KEY2 NOT_CR: CMP AH,22H ; IS IT THE "G" KEY JE TYPE_BUFF ; IF YES, THAN GET THE WINDOW JMP GET_KB_KEY1 ; JUST GET ANOTHER KEY TYPE_BUFF: MOV SEND_KEYS,1 ; SIGNAL TO SEND THE KEYS RET GET_KB_KEY2: XOR AH,AH INT 16H ; GET A KEYSTROKE GOT_KEY2: MOV DX,BOT_RIGHT CMP AH,48H ; IS IT UP ARROW? JE SUB_ROW ; SUBTRACT A ROW FROM WINDOW CMP AH,50H ; IS IT DOWN ARROW? JE ADD_ROW ; ADD A ROW TO THE WINDOW CMP AH,4DH ; IS IT RIGHT ARROW? JE ADD_COL ; ADD A COLUMN TO THE WINDOW CMP AH,4BH ; IS IT LEFT ARROW? JE SUB_COL ; SUBTRACT A COLUMN FROM WINDOW JMP NOT_ARROW_KEY SUB_COL: DEC DL ; SUBTRACT A COLUMN CMP DL,LEFT_SIDE ; DONT ERASE IT COMPLETELY JL GET_KB_KEY2 MOV RIGHT_SIDE,DL ; SAVE NEW RIGHT SIDE COLUMN INC DL JMP SHORT COL_LOOP ADD_COL: INC DL ; ADD A COLUMN CMP DL,CRT_COLS ; AT RIGHT EDGE OF SCREEN? JAE GET_KB_KEY2 ; STOP WHEN SCREEN IS FILLED MOV RIGHT_SIDE,DL ; SAVE NEW RIGHT SIDE COLUMN COL_LOOP: CALL REV_VIDEO ; REVERSE THIS CHARACTER DEC DH ; MOVE TO NEXT ROW CMP DH,TOP_ROW ; AT TOP ROW YET? JGE COL_LOOP ; LOOP UNTIL AT TOP ROW JMP GET_KB_KEY2 SUB_ROW: DEC DH CMP DH,TOP_ROW ; AT TOP OF WINDOW? JL GET_KB_KEY2 ; DONT ERASE IT COMPLETELY MOV BOT_ROW,DH INC DH JMP SHORT ROW_LOOP ADD_ROW: INC DH CMP DH,ROWS ; AT BOTTOM OF SCREEN? JG GET_KB_KEY2 ; STOP WHEN SCREEN IS FILLED MOV BOT_ROW,DH ROW_LOOP: CALL REV_VIDEO ; REVERSE THIS CHARACTER DEC DL ; MOVE TO NEXT COLUMN CMP DL,LEFT_SIDE ; AT LEFT EDGE YET? JGE ROW_LOOP ; CONTINUE UNTIL AT LEFT EDGE JMP GET_KB_KEY2 NOT_ARROW_KEY: CMP AH,19H ; WAS IT THE "P" KEY? JNE NOT_P MOV SEND_CHAR,OFFSET PRINT_CHAR JMP READ_WINDOW NOT_P: MOV BUFF_NEXT,BUFF_START MOV BUFF_LAST,BUFF_START MOV SEND_CHAR,OFFSET BUFF_CHAR CMP AH,1FH ; WAS IT THE "S" KEY? JNE NOT_S MOV SEND_CHAR,OFFSET BUFF_CHAR JMP READ_WINDOW NOT_S: CMP AH,22H ; IS IT THE "G" KEY JNE NOT_G MOV SEND_KEYS,1 JMP READ_WINDOW NOT_G: CMP AH,21H ; IS IT THE "F" KEY JNE NOT_F MOV WRIT_FILE,0 CALL GET_FILENAME CMP WRIT_FILE,-1 ; WAS ESCAPE REQUESTED? JE ERASE_BOX CALL READ_WINDOW MOV WRIT_FILE,1 TEST BUSY_FLAGS,00000011B ; IS INT21 OR INT13 BUSY? JNZ RETURN ; IF YES, WAIT TILL LATER CALL WRITE_TO_FILE ; IF NOT, DO IT NOW RETURN: RET NOT_F: CMP AH,1 ; IS IT ESCAPE? JE ERASE_BOX ; IF YES, ERASE BOX AND EXIT CMP AL,13 ; IS IT A CARRIAGE RETURN? JE DISPLAY_HELP ; IF YES, DISPLAY HELP JMP GET_KB_KEY2 ; OTHERWISE JUST GET ANOTHER KEY ERASE_BOX: MOV SEND_CHAR,OFFSET RETURN JMP READ_WINDOW DISPLAY_HELP: CALL EXCHANGE_HELP ; PUT UP THE HELP MENU XOR AH,AH INT 16H ; GET ANOTHER KEYSTROKE PUSH AX ; SAVE THE KEYSTROKE CALL EXCHANGE_HELP ; PULL DOWN THE HELP MENU POP AX ; GET BACK THE KEYSTROKE JMP GOT_KEY2 ; ********************************************************************* REV_VIDEO: CALL READ_CHAR ; READ CHARACTER AND ATTRIBUTE MOV BL,AH ; SAVE ATTRIBUTE IN BL AND BL,10001000B ; GET BLINK AND INTENSITY BITS AND AH,01110111B ; NOW LOOK ONLY AT COLOR BITS MOV CL,4 ; ROTATE FOUR COUNTS ROR AH,CL ; ROTATE FOREGROUND AND BACKGROUND OR BL,AH ; PUT BACK BLINK AND INTENSITY BITS CALL DISPLAY_CHAR ; WRITE CHARACTER AND ATTRIBUTE RET ; ********************************************************************* READ_WINDOW: MOV DX,TOP_LEFT ; GET LOCATION OF FIRST CORNER READ_LOOP: CALL REV_VIDEO ; PUT ATTRIBUTE BACK TO NORMAL CALL READ_CHAR ; READ THE CHARACTER CALL SEND_CHAR ; CALL TO THE POINTER INC DL ; NEXT CHAR IN ROW CMP DL,RIGHT_SIDE ; AT THE RIGHT BORDER YET? JLE READ_LOOP ; DO ALL CHARACTERS IN THIS ROW CALL CR_LF ; SEND CR-LF AFTER EACH ROW INC DH ; MOVE TO NEXT ROW MOV DL,LEFT_SIDE ; BACK TO LEFT EDGE CMP DH,BOT_ROW ; AT THE BOTTOM BORDER YET? JLE READ_LOOP ; READ ENTIRE WINDOW RET ; ********************************************************************* CR_LF: MOV AL,13 CALL SEND_CHAR ; SEND A CARRIAGE RETURN MOV AL,10 CALL SEND_CHAR ; SEND A LINE FEED RET ; ********************************************************************* DISPLAY_CHAR: PUSH BX ; SAVE THE ATTRIBUTE CALL GET_CURS_ADDR ; GET ADDRESS OF BIOS CURSOR MOV ES:[BX],DX ; TELL BIOS WHERE THE CURSOR IS POP BX ; GET BACK THE ATTRIBUTE MOV BH,ACTIVE_PAGE ; GET ACTIVE PAGE PUSH CX ; SAVE THE LOOP COUNT MOV CX,1 ; WRITE 1 CHARACTER MOV AH,9 ; WRITE CHARACTER AND ATTRIBUTE INT 10H POP CX ; RECOVER LOOP COUNT RET ; DONE WRITING THE CHARACTER ; ********************************************************************* READ_CHAR: CALL GET_CURS_ADDR ; GET ADDRESS OF BIOS CURSOR MOV ES:[BX],DX ; TELL BIOS WHERE THE CURSOR IS MOV BH,ACTIVE_PAGE ; GET ACTIVE PAGE MOV AH,8 ; BIOS FUNCTION TO READ CHARACTER INT 10H ; READ THE CHARACTER/ATTRIBUTE RET ; ********************************************************************* PRINT_CHAR: PUSH DX XOR AH,AH ; USE FUNCTION 0 XOR DX,DX ; PRINTER NUMBER 0 INT 17H ; BIOS PRINT CHARACTER FUNCTION ROR AH,1 ; LOOK AT BIT ZERO JNC PRINT_OK ; DID A TIMEOUT OCCUR? MOV SEND_CHAR,OFFSET RETURN PRINT_OK: POP DX RET ; DONE PRINTING CHARACTER ; ********************************************************************* BUFF_CHAR: MOV BX,BUFF_LAST ; GET LOCATION OF LAST CHARACTER MOV [BX],AL ; PUT THE CHARACTER IN BUFFER INC BX ; ADVANCE THE POINTER MOV BUFF_LAST,BX ; CHECK FOR BUFFER FULL CMP BX,BUFF_END ; IS THE BUFFER FULL YET? JNE BUFF_OK ; IF NOT, KEEP GOING MOV SEND_CHAR,OFFSET RETURN BUFF_OK: RET ; NOW ITS IN THE BUFFER ; ********************************************************************* GET_CURS_ADDR: MOV BL,ACTIVE_PAGE ; GET THE CURRENT PAGE NUMBER XOR BH,BH ; CONVERT TO A WORD OFFSET SHL BX,1 ; TIMES TWO FOR A WORD ADD BX,OFFSET CURSOR_POSN ; ADD IN BASE ADDRESS RET ; ********************************************************************* EXCHANGE_HELP: XOR DX,DX ; START AT TOP LEFT CORNER LEA SI,HELP_MENU EXCHANGE_LOOP: CMP DL,12 ; AT LAST COLUMN IN THIS ROW YET? JL SWAP_CHAR XOR DL,DL ; BACK TO FIRST COLUMN INC DH ; DO THE NEXT ROW CMP DH,7 ; AT LAST ROW YET? JL SWAP_CHAR ; QUIT WHEN LAST ROW IS DONE RET SWAP_CHAR: CALL READ_CHAR ; READ CHARACTER AT THIS POSITION XCHG AL,CS:[SI] ; SWAP WITH THE HELP TEXT MOV BL,AH ; ATTRIBUTE IS THE SAME CALL DISPLAY_CHAR ; PUT NEW CHARACTER ON SCREEN INC DL ; POINT TO NEXT POSITION INC SI JMP EXCHANGE_LOOP ; ********************************************************************* GET_FILENAME: LEA SI,FILE_PROMPT ; POINT TO THE PROMPT FOR SOURCE XOR DI,DI ; USE THE PSP FOR BUFFER XOR DX,DX ; PUT PROMPT AT TOP LEFT CORNER MOV CX,40 ; USE MAX OF 40 CHARACTERS DISPLAY_PROMPT: PUSH CX ; SAVE LOOP COUNT CALL READ_CHAR ; GET CHARACTER ON THIS LINE MOV CS:[DI],AX ; STORE IT IN THE PSP INC DI ; ADD TWO FOR NEXT CHARACTER INC DI MOV AL,CS:[SI] ; GET NEXT PROMPT CHARACTER INC SI ; NEXT CHARACTER IN PROMPT MOV BL,47H ; ATTRIBUTE FOR PROMPT CALL DISPLAY_CHAR ; PUT UP THE PROMPT CHARACTER INC DL ; POINT TO NEXT COLUMN POP CX ; GET BACK LOOP COUNT LOOP DISPLAY_PROMPT ; ENTIRE PROMPT AND FILENAME FIND_LAST_LETTER: DEC SI ; BACKUP TO LAST LETTER DEC DL ; BACKUP TO LAST COLUMN CMP BYTE PTR [SI],0 ; IS THIS A LETTER? JE FIND_LAST_LETTER; BACKUP UNTIL A LETTER IS FOUND INC DL ; PUT BLINKING BOX AT LAST LETTER READ_KB: MOV AL,219 ; ASCII FOR BOX CHARACTER MOV BL,47H+80H ; MAKE IT A BLINKING BOX CHARACTER CALL DISPLAY_CHAR ; WRITE THE BLINKING BOX XOR AH,AH ; FUNCTIO 0 TO GET NEXT KEY INT 16H ; BIOS KEYBOARD INPUT CMP AL,13 ; IS IT A CARRIAGE RETURN? JE ERASE_PROMPT CMP AL,8 ; IS IT A BACKSPACE? JE BACK_SPACE CMP AH,1 ; IS IT ESCAPE? JE ESC_RET CMP AL,"." ; IS IT A VALID LETTER? JL READ_KB CMP AL,"z" ; IS IT A VALID LETTER? JG READ_KB CMP DL,39 ; ONLY ALLOW 40 CHARACTERS JGE READ_KB TTY_KEY: MOV BL,47H ; ATTRIBUTE FOR FILENAME CALL DISPLAY_CHAR ; WRITE THE LETTER INC DL ; MOVE TO NEXT COLUMN JMP READ_KB ; GET ANOTHER KEYSTROKE BACK_SPACE: CMP DL,16 ; AT BEGINNING OF LINE? JLE READ_KB ; IF YES, CAN'T BACKUP FROM HERE MOV AL,0 ; WRITE A NORMAL BLANK (ASCII 0) MOV BL,47H ; ATTRIBUTE FOR FILENAME CALL DISPLAY_CHAR ; WRITE THE LETTER DEC DL ; BACKUP THE CURSOR JMP READ_KB ; THEN GET THE NEXT KEY ESC_RET: MOV WRIT_FILE,-1 ; INDICATE ESCAPE IS REQUESTED ERASE_PROMPT: XOR AL,AL ; GET RID OF THE CURSOR CALL DISPLAY_CHAR ; WRITE THE LETTER LEA DI,FILE_PROMPT ; COPY TO FILENAME XOR SI,SI ; COPY FROM PSP XOR DX,DX ; PROMPT IS AT ROW ZERO MOV CX,40 ; COPY ALL 40 CHARACTERS ERASE_LOOP: CALL READ_CHAR ; GET CHARACTER ON THIS LINE MOV CS:[DI],AL ; PUT IN BACK IN MEMORY INC DI MOV AX,CS:[SI] ; GET THE ORIGINAL CHARACTER BACK MOV BL,AH ; PUT ATTRIBUTE INTO BL INC SI INC SI CALL DISPLAY_CHAR ; WRITE ORIGINAL CHARACTER INC DL ; MOVE TO NEXT COLUMN LOOP ERASE_LOOP ; ERASE THE ENTIRE PROMPT RET SNIPPER ENDP ; ----------------------------------------------------------------------; ; THIS COPIES THE BUFFER CONTENTS TO A FILE. IT SHOULD ONLY BE CALLED ; ; WHEN DOS IS IN A STABLE AND REENTRANT CONDITION. ; ; ----------------------------------------------------------------------; WRITE_TO_FILE PROC NEAR ASSUME DS:NOTHING, ES:NOTHING MOV WRIT_FILE,0 ; TURN OFF REQUEST FLAG PUSH AX ; MUST PRESERVE ALL REGISTERS PUSH BX PUSH CX PUSH DX PUSH DS PUSH ES PUSH CS POP DS ASSUME DS:CSEG ; DS POINTS TO OUR CODE SEGMENT MOV AX,3524H ; GET DOS CRITICAL ERROR VECTOR INT 21H ; DOS FUNCTION TO GET VECTOR PUSH BX ; SAVE OLD VECTOR ON STACK PUSH ES ; REPLACE THE DOS SEVERE ERROR INTERRUPT WITH OUR OWN ROUTINE. MOV DX,OFFSET NEWINT24 MOV AX,2524H ; SETUP TO CHANGE INT 24h VECTOR INT 21H ; CHANGE DOS SEVERE ERROR VECTOR MOV DX,OFFSET FILENAME ; POINT TO FILENAME ; FIRST TRY TO OPEN THE FILE. IF DOS RETURNS WITH THE CARRY FLAG SET, ; THE FILE DIDN'T EXIST AND WE MUST CREATE IT. ONCE THE FILE IS OPENED, ; ADVANCE THE FILE POINTER TO THE END OF FILE TO APPEND. MOV AX,3D02H ; DOS FUNCTION TO OPEN FILE INT 21H ; DOS WILL RETURN WITH CARRY FLAG JC FILE_NOT_FOUND ; SET IF FILE DOESN'T EXIST. MOV BX,AX ; KEEP HANDLE IN BX ALSO XOR CX,CX ; MOVE DOS FILE POINTER TO THE XOR DX,DX ; END OF THE FILE. THIS LETS US MOV AX,4202H ; APPEND THIS TO AN EXISTING FILE INT 21H ; DOS FUNCTION TO MOVE POINTER JNC WRITE_FILE ; IF NO ERROR, CONTINUE TO WRITE DOS_ERROR: CMP ERR_STAT,0 ; DID A SEVERE ERROR OCCUR? JNE REP_VECTOR ; IF SEVERE ERROR, JUST QUIT JMP SHORT CLOSE_FILE; JUST CLOSE THE FILE FILE_NOT_FOUND: CMP ERR_STAT,0 ; DID A SEVERE ERROR OCCUR? JNE REP_VECTOR ; IF SEVERE ERROR, JUST QUIT MOV CX,0020H ; ATTRIBUTE FOR NEW FILE MOV AH,3CH ; CREATE FILE FOR WRITING INT 21H ; DOS FUNCTION TO CREATE FILE JC DOS_ERROR ; ON ANY ERROR, TAKE JUMP MOV BX,AX ; SAVE HANDLE IN BX WRITE_FILE: MOV DX,BUFF_START ; POINT TO BUFFER MOV CX,BUFF_LAST ; GET BUFFER POINTER SUB CX,DX ; NUMBER OF CHARS IN BUFFER MOV AH,40H ; DOS WRITE TO A DEVICE FUNCTION INT 21H ; WRITE TO THE FILE CLOSE_FILE: MOV AH,3EH ; DOS FUNCTION TO CLOSE THE FILE INT 21H REP_VECTOR: POP DS ; GET INT 24H VECTOR FROM STACK POP DX MOV AX,2524H ; RESTORE CRITICAL ERROR VECTOR INT 21H ; DOS FUNCTION TO CHANGE VECTOR POP ES ; FINALLY RESTORE ALL REGISTERS POP DS POP DX POP CX POP BX POP AX RET ; FINISHED WRITING TO DISK WRITE_TO_FILE ENDP ; ----------------------------------------------------------------------; ; INTERRUPT 09 ROUTINE. WATCH FOR TRIGGER KEY TO POP UP. ; ; ----------------------------------------------------------------------; NEWINT09 PROC FAR ASSUME DS:NOTHING, ES:NOTHING STI ; ALLOW OTHER INTERRUPTS PUSH AX ; MUST SAVE PROCESSOR STATE IN AL,60H ; GET THE SCAN CODE CMP AL,HOTKEY ; IS IT THE HOT KEY? JE TRIGGER ; IF YES, CHECK THE MASK INT09_EXIT: POP AX ; RESTORE THE PROCESSOR STATE JMP OLDINT09 ; CONTINUE WITH ROM ROUTINE TRIGGER: MOV AH,2 ; GET KEYBOARD STATUS INT 16H ; BIOS KEYBOARD SERVICE AND AL,0FH ; Take lower four bits CMP AL,SHIFT_MASK ; IS ALT KEY DOWN? JNZ INT09_EXIT ; IF NOT, IGNORE IT TEST BUSY_FLAGS,00000100B ; IS SNIPPER ALREADY ACTIVE? JNZ INT09_EXIT ; IF ACTIVE, THEN EXIT OR BUSY_FLAGS,00000100B ; ITS ACTIVE NOW PUSHF CALL OLDINT09 ; LET ROM PROCESS THE KEY PUSH BX ; MUST PRESERVE ALL REGISTERS PUSH CX PUSH DX PUSH BP PUSH SI PUSH DI PUSH DS PUSH ES PUSH CS POP DS ; SET DS TO CSEG MOV AX,BIOS_SEG ; ES POINTS TO BIOS DATA AREA MOV ES,AX ASSUME DS:CSEG, ES:BIOS_SEG CALL GET_CURS_ADDR ; CURSOR ADDRESS FOR THIS PAGE PUSH ES:[BX] ; SAVE THE CURSOR LOCATION CALL SNIPPER ; DO THE WINDOW CALL GET_CURS_ADDR ; CURS0R ADDRESS FOR THIS PAGE POP ES:[BX] ; GET BACK CURSOR POSITION AND BUSY_FLAGS,11111011B ; SNIPPER IS NOT ACTIVE POP ES ; RESTORE ALL REGISTERS POP DS POP DI POP SI POP BP POP DX POP CX POP BX POP AX IRET ; NOW WERE ALL DONE NEWINT09 ENDP ; ----------------------------------------------------------------------; ; INTERRUPT 13 ROUTINE. SET BIOS BUST BIT ; ; ----------------------------------------------------------------------; NEWINT13 PROC FAR ASSUME DS:NOTHING, ES:NOTHING OR BUSY_FLAGS,00000010B ; SET BIOS BUSY BIT PUSHF CALL OLDINT13 ; DO THE BIOS FUNCTION PUSHF ; SAVE RESULT FLAGS AND BUSY_FLAGS,11111101B ; CLEAR BIOS BUSY BIT POPF ; GET BACK RESULT FLAGS STI ; MUST RETURN WITH INTERUPTS ON RET 2 ; RETURN BIOS RESULT FLAGS NEWINT13 ENDP ; ----------------------------------------------------------------------; ; INTERRUPT 16 ROUTINE. INSERT KEYSTROKES FROM BUFFER ; ; ----------------------------------------------------------------------; NEWINT16 PROC FAR ASSUME DS:NOTHING, ES:NOTHING PUSH BX CMP SEND_KEYS,1 ; SENDING KEYS FROM BUFFER? JE INSERT_KEY ; IF YES, THEN GET NEXT ONE CMP WRIT_FILE,1 ; ANYTHING TO WRITE TO DISK? JE CHECK_DOS_STAT ; IF YES, THIS IS THE TIME BIOS_KB: POP BX JMP OLDINT16 ; JUST DO NORMAL KB ROUTINE CHECK_DOS_STAT: CMP DOS_STAT,0AH ; DOING READ STRING? JE BEGIN_NOW ; IF YES, ITS SAFE TO BEGIN CMP DOS_STAT,8 ; DOING KEYBOARD INPUT? JNE BIOS_KB ; IF YES, ITS SAFE TO BEGIN BEGIN_NOW: STI ; GET INTERRUPTS BACK ON CALL WRITE_TO_FILE ; EMPTY THE BUFFER JMP BIOS_KB ; CONTINUE WITH BIOS ROUTINE INSERT_KEY: STI ; INTERRUPTS BACK ON MOV BX,BUFF_NEXT ; GET ADDRESS OF NEXT BYTE CMP BX,BUFF_LAST ; AT END OF BUFFER YET? JL GET_A_KEY ; IF NOT, GET THE NEXT ONE MOV SEND_KEYS,0 ; WHEN DONE, TURN OFF SEND SWITCH GET_A_KEY: MOV AL,CS:[BX] ; GET THE NEXT KEY CODE CMP AL,10 ; IS IT A LINE FEED? JNE NOT_LF ; DONT RETURN THE LINE FEEDS INC BUFF_NEXT ; SKIP TO NEXT KEY JMP INSERT_KEY NOT_LF: CMP AH,1 ; REQUEST FOR STATUS ONLY? JE RETURN_STATUS ; IF YES, RETURN STATUS ONLY CMP AH,0 ; REQUEST TO GET THE NEXT KEY JNE BIOS_KB ; IF NOT, IGNORE THIS FUNCTION INC BX ; REMOVE THIS KEY FROM OUR BUFFER MOV BUFF_NEXT,BX ; SAVE THE POINTER TO NEXT KEY RETURN_STATUS: OR BL,1 ; CLEAR ZERO FLAG TO INDICATE A POP BX ; KEY IS AVAILIABLE RET 2 ; RETURN WITH THESE FLAGS NEWINT16 ENDP ; ----------------------------------------------------------------------; ; INTERRUPT 21 ROUTINE. THIS ROUTINE IS USED TO MONITOR DOS FUNCTION ; ; CALLS. IF THE BUFFER NEEDS TO BE FLUSHED, IT WIL BE DONE HERE. ; ; ----------------------------------------------------------------------; NEWINT21 PROC FAR ASSUME DS:NOTHING, ES:NOTHING STI OR AH,AH ; DOING FUNCTION ZERO? JNE NOT_ZERO MOV AH,4CH ; IF YES, CHANGE IT TO A 4CH NOT_ZERO: OR BUSY_FLAGS,00000001B ; SET DOS BUSY BIT MOV DOS_STAT,AH PUSHF ; SIMULATE AN INTERRUPT CALL OLDINT21 ; DO THE DOS FUNCTION PUSHF ; SAVE THE RESULT FLAGS AND BUSY_FLAGS,11111110B ; CLEAR DOS BUSY BIT CMP WRIT_FILE,1 ; ANYTHING TO WRITE TO DISK? JNE NO_WRITE ; IF NOT JUST RETURN CALL WRITE_TO_FILE ; SAFE TO ACCESS DISK NOW NO_WRITE: POPF ; RECOVER DOS RESULT FLAGS RET 2 ; RETURN WITH DOS RESULT FLAGS NEWINT21 ENDP ; ----------------------------------------------------------------------; ; NEW INTERRUPT 24H (CRITICAL DOS ERROR). THIS INTERRUPT IS ONLY IN ; ; EFFECT ONLY DURING A WRITE SCREEN. IT IS REQUIRED TO SUPPRESS THE ; ; 'ABORT, RETRY, IGNORE' MESSAGE. ALL FATAL DISK ERRORS ARE IGNORED. ; ; ----------------------------------------------------------------------; NEWINT24 PROC FAR ASSUME CS:CSEG, DS:NOTHING, ES:NOTHING STI ; TURN INTERRUPTS BACK ON INC ERR_STAT ; SET THE ERROR FLAG XOR AL,AL ; TELLS DOS TO IGNORE THE ERROR IRET ; THATS ALL WE DO HERE NEWINT24 ENDP ; ----------------------------------------------------------------------; ; HERE IS THE CODE USED TO INITIALIZE SNIPPER. ; ; ----------------------------------------------------------------------; ASSUME CS:CSEG, DS:CSEG, ES:CSEG INITIALIZE: LEA DX,COPYRIGHT MOV AH,9 ; DOS DISPLAY STRING SERVICE INT 21H ; DISPLAY TITLE MESSAGE ; SEARCH FOR AN PREVIOUSLY INSTALLED COPY OF SNIPPER NOT BYTE PTR START ; MODIFY TO AVOID FASLE MATCH XOR BX,BX ; START SEARCH AT SEGMENT ZERO MOV AX,CS ; COMPARE TO THIS CODE SEGMENT NEXT_SEGMENT: INC BX ; LOOK AT NEXT SEGMENT CMP AX,BX ; UNTIL REACHING THIS CODE SEG MOV ES,BX JE NOT_INSTALLED LEA SI,START ; SETUP TO COMPARE STRINGS MOV DI,SI MOV CX,16 ; 16 BYTES MUST MATCH REP CMPSB ; COMPARE DS:SI TO ES:DI OR CX,CX ; DID THE STRINGS MATCH? JNZ NEXT_SEGMENT ; IF NO MATCH, TRY NEXT SEGMENT LEA DX,INSTALLED_MSG JMP SHORT ERR_EXIT NOT_INSTALLED: MOV AH,30H INT 21H ; GET DOS VERSION NUMBER CMP AL,2 ; IS IT HIGHER THAN 2.0? JAE VER_OK ; IF YES, PROCEED LEA DX,BAD_DOS_MSG ERR_EXIT: MOV AH,9 ; DOS DISPLAY STRING SERVICE INT 21H ; DISPLAY ERRER MESSAGE RET ; RETURN TO DOS VER_OK: INC SI ; POINT TO FIRST PARAMETER MOV SI,81H ; POINT TO PARAMETER AREA CALL GET_PARAM ; GET FIRST PARAMETER (ROWS) PUSH AX ; SAVE THE ROW COUNT CALL GET_PARAM ; GET SECOND PARAMETER (COLUMNS) ADD AX,2 ; ADD SPACE FOR CR AND LF POP BX ; GET BACK FIRST PARAMETER MUL BX ; PRODUCT OF ROWS AND COLUMNS OR AX,AX ; WAS ANYTHING ENTERED? JZ NO_PARAMS ; IF NOT, USE DEFAULT VALUE CMP AX,10000 ; MAXIMUM BUFFER IS 10000 BYTES JLE SIZE_IS_OK MOV AX,10000 SIZE_IS_OK: ADD AX,BUFF_START MOV BUFF_END,AX ; SET THE NEW BUFFER SIZE NO_PARAMS: MOV AX,BIOS_SEG ; LOOK AT BIOS DATA AREA MOV ES,AX ASSUME ES:BIOS_SEG CMP ROWS,0 ; IS NUMBER OF ROWS ENTERED HERE JNE MUST_BE_EGA ; IF YES, AN EGA MAY BE PRESENT MOV ROWS,24 ; IF NOT EGA, MUST BE 24 ROWS MUST_BE_EGA: ASSUME ES:NOTHING MOV AX,3509H ; GET KEYBOARD BREAK VECTOR INT 21H MOV WORD PTR [OLDINT09],BX ; SAVE SEGMENT MOV WORD PTR [OLDINT09+2],ES; SAVE OFFSET MOV DX, OFFSET NEWINT09 MOV AX, 2509H INT 21H ; DOS FUNCTION TO CHANGE VECTOR MOV AX,3513H ; GET BIOS DISK INTERRUPT VECTOR INT 21H MOV WORD PTR [OLDINT13],BX ; SAVE SEGMENT MOV WORD PTR [OLDINT13+2],ES; SAVE OFFSET MOV DX, OFFSET NEWINT13 MOV AX, 2513H INT 21H ; DOS FUNCTION TO CHANGE VECTOR MOV AX,3516H ; GET KEYBOARD INPUT VECTOR INT 21H MOV WORD PTR [OLDINT16],BX ; SAVE SEGMENT MOV WORD PTR [OLDINT16+2],ES; SAVE OFFSET MOV DX, OFFSET NEWINT16 MOV AX, 2516H INT 21H ; DOS FUNCTION TO CHANGE VECTOR MOV AX,3521H ; GET DOS FUNCTION VECTOR INT 21H MOV WORD PTR [OLDINT21],BX MOV WORD PTR [OLDINT21+2],ES MOV DX, OFFSET NEWINT21 MOV AX, 2521H INT 21H ; DOS FUNCTION TO CHANGE VECTOR ; ----------------------------------------------------------------------; ; DEALLOCATE OUR COPY OF THE ENVIORNMENT. ; ; EXIT USING INT 27H. LEAVE CODE AND SPACE FOR BUFFER RESIDENT. ; ; ----------------------------------------------------------------------; MOV AX,DS:[002CH] ; GET SEGMENT OF ENVIORNMENT MOV ES,AX ; PUT IT INTO ES MOV AH,49H ; RELEASE ALLOCATED MEMORY INT 21H MOV DX,BUFF_END ; LEAVE THIS MUCH RESIDENT INT 27H ; TEMINATE AND STAY RESIDENT ; ------------------------------------------------------; ; GET_PARAM RETRIEVES AN INTEGER FROM THE COMMAND LINE. ; ; ------------------------------------------------------; GET_PARAM: XOR AX,AX ; CLEAR AX FOR TOTAL GET_DIGIT: MOV BL,[SI] ; GET CHARACTER INTO BL CMP BL,0DH ; IS IT THE LAST ONE? JE DONE INC SI ; POINT TO NEXT CHARACTER CMP BL,"," ; IS IT THE DELIMITER? JE DONE SUB BL,30H ; CONVERT ASCII TO INTEGER JC GET_DIGIT ; IS IT A VALID DIGIT CMP BL,9 JA GET_DIGIT ; IF NOT VALID, JUST SKIP IT MOV BH,10 ; TIMES 10 FOR NEXT DIGIT MUL BH ; MULTIPLY SUM AND ADD THIS DIGIT ADD AL,BL ; ADD DIGIT TO SUM JMP GET_DIGIT ; READ ALL CHARACTERS ON LINE DONE: RET CSEG ENDS END START