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Assembly Source File | 1989-06-26 | 25.9 KB | 791 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 INIT ;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 1.1 (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 INIT 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 UNTILL 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 lo er 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 PUSHF ;SAVE ENTRY FLAGS STI ;ALLOW INTERRUPTS CMP AH,4BH ;IF EXEC JNE NOT_EXEC POPF JMP CS:OLDINT21 ;GO DIRECT NOT_EXEC: 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 POPF ;RESTORE ORIGINAL FLAGS PUSHF ;SIMULATE AN INTERRUPT CALL CS: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 STI 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 INIT: 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