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Assembly Source File | 1988-04-12 | 25.7 KB | 813 lines

;---------------------------------------------------------------------- ; SPECTRUM is a memory resident utility that allows the EGA palette ; registers to be mapped to any of the 64 possible colors provided by ; the EGA. The interface uses the cursor pad keys to select and change ; the colors. RIGHT/LEFT arrow selects the color to be mapped. UP/DOWN ; arrow changes the 2/3 intensity color bits RGB. PGUP/PGDN changes the ; 1/3 intensity color bits rgb. Home restores the default color mapping. ; ESC exits and restores the colors at entry. END exits and makes the ; current screen colors permanent. SPECTRUM is reasonably colorfast, but ; if colors are lost, pop up and exit SPECTRUM to restore the colors. ;====================================================================== CSEG SEGMENT PARA PUBLIC 'CODE' ORG 100H ;COM file format ASSUME CS:CSEG,DS:CSEG,ES:CSEG,SS:CSEG ;---------------------------------------------------------------------- ; Equates - substituted literally when assembled. ;---------------------------------------------------------------------- CR EQU 0DH ;HEX for carriage return LF EQU 0AH ; and line feed ;CTRL-TILDE HOTKEY EQU 29H ;SCAN code for tilde SHIFT_MASK EQU 04H ;Mask to pick out 'shifts' ;1000 = ALT 0100 = CTRL ;0010 = L SHIFT 0001 = R SHIFT NROW EQU 10 ;Number of rows in the window NCOL EQU 80 ;Number of cols in the window BOX_ROW EQU 10 ;Top row of window on screen BOX_COL EQU 0 ;Left col of window on screen BW_ATTR EQU 70H ;Monochrome window CO_ATTR EQU 17H ;Color window ;---------------------------------------------------------------------- ; COM file entry point is at 100h ;---------------------------------------------------------------------- ENTPT: JMP INITIALIZE ;Perform initialization COPYRIGHT DB "SPECTRUM 1.0 (c) 1987, Ziff-Davis Publishing Corp." DB CR,LF,"$",01AH AUTHOR DB "Programmed by Robert L. Hummel" ;---------------------------------------------------------------------- ; Data used by INT_9 procedure. Other data precedes other procedures. ;---------------------------------------------------------------------- OLD_INT_9 DD 0 ;Storage for old vectors OLD_INT_10 DD 0 OLD_INT_21 DD 0 DOS_FLAG DD 0 ;Address of dos critical flag INFO_PTR DD 00000487H ;0:487H ACTIVE DB 0 ;Inside pop-up LO_FN_FLAG DB 0 ;When inside Int 21h DISPLAY_PAGE DB 0 ;Used by screen save CURSOR_POS DW 0 ; to restore info ATTRIBUTE DB 0 ;Window color ;====================================================================== ; New Interrupt 9 routine. Invoked each key-press. ; Test to see if our key combination has been typed. ;---------------------------------------------------------------------- INT_9 PROC FAR ASSUME CS:CSEG, DS:NOTHING, ES:NOTHING, SS:NOTHING ;(Flags saved by INT) STI ;Allow interrupts PUSH AX ;Save used register IN AL,60H ;Get key scan code CMP AL,HOTKEY ;Check if hot-key JNE PROCESS_KEY ;If not, continue on. MOV AH,2 ;Get shift status fn INT 16H ;Thru BIOS AND AL,0FH ;Test only for 'shift' keys CMP AL,SHIFT_MASK ;If they match our combination JE OUR_KEY ;then is our signal PROCESS_KEY: POP AX ;Restore register JMP DWORD PTR CS:OLD_INT_9 ;Process key as normal OUR_KEY: ;---------------------------------------------------------------------- ; Reset the keyboard interrupt controller (forget the key stroke) ;---------------------------------------------------------------------- IN AL,61H ;These instructions reset MOV AH,AL ; the keyboard. OR AL,80H OUT 61H,AL MOV AL,AH JMP SHORT $+2 ;I/O delay for fast AT's OUT 61H,AL CLI ;Disable interrupts and MOV AL,20H ;reset the int controller OUT 20H,AL STI ;Allow interrupts ;---------------------------------------------------------------------- ; If SPECTRUM is already active, or DOS is busy, simply return. ;---------------------------------------------------------------------- CMP CS:ACTIVE,0 ;If already active JNE RETURN_A ; can't call again PUSH DS ;Save used registers PUSH BX LDS BX,CS:DOS_FLAG ;If DOS critical flag is not CMP BYTE PTR [BX],0 ; busy (= 0) JE INVOKE ;We can pop up CMP CS:LO_FN_FLAG,0 ;If busy from low function JNE INVOKE ; of Int 21h, go pop up RETURN_B: POP BX ;Restore other registers POP DS RETURN_A: POP AX ;Restore register IRET ;Go back where we came from INVOKE: ;---------------------------------------------------------------------- ; Test, and pop up, only if the EGA is the active monitor. ;---------------------------------------------------------------------- LDS BX,CS:INFO_PTR ;Get address of info byte LDS BX,[BX] ; and then byte itself TEST BL,08H ;Bit = 0 if EGA is active JNZ RETURN_B ; else don't pop up ;----------------------------------------------------------------------------- ; Check for valid text video mode. Set colors for BW or color modes. ;----------------------------------------------------------------------------- MOV ATTRIBUTE,CO_ATTR ;Assume color window MOV AH,0FH ;Get current video mode fn INT 10H ; Thru BIOS MOV DISPLAY_PAGE,BH ;Save current page CMP AL,3 ;One of the color text modes? JBE MODE_OK ; thats ok MOV ATTRIBUTE,BW_ATTR ;Assume mono window CMP AL,7 ;MONO 80x25 is valid JNE RETURN_B ; else don't pop up MODE_OK: ;----------------------------------------------------------------------------- ; If here, routine becomes active, save all other used registers. ;----------------------------------------------------------------------------- INC CS:ACTIVE ;Set flag to prevent re-entry PUSH CX ;Save all registers for return PUSH DX PUSH DI PUSH SI PUSH ES PUSH BP PUSH CS ;Put our CS into these regs POP DS ;So we can find our data PUSH CS POP ES ;And our string moves ASSUME DS:CSEG,ES:CSEG ;Tell the Assembler ;----------------------------------------------------------------------------- ; Save the details of the current screen for later restoration. ;----------------------------------------------------------------------------- MOV AH,3 ;Get cursor position fn INT 10H ;Thru BIOS MOV CURSOR_POS,DX ;Save position ;----------------------------------------------------------------------------- ; Save section of screen we will be writing over. ;----------------------------------------------------------------------------- MOV DI,OFFSET SCREEN_BUF ;Destination for save MOV SI,0FFFFH ;Switch tells proc to save CALL SCREEN CALL CLR_BOX ;Clear box & draw border CALL SPECTRUM ;Do all color mapping ;----------------------------------------------------------------------------- ; Restore the screen to original state. ;----------------------------------------------------------------------------- MOV SI,OFFSET SCREEN_BUF ;Address of saved screen CALL SCREEN ;Restore MOV AH,2 ;Set Cursor position fn MOV DX,CURSOR_POS ;Restore old cursor position INT 10H ;Thru BIOS MOV ACTIVE,0 ;Turn off active flag POP BP ;Restore all used registers POP ES POP SI POP DI POP DX POP CX POP BX POP DS POP AX IRET ;Interrupt gets IRET INT_9 ENDP ;====================================================================== ; Spectrum data & equates. ;---------------------------------------------------------------------- RT_ARROW EQU 4DH ;Extended ASCII for keys LT_ARROW EQU 4BH UP_ARROW EQU 48H DN_ARROW EQU 50H PAGE_UP EQU 49H PAGE_DN EQU 51H END_KEY EQU 4FH HOME EQU 47H ESCAPE EQU 1BH ;ASCII for escape DEFAULT_COLORS DB 00H,01H,02H,03H,04H,05H,14H,07H ;Restore with home DB 38H,39H,3AH,3BH,3CH,3DH,3EH,3FH OLD_COLORS DB 00H,01H,02H,03H,04H,05H,14H,07H ;May be set by loader DB 38H,39H,3AH,3BH,3CH,3DH,3EH,3FH BOX_PTR DB 0 ;Arrow location counter ;---------------------------------------------------------------------- ; Display and set the colors for the EGA card by re-mapping the palette ; registers. Works best with EGD, but ok with CGD or MD. ;---------------------------------------------------------------------- SPECTRUM PROC NEAR ASSUME CS:CSEG, DS:CSEG, ES:CSEG MOV BOX_PTR,0 ;Point to 1st box CALL SP_3 ;Copy last known colors ;to scratch copy & set regs ;---------------------------------------------------------------------- ;Set the pointer to the first box and listen for the required keystrokes ; > move right to next box < move left to previous box ; ^ increment rgb signal v decrement rgb signal ; pgup increment RGB signal pgdn decrement RGB signal ; ESC abort changes END save changes ; HOME load default colors ;---------------------------------------------------------------------- SP_1: MOV AH,2 ;Position cursor fn MOV DH,BOX_ROW+5 ;Row MOV DL,BOX_PTR ;Column SHL DL,1 ; times 4 SHL DL,1 ADD DL,9 ; plus offset INT 10H ;Thru BIOS MOV AX,0E18H ;Write TTY, arrow char INT 10H ;Thru BIOS MOV AX,0E08H ;Backspace under it INT 10H ;THRU BIOS SP_2: XOR AH,AH ;Wait for keystroke in AL INT 16H ;Thru BIOS CMP AL,ESCAPE ;If ESCAPE character, leave JNE CMP_0A SP_3: MOV SI,OFFSET OLD_COLORS ;Copy old colors MOV DI,OFFSET NEW_COLORS ; to scratch copy SP_4: MOV CX,16 ;Bytes to move REP MOVSB ; move 'em CALL COLOR_BARS ;Set palette registers RET ;Return to calling procedure CMP_0A: XOR AL,AL ;If not extended ASCII JNZ SP_2 ; ignore it CMP AH,END_KEY ;END key means JNE CMP_0B MOV SI,OFFSET NEW_COLORS ;New colors become MOV DI,OFFSET OLD_COLORS ; permanent JMP SP_4 CMP_0B: CMP AH,HOME ;HOME means JNE CMP_0C MOV SI,OFFSET DEFAULT_COLORS ;Reset to power-up colors MOV DI,OFFSET NEW_COLORS ; in scratch copy CALL SP_4 ;Change the registers JMP SP_1 ;Go wait for more keys CMP_0C: CMP AH,RT_ARROW ;Right arrow means JNE CMP_1 INC BOX_PTR ; move to next box CMP_0: MOV AX,0E20H ;Write space over arrow INT 10H ;Thru BIOS AND BOX_PTR,15 ;Modulo 16 arithmetic JMP SP_1 ;Redraw arrow CMP_1: CMP AH,LT_ARROW ;Previous box JNE CMP_2 DEC BOX_PTR JMP CMP_0 ;Adjust pointer ;---------------------------------------------------------------------- ; Decode the palette value in case we need it. ;---------------------------------------------------------------------- CMP_2: XOR BH,BH ;What register are we MOV BL,BOX_PTR ; pointing to? MOV CL,BYTE PTR NEW_COLORS[BX] ;Get palette value MOV CH,CL ;Duplicate AND CX,3807H ;CH=rgb, CL=RGB CMP AH,UP_ARROW JNE CMP_3 INC CL ;Next RGB color CMP_2A: AND CL,7 ;7 = 00000111B JMP SHORT COMBINE CMP_3: CMP AH,DN_ARROW JNE CMP_4 DEC CL ;Previous RGB color JMP CMP_2A CMP_4: CMP AH,PAGE_UP JNE CMP_5 ADD CH,8 ;next rgb color CMP_4A: AND CH,38H ;38H = 00111000b JMP SHORT COMBINE CMP_5: CMP AH,PAGE_DN JNE CMP_6 ADD CH,38H ;Previous rgb color JMP CMP_4A COMBINE: OR CL,CH ;Combine CL & CH MOV BYTE PTR NEW_COLORS[BX],CL ;Update color table CALL COLOR_BARS ; and palette registers CMP_6: JMP SP_1 ;Wait for next keystroke SPECTRUM ENDP ;====================================================================== ; COLOR_BARS calls the EGA BIOS to map the attributes 0 thru 15 to the ; values in NEW_COLORS using the palette registers. To simplify use ; of the utility, the colors are labeled by a two digit number. The ; first digit is the decimal equivalent of the three major colors RGB. ; The second digit is rgb similarly. Finally, two rows of blocks of the ; color are displayed on screen. ; This routine depends heavily on values remaining in registers ; after BIOS calls. Pay attention when modifying. ; No registers are preserved. ;---------------------------------------------------------------------- COLOR_BARS PROC NEAR CLD ;String moves forward MOV SI,OFFSET NEW_COLORS ;Set palette value to these MOV CX,16 ;Number of palette values MOV DL,BOX_COL+8 ;Col for numerical labels CLR_BAR1: PUSH CX ;Save counter MOV DH,BOX_ROW+6 ;Row for register # labels MOV AH,2 ;Position cursor function MOV BH,DISPLAY_PAGE INT 10H ;Thru BIOS MOV AL,16 ;Get palette # SUB AL,CL ; in AL PUSH AX ;Save palette # XOR AH,AH AAA ;Convert AL to decimal digits MOV CL,4 ;AH=10's, AL=1's SHL AH,CL OR AL,AH CALL HEX2CON ;Write to screen SUB DH,4 ;Row for value # labels MOV AH,2 ;Position cursor function INT 10H ;Thru BIOS LODSB ;Get value in AL POP BX ;Retrieve palette # in BL MOV BH,AL ;Attribute in BH MOV AX,1000H ;Set palette register fn INT 10H ;Thru BIOS ;---------------------------------------------------------------------- ; Translate the hex color code into our (RGB)(rgb) numbering and display. ;---------------------------------------------------------------------- MOV AL,BH ;Retrieve attribute MOV AH,AL ;rgbRGB in both AH & AL MOV CL,3 ;Shift count SHR AL,CL ;Put rgb in lower 4 bits AND AH,7 ;RGB bits MOV CL,4 ;Shift count SHL AH,CL ;Put RGB in upper 4 bits OR AL,AH ;Combine into single byte CALL HEX2CON ;Print AL to CON as 2 hex ; digits. MOV BH,DISPLAY_PAGE DEC DL ;Box begins 1 col to the left CALL DRAW_BAR ;Draw two rows ADD DL,5 ;Col for next label POP CX ;Restore counter LOOP CLR_BAR1 RET COLOR_BARS ENDP ;====================================================================== ; DRAW_BAR - Draw two rows of Block graphics char to show foreground ; color. AX,DX,CX destroyed. ;---------------------------------------------------------------------- DRAW_BAR PROC NEAR CALL DRAW_1 ;Call ourself to repeat DRAW_1: INC DH ;Down one row MOV AH,2 ;Position cursor function INT 10H ;Thru BIOS MOV AX,09DBH ;Write repeated char/attr MOV CX,4 ; 4 copies of block INT 10H ; Thru BIOS RET ;Double duty DRAW_BAR ENDP ;====================================================================== ; HEX2CON - print AL to CON as 2 hex digits. ; AX destroyed. Other registers preserved. ;----------------------------------------------------------------------------- HEX2CON PROC NEAR PUSH AX ;Save reg for second digit PUSH CX ;Save CX for use in shift MOV CL,4 ;Shift 4 bits SHR AL,CL ;Get high 4 bits in low end POP CX ;Restore register CALL H2C ;Print the digit in AL POP AX ;Get back original AL AND AL,0FH ;Take second digit H2C: ADD AL,90H ;Convert AL to ASCII DAA ADC AL,40H DAA MOV AH,0EH ;Write TTY INT 10H ; Thru BIOS RET ;Double duty HEX2CON ENDP ;====================================================================== ; Perform the screen save/restore. ; SAVE: SI=FFFF, DI=buffer address ; RESTORE: SI=buffer address, DI=don't care ;---------------------------------------------------------------------- SCREEN PROC NEAR CLD ;String moves forward MOV BH,DISPLAY_PAGE ;Just to be sure, reset page MOV CX,NROW ;Row loop MOV DH,BOX_ROW ;Init row pointer ROW_LOOP: PUSH CX ;Prepare for... MOV CX,NCOL ;...column loop MOV DL,BOX_COL ;Column Pointer COL_LOOP: PUSH CX ;Need for write-char fn MOV AH,2 ;Position cursor fn INT 10H ;Thru BIOS CMP SI,0FFFFH ;SI =FFFF if SAVE JE DO_SAVE ;RESTORE LODSW ;AX <- [SI] ;AH=ATTR AL=CHAR MOV BL,AH ;Put attribute where needed MOV AH,9 ;Write char fn MOV CX,01 ;Write one copy of char INT 10H ;Thru BIOS JMP SHORT DO_LOOP DO_SAVE: MOV AH,8 ;Get char & attribute fn INT 10H ;Thru BIOS STOSW ;[di+=2]=ax DO_LOOP: INC DL ;Next column POP CX ;Restore Counter LOOP COL_LOOP ;Close Inner loop POP CX ;Return to outer loop INC DH ;Next row LOOP ROW_LOOP ;Close Outer loop RET SCREEN ENDP ;====================================================================== ; Clear a window (box) for our information on the screen. ; Add a border, name, and help line for a nice touch. ;---------------------------------------------------------------------- BOX_MSG DB BOX_COL+2,BOX_ROW,0B5H,"SPECTRUM 1.0",0C6H,0 BOX_CHARS DB 0C9H,0CDH,0BBH,0BAH,020H,0BAH,0C8H,0CDH,0BCH HELP_MSG DB BOX_COL+7,BOX_ROW+NROW-2 DB "COLOR=",27,26," RGB=",24,25," rgb=PgUp/Dn " DB "Save=END Cancel=ESC Default=HOME",0 CLR_BOX PROC NEAR MOV AX,0600H ;Scroll entire window fn MOV CH,BOX_ROW ;Upper row MOV CL,BOX_COL ;Left column MOV DH,BOX_ROW + NROW - 1 ;Bottom row MOV DL,BOX_COL + NCOL - 1 ;Right column MOV BH,ATTRIBUTE ;Window color INT 10H ;Thru BIOS MOV BH,DISPLAY_PAGE ;Use current page MOV SI,OFFSET BOX_CHARS ;Window border chars MOV DX,CX ;Cursor from last call MOV CX,NROW ;Number of rows to draw CB_1: PUSH CX ;Save counter MOV DL,BOX_COL ;Starting column MOV AH,2 ;Position cursor INT 10H ; Thru BIOS LODSB ;Get leftmost char MOV AH,0EH ;Write char TTY INT 10H ; Thru BIOS LODSB ;Get middle char MOV AH,0AH ;Write repeated char MOV CX,NCOL-2 ; This many times INT 10H ; Thru BIOS MOV AH,2 ;Position cursor MOV DL,BOX_COL + NCOL - 1 ;Col = righthand edge INT 10H ; Thru BIOS LODSB ;Get rightmost char MOV AH,0EH ;Write char TTY INT 10H ; Thru BIOS INC DH ;Next row POP CX ;Restore counter CMP CL,NROW ;If first row JE CB_2 ; choose next 3 chars CMP CL,2 ;If last row JE CB_2 ; choose next 3 chars SUB SI,3 ;Else, repeat these 3 again CB_2: LOOP CB_1 ;Row loop MOV SI,OFFSET BOX_MSG ;Write program name on box CALL WR_MESSAGE MOV SI,OFFSET HELP_MSG ;And help line on bottom CALL WR_MESSAGE RET CLR_BOX ENDP ;====================================================================== ; Fill in the window information on screen. String format is col,row,text,0. ; DS:SI points to string. ;---------------------------------------------------------------------- WR_MESSAGE PROC NEAR MOV BH,DISPLAY_PAGE ;This page LODSW ;Get intended position MOV DX,AX ; in DX MOV AH,2 ;Position cursor MSG_LOOP: INT 10H ;Thru BIOS MOV AH,0EH ;Write AL as TTY LODSB ;Get next char OR AL,AL ;If 0, end of string JNZ MSG_LOOP ; else, repeat RET WR_MESSAGE ENDP ;====================================================================== ; Video Int 10h intercept. If mode is changed, reset colors. ; A font load changes modes internally and causes a reload. ;---------------------------------------------------------------------- INT_10 PROC FAR OR AH,AH ;If video mode change JZ VIDEO_1 ; handle specially CMP AH,11H ;Or possible font load JZ VIDEO_1 ; (internal mode change) JMP DWORD PTR CS:OLD_INT_10 ;Resume old Video interrupt VIDEO_1: STI ;Allow interrupts PUSHF ;Simulate original interrupt CALL DWORD PTR CS:OLD_INT_10 ; and return here PUSH AX ;Save used registers PUSH BX MOV AH,0FH ;Get current video mode INT 10H ; Thru BIOS CMP AL,4 ;If color text modes JBE VIDEO_2 CMP AL,7 ; or mono text mode JNE VIDEO_4 VIDEO_2: PUSH CX ;Reset the palette regs PUSH SI MOV CX,16 ;# of registers to set MOV SI,OFFSET CS:OLD_COLORS+15 ;end of colors VIDEO_3: MOV AX,1000H ;Set palette register MOV BL,CL DEC BL ;Palette # in BL MOV BH,CS:[SI] ;Attribute in BH DEC SI ;Move pointer INT 10H ; Thru BIOS LOOP VIDEO_3 POP SI ;Restore registers POP CX VIDEO_4: POP BX POP AX RET 2 ;Far return, pop flags ;to simulate IRET INT_10 ENDP ;====================================================================== ; DOS Int 21h intercept. Set flag while uninterruptable ; The purpose of this procedure is to keep pop-up from taking control ; of the machine when doing so would cause a crash. ; (Function 0 changed to 4CH to avoid DOS problems with CS register.) ;---------------------------------------------------------------------- INT_21 PROC FAR MOV CS:LO_FN_FLAG,0 ;Assume Not function 1-Ch CMP AH,0 ;If program is using DOS fn 0 JNE CHECK MOV AH,4CH ;Change it to 4Ch GO_DIRECT: JMP DWORD PTR CS:OLD_INT_21 ;Jump to original routine CHECK: CMP AH,0CH ;DOS functions call under 0DH JA GO_DIRECT INC CS:LO_FN_FLAG ;Is low function PUSHF ;Simulate interrupt CALL DWORD PTR CS:OLD_INT_21 ; with FAR CALL MOV CS:LO_FN_FLAG,0 ;Turn off flag RET 2 ;Return to INT source and ;discard old flags INT_21 ENDP ;====================================================================== ; Data here is allocated after the program loads into memory to save space ; in the COM file so the basic listing will be smaller. ; PC variable used to keep track of relative addresses. ;---------------------------------------------------------------------- PC = $ ;Set imaginary counter SCREEN_BUF = PC ;DB NROW*NCOL*2 DUP(?) PC = PC + NROW * NCOL * 2 NEW_COLORS = PC ;DB 16 DUP(?) PC = PC + 16 LAST_BYTE = PC ;====================================================================== ; Hook the necessary interrupts to avoid a collision. ; Terminate and Stay Resident (TSR). ;---------------------------------------------------------------------- INITIALIZE PROC NEAR ASSUME CS:CSEG, DS:CSEG, ES:NOTHING, SS:CSEG MOV DX,OFFSET COPYRIGHT ;Say who we are as we leave MOV AH,9 ;Display string function INT 21H ;Thru DOS ;---------------------------------------------------------------------- ; If command line parameters are present, load them into the registers ;---------------------------------------------------------------------- CMP BYTE PTR DS:[80H],48 ;Must be 48 chars min to load JB NO_ARGS MOV SI,82H ;First parameter MOV DI,OFFSET OLD_COLORS ;Destination MOV CX,16 PARM_LOOP: LODSW ;Get digits AND AX,0CFCFH ;Ascii to hex SHL AH,1 SHL AH,1 SHL AH,1 OR AL,AH ;Combine in AH STOSB ;Put in OLD_COLORS INC SI ;Skip past delimiter MOV BH,AL ;Palette value in BH MOV AX,1000H ;Set palette fn MOV BL,16 ;Get palette number SUB BL,CL ; in BL INT 10H ;Thru BIOS LOOP PARM_LOOP NO_ARGS: ;---------------------------------------------------------------------- ; Check if already loaded in memory. Don't load multiple copies. ;---------------------------------------------------------------------- MOV WORD PTR [ENTPT+0],0 ;Modify to avoid false match MOV WORD PTR [ENTPT+2],0 XOR BX,BX ;BX = segment to compare MOV AX,CS ;AX = our segment NEXT_PARA: INC BX ;Next paragraph CMP AX,BX ;If current paragraph... MOV ES,BX ;Set search segment JE END_SEARCH ;...stop MOV SI,OFFSET COPYRIGHT ;String to compare MOV DI,SI ;Offset is same MOV CX,16 ;Compare first 16 bytes REP CMPSB ;CMP DS:SI TO ES:DI OR CX,CX ;All matched? JNZ NEXT_PARA ;No. ;Found a copy in memory CMP BYTE PTR DS:[80H],48 ;If no parameters JL LEAVE_NO_TRACE ; do nothing MOV SI,OFFSET OLD_COLORS ;Load colors into memory MOV DI,SI MOV CX,16 REP MOVSB ;From DS:SI to ES:DI LEAVE_NO_TRACE: MOV AX,4C01H ;Terminate with 'error' INT 21H ;Thru DOS END_SEARCH: ;---------------------------------------------------------------------- ; Get a pointer to the DOS Critical Flag, a one-byte location in low memory ; that is set when DOS is in an uninterruptable state. Location is returned ; in ES:BX. This is undocumented, but works in DOS 2.0 - 3.21 ;---------------------------------------------------------------------- MOV AH,34H ;Get Interrupt Flag address INT 21H MOV WORD PTR DOS_FLAG[0],BX ;offset MOV WORD PTR DOS_FLAG[2],ES ;segment ;---------------------------------------------------------------------- ; Hook the keyboard interrupt 9h for the hot-key detection routine. ; Hook DOS Interrupt 21h to set busy flag. ;---------------------------------------------------------------------- PUSH DS ;Reset ES to point to same POP ES ; segment as DS MOV AL,9 ;Interrupt number MOV DI,OFFSET OLD_INT_9 ;Store vector here MOV DX,OFFSET INT_9 ;New interrupt procedure CALL SET_INT ;Make change MOV AL,10H MOV DI,OFFSET OLD_INT_10 MOV DX,OFFSET INT_10 CALL SET_INT MOV AL,21H MOV DI,OFFSET OLD_INT_21 MOV DX,OFFSET INT_21 CALL SET_INT ;---------------------------------------------------------------------- ; Deallocate the copy of the environment loaded with the program. ; Establish memory residency and terminate. ;---------------------------------------------------------------------- MOV AX,WORD PTR DS:[2CH] ;Address of environment MOV ES,AX ;In ES register MOV AH,49H ;Release allocated memory INT 21H ;Thru DOS MOV DX,(OFFSET LAST_BYTE - OFFSET CSEG + 15) SHR 4 MOV AX,3100H ;Keep (TSR) INT 21H ;Thru DOS INITIALIZE ENDP ;====================================================================== ; Get/Save/Set the interrupt vector. AL contains vector number. ; ES:DI points to DWORD destination for old address. ; DS:DX points to new interrupt address. AX destroyed. ;---------------------------------------------------------------------- SET_INT PROC NEAR ASSUME CS:CSEG, DS:CSEG, ES:CSEG, SS:CSEG PUSH AX ;Save vector # in AL MOV AH,35H ;Get address function INT 21H ;Thru DOS MOV WORD PTR [DI+0],BX ;Save address in ES:DI MOV WORD PTR [DI+2],ES POP AX ;Get AL back MOV AH,25H ;Set new address to DS:DX INT 21H ;Thru DOS RET SET_INT ENDP CSEG ENDS END ENTPT