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Assembly Source File | 1993-05-10 | 34.9 KB | 644 lines

; ; Program ScrBlank ( Chapter 11 ) ; page 55,132 ; ; This program installs additional handlers for following interrupts: ; 09h - keyboard ; 1Ch - timer ; 10h - video ; 33h - mouse ; 2Fh - multiplex handler ; ; New function 193 (0C1h) is added to interrupt 2Fh ; This function has following subfunctions: ; 00 - installation check ; 01 - activates the driver ; 02 - deactivates the driver ; 03 - report the driver state; returns the state in AH (1 - on, 2 - off) ; 04 - switch border blinking On/Off ; To call new function put its number into the AH register, ; the subfunction number into AL and call interrupt 1Ch ; NewFunc equ 0E0h TSRId equ 193 CheckIn equ 0 ; subfunction "check installation" SwOn equ 1 ; subfunction "turn program on" SwOff equ 2 ; subfunction "turn program off" RepSt equ 3 ; subfunction "report status" RestPal equ 4 BordSw equ 5 InAct equ 0 ; this value indicates "INACTIVE" Act equ 13h ; this value indicate "ACTIVE" BlinkB equ 1 MaxTick equ 5460 ; 5460 ticks = 5 minutes _Text segment para public 'CODE' assume cs:_Text,ds:nothing,es:nothing ;==================== Resident data ===================================== org 90h ;=== COM - variant jmp Start ;=== COM - Variant ActInd db Act ; activity indicator; if 0 - inactive NumTick dw 0 ; number of timer ticks since last key NumTk1 dw 0 BlankId db 0 ; screen blank indicator; if 0 - not blankedA Blanked equ 13h ; signature "screen is blanked" BIOSSeg dw 40h ; segment address of BIOS data area ComSeg dw 0 ; segment addres of resident part (CS) IndStat db 0 Within equ 13 ; sign of using INT 10 from ScrBlank ZerPal db 16 dup (0), 0 ; zero value for palette registers CurPal db 0,1,2,3,4,5,14h,7,38h,39h,3Ah,3Bh,3Ch,3Dh,3Eh,3Fh,0 Border db 0 DefBord db 0 BlinkId db 0 PresEGA db 0 ;=== save area for registers AX09 dw 0 BX09 dw 0 CX09 dw 0 DX09 dw 0 ES09 dw 0 FLAG09 db 0 AX1C dw 0 BX1C dw 0 CX1C dw 0 DX1C dw 0 ES1C dw 0 FLAG1C db 0 org 100h ;=== COM - Variant Addr100:jmp start ;=== COM - Variant ;===================== Resident code ==================================== RestScr proc near cmp PresEGA,0 ; is EGA/VGA present? jnz REGAVGA ; if so, use EGA/VGA BIOS functions ;=== Restore screen for CGA/MDA/Hercules mov es,BIOSSeg ; BIOS data accessable through ES mov al,es:[65h] ; get current content of mode register or al,08h ; set bit "video enable" mov es:[65h],al ; put changed content of mode register mov dx,3B8h ; address of video port - MDA/Hercules out dx,al ; set mode register to "beam on" mov dl,0D8h ; low part of address - CGA out dx,al ; set mode register to "beam on" mov IndStat,Within ; set indicator "Within Scrblank" mov ax,0B00h ; function 0Bh - Set Border/Palette mov bh,0 ; subfunction 00h - Set Border Color mov bl,DefBord ; BL - default border color int 10h ; BIOS video service call mov IndStat,0 ; clear indicator "Within ScrBlank" jmp ExRest ; exit from additional handler ;=== Restore screen for EGA/VGA REGAVGA:mov ax,1002h ; function "set all palette registers" mov es,ComSeg ; ES points to current segment mov dx,offset CurPal ; address of 17 defualt palette mov IndStat,Within ; set indicator "Within Scrblank" int 10h ; BIOS video service call mov IndStat,0 ; clear indicator "Within ScrBlank" ExRest: ret ; exit from procedure RestScr endp BlnkScr proc near ;=== Blank the screen mov BlankId,Blanked ; set blank indicator mov NumTick,0 ; clear ticks counter mov Border,0 ; border will be black (first in chain) mov NumTk1,0 ; clear counter for border blinking cmp PresEGA,0 ; EGA/VGA adapter present? jnz BEGAVGA ; if so, process EGA/VGA ;--- Blank the screen for CGA/MDA/Hercules mov es,BIOSSeg ; BIOS data accessable through ES mov al,es:[65h] ; get current content of mode register and al,not 08h ; clear bit "video enable" mov es:[65h],al ; put changed content of mode register mov dh,3 ; high part of video port address mov dl,0B8h ; low part of address - MDA/HERCULES out dx,al ; set mode register to "beam off" mov dl,0D8h ; low part of address - CGA out dx,al ; set mode register to "beam off" jmp ExBln ;--- Blank the screen for EGA/VGA BEGAVGA:mov ax,1002h ; function "set all palette registers" mov es,ComSeg ; ES points to current segment mov dx,offset ZerPal ; address of 17 zero values into ES:DX mov IndStat,Within ; set indicator "Within Scrblank" int 10h ; BIOS video service call mov IndStat,0 ; clear indicator "Within ScrBlank" ExBln: ret BlnkScr endp BliBord proc near ;=== is it time to change the border color? inc NumTk1 ; number of ticks before changing border cmp NumTk1,91 ; have 5 seconds gone? jl ExBord ; if not, exit from handler ;=== test whether blinking border is requested cmp BlinkId,BlinkB ; blinking requested jne ExBord ; if not, exit from handler ;=== prepare the new color value mov NumTk1,0 ; clear counter of ticks for border inc Border ; next color of border and Border,03h ; only colors 0-3 valid (CGA compatible) ;=== set the new border color mov ax,0B00h ; function 0Bh - "Set Palette/Border" mov bh,0 ; subfunction 00h - Set Border Color mov bl,Border ; BL - border color mov IndStat,Within ; set indicator "Within Scrblank" cmp PresEga,0 ; EGA/VGA present? jnz BliEGA int 10h ; BIOS video service call jmp ClStat ;=== make border blinking on EGA/VGA BliEGA: xchg bh,bl ; Border Color into BH, zero into BL mov ah,10h ; function 10h - Get/Set Palette mov al,01h ; subfunction 01h - Set Border Color int 10h ; BIOS video service call ClStat: mov IndStat,0 ; clear indicator "Within ScrBlank" ExBord: ret ; exit from procedure BliBord endp NewMous proc near ;=== save AX and flags mov AX33,ax ; save original value of AX register lahf ; original flags into AH register mov Flag33,ah ; save original flags mov ax,AX33 ; restore original value of AX register ;=== check function of mouse handler cmp al,0Bh ; read motion counters? je CallMou ; if so, call original handler cmp al,04h ; position cursor? je CallMou ; if so, call original handler cmp al,03h ; read mouse state? jne ToOldM ; if not, to old handler ;=== call original handler CallMou:pushf call dword ptr StdMous ; call standard handler ;=== check whether buttons state and mouse location changed since last call mov ax,AX33 ; restore original value of AX register TstBX: cmp bx,PrevBX ; buttons state changed? jne RestS ; to saving current position and state TstCX: cmp cx,PrevCX ; X coordinate changed? jne RestS ; to saving current position and state TstDX: cmp dx,PrevDX ; Y coordinate changed? jne RestS ; to saving current position and state jmp ToOldM ; to original mouse handler ;=== restore AX and flags and exit from the handler Exit33: mov ah,FLAG09 ; original flags int AH register sahf ; restore original flags mov ax,AX33 ; restore original value of AX register mov NumTick,0 ; mouse active - clear ticks counter iret ; exit from handler ;=== save buttons state and mouse location for next use RestS: mov PrevBX,bx ; save current buttons state mov PrevCX,cx ; save current X coordinate mov PrevDX,dx ; save current Y coordinate ;=== check if screen is blanked and restore it if mouse is active ProcM: cmp BlankId,Blanked ; is screen blanked? jne Exit33 ; if not - nothing to do mov BlankId,0 ; clear blank indicator mov NumTick,0 ; mouse active - clear ticks counter ;--- save register used mov BX33,bx ; save original value of BX register mov CX33,cx ; save original value of CX register mov DX33,dx ; save original value of DX register mov ES33,es ; save original value of ES register call RestScr ;--- restore registers mov es,ES33 ; restore original value of ES register mov dx,DX33 ; restore original value of DX register mov cx,CX33 ; restore original value of CX register mov bx,BX33 ; restore original value of BX register jmp Exit33 ;=== pass the control to the standard handler of the interrupt 33h ToOldM: mov ah,FLAG09 ; original flags int AH register sahf ; restore original flags mov ax,AX33 ; restore original value of AX register jmp dword ptr StdMous StdMous dw ?,? OldOffM equ StdMous[0] ; here will be ofsset OldSegM equ StdMous[2] ; here will be segment Flag33 db ? AX33 dw ? BX33 dw ? CX33 dw ? DX33 dw ? ES33 dw ? PrevBX dw 0 PrevCX dw 0 PrevDX dw 0 NewMous endp NewInt9 proc near ; additional handler for interrupt 09h mov AX09,ax ; save original value of AX register lahf ; original flags into AH register mov FLAG09,ah ; save original flags mov NumTick,0 ; key pressed - clear ticks counter cmp BlankId,Blanked ; is screen blanked? jne ToOld9 ; if not - nothing to do mov BlankId,0 ; clear blank indicator ;=== Save register used mov BX09,bx ; save original value of BX register mov CX09,cx ; save original value of CX register mov DX09,dx ; save original value of DX register mov ES09,es ; save original value of ES register call RestScr ;=== Read a key from keyboard and ignore this keystroke GetKey: in al,60h ; read key code in al,61h ; read port B of PIC or al,80h ; set bit 7 to 1 out 61h,al ; send this value inti port B jmp $+2 ; wait for some time on fast PCs and al,not 80h ; clear bit 7 out 61h,al ; send into port B mov al,20h ; signal "end of interrupt processing" out 20h,al ; send to Interrupt Controller ;=== restore registers mov ah,FLAG09 ; original flags int AH register sahf ; restore original flags mov es,ES09 ; restore original value of ES register mov dx,DX09 ; restore original value of DX register mov cx,CX09 ; restore original value of CX register mov bx,BX09 ; restore original value of BX register mov ax,AX09 ; restore original value of AX register iret ;=== Pass the control to the standard handler of the interrupt 09h ToOld9: mov ah,FLAG09 ; original flags int AH register sahf ; restore original flags mov ax,AX09 ; restore original value of AX register db 0EAh ; this is code for JMP FAR OldOff9 dw 0 ; here will be ofsset OldSeg9 dw 0 ; here will be segment NewInt9 endp NewInt10 proc pushf ; push original flag onto stack cmp IndStat,Within ; INT 10 requested from ScrBlank? je ToOld10 ; if so, go to standard handler cmp ah,10h ; palette/border servicing? jne ToOld10 ; if not, to old handler cmp al,00h ; Set Palette Register function? jne Not00h ; if not - check other function mov al,bh ; save original color value mov bh,0 ; BX contains number of register mov CurPal[bx],al ; change color value in paleete mov bh,al ; restore original color value mov al,0 ; restore value 00 for AL register jmp ToOld10 ; to original handler of INT 10h Not00h: cmp al,01h ; Set Border Color function? jne Not01h ; if not - check for other function mov CurPal[16],bh ; save changed border color jmp ToOld10 ; if not, to old handler Not01h: cmp al,02h ; Set Entire Palette Function jne Not02h ; if not - check other function mov CX10,cx ; save CX register mov cx,17 ; CX will be cycle counter mov BX10,bx ; save BX register mov bx,0 ; BX - number of source register mov DI10,di ; save DI register mov di,dx ; offset of new pallete (ES:DX) into DX CopyPal:mov al,es:[di] ; copy one paleete register into AL mov CurPal[bx],al ; save it for screen restoring inc bx ; advance target (palette for restoring) inc di ; advance source (palette to be set now) loop CopyPal ; next step (17 times) mov cx,CX10 ; restore CX mov bx,BX10 ; restore CX mov di,DI10 ; restore DI mov al,02h ; restore AL jmp ToOld10 ; to old handler Not02h: cmp ah,0Bh ; Set Palette/Border function (CGA)? jne Not0Bh ; if not - check other function cmp bh,0 ; Set Border Color subfunction? jne Not0Bh ; if not, check for other functions mov CurPal[16],bl ; save changed border color (EGA/VGA) mov DefBord,bl ; save changed border color (CGA) jmp ToOld10 ; to old handler Not0Bh: ToOld10:popf db 0EAh ; this is code for JMP FAR OldO10 dw 0 ; here will be ofsset OldS10 dw 0 ; here will be segment BX10 dw ? CX10 dw ? DI10 dw ? NewInt10 endp ;=== Handler proc near ; additional handler for interrupt 1Ch mov AX1C,ax ; save original value of AX register lahf ; original flags into AH register mov FLAG1C,ah ; save original flags mov ax,AX1C ; restore original value of AX register cmp ActInd,Act ; is activity indicator set? jne ToOld1C ; if not, pass control to old handler ;=== Check whether the screen is already blanked Process:mov BX1C,bx ; save original value of BX register mov CX1C,cx ; save original value of CX register mov DX1C,dx ; save original value of DX register mov ES1C,es ; save original value of ES register cmp BlankId,Blanked ; is screen blanked? jne ChkTime ; if not, check whether time has gone call BliBord ; show blinking border jmp Rest1C ;=== Has the time gone? ChkTime:inc NumTick ; increase ticks counter cmp NumTick,MaxTick ; is it time to blank screen jl Rest1C ; if not, procced to standard handler call BlnkScr ;=== Restore registers Rest1C: mov es,ES1C ; restore original value of ES register mov dx,DX1C ; restore original value of DX register mov cx,CX1C ; restore original value of CX register mov bx,BX1C ; restore original value of BX register ;=== Pass the control to the standard handler of the interrupt 1Ch ToOld1C:mov ah,FLAG1C ; original flags into AH register sahf ; restore original flags mov ax,AX1C ; restore original value of AX register db 0EAh ; this is code for JMP FAR OldOffC dw 0 ; here will be ofsset OldSegC dw 0 ; here will be segment Handler endp MulHand proc near ; NEW MULTIPLEX HANDLER pushf ; push original flags cmp ah,TSRId ; is user function specified? jne ToOld2F ; if not - to old handler cmp bx,AddSign ; does BX contain additional signature jne ToOld2F ; if not - caller isn't ScrBlank cmp al,CheckIn ; Installation Check? jne Other1 ; if not - check for other function mov al,0FFh ; standard convention for Presence mov bx,PresSign ; presence signature into BX Other1: cmp al,SwOn ; function "Switch ON?" jne Other2 ; if not, continue testing mov ActInd,Act ; set indicator to ACTIVE (ON) jmp Exit2F ; to exit from handler Other2: cmp al,SwOff ; function "Switch OFF"? jne Other3 ; if not, continue testing mov ActInd,InAct ; set indicator to INACTIVE (OFF) jmp Exit2F ; to exit from handler Other3: cmp al,RepSt ; function "Report state"? jne Other4 ; if not, continue testing mov ah,ActInd ; set indicator to INACTIVE (OFF) jmp Exit2F ; to exit from handler Other4: cmp al,BordSw ; function "Toggle Border Blinking" jne Other5 ; if not, continue testing xor BlinkId,BlinkB ; toggle blinking indicator mov ah,BlinkId ; return new blinking state jmp Exit2F ; to exit from handler Other5: Exit2F: popf iret ToOld2F:popf JMPto2F:jmp dword ptr Old2Fh Old2Fh dw ?,? OldmulO equ Old2Fh[+0] OldMulS equ Old2Fh[+2] MulHand endp AddSign dw 1951 PresSign dw 7654 ;=== Installation part of the program BegInst label byte ; This is start of installation part ParmInd db 0 PspAddr dw ? RetCode db 0 InvPCod equ 16 HelpCod equ 5 DefPal db 0,1,2,3,4,5,14h,7,38h,39h,3Ah,3Bh,3Ch,3Dh,3Eh,3Fh,0 ;=== Set segment register Start: mov ah,51h ; get PSP address (undocumented) int 21h ; DOS service call mov PspAddr,bx ; save segment address of PSP mov ComSeg,cs ; save address of command segment mov sp,0F000h ; set stack to command segment's top mov es,PspAddr ; ES points to PSP mov ds,ComSeg ; DS = CS - data and code are the same ;=== Check whether the program is already installed mov ah,TSRId ; user subfunction of multiplex handler mov al,CheckIn ; AL - installation check mov bx,AddSign ; BX - additional signature int 2Fh ; multiplex handler call cmp al,0FFh ; common convention satisfied: jne InsSta ; if not - start installation cmp bx,PresSign ; does BX contain presence signature? jne InsSta ; if not - start installation jmp Already ; otherwise program is already installed ;=== The process of installation starts here ;=== Free the environment memory block InsSta: mov es,es:[2Ch] ; address of environment block into ES mov ah,49h ; function 49h - free memory block int 21h ; DOS service call ;=== Test whether EGA/VGA are present mov PresEGA,10h mov bl,10h ; 10h - get EGA/VGA configuration mov ah,12h ; function 12h - get/set information int 10h ; BIOS video service call xor PresEGA,bl ; if EGA/VGA present PresEGA <> 0 ;=== set internal variables for resident part mov es,PspAddr ; ES points to start of PSP mov ActInd,Act ; program is ON immediately after start mov NumTick,0 ; clear counter for screen blanking mov NumTk1,0 ; clear counter for border colors play mov BlankId,0 ; screen isn't blanked mov IndStat,0 ; INT 10h isn't called from within TSR mov BlinkId,BlinkB ; border blinking is ON mov Border,0 ; initial border is black mov DefBord,0 ; default border is black mov cx,17 ; CX will be cycle counter mov bx,0 ; BX will be index AssPal: mov al,DefPal[bx] ; read one value for palette register mov ZerPal[bx],0 ; clear one register of default palette mov CurPal[bx],al ; load one register for current palette inc bx ; advance index to process next value loop AssPal ; next step (17 times) ;=== Output initial message Install:mov ah,09 ; function 09 - text string output lea dx,BegMsg ; DX - address of message int 21h ; DOS service call ;=== Install handler for multiplex interrupt 2Fh mov ax,352Fh ; get interrupt vector 2Fh int 21h ; DOS service call mov OldMulO,bx ; save offsett of old handler for 1Ch mov OldMulS,es ; save segment of old handler for 1Ch mov dx,offset MulHand ; offset of new Multiplex Handler mov ah,25h ; function 25h - set interrupt vector int 21h ; DOS service call ;=== Install handler for BIOS interrupt 09h (keyboard) mov ax,3509h ; get interrupt vector 09h int 21h ; DOS service call mov cs:OldOff9,bx ; save offsett of old handler for 09h mov cs:OldSeg9,es ; save segment of old handler for 09h mov ah,25h ; function 25h - set interrupt vector mov dx,offset NewInt9 ; address of new INT 09 handler int 21h ; DOS service call ;=== Install handler for BIOS interrupt 1Ch (timer) mov ax,351Ch ; get interrupt vector 1Ch int 21h ; DOS service call mov cs:OldOffC,bx ; save offsett of old handler for 1Ch mov cs:OldSegC,es ; save segment of old handler for 1Ch mov ah,25h ; function 25h - set interrupt vector mov dx,offset Handler ; address of handler int 21h ; DOS service call ;=== Install handler for BIOS interrupt 10h (video) mov ax,3510h ; get interrupt vector 10h int 21h ; DOS service call mov cs:OldO10,bx ; save offsett of old handler for 10h mov cs:OldS10,es ; save segment of old handler for 10h mov ah,25h ; function 25h - set interrupt vector mov dx,offset NewInt10 ; address of new INT 09 handler int 21h ; DOS service call ;=== Install handler for interrupt 33h (mouse) mov ax,3533h ; get interrupt vector 33h int 21h ; DOS service call mov cs:OldOffM,bx ; save offsett of old handler for 33h mov cs:OldSegM,es ; save segment of old handler for 33h mov ah,25h ; function 25h - set interrupt vector mov dx,offset NewMous ; address of new INT 33 handler int 21h ; DOS service call ;=== output the message "program is installed" lea dx,Loaded ; DX - address of message mov ah,09h ; function 09 - output string int 21h ; DOS service call ;=== Calculate the size of the resident part and exit the program lea dx,BegInst add dx,110h ; PSP length plus 16 byte (insurance) mov cx,4 ; set counter for shift shr dx,cl ; 4 bits to the right - divide by 16 mov ax,3100h ; 31h - terminate and state resident int 21h ; DOS service call ;=== Process situation "Resident part is already installed" Already: ;=== Check whether parameters are present mov es,PspAddr ; addres of PSP into ES cmp byte ptr es:[80h],1 ; are there parameters? jle NoParm ; if not, skip parameters processing ;=== Skip separators "/", "-" and blanks mov bx,80h ; BX - beginning of parameter string TestSep:inc bx ; BX points to next character cmp bl,byte ptr es:[80h] ; end of parameter string? jge NoParm ; if so - parameters not found cmp byte ptr es:[bx],'/' ; is current character separator? je TestSep ; if so - try next character cmp byte ptr es:[bx],'-' ; is current character separator? je TestSep ; if so - try next character cmp byte ptr es:[bx],' ' ; is current character blank? je Testsep ; if so - try next character ;=== Separator found - process parameter string FndSep: cmp byte ptr es:[bx],'?' ; question mark specified? je Help ; if so, process "HELP" and byte ptr es:[bx],0DFh ; force first letter uppercase cmp byte ptr es:[bx],'H' ; is first letter 'H'? je Help ; if so, process "HELP" cmp byte ptr es:[bx],'R' ; is first letter 'R'? je PalRest ; if so, process "Restore Palette" cmp byte ptr es:[bx],'B' ; is first letter 'B'? je SwBord ; if so, process "Switch Border Blink" cmp byte ptr es:[bx],'O' ; is first letter 'O'? jne InvParm ; if not - missing or invalid parameter and byte ptr es:[bx+1],0DFh ; force second letter uppercase cmp byte ptr es:[bx+1],'N' ; is second letter 'N'? je FuncOn ; if so, process "ON" cmp byte ptr es:[bx+1],'F' ; is second letter 'F'? jne InvParm ; if not - invalid parameter and byte ptr es:[bx+2],0DFh ; force third letter uppercase cmp byte ptr es:[bx+2],'F' ; is third letter 'F'? jne InvParm ; if not, process "INVALID PARMS" ;=== Function "Switch OFF" FuncOff:mov al,SwOff ; code for function "OFF" into AL lea dx,MakeOff ; DS:DX - addres of message "Turned OFF" mov RetCode,SwOff ; return code "SWITCHED OFF" jmp CallMul ; to switch program state ;=== Function "Switch ON" FuncOn: mov al,SwOn ; subfunction "Turn ON" mov RetCode,SwON ; return code "SWITCHED ON" lea dx,MakeOn ; DS:DX - addres of message "Turned ON" ;=== Call multiplex handler (function code in AL) CallMul:mov ah,TSRId ; AH - TSR's identifier mov bx,AddSign ; BX - additional signature int 2Fh ; call multiplex handler ;=== Print a message (address in DS:DX) PrnMsg: mov ah,09h ; function 09 - output text string int 21h ; DOS service call ;=== Exit from program (return code in RetCode) ExitPrg:mov ah,4Ch ; function 4Ch - terminate process mov al,RetCode ; al - return code (ErrorLevel) int 21h ; DOS service call ;=== Function :Switch Border Blinking" SwBord: mov al,BordSw ; AL - subfunction "Toggle Blinking" mov ah,TSRId ; AH - TSR's identifier mov bx,AddSign ; BX - additional signature mov dx,' N' ; set tail of message to "N " int 2Fh ; call multiplex handler cmp ah,BlinkB ; is border blinking? je BordDon ; if so, output correspondent message mov dx,'FF' ; set tail of message to "FF" BordDon:mov OnOff,dx ; form either "ON" or "OFF" mov RetCode,BordSw ; return code lea dx,TogBor ; address of message "Toggled" jmp PrnMsg ; to print message and finish program ;=== Process the situation "no parameter" NoParm: mov al,RepSt ; AL - subfunction "Report Status" mov ah,TSRId ; AH - function of INT 2Fh (identifier) mov bx,AddSign ; BX - additional signature int 2Fh ; multiplex handler call lea dx,MakeOff ; DS:DX - addres of message "Turned OFF" mov RetCode,SwOff ; return code "SWITCHED OFF" cmp ah,Act ; is code "Turned ON" returned? jne PrnMsg ; if not, exit; "OFF" will be output lea dx,MakeOn ; DS:DX - addres of message "Turned ON" mov RetCode,SwOn ; return code "SWITCHED ON" jmp PrnMsg ; to print message and exit ;=== Restore Palette Palrest:mov ax,1002h ; function "set all palette registers" mov es,ComSeg ; ES points to current segment mov dx,offset DefPal ; address of 17 defualt palette int 10h ; BIOS video service call lea dx,PalMsg ; DS:DX - address of message "Palette.." jmp PrnMsg ; to print message and exit ;=== Output help message Help: lea dx,BegMsg ; DS:DX - address of initial message mov RetCode,HelpCod ; return code "HELP message output" Help2: mov ah,09h ; function 09 - output text string int 21h ; DOS service call lea dx,ParmTxt ; DS:DX - address of HELP message jmp PrnMsg ; to print message and exit ;=== Process the situation "INVALID PARAMETERS" InvParm:lea dx,Invalid ; DS:DX addres of message "Invalid" mov RetCode,InvPCod ; return code "Invalid Parameters" jmp Help2 ; to print message and exit ;=== Data for non-resident part of the program CR equ 0Ah LF equ 0Dh EndMsg equ 24h Invalid db CR,LF,'Can not interprete parameters specified.' db CR,LF,'The valid form of command line is:',CR,LF,EndMsg PalMsg db CR,LF,'The default palette has been restored',CR,LF,EndMsg BegMsg db CR,LF,'The resident screen blanker version 4.2 19.11.92' db CR,LF,'Copyright (C) 1992 V.B.Maljugin, Russia, Voronezh' db CR,CR,LF,'Puts out the screen when the keyboard is 5 minutes idle' db CR,LF,'The MDA/CGA/Hercules/EGA/MCGA/VGA adapters are supported' CrLf db CR,LF,EndMsg Loaded db CR,LF,'The screen blanker is installed successfully',CR,LF,EndMsg MakeOn db CR,LF,'The screen blanker is now ACTIVE',CR,LF,EndMsg MakeOff db CR,LF,'The Screen blanker is now INACTIVE',CR,LF,EndMsg TogBor db CR,LF,'The border blinking from now will be O' OnOff dw 2020h db EndMsg HelpTxt db CR,LF,CR,LF, 'Call: ' ParmTxt db CR,LF,'ScrBlank [on | off | b | r | /? | /h | -? | -h] ',CR,LF db CR,LF,'Parameters: ' db CR,LF,'on - make the screen blanker active ' db CR,LF,'off - make the screen blanker inactive ' db CR,LF,'b - toggle the border blinking ' db CR,LF,'r - restore the default palette ' db CR,LF,'rest of list - output this text',CR,LF db CR,LF,'Call this program without parameters to determine its ' db 'current state.', CR,LF,EndMsg _text ends end Addr100 ; COM variant ; end Start