Microsoft Programmer's Library 1.3

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Assembly Source File | 1988-08-11 | 15.1 KB | 668 lines

page ,132 ;*************************************************************************** ; * ; Copyright (C) 1987 by Microsoft Inc. * ; * ;*************************************************************************** title SetScan - Set An EGA Scan to the Given Colors .286c ;Allow iAPX80286 instructions memM equ 1 ;define middle model program ?PLM=1 ?WIN=0 .xlist include cmacros.inc include ega.inc .list ScreenWidthB equ 80 ;Width of screen in bytes ScreenSize equ 14000 ;Size of screen plane in words ;** define segment for ring 2 IOPL code createSeg _SCRIO, SCRIO, byte, public, CODE scrioOFFSET equ OFFSET _SCRIO: sBegin data ;** These routines assume that the following two external values are ; initialized before any routine is called. extrn _dpoffset:word ;EGA display page offset extrn _psel:word ;selector array for EGA memory sEnd data sBegin scrio assumes cs,_scrio assumes ds,data ;** SetDVideo - disable video ; ; SetDVideo disable video to prevent snow and flicker during state ; changes of the EGA. A call to SetEVideo must be made to reenable ; the video. ; ; SetDVideo (); ; ; Entry none ; Exit EGA video blanked ; Returns none ; Calls dvideo cProc SetDvideo,<FAR,PUBLIC>,<> cBegin call bvd ;blank video display cEnd ;** SetEVideo - enable video ; ; SetEVideo renables video ; ; SetEVideo (); ; ; Entry none ; Exit EGA video restored ; Returns none ; Calls evideo cProc SetEvideo,<FAR,PUBLIC>,<> cBegin call evd ;enable video display cEnd ;** SetScan - Set One Scan to Given Colors ; ; The given scan line is set to the colors passed in. ; ; SetScan (row, count, values); ; ; Entry row = row to write ; count = number of bytes of display data ; values = pointer to character array of bit values ; Exit display page forced to 0 ; display row updated ; Returns none ; The display adapter must be initialized before invoking this ; routine. cProc SetScan,<FAR,PUBLIC>,<si,di,es> parmW Y parmW count parmW pMapped cBegin cld xor bx,bx ;force display to page 0 call sdp ;set display page mov ax,Y ;Compute start of scan that will mov di,ScreenWidthB ; be set to the passed colors mul di mov di,ax mov si,_psel ;es:di --> scan on the EGA mov es,word ptr [si] mov dx,rGraphics ;Set the Graphics Controller's mov al,rBitmask ; address register to point to out dx,al ; the bitmask register inc dx ;--> Graphics Controller's data register mov ah,10000000b ;Set mask for initial pixel mov cx,count ;Set count of pixels jcxz ssr2 ;None, exit now mov si,offset pMapped ;ds:si --> pixel colors xor bx,bx ;Zero is always handy! ssr1: mov al,ah ;Set BitMask register to only alter out dx,al ; pixel of interest ror ah,1 ;Set up for next pixel lodsb ;Get color for this pixel ; The BitMask register allows bits to be protected from changes. ; It works in conjunction with some internal EGA latches. Every ; time a read operation from EGA memory is performed, the latches ; are loaded with the data read from each plane (one 8-bit latch ; per plane). Wherever the BitMask register is a "0", the EGA ; writes data from the latches. Wherever the BitMask register is ; a "1", the data from the host is written. This is not implemented ; in the hardware as a read/modify/write operation, so the user ; must load the latches explicitly. xchg es:[di],al ;Load latches, write color to the pixel adc di,bx ;Possibly --> next destination byte loop ssr1 ;Until all pixels drawn. ssr2: mov al,0ffh ;Set mask for all pixel out dx,al cEnd ;** SetScanClear - clear video display memory ; ; SetScanClear clears the 28000 bytes of video memory starting at ; the page offset specified in _dpoffset. ; ; SetScanClear (); ; ; Entry none ; Exit EGA video memory cleared ; Returns none ; Calls cdm cProc SetScanClear,<FAR,PUBLIC>,<> cBegin call bvd ;blank video display mov cx,_dpoffset call cdm ;clear display memory call evd ;enable video display cEnd ;** SetScanRestore - restore graphics display ; ; Restore active EGA display page from saved image ; SetScanRestore (ressel); ; ; Entry ressel = far pointer to array of selectors to segments ; containing graphics image to be restored ; _dpoffset = offset of active display page ; Exit graphics image restored ; Returns none cProc SetScanRestore,<FAR,PUBLIC>,<si,di,es,ds> parmD ressel cBegin mov cx,_dpoffset ;(cx) = display page to clear call cdm ;clear display memory mov bx,_psel ;(es) = display selector mov es,word ptr [bx] ; Restore graphics memory. ; This is done by enabling each 32k bank of graphics memory ; and copying memory from the restore segments. mov dx,rGraphics ;Set the Graphics Controller's mov ax,0*256+rMode out dx,ax mov al,rBitmask ; address register to point to mov ah,0ffh ;Set mask for initial pixel out dx,ax ; the bitmask register mov dx,rSequencer ;(dx) = sequencer register address mov al,rMapMask ;write to sequencer map mask register mov ah,C0 ;select plane C0 out dx,ax push ds ;save (ds) for later mov bx,_dpoffset ;move display offset to stack push bx lds bx,ressel ;(ds:bx) = address of restore selector mov ds,[bx] ;(ds) = first selector xor si,si ;(si) = offset into restore segment pop di ;(di) = offset into display memory push di mov cx,ScreenSize ;copy image to plane C0 rep movsw mov ah,C1 ;select plane C1 out dx,ax pop di ;(di) = offset into display memory push di mov cx,ScreenSize ;copy image to plane C1 rep movsw lds bx,ressel ;(ds:bx) = address of restore selector mov ds,[bx+2] ;(ds) = second selector xor si,si ;(si) = offset into restore segment mov ah,C2 ;select plane C2 out dx,ax pop di ;(di) = offset into display memory push di mov cx,ScreenSize ;copy image to plane C2 rep movsw mov ah,C3 ;select plane C3 out dx,ax pop di ;(di) = offset into display memory mov cx,ScreenSize ;copy image to C3 rep movsw pop ds ; set start address register mov bx,_dpoffset call sdp ;set display page cEnd ;** SetScanRFont - restore EGA font table ; ; SetScanRFont restores the EGA font tables saved by SetScanSFont. ; ; SetScanRFont (fontsel); ; ; Entry fontsel = selector for font save memory ; Exit EGA font table restored from font save segment ; Returns none ; Calls ifa, tfa cProc SetScanRFont,<FAR,PUBLIC>,<si,di,es> parmW frsel cBegin mov si,_psel ;(es) = display selector mov es,word ptr [si] push ds call ifa ;initialize font addressing mov bx,frsel ;(bx) = font restore selector mov ds,bx ;(ds) = font selector xor si,si ;(si) = offset into restore segment xor di,di ;(di) = offset into display mov cx,08000h ;copy 32k words to plane C2 rep movsw ;copy memory pop ds call tfa ;terminate font table addressing cEnd ;** SetScanSave - Save graphics display ; ; Copy active page of display memory to RAM save buffer. ; ; SetScanSave (savesel); ; ; Entry savsel = far pointer to array of selectors for segments ; used to save graphics image ; _dpoffset = offset of active EGA display page ; Exit graphics image saved ; Returns none cProc SetScanSave,<FAR,PUBLIC>,<si,di,ds,es> parmD savesel ;far pointer to array of save selectors cBegin les bx,savesel ;(es:bx) = address of save selector mov es,es:[bx] ;(es) = first selector mov bx,_dpoffset ;(bx) = offset into display memory push bx mov dx,rGraphics ;(dx) = address of graphics controller mov al,rReadMap mov ah,rmC0 ;set read map select to plane 0 out dx,ax ; mov si,_psel ;(ds) = display selector mov ds,word ptr [si] mov si,bx ;(si) = offset into display xor di,di ;offset into save memory mov cx,ScreenSize ;copy image from plane C0 rep movsw ;copy memory mov ah,rmC1 ;select plane 1 out dx,ax mov si,bx ;(si) = offset into display mov cx,ScreenSize ;copy image from plane C1 rep movsw les bx,savesel ;(es:bx) = address of save selector mov es,es:[bx+2] ;(es) = second selector pop bx ;(bx) = offset into display memory mov ah,rmC2 ;select plane 2 out dx,ax mov si,bx ;(si) = offset into display xor di,di ;offset into save memory mov cx,ScreenSize ;copy image from plane C2 rep movsw ;copy memory mov ah,rmC3 ;select plane 3 out dx,ax mov si,bx ;(si) = offset into display mov cx,ScreenSize ;copy image from C3 rep movsw mov ah,rmC0 ;set read map select to plane 0 out dx,ax ; cEnd ;** SetScanSFont - save font tables ; ; SetScanSFont (fontsel); ; ; Entry fontsel = selector for font save memory ; Exit EGA font table saved in font save segment ; Returns none ; Calls ifa, tfa cProc SetScanSFont,<FAR,PUBLIC>,<si,di,es> parmW fssel cBegin call ifa ;initialize font addressing push ds mov bx,fssel ;(bx) = font save selector mov es,bx ;(es) = font save selector mov si,_psel ;(ds) = display selector mov ds,word ptr [si] xor si,si ;(si) = offset into display xor di,di ;offset into save memory mov cx,8000h ;copy 32k words from plane C0 rep movsw ;copy memory pop ds ;(ds) = data segment selector cEnd ;* bvd - blank video display ; ; bvd blanks the video display by preventing access to the ; palette registers. ; ; Entry none ; Exit display blanked ; Returns none ; Calls wvs ; Uses al, dx cProc bvd,<NEAR>,<> cBegin call wvs ;wait for vertical resynch mov dx,rAttread ;read feature control to reset in al,dx ;internal flipflop to force address mov dx,rAttwrite mov al,000H ;disable access to palette out dx,al cEnd ;* cdm - clear display memory ; ; cdm clears the 28000 bytes of memory starting at the address ; pointed to by (cx) ; ; Entry cx = offset of page to clear ; Exit display memory cleared ; Returns none ; Calls sdm ; Uses ax, bx, cx, dx cProc cdm,<NEAR,PUBLIC>,<di, es> cBegin mov bx,_psel ;(es) = display selector mov es,word ptr [bx] mov bx,cx ;(bx) = display offset ; Clear graphics memory. ; This is done by enabling each 32k bank of graphics memory ; and storing zeroes. mov dx,rGraphics ;Set the Graphics Controller's mov al,rBitmask ; address register to point to mov ah,0ffh ;Set mask for initial pixel out dx,ax ; the bitmask register mov dx,rSequencer ;(dx) = sequencer register address mov al,rMapMask ;write to sequencer map mask register mov ah,C0 ;select plane C0 out dx,ax mov di,bx ;(di) = offset into display memory mov cx,ScreenSize ;copy image to plane C0 xor ax,ax rep stosw mov al,rMapMask ;write to sequencer map mask register mov ah,C1 ;select plane C1 out dx,ax mov di,bx ;(di) = offset into display memory mov cx,ScreenSize ;copy image to plane C1 xor ax,ax rep stosw mov al,rMapMask ;write to sequencer map mask register mov ah,C2 ;select plane C2 out dx,ax mov di,bx ;(di) = offset into display memory mov cx,ScreenSize ;copy image to plane C2 xor ax,ax rep stosw mov al,rMapMask ;write to sequencer map mask register mov ah,C3 ;select plane C3 out dx,ax mov di,bx ;(di) = offset into display memory mov cx,ScreenSize ;copy image to C3 xor ax,ax rep stosw call sdm ;set display mode cEnd ;* evd - enable video display ; ; evd enables the video display by reenabling access to the ; palette registers ; ; Entry none ; Exit video display restored ; Returns none ; Calls none ; Uses al, dx cProc evd,<NEAR>,<> cBegin mov dx,rAttread ;read feature control to reset in al,dx ;internal flipflop to force address mov dx,rAttwrite mov al,020H ;allow access to palette out dx,al cEnd ;** ifa - initialize font addressing ; ; initialize EGA to allow read of font tables ; ; Entry none ; Exit EGA addressing set up ; Returns none cProc ifa,<NEAR>,<> cBegin mov dx,rGraphics mov ax,0204h cli out dx,ax ;Read Map Select register mov ax,0005h out dx,ax ;Graphics Mode register mov ax,0406h out dx,ax ;Graphics Misc register mov dx,rSequencer mov ax,0C02h out dx,ax ;Write Map Select mov ax,0404h out dx,ax ;Turn on odd/even sti cEnd ;* sdm - set display mode ; ; sdm restores the EGA to the default graphics mode ; ; Entry none ; Exit default graphics display mode reestablished ; Returns none ; Calls none ; Uses ax, dx cProc sdm,<NEAR>,<si,di,es> cBegin mov dx,rSequencer ;Enable all planes for writing mov ah,C0+C1+C2+C3 mov al,rMapMask out dx,ax mov dx,rGraphics ;-->Graphics Controller mov ax,0*256+rEnableSR ;Clear any set/reset enable out dx,ax ; Color Write Mode takes data from the host as a color. D0 of ; the host data is taken as the color for plane C0, D1 for plane ; C1, etc. The color for each plane is written to all bits of ; the destination byte which are enabled in the BitMask Register. mov ax,(mColorWrite+mDataRead)*256+rMode out dx,ax ; The Data Rotate register allows a boolean function between ; the data from the host and the data in the EGA's latches ; to occur. It also allows the data from the host to be ; rotated by some count before the operation occurs. mov ax,(drSet*256)+rDataRotate out dx,ax cEnd ;* sdp - set display page ; ; sdp sets the current display page by setting the display offset ; to the value in bx ; ; Entry bx = page offset ; Exit disply page address set ; Returns none ; Calls wvs ; Uses ax,dx cProc sdp,<NEAR>,<> cBegin call wvs ;wait for vertical synch mov dx,rCRTC ;(dx) = CRT controller mov al,rSahr ;(al) = high address register mov ah,bh ;(ah) = upper byte of address out dx,ax mov al,rSalr mov ah,bl ;(ah) = low byte of address out dx,ax cEnd ;** tfa - terminate font addressing ; ; terminate font table addressing mode ; ; Entry none ; Exit EGA returned to normal addressing mode ; Returns none cProc tfa,<NEAR>,<> cBegin mov cx,0e06h ;Setup color buffer with chaining mov dx,rGraphics mov ax,0004h cli out dx,ax ;Read Map Select register mov ax,1005h out dx,ax ;Graphics Mode register mov ax,0e06h ;Setup color buffer with chaining out dx,ax ;Graphics Misc register mov dx,rSequencer mov ax,0302h out dx,ax ;Write Map Select mov ax,0004h out dx,ax ;Turn off odd/even sti cEnd ;* wvs - wait for vertical synch ; ; wvs waits for the leading edge of the vertical synch pulse ; ; Entry none ; Exit leading edge of vertical synch encountered ; Returns none ; Calls none ; Uses al, dx cProc wvs,<NEAR>,<> cBegin mov dx,rAttread ;read feature control to reset ; wait until not in vertical retrace wvs1: in al,dx ;internal flipflop to force address test al,mVRetrace ;check for vertical retrace jnz wvs1 ;if vertical retrace set ; wait for start of vertical retrace wvs2: in al,dx ;internal flipflop to force address test al,mVRetrace ;check for vertical retrace jz wvs2 ;if vertical retrace not set cEnd sEnd scrio end