ref: 5288bbb7556c87e95b0813bf5769eec6b3caf9bc
dir: /vl.asm/
SCREENSEG = 0a000h DATASEG EXTRN TimeCount:WORD ; incremented every 70th of a second EXTRN linewidth:WORD starttime dw ? CODESEG ;============== ; ; VL_SetCRTC ; ;============== PROC VL_SetCRTC crtc:WORD PUBLIC VL_SetCRTC ; ; wait for a display signal to make sure the raster isn't in the middle ; of a sync ; cli mov dx,STATUS_REGISTER_1 @@waitdisplay: in al,dx test al,1 ;1 = display is disabled (HBL / VBL) jnz @@waitdisplay ; ; set CRTC start ; ; for some reason, my XT's EGA card doesn't like word outs to the CRTC ; index... ; mov cx,[crtc] mov dx,CRTC_INDEX mov al,0ch ;start address high register out dx,al inc dx mov al,ch out dx,al dec dx mov al,0dh ;start address low register out dx,al mov al,cl inc dx out dx,al sti ret ENDP ;============================================================================ ; ; VL_ScreenToScreen ; ; Basic block copy routine. Copies one block of screen memory to another, ; using write mode 1 (sets it and returns with write mode 0). bufferofs is ; NOT accounted for. ; ;============================================================================ PROC VL_ScreenToScreen source:WORD, dest:WORD, wide:WORD, height:WORD PUBLIC VL_ScreenToScreen USES SI,DI pushf cli mov dx,SC_INDEX mov ax,SC_MAPMASK+15*256 out dx,ax mov dx,GC_INDEX mov al,GC_MODE out dx,al inc dx in al,dx and al,NOT 3 or al,1 out dx,al popf mov bx,[linewidth] sub bx,[wide] mov ax,SCREENSEG mov es,ax mov ds,ax mov si,[source] mov di,[dest] ;start at same place in all planes mov dx,[height] ;scan lines to draw mov ax,[wide] @@lineloop: mov cx,ax rep movsb add si,bx add di,bx dec dx jnz @@lineloop mov dx,GC_INDEX+1 in al,dx and al,NOT 3 out dx,al mov ax,ss mov ds,ax ;restore turbo's data segment ret ENDP