ref: 306bd81b628115bc2167ae40793b1c45365195ee
dir: /vh.asm/
; ID_VL.ASM IDEAL MODEL MEDIUM,C INCLUDE 'ID_VL.EQU' SCREENSEG = 0a000h UPDATEWIDE = 20 UPDATEHIGH = 13 DATASEG EXTRN bufferofs :WORD EXTRN displayofs :WORD EXTRN ylookup :WORD EXTRN linewidth :WORD EXTRN blockstarts :WORD ;offsets from drawofs for each update block EXTRN update :BYTE CODESEG ;================= ; ; VH_UpdateScreen ; ;================= PROC VH_UpdateScreen PUBLIC VH_UpdateScreen USES si,di 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,252 or al,1 out dx,al mov bx,UPDATEWIDE*UPDATEHIGH-1 ; bx is the tile number mov dx,[linewidth] ; ; see if the tile needs to be copied ; @@checktile: test [update+bx],1 jnz @@copytile @@next: dec bx jns @@checktile ; ; done ; mov dx,GC_INDEX+1 in al,dx and al,NOT 3 or al,0 out dx,al ret ; ; copy a tile ; @@copytile: mov [update+bx],0 shl bx,1 mov si,[blockstarts+bx] shr bx,1 mov di,si add si,[bufferofs] add di,[displayofs] mov ax,SCREENSEG mov ds,ax REPT 16 mov al,[si] mov [di],al mov al,[si+1] mov [di+1],al mov al,[si+2] mov [di+2],al mov al,[si+3] mov [di+3],al add si,dx add di,dx ENDM mov ax,ss mov ds,ax jmp @@next ENDP END