🚀 go-pugleaf

Date Entered: 11-04-92 15:38
JA>void PutBlock( int x, int y, int height, int width, char far * buffer )
  >{   _asm {
  >        push    di
  >        push    si
  >        push    es
  >        push    ds
  >        mov     ax, 320
  >        mul     y       ; AX = y * 320
  >        add     ax, x   ;             + x
  >        mov     di, ax  ; ES:DI = destination of pixels
  >        mov     ax, 0A000h
  >        mov     es, ax  ; Segment of VGA memory
  >        mov     dx, height
  >        mov     bx, width
  >        mov     ax, 320
  >        sub     ax, bx
  >        lds     si, buffer

JA>rowloop:
  >        mov     cx, bx  ; width of row
  >        shr     cx, 1   ; number of words

  >        rep     movsw   ; copy as many words as possible
  >        adc     cx, cx  ; move the odd byte
  >        rep     movsb

  JNC  @@Even
  MOVSB
@@Even:
  REP MOVSW

  is quicker on my computer, and because the possible odd byte is moved
first, we get even 16-bit moves.  I assume anyways.  It was faster in large
and small moves.  Although, I think I was using ADC CX,0 in my test.

  >        add     di, ax  ; Go to next pixel row
  >        dec     dx      ;
  >        jnz     rowloop
  >        ; Done
  >        pop     ds
  >        pop     es
  >        pop     si
  >        pop     di
  >        }
  >}
.----------------------------------------------------.
| Colin Buckley -- 486 Powered (Packing Extra Socks) |
| Toronto, Ontario, Canada                           |
| InterNet: colin.buckley@rose.com                   |
|                                                    |
| So Eager to Play, So Relunctant to Admit it...     |
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