AmigaExamples/024.simple_text/blit.s

42 lines
886 B
ArmAsm

include "includes.i"
xdef BlitFillColor
BlitFillColor:
;; kills a0,d2,d3,d5,d5
;; a0 - bitplane
;; d0 - color#
;; d1 - height
;; d2 - ypos
;; movem.l d2-d5/a0,-(sp)
mulu.w #BITPLANE_WIDTH_BYTES*SCREEN_BIT_DEPTH,d2
add.l d2,a0
move.b #0,d3 ; bitplane #
.loop:
move.w d1,d4
btst d3,d0 ; is the color's bit set in this plane?
beq .zero
move.w #BLIT_DEST|$FF,d5 ; yes ? all ones
bra .doblit
.zero
move.w #BLIT_DEST|$0,d5 ; no ? all zeros
.doblit
WaitBlitter
move.w #0,BLTCON1(A6)
move.w d5,BLTCON0(A6)
move.w #BITPLANE_WIDTH_BYTES*(SCREEN_BIT_DEPTH-1),BLTDMOD(a6)
move.l a0,BLTDPTH(a6)
lsl.w #6,d4
ori.w #BITPLANE_WIDTH_WORDS,d4
move.w d4,BLTSIZE(a6)
add.b #1,d3
add.w #BITPLANE_WIDTH_BYTES,a0
cmp.b #SCREEN_BIT_DEPTH,d3 ; all planes for a single line done ?
bne .loop ; no ? do the next plane
;; movem.l (sp)+,d2-d5/a0
rts