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Simplifying char blit

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This commit is contained in:
alpine9000
2016-04-01 15:49:44 +11:00
parent c80864f48a
commit a79566d429
1 changed files with 14 additions and 38 deletions
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025.scroll_text/blitchar.s
+14 -38
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@@ -8,6 +8,12 @@ BLIT_WIDTH_WORDS equ 1 ; blit 2 words to allow shifting
BLIT_WIDTH_BYTES equ BLIT_WIDTH_WORDS*2
FONTMAP_WIDTH_BYTES equ 32
if MASKED_FONT==1
BLTCON0_VALUE equ BLIT_SRCA|BLIT_SRCB|BLIT_SRCC|BLIT_DEST|BLIT_LF_MINTERM
else
BLTCON0_VALUE equ BLIT_SRCB|BLIT_SRCC|BLIT_DEST|BLIT_LF_MINTERM
endif
BlitChar8:
;; a0 - bitplane
;; d0 - xpos
@@ -18,19 +24,14 @@ BlitChar8:
;; blitter config that is shared for every character
if MASKED_FONT==1
move.w #BLIT_SRCA|BLIT_SRCB|BLIT_SRCC|BLIT_DEST|BLIT_LF_MINTERM,d6 ; BLTCON0 value (masked version)
move.w #FONTMAP_WIDTH_BYTES-BLIT_WIDTH_BYTES,BLTAMOD(a6) ; A modulo (only used for masked version)
else
move.w #BLIT_SRCB|BLIT_SRCC|BLIT_DEST|BLIT_LF_MINTERM,d6 ; BLTCON0 value
endif
move.w #FONTMAP_WIDTH_BYTES-BLIT_WIDTH_BYTES,BLTBMOD(a6) ; B modulo
move.w #BITPLANE_WIDTH_BYTES-BLIT_WIDTH_BYTES,BLTCMOD(a6) ; C modulo
move.w #BITPLANE_WIDTH_BYTES-BLIT_WIDTH_BYTES,BLTDMOD(a6) ; D modulo
mulu.w #BITPLANE_WIDTH_BYTES*SCREEN_BIT_DEPTH,d1 ; ypos bytes
move.w #$ffff,BLTAFWM(a6) ; mask out extra word used for shifting
move.w #$ffff,BLTADAT(a6) ;??? preload source mask so only BLTA?WM mask is used
move.l #font,a5 ; font pointer
move.w #$ffff,BLTAFWM(a6) ; don't mask first word
move.l #font,a1 ; font pointer
move.l #fontMask,d7 ; font mask pointer
move.w #FONTMAP_WIDTH_BYTES*SCREEN_BIT_DEPTH*FONT_HEIGHT,d3 ; bytes per font line
@@ -46,9 +47,8 @@ DrawChar8:
;; d1 - ypos bytes
;; d2* - char
;; d3 - bytes per font line
;; d6 - bltcon0 value
;; a4* - bitplane
;; a5 - #font
;; a1 - #font
;; d7 - #fontMask
sub.w #'!',d2 ; index = char - '!'
@@ -58,8 +58,6 @@ DrawChar8:
andi.w #$1f,d2 ; char index in line (char index - start of line index)
add.l #1,d5 ; while we have a weird font image, '!' starts on second line
move.l a5,a1 ; #font
mulu.w d3,d5 ; d5 *= #FONTMAP_WIDTH_BYTES*SCREEN_BIT_DEPTH*FONT_HEIGHT
@@ -76,59 +74,37 @@ DrawChar8:
endif
.blitChar8:
;; kills a4,d2,d4,d5
;; d0 - xpos
;; d1 - ypos bytes
;; d2.0 - odd character = 1, even character = 0
;; d3 - bytes per font line
;; d6 - bltcon0 value
;; a4 - display
;; a1 - object
;; a2 - mask
add.l #(FONT_HEIGHT*SCREEN_BIT_DEPTH*FONTMAP_WIDTH_BYTES)-FONTMAP_WIDTH_BYTES+0,a1
add.l #(FONT_HEIGHT*SCREEN_BIT_DEPTH*FONTMAP_WIDTH_BYTES)-FONTMAP_WIDTH_BYTES+0,a2
move.l d0,d4 ; xpos
move.l d0,d5 ; xpos
lsr.w #3,d4 ; d4 = xpos bytes
WaitBlitter
btst #0,d2 ; check if odd or even char
beq .evenChar ;
.oddChar
.oddChar:
move.w #$00ff,BLTALWM(a6) ; select the second (odd) character in the word
move.w #$8000,d5
move.w #BLTCON0_VALUE|$8000,BLTCON0(a6)
move.w #$8002,BLTCON1(a6) ; set the shift bits 12-15, bits 00-11 cleared
bra .continue
.evenChar:
move.w #$FF00,BLTALWM(a6) ; select the first character in the word
move.w #0,d5
move.w #BLTCON0_VALUE,BLTCON0(a6)
move.w #$2,BLTCON1(a6) ; set the shift bits 12-15, bits 00-11 cleared
.continue:
ori.l #2,d5
move.w d5,BLTCON1(A6) ; set the shift bits 12-15, bits 00-11 cleared
if MASKED_FONT==1
move.l a2,BLTAPTH(a6) ; mask bitplane
endif
move.l a1,BLTBPTH(a6) ; source bitplane
or.w d6,d5 ; d5 = BLTCON0 value
move.w d5,BLTCON0(a6) ; set minterm, dma channel and shift
add.l d4,a4 ; dest += XPOS_BYTES
add.l d1,a4 ; dest += YPOS_BYTES
add.l #(FONT_HEIGHT*SCREEN_BIT_DEPTH*BITPLANE_WIDTH_BYTES)-BITPLANE_WIDTH_BYTES+0,a4
move.l a4,BLTCPTH(a6) ; background top left corner