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- 2005-2-11
- 最后登录
- 1970-1-1
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发表于 2007-9-9 19:11:42
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代码:
;将6400B的16灰度的数据(放在vidbuf)转换成4灰度的数据(放在srcbuf)
srcbuf =$6380;_GBUF
vidbuf =$3000;图片数据缓冲
.org $2000
ChgData:
lda #<vidbuf
sta $90
LDA #>vidbuf
sta $91
LDA #<srcbuf-1
sta $92
LDA #>srcbuf
sta $93
LDA #$50
sta $94
WB_LOOP1:
LDX #$50
LDY #$00
WB_LOOP2:
LDA ($90),Y
ASL
ROL $95
ASL
ROL $95
ASL
ASL
ASL
ROL $95
ASL
ROL $95
INY
LDA ($90),Y
ASL
ROL $95
ASL
ROL $95
ASL
ASL
ASL
ROL $95
ASL
ROL $95
INY
TYA
PHA
LSR
TAY
LDA $95
STA ($92),Y
PLA
TAY
DEX
BNE WB_LOOP2
CLC
LDA $90
ADC #$50
STA $90
BCC WB_ADC1
INC $91
WB_ADC1:
CLC
LDA $92
ADC #$28
STA $92
BCC WB_ADC2
INC $93
WB_ADC2:
DEC $94
BNE WB_LOOP1
RTS |
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