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- 2005-5-25
- 最后登录
- 1970-1-1
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发表于 2007-7-27 11:06:52
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显示全部楼层
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;;在INT $C719后JSR ToGrayBuffer就可以在4灰度下显示文子了;;
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;将显存$19C0的内容发送到$1380
;$03d0:背景色0~3,$03d1:前景色0~3
;若背景色大于3,则背景色为0
;若前景色大于3,则前景色为3
ToGrayBuffer:
LDA $03D0
CMP #$04
BCC qjs
LDA #$00
STA $03D0
qjs:
LDA $03D1
CMP #$04
BCC send
LDA #$03
STA $03D1
send:
LDA #$C0
STA $80
LDA #$19
STA $81
LDA #$80
STA $82
LDA #$13
STA $83
LDY #$00
LDA $03D0
ASL
ASL
ASL
ASL
ASL
ASL
STA $84
LDA $03D1
ASL
ASL
ASL
ASL
ASL
ASL
STA $85
LDA #$00
STA $86
STA $87
send7:
LDX #$08
LDA ($80),Y
STA $88
send1:
ASL $88
BCC send2
LDA $85
ASL
ROL $87
ROL $86
ASL
ROL $87
ROL $86
CLC
BCC send3
send2:
LDA $84
ASL
ROL $87
ROL $86
ASL
ROL $87
ROL $86
send3:
DEX
BNE send1
LDA $86
STA ($82),Y
INC $82
BNE send4
INC $83
send4:
LDA $87
STA ($82),Y
INC $82
BNE send5
INC $83
send5:
INC $80
BNE send6
INC $81
send6:
LDA $81
CMP #$20
BNE send8
RTS
send8:
JMP send7 |
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