mirror of
https://gitlab.com/camelot/kickc.git
synced 2024-09-09 08:54:40 +00:00
111 lines
1.6 KiB
NASM
111 lines
1.6 KiB
NASM
.pc = $801 "Basic"
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:BasicUpstart(main)
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.pc = $80d "Program"
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main: {
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.label screen = $400
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.label __2 = 6
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.label __4 = 8
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.label __6 = 4
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.label line = 2
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.label __7 = 8
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.label __8 = 6
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.label __9 = 4
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lda #<0
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sta.z line
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sta.z line+1
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__b1:
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// for (line = 0; line < 40*24; line += 40)
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lda.z line+1
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cmp #>$28*$18
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bcc __b4
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bne !+
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lda.z line
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cmp #<$28*$18
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bcc __b4
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!:
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ldx #0
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// Cleare the bottom line
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__b5:
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// for (byte c=0; c<40; ++c)
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cpx #$28
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bcc __b6
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// }
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rts
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__b6:
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// line+c
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txa
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clc
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adc.z line
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sta.z __6
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lda #0
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adc.z line+1
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sta.z __6+1
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// screen[line+c] = ' '
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clc
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lda.z __9
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adc #<screen
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sta.z __9
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lda.z __9+1
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adc #>screen
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sta.z __9+1
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lda #' '
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ldy #0
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sta (__9),y
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// for (byte c=0; c<40; ++c)
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inx
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jmp __b5
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__b4:
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ldx #0
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__b2:
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// for (byte c=0; c<40; ++c)
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cpx #$28
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bcc __b3
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// line += 40
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lda #$28
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clc
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adc.z line
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sta.z line
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bcc !+
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inc.z line+1
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!:
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jmp __b1
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__b3:
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// line+c
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txa
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clc
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adc.z line
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sta.z __2
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lda #0
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adc.z line+1
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sta.z __2+1
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// line+c+40
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txa
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clc
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adc.z line
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sta.z __4
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lda #0
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adc.z line+1
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sta.z __4+1
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// screen[line+c] = screen[line+c+40]
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clc
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lda.z __7
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adc #<screen+$28
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sta.z __7
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lda.z __7+1
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adc #>screen+$28
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sta.z __7+1
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clc
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lda.z __8
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adc #<screen
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sta.z __8
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lda.z __8+1
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adc #>screen
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sta.z __8+1
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ldy #0
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lda (__7),y
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sta (__8),y
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// for (byte c=0; c<40; ++c)
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inx
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jmp __b2
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}
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