44 lines
459 B
Plaintext
44 lines
459 B
Plaintext
;;
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;; setPixel() function.
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;; Sets the color of a pixel on the screen.
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;;
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.global _setPixel
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_setPixel:
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mov.l #127,r1
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cmp/hi r1,r4
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bt end
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mov.l #63,r1
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cmp/hi r1,r5
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bt end
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mov r4,r0
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shll2 r5
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shll2 r5
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mov #-3,r1
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shld r1,r4
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add r4,r7
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add r5,r7
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mov.b @r7,r1
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mov #7,r2
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and r0,r2
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neg r2,r2
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mov.l #128,r3
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shld r2,r3
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tst r6,r6
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bt white
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black:
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or r3,r1
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rts
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mov.b r1,@r7
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white:
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not r3,r3
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and r3,r1
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rts
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mov.b r1,@r7
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end:
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rts
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nop
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.end
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