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26 lines
378 B
ArmAsm
26 lines
378 B
ArmAsm
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;;
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;; Kevin Ruland
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;;
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;; unsigned char __fastcall__ revers (unsigned char onoff)
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;;
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.export _revers
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.include "apple2.inc"
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_revers:
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ldy TEXTTYP ; Stash old value
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and #$FF ; Test for any bit
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bne reverse ; Nothing set
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lda #$FF
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reverse:
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ora #$3F
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sta TEXTTYP
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tya ; What was the old value?
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eor #$FF ; Normal = $FF, Reverse = $3F
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beq L2
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lda #01
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L2:
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rts
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