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26 lines
404 B
ArmAsm
26 lines
404 B
ArmAsm
;;
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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 INVFLG ; Stash old value
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and #$FF ; Test for any bit
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beq normal ; Nothing set
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lda #~$3F ; Not Inverse
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normal:
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eor #$FF ; Xor Normal
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sta INVFLG
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tya ; What was the old value?
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eor #$FF ; Normal = $FF, Inverse = $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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