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24 lines
397 B
ArmAsm
24 lines
397 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 #~$3F ; Not Inverse
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normal: eor #$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 :+
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lda #$01
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: ldx #$00
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rts
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