; unsigned char __fastcall__ revers (unsigned char onoff)
;
- .export _revers
+ .export _revers
- .include "apple2.inc"
+ .include "apple2.inc"
_revers:
- tax ; Test onoff
- beq normal ; If zero, "normal" must be set
- ldx #$3F+1 ; Set "inverse"
-normal: dex ; $00->$FF, $40->$3F
- lda #$00 ; Preload return code for "normal"
- ldy INVFLG ; Load current flag value
- stx INVFLG ; Save new flag value
- bmi :+ ; Jump if current value is $FF (normal)
- lda #$01 ; Return "inverse"
-: ldx #$00
- rts
+ tax ; Test onoff
+ beq normal ; If zero, "normal" must be set
+ ldx #$3F+1 ; Set "inverse"
+normal: dex ; $00->$FF, $40->$3F
+ lda #$00 ; Preload return code for "normal"
+ ldy INVFLG ; Load current flag value
+ stx INVFLG ; Save new flag value
+ bmi :+ ; Jump if current value is $FF (normal)
+ lda #$01 ; Return "inverse"
+: ldx #$00
+ rts