mirror of
https://github.com/cc65/cc65.git
synced 2024-12-25 17:29:50 +00:00
24 lines
640 B
ArmAsm
24 lines
640 B
ArmAsm
;
|
|
; 2019-09-16, Greg King
|
|
;
|
|
; unsigned char __fastcall__ revers (unsigned char onoff);
|
|
;
|
|
|
|
.export _revers
|
|
|
|
.include "cx16.inc"
|
|
|
|
.proc _revers
|
|
ldy #$00 ; Assume revers off
|
|
tax ; Test on/off
|
|
beq :+ ; Jump if off
|
|
ldy #$80 ; Load "on" value
|
|
ldx #>$0000 ; Zero high byte of result
|
|
: lda RVS ; Load old value
|
|
sty RVS ; Set new value
|
|
clc
|
|
rol a ; Convert bit-mask into boolean
|
|
rol a
|
|
rts
|
|
.endproc
|