mirror of
https://github.com/cc65/cc65.git
synced 2024-06-28 19:29:53 +00:00
53dd513176
which included commits to RCS files with non-trunk default branches. git-svn-id: svn://svn.cc65.org/cc65/trunk@3 b7a2c559-68d2-44c3-8de9-860c34a00d81
24 lines
503 B
ArmAsm
24 lines
503 B
ArmAsm
;
|
|
; Ullrich von Bassewitz, 07.08.1998
|
|
;
|
|
; unsigned char revers (unsigned char onoff);
|
|
;
|
|
.include "atari.inc"
|
|
|
|
.export _revers
|
|
|
|
_revers:
|
|
ldx #$00 ; Assume revers off
|
|
tay ; Test onoff
|
|
beq L1 ; Jump if off
|
|
ldx #$80 ; Load on value
|
|
L1: ldy #$00 ; Assume old value is zero
|
|
lda INVFLG ; Load old value
|
|
stx INVFLG ; Set new value
|
|
beq L2 ; Jump if old value zero
|
|
iny ; Make old value = 1
|
|
L2: ldx #$00 ; Load high byte of result
|
|
tya ; Load low byte, set CC
|
|
rts
|
|
|