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cc65/libsrc/cbm610/revers.s
cuz 36fe6284a8 For the CBM platforms, make revers() machine dependent and use the RVS flag
of the different machines instead of a separate one.
For the C128, make the textcolor() function work in 40 and 80 column mode.


git-svn-id: svn://svn.cc65.org/cc65/trunk@1787 b7a2c559-68d2-44c3-8de9-860c34a00d81
2002-12-19 20:29:27 +00:00

28 lines
555 B
ArmAsm

;
; Ullrich von Bassewitz, 07.08.1998
;
; unsigned char revers (unsigned char onoff);
;
.export _revers
.include "cbm610.inc"
.proc _revers
ldx #$00 ; Assume revers off
tay ; Test onoff
beq L1 ; Jump if off
ldx #$80 ; Load on value
ldy #$00 ; Assume old value is zero
L1: lda RVS ; Load old value
stx RVS ; 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
.endproc