2 ; Ullrich von Bassewitz, 07.08.1998
4 ; unsigned char revers (unsigned char onoff);
10 ; ------------------------------------------------------------------------
16 ldx #$00 ; Assume revers off
19 ldx #$80 ; Load on value
20 ldy #$00 ; Assume old value is zero
21 L1: lda rvs ; Load old value
22 stx rvs ; Set new value
23 beq L2 ; Jump if old value zero
24 iny ; Make old value = 1
25 L2: ldx #$00 ; Load high byte of result
26 tya ; Load low byte, set CC
31 ; ------------------------------------------------------------------------