git.sur5r.net Git - cc65/blob - libsrc/geos/conio/revers.s

   1
   2 ;
   3 ; Maciej 'YTM/Elysium' Witkowiak
   4 ;
   5 ; 27.10.2001
   6
   7 ; unsigned char revers (unsigned char onoff);
   8
   9             .export _revers
  10             .importzp tmp1
  11
  12             .include "../inc/geossym.inc"
  13             .include "../inc/const.inc"
  14
  15 _revers:
  16             tax
  17             bne L0                      ; turn on
  18             lda #0
  19             .byte $2c
  20 L0:         lda #SET_REVERSE
  21             sta tmp1
  22
  23             lda currentMode
  24             tax
  25             and #SET_REVERSE
  26             tay                         ; store old value
  27             txa
  28             and #%11011111              ; mask out
  29             ora tmp1                    ; set new value
  30             sta currentMode
  31
  32             ldx #0
  33             tya
  34             beq L1
  35             lda #1
  36 L1:         rts