git.sur5r.net Git - cc65/blob - libsrc/atari5200/bgcolor.s

   1 ;
   2 ; Christian Groessler, 05-Apr-2019
   3 ;
   4
   5         .export         _bgcolor
   6
   7         .include        "atari5200.inc"
   8
   9         .constructor    init_old_bgcolor
  10
  11 .bss
  12
  13 old_bg_color:
  14         .res    1
  15
  16 .code
  17
  18 _bgcolor:
  19         and     #3
  20         tax
  21         lda     COLOR0,x
  22         ldx     old_bg_color
  23         sta     COLOR4                  ; set new value
  24         sta     old_bg_color
  25         txa
  26         ldx     #0                      ; fix X
  27         rts
  28
  29 .segment        "ONCE"
  30
  31 init_old_bgcolor:
  32         lda     COLOR0+3                ; see also conioscreen.s for initialization
  33         sta     old_bg_color
  34         rts
  35
  36         .end