git.sur5r.net Git - cc65/blob - libsrc/pce/vdc.s

   1         .export         vdc_init
   2
   3         .include        "pce.inc"
   4
   5 ; FIXME: implement selection of different video modes at runtime
   6 HIRES   = 1
   7
   8 vdc_init:
   9         lda     VDC_CTRL
  10
  11         VREG    VDC_CR , $0000  ; disable display and interrupts
  12         VREG    VDC_BXR, $0000  ; no scrolling
  13         VREG    VDC_BYR, $0000
  14         VREG    VDC_MWR, $0070  ; 128 x 64 tiles (1024 x 512 pixels)
  15         VREG    VDC_VSR, $1702  ; CRTC
  16         VREG    VDC_VDR, $00DF  ; CRTC - VDS
  17         VREG    VDC_VCR, $000C  ; CRTC - VDE
  18         VREG    VDC_DCR, $0000
  19
  20 .if      HIRES
  21         VREG    VDC_HSR, $0C02  ; CRTC
  22         VREG    VDC_HDR, $043C  ; CRTC - HDS
  23         lda     #$06
  24 .else
  25         VREG    VDC_HSR, $0202  ; CRTC
  26         VREG    VDC_HDR, $041F  ; CRTC - HDS
  27         lda     #$04
  28 .endif
  29         sta     VCE_CTRL
  30
  31         lda     VDC_CTRL
  32         rts