git.sur5r.net Git - cc65/blob - libsrc/cbm510/kplot.s

   1 ;
   2 ; Ullrich von Bassewitz, 13.09.2001
   3 ;
   4 ; PLOT routine for the 510.
   5 ;
   6
   7         .export         k_plot
   8         .import         __VIDRAM_START__
   9         .importzp       crtc
  10
  11         .include        "zeropage.inc"
  12         .include        "io.inc"
  13
  14         .macpack        generic
  15
  16 ; ------------------------------------------------------------------------
  17 ;
  18
  19 .proc   k_plot
  20
  21         bcs     get
  22
  23         stx     CURS_Y
  24         sty     CURS_X
  25
  26         lda     LineLSBTab,x
  27         sta     SCREEN_PTR
  28         sta     CRAM_PTR
  29         lda     LineMSBTab,x
  30         sta     SCREEN_PTR+1
  31         sub     #>__VIDRAM_START__
  32         add     #>COLOR_RAM
  33         sta     CRAM_PTR+1
  34
  35 get:    ldx     CURS_Y
  36         ldy     CURS_X
  37
  38         rts
  39
  40 .endproc
  41
  42 ; -------------------------------------------------------------------------
  43 ; Low bytes of the start address of the screen lines
  44
  45 .rodata
  46
  47 .macro  LineLoTab
  48         .repeat 25, I
  49         .byte   <(__VIDRAM_START__ + I * 40)
  50         .endrep
  51 .endmacro
  52
  53 LineLSBTab:     LineLoTab
  54
  55 ; -------------------------------------------------------------------------
  56 ; High bytes of the start address of the screen lines
  57
  58 .macro  LineHiTab
  59         .repeat 25, I
  60         .byte   >(__VIDRAM_START__ + I * 40)
  61         .endrep
  62 .endmacro
  63
  64 LineMSBTab:     LineHiTab
  65
  66