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

   1 ; setup default CONIO screen (20x24, Antic mode 6, BASIC mode 1)
   2 ;
   3 ; 28-May-2014, Christian Groessler <chris@groessler.org>
   4
   5                 .include "atari5200.inc"
   6
   7 SCREEN_BUF_SIZE =       20 * 24
   8 SCREEN_BUF      =       $4000 - SCREEN_BUF_SIZE
   9
  10                 .export screen_setup
  11                 .export screen_width, screen_height
  12                 .export conio_color
  13
  14 screen_width    =       20
  15 screen_height   =       24
  16
  17
  18                 .segment "ONCE"
  19
  20 screen_setup:
  21
  22                 ; initialize SAVMSC
  23                 lda     #<SCREEN_BUF
  24                 sta     SAVMSC
  25                 lda     #>SCREEN_BUF
  26                 sta     SAVMSC+1
  27
  28                 ; initialize cursor position
  29                 lda     #0
  30                 sta     COLCRS_5200
  31                 sta     ROWCRS_5200
  32
  33                 ; clear screen buffer
  34                 ldy     #<(SCREEN_BUF_SIZE-1)
  35                 ldx     #>(SCREEN_BUF_SIZE-1)
  36 clrscr:         sta     (SAVMSC),y
  37                 dey
  38                 cpy     #$FF
  39                 bne     clrscr
  40                 dex
  41                 cpx     #$FF
  42                 bne     clrscr
  43
  44                 ; set default colors
  45
  46                 lda     #GTIA_COLOR_WHITE
  47                 sta     COLOR0
  48                 lda     #GTIA_COLOR_LIGHTRED
  49                 sta     COLOR1
  50                 lda     #GTIA_COLOR_LIGHTGREEN
  51                 sta     COLOR2
  52                 lda     #GTIA_COLOR_BLACK
  53                 sta     COLOR3
  54                 sta     COLOR4          ; background
  55
  56                 ; set display list
  57
  58                 lda     #<dlist
  59                 sta     SDLSTL
  60                 lda     #>dlist
  61                 sta     SDLSTH
  62
  63                 rts
  64
  65                 .data
  66
  67 conio_color:    .byte   0
  68
  69                 .segment "DLIST"
  70
  71 ; display list for 20x24 text mode
  72
  73 dlist:          .repeat 3
  74                 .byte   DL_BLK8
  75                 .endrepeat
  76
  77                 .byte   DL_CHR20x8x2 | DL_LMS
  78                 .word   SCREEN_BUF
  79
  80                 .repeat 23
  81                 .byte   DL_CHR20x8x2
  82                 .endrepeat
  83
  84                 .byte  DL_JVB
  85                 .word   dlist
  86
  87 ; end of display list
  88
  89 .assert ((* >> 10) = (dlist >> 10)), error, "Display list crosses 1K boundary"
  90
  91                 .end