arch/m68k-amiga/timer/initcustom.c

   1 /*
   2     Copyright © 1995-2011, The AROS Development Team. All rights reserved.
   3
   4     Desc: Detect custom chipset revisions and PAL/NTSC state
   5     Lang: english
   6 */
   7
   8 #define DEBUG 0
   9
  10 #include <aros/debug.h>
  11 #include <aros/symbolsets.h>
  12 #include <graphics/gfxbase.h>
  13 #include <hardware/custom.h>
  14 #include <hardware/cia.h>
  15
  16 #include <timer_platform.h>
  17
  18 static UWORD getline(void)
  19 {
  20         volatile struct Custom *custom = (struct Custom*)0xdff000;
  21         UBYTE vposb;
  22         UWORD vpos;
  23
  24         vposb = custom->vhposr >> 8;
  25         while (vposb == (custom->vhposr >> 8));
  26         vpos = ((custom->vposr & 7) << 8) | (custom->vhposr >> 8);
  27         return vpos;
  28 }
  29
  30 static UWORD gethighestline(UWORD linecnt)
  31 {
  32         volatile struct Custom *custom = (struct Custom*)0xdff000;
  33         UBYTE vposb;
  34         UWORD vpos, highest;
  35
  36         highest = 0;
  37         while (linecnt-- != 0) {
  38                 vposb = custom->vhposr >> 8;
  39                 while (vposb == (custom->vhposr >> 8));
  40                 vposb++;
  41                 vpos = ((custom->vposr & 7) << 8) | vposb;
  42                 if (vpos > highest)
  43                         highest = vpos;
  44         }
  45         return highest;
  46 }
  47
  48 void InitCustom(struct GfxBase *gfx)
  49 {
  50         volatile struct Custom *custom = (struct Custom*)0xdff000;
  51         UWORD vposr;
  52         UWORD flags = 0;
  53         UWORD pos;
  54
  55         Disable();
  56
  57         custom->vposw = 0x8000;
  58         custom->bplcon0 = 0x0200;
  59
  60         while(getline() != 0);
  61         pos = gethighestline(400);
  62         if (pos > 300)
  63                 flags |= PAL;
  64         else
  65                 flags |= NTSC;
  66
  67         vposr = custom->vposr & 0x7f00;
  68         if (!(vposr & 0x1000))
  69                 flags |= REALLY_PAL;
  70         custom->fmode = 0;
  71
  72         Enable();
  73
  74         if (vposr >= 0x2200) {
  75                 gfx->MemType = BUS_32 | DBL_CAS;
  76         }
  77
  78         gfx->DisplayFlags = flags;
  79
  80         SysBase->VBlankFrequency = (flags & PAL) ? 50 : 60;
  81 }