arch/m68k-amiga/graphics/vbeampos.c

   1 /*
   2     Copyright © 1995-2013, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     Desc: Read the current vertical position of the beam
   6     Lang: english
   7 */
   8 #include <aros/debug.h>
   9 #include "graphics_intern.h"
  10
  11 #include <clib/graphics_protos.h>
  12
  13 /* See rom/graphics/vbeampos.c for documentation */
  14
  15 AROS_LH0(LONG, VBeamPos,
  16     struct GfxBase *, GfxBase, 64, Graphics)
  17 {
  18     AROS_LIBFUNC_INIT
  19
  20     volatile struct Custom *custom = (struct Custom*)0xdff000;
  21     UWORD v1, v2;
  22
  23     for (;;) {
  24         v1 = custom->vhposr >> 8;
  25         v2 = custom->vposr;
  26         if (v1 == (custom->vhposr >> 8))
  27             break;
  28     }
  29
  30     return v1 | ((v2 & 7) << 8);
  31
  32     AROS_LIBFUNC_EXIT
  33 } /* VBeamPos */