arch/m68k-amiga/expansion/readexpansionbyte.c

   1 /*
   2     Copyright © 1995-2013, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     Desc:
   6     Lang: english
   7 */
   8 #include "expansion_intern.h"
   9
  10 #include <clib/expansion_protos.h>
  11
  12 /* See rom/expansion/readexpansionbyte.c for documentation */
  13
  14 AROS_LH2(UBYTE, ReadExpansionByte,
  15     AROS_LHA(APTR , board, A0),
  16     AROS_LHA(ULONG, offset, D0),
  17     struct ExpansionBase *, ExpansionBase, 16, Expansion)
  18 {
  19     AROS_LIBFUNC_INIT
  20
  21         UBYTE v;
  22         UWORD loffset;
  23         volatile UBYTE *p = (UBYTE*)board;
  24
  25         offset *= 4;
  26         if (((ULONG)board) & 0xff000000)
  27                 loffset = 0x100;
  28         else
  29                 loffset = 0x002;
  30         v = (p[offset + loffset] & 0xf0) >> 4;
  31         v |= p[offset] & 0xf0;
  32         return v;
  33
  34     AROS_LIBFUNC_EXIT
  35 } /* ReadExpansionByte */