Games/Doom/m_swap.c

   1 // Emacs style mode select   -*- C++ -*-
   2 //-----------------------------------------------------------------------------
   3 //
   4 // $Id$
   5 //
   6 // Copyright (C) 1993-1996 by id Software, Inc.
   7 //
   8 // This source is available for distribution and/or modification
   9 // only under the terms of the DOOM Source Code License as
  10 // published by id Software. All rights reserved.
  11 //
  12 // The source is distributed in the hope that it will be useful,
  13 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 // FITNESS FOR A PARTICULAR PURPOSE. See the DOOM Source Code License
  15 // for more details.
  16 //
  17 // $Log$
  18 // Revision 1.1  2000/02/29 18:21:04  stegerg
  19 // Doom port based on ADoomPPC. Read README.AROS!
  20 //
  21 //
  22 // DESCRIPTION:
  23 //      Endianess handling, swapping 16bit and 32bit.
  24 //
  25 //-----------------------------------------------------------------------------
  26
  27 static const char
  28 rcsid[] = "$Id$";
  29
  30
  31 #ifdef __GNUG__
  32 #pragma implementation "m_swap.h"
  33 #endif
  34 #include "m_swap.h"
  35
  36
  37 // Needed with big endian.
  38 #ifdef __BIG_ENDIAN__
  39
  40 // Swap 16bit, that is, MSB and LSB byte.
  41 unsigned short SwapSHORT(unsigned short x)
  42 {
  43     // No masking with 0xFF should be necessary.
  44     return (unsigned short)((x>>8) | (x<<8));
  45 }
  46
  47 // Swapping 32bit.
  48 unsigned long SwapLONG( unsigned long x)
  49 {
  50     return
  51         (x>>24)
  52         | ((x>>8) & 0xff00)
  53         | ((x<<8) & 0xff0000)
  54         | (x<<24);
  55 }
  56
  57
  58 #endif
  59
  60