m_swap.c

来自「The source code of Doom legacy for windo」· C语言 代码 · 共 59 行

// Emacs style mode select   -*- C++ -*- 
//-----------------------------------------------------------------------------
//
// $Id: m_swap.c,v 1.3 2001/02/24 13:35:20 bpereira Exp $
//
// Copyright (C) 1993-1996 by id Software, Inc.
// Portions Copyright (C) 1998-2000 by DooM Legacy Team.
//
// This program is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public License
// as published by the Free Software Foundation; either version 2
// of the License, or (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
//
// $Log: m_swap.c,v $
// Revision 1.3  2001/02/24 13:35:20  bpereira
// no message
//
// Revision 1.2  2000/02/27 00:42:10  hurdler
// fix CR+LF problem
//
// Revision 1.1.1.1  2000/02/22 20:32:32  hurdler
// Initial import into CVS (v1.29 pr3)
//
//
// DESCRIPTION:
//      Endianess handling, swapping 16bit and 32bit.
//
//-----------------------------------------------------------------------------


// Not needed with big endian.
#ifdef __BIG_ENDIAN__

// Swap 16bit, that is, MSB and LSB byte.
unsigned short SwapSHORT(unsigned short x)
{
    // No masking with 0xFF should be necessary.
    return (x>>8) | (x<<8);
}

// Swapping 32bit.
unsigned long SwapLONG(unsigned long x)
{
    return
        (x>>24)
        | ((x>>8) & 0xff00)
        | ((x<<8) & 0xff0000)
        | (x<<24);
}


#endif