Update.
[glibc.git] / bits / byteswap.h
blob73189cfe5c6315fca2049c3a994e5164a074367b
1 /* Macros to swap the order of bytes in integer values.
2 Copyright (C) 1997, 1998 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Library General Public License as
7 published by the Free Software Foundation; either version 2 of the
8 License, or (at your option) any later version.
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Library General Public License for more details.
15 You should have received a copy of the GNU Library General Public
16 License along with the GNU C Library; see the file COPYING.LIB. If not,
17 write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
18 Boston, MA 02111-1307, USA. */
20 #if !defined _BYTESWAP_H && !defined _NETINET_IN_H
21 # error "Never use <bits/byteswap.h> directly; include <byteswap.h> instead."
22 #endif
24 /* Swap bytes in 16 bit value. */
25 #ifdef __GNUC__
26 # define __bswap_16(x) \
27 (__extension__ \
28 ({ unsigned short int __bsx = (x); \
29 ((((__bsx) >> 8) & 0xff) | (((__bsx) & 0xff) << 8)); }))
30 #else
31 static __inline unsigned short int
32 __bswap16 (unsigned short int x)
34 return ((((x) >> 8) & 0xff) | (((x) & 0xff) << 8));
36 #endif
38 /* Swap bytes in 32 bit value. */
39 #ifdef __GNUC__
40 # define __bswap_32(x) \
41 (__extension__ \
42 ({ unsigned int __bsx = (x); \
43 ((((__bsx) & 0xff000000) >> 24) | (((__bsx) & 0x00ff0000) >> 8) | \
44 (((__bsx) & 0x0000ff00) << 8) | (((__bsx) & 0x000000ff) << 24)); }))
45 #else
46 static __inline unsigned int
47 __bswap32 (unsigned int x)
49 return ((((__bsx) & 0xff000000) >> 24) | (((__bsx) & 0x00ff0000) >> 8) |
50 (((__bsx) & 0x0000ff00) << 8) | (((__bsx) & 0x000000ff) << 24));
52 #endif
54 #if defined __GNUC__ && __GNUC__ >= 2
55 /* Swap bytes in 64 bit value. */
56 # define __bswap_64(x) \
57 (__extension__ \
58 ({ union { unsigned long long int __ll; \
59 unsigned long int __l[2]; } __v, __r; \
60 __v.__ll = (x); \
61 __r.__l[0] = __bswap_32 (__v.__l[1]); \
62 __r.__l[1] = __bswap_32 (__v.__l[0]); \
63 __r.__ll; }))
64 #endif