1 /* Macros to swap the order of bytes in integer values.
2 Copyright (C) 1997,1998,2000-2002,2005,2008,2011
3 Free Software Foundation, Inc.
4 This file is part of the GNU C Library.
6 The GNU C Library is free software; you can redistribute it and/or
7 modify it under the terms of the GNU Lesser General Public
8 License as published by the Free Software Foundation; either
9 version 2.1 of the License, or (at your option) any later version.
11 The GNU C Library is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 Lesser General Public License for more details.
16 You should have received a copy of the GNU Lesser General Public
17 License along with the GNU C Library; if not, write to the Free
18 Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
21 #if !defined _BYTESWAP_H && !defined _NETINET_IN_H && !defined _ENDIAN_H
22 # error "Never use <bits/byteswap.h> directly; include <byteswap.h> instead."
25 #ifndef _BITS_BYTESWAP_H
26 #define _BITS_BYTESWAP_H 1
28 /* Swap bytes in 16 bit value. */
29 #define __bswap_constant_16(x) \
30 ((((x) >> 8) & 0xffu) | (((x) & 0xffu) << 8))
33 # define __bswap_16(x) \
35 ({ unsigned short int __bsx = (x); __bswap_constant_16 (__bsx); }))
37 static __inline
unsigned short int
38 __bswap_16 (unsigned short int __bsx
)
40 return __bswap_constant_16 (__bsx
);
44 /* Swap bytes in 32 bit value. */
45 #define __bswap_constant_32(x) \
46 ((((x) & 0xff000000u) >> 24) | (((x) & 0x00ff0000u) >> 8) | \
47 (((x) & 0x0000ff00u) << 8) | (((x) & 0x000000ffu) << 24))
50 # define __bswap_32(x) \
52 ({ register unsigned int __bsx = (x); __bswap_constant_32 (__bsx); }))
54 static __inline
unsigned int
55 __bswap_32 (unsigned int __bsx
)
57 return __bswap_constant_32 (__bsx
);
61 #if defined __GNUC__ && __GNUC__ >= 2
62 /* Swap bytes in 64 bit value. */
63 # define __bswap_constant_64(x) \
64 (__extension__ ((((x) & 0xff00000000000000ull) >> 56) \
65 | (((x) & 0x00ff000000000000ull) >> 40) \
66 | (((x) & 0x0000ff0000000000ull) >> 24) \
67 | (((x) & 0x000000ff00000000ull) >> 8) \
68 | (((x) & 0x00000000ff000000ull) << 8) \
69 | (((x) & 0x0000000000ff0000ull) << 24) \
70 | (((x) & 0x000000000000ff00ull) << 40) \
71 | (((x) & 0x00000000000000ffull) << 56)))
73 # define __bswap_64(x) \
75 ({ union { __extension__ unsigned long long int __ll; \
76 unsigned int __l[2]; } __w, __r; \
77 if (__builtin_constant_p (x)) \
78 __r.__ll = __bswap_constant_64 (x); \
82 __r.__l[0] = __bswap_32 (__w.__l[1]); \
83 __r.__l[1] = __bswap_32 (__w.__l[0]); \
88 #endif /* _BITS_BYTESWAP_H */