1 /* Macros to swap the order of bytes in 16-bit integer values.
2 Copyright (C) 1997-2013 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 Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the 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 Lesser General Public License for more details.
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <http://www.gnu.org/licenses/>. */
19 #ifndef _BITS_BYTESWAP_H
20 # error "Never use <bits/byteswap-16.h> directly; include <byteswap.h> instead."
23 #if defined __GNUC__ && __GNUC__ >= 2
24 # define __bswap_16(x) \
26 ({ register unsigned short int __v, __x = (unsigned short int) (x); \
27 if (__builtin_constant_p (x)) \
28 __v = __bswap_constant_16 (__x); \
30 __asm__ __volatile__ ("shl %0 = %1, 48 ;;" \
31 "mux1 %0 = %0, @rev ;;" \
33 : "r" ((unsigned short int) (__x))); \
36 /* This is better than nothing. */
37 static __inline
unsigned short int
38 __bswap_16 (unsigned short int __bsx
)
40 return __bswap_constant_16 (__bsx
);