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756b23ec | 1 | /* Macros to swap the order of bytes in 16-bit integer values. |
568035b7 | 2 | Copyright (C) 1997-2013 Free Software Foundation, Inc. |
756b23ec MF |
3 | This file is part of the GNU C Library. |
4 | ||
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. | |
9 | ||
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. | |
14 | ||
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/>. */ | |
18 | ||
19 | #ifndef _BITS_BYTESWAP_H | |
20 | # error "Never use <bits/byteswap-16.h> directly; include <byteswap.h> instead." | |
21 | #endif | |
22 | ||
23 | #if defined __GNUC__ && __GNUC__ >= 2 | |
24 | # define __bswap_16(x) \ | |
25 | (__extension__ \ | |
2e09a79a | 26 | ({ unsigned short int __v, __x = (unsigned short int) (x); \ |
756b23ec MF |
27 | if (__builtin_constant_p (x)) \ |
28 | __v = __bswap_constant_16 (__x); \ | |
29 | else \ | |
30 | __asm__ __volatile__ ("shl %0 = %1, 48 ;;" \ | |
31 | "mux1 %0 = %0, @rev ;;" \ | |
32 | : "=r" (__v) \ | |
33 | : "r" ((unsigned short int) (__x))); \ | |
34 | __v; })) | |
35 | #else | |
36 | /* This is better than nothing. */ | |
37 | static __inline unsigned short int | |
38 | __bswap_16 (unsigned short int __bsx) | |
39 | { | |
40 | return __bswap_constant_16 (__bsx); | |
41 | } | |
42 | #endif |