1 | /* Macros to swap the order of bytes in 16-bit integer values. |
2 | Copyright (C) 2012-2018 Free Software Foundation, Inc. |
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 | #ifdef __GNUC__ |
24 | # if __GNUC__ >= 2 |
25 | # define __bswap_16(x) \ |
26 | (__extension__ \ |
27 | ({ unsigned short int __v, __x = (unsigned short int) (x); \ |
28 | if (__builtin_constant_p (__x)) \ |
29 | __v = __bswap_constant_16 (__x); \ |
30 | else \ |
31 | __asm__ ("rorw $8, %w0" \ |
32 | : "=r" (__v) \ |
33 | : "0" (__x) \ |
34 | : "cc"); \ |
35 | __v; })) |
36 | # else |
37 | /* This is better than nothing. */ |
38 | # define __bswap_16(x) \ |
39 | (__extension__ \ |
40 | ({ unsigned short int __x = (unsigned short int) (x); \ |
41 | __bswap_constant_16 (__x); })) |
42 | # endif |
43 | #else |
44 | static __inline unsigned short int |
45 | __bswap_16 (unsigned short int __bsx) |
46 | { |
47 | return __bswap_constant_16 (__bsx); |
48 | } |
49 | #endif |
50 | |