| 1 | /* Macros to swap the order of bytes in 16-bit integer values. |
|---|
| 2 | Copyright (C) 2012-2016 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 | |
|---|