/* Macros to swap the order of bytes in 16-bit integer values. Copyright (C) 1997-2012 Free Software Foundation, Inc. This file is part of the GNU C Library. The GNU C Library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. The GNU C Library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with the GNU C Library; if not, see . */ #ifndef _BITS_BYTESWAP_H # error "Never use directly; include instead." #endif #if defined __GNUC__ && __GNUC__ >= 2 # define __bswap_16(x) \ (__extension__ \ ({ register unsigned short int __v, __x = (x); \ if (__builtin_constant_p (x)) \ __v = __bswap_constant_16 (__x); \ else \ __asm__ __volatile__ ("shl %0 = %1, 48 ;;" \ "mux1 %0 = %0, @rev ;;" \ : "=r" (__v) \ : "r" ((unsigned short int) (__x))); \ __v; })) #else /* This is better than nothing. */ static __inline unsigned short int __bswap_16 (unsigned short int __bsx) { return __bswap_constant_16 (__bsx); } #endif