ports/sysdeps/ia64/bits/byteswap-16.h

   1 /* Macros to swap the order of bytes in 16-bit integer values.
   2    Copyright (C) 1997-2012 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 #if defined __GNUC__ && __GNUC__ >= 2
  24 # define __bswap_16(x) \
  25      (__extension__                                                           \
  26       ({ register unsigned short int __v, __x = (x);                          \
  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