l4/pkg/uclibc/lib/contrib/uclibc/libc/sysdeps/linux/i386/bits/byteswap.h

   1 /* Macros to swap the order of bytes in integer values.
   2    Copyright (C) 1997, 1998, 2000, 2002, 2003 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 _ASM_BITS_BYTESWAP_H
  20 #define _ASM_BITS_BYTESWAP_H 1
  21
  22 #define __bswap_non_constant_16(x) \
  23      (__extension__                                                           \
  24       ({ register unsigned short int __v;                                     \
  25          __asm__ ("rorw $8, %w0"                                              \
  26                   : "=r" (__v)                                                \
  27                   : "0" (x)                                                   \
  28                   : "cc");                                                    \
  29          __v; }))
  30
  31 /* To swap the bytes in a word the i486 processors and up provide the
  32    `bswap' opcode.  On i386 we have to use three instructions.  */
  33 #if !defined __i486__ && !defined __pentium__ && !defined __pentiumpro__ \
  34       && !defined __pentium4__
  35 # define __bswap_non_constant_32(x) \
  36      (__extension__                                                           \
  37       ({ register unsigned int __v;                                           \
  38          __asm__ ("rorw $8, %w0;"                                             \
  39                   "rorl $16, %0;"                                             \
  40                   "rorw $8, %w0"                                              \
  41                   : "=r" (__v)                                                \
  42                   : "0" (x)                                                   \
  43                   : "cc");                                                    \
  44          __v; }))
  45 #else
  46 # define __bswap_non_constant_32(x) \
  47      (__extension__                                                           \
  48       ({ register unsigned int __v;                                           \
  49          __asm__ ("bswap %0" : "=r" (__v) : "0" (x));                         \
  50          __v; }))
  51 #endif
  52
  53 #endif
  54
  55 #include <bits/byteswap-common.h>