diff options
Diffstat (limited to 'sysdeps/x86_64/bits/byteswap.h')
| -rw-r--r-- | sysdeps/x86_64/bits/byteswap.h | 133 |
1 files changed, 133 insertions, 0 deletions
diff --git a/sysdeps/x86_64/bits/byteswap.h b/sysdeps/x86_64/bits/byteswap.h new file mode 100644 index 0000000000..e1c861c75f --- /dev/null +++ b/sysdeps/x86_64/bits/byteswap.h @@ -0,0 +1,133 @@ +/* Macros to swap the order of bytes in integer values. + Copyright (C) 1997, 1998, 2000, 2002, 2003 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, write to the Free + Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA + 02111-1307 USA. */ + +#if !defined _BYTESWAP_H && !defined _NETINET_IN_H +# error "Never use <bits/byteswap.h> directly; include <byteswap.h> instead." +#endif + +#ifndef _BITS_BYTESWAP_H +#define _BITS_BYTESWAP_H 1 + +#include <bits/wordsize.h> + +/* Swap bytes in 16 bit value. */ +#define __bswap_constant_16(x) \ + ((((x) >> 8) & 0xff) | (((x) & 0xff) << 8)) + +#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__ ("rorw $8, %w0" \ + : "=r" (__v) \ + : "0" (__x) \ + : "cc"); \ + __v; })) +#else +/* This is better than nothing. */ +# define __bswap_16(x) \ + (__extension__ \ + ({ register unsigned short int __x = (x); __bswap_constant_16 (__x); })) +#endif + + +/* Swap bytes in 32 bit value. */ +#define __bswap_constant_32(x) \ + ((((x) & 0xff000000) >> 24) | (((x) & 0x00ff0000) >> 8) | \ + (((x) & 0x0000ff00) << 8) | (((x) & 0x000000ff) << 24)) + +#if defined __GNUC__ && __GNUC__ >= 2 +# if __WORDSIZE == 64 || (defined __i486__ || defined __pentium__ \ + || defined __pentiumpro__ || defined __pentium4__ \ + || defined __k8__ || defined __athlon__ \ + || defined __k6__) +/* To swap the bytes in a word the i486 processors and up provide the + `bswap' opcode. On i386 we have to use three instructions. */ +# define __bswap_32(x) \ + (__extension__ \ + ({ register unsigned int __v, __x = (x); \ + if (__builtin_constant_p (__x)) \ + __v = __bswap_constant_32 (__x); \ + else \ + __asm__ ("bswap %0" : "=r" (__v) : "0" (__x)); \ + __v; })) +# else +# define __bswap_32(x) \ + (__extension__ \ + ({ register unsigned int __v, __x = (x); \ + if (__builtin_constant_p (__x)) \ + __v = __bswap_constant_32 (__x); \ + else \ + __asm__ ("rorw $8, %w0;" \ + "rorl $16, %0;" \ + "rorw $8, %w0" \ + : "=r" (__v) \ + : "0" (__x) \ + : "cc"); \ + __v; })) +# endif +#else +# define __bswap_32(x) \ + (__extension__ \ + ({ register unsigned int __x = (x); __bswap_constant_32 (__x); })) +#endif + + +#if defined __GNUC__ && __GNUC__ >= 2 +/* Swap bytes in 64 bit value. */ +# define __bswap_constant_64(x) \ + ((((x) & 0xff00000000000000ull) >> 56) \ + | (((x) & 0x00ff000000000000ull) >> 40) \ + | (((x) & 0x0000ff0000000000ull) >> 24) \ + | (((x) & 0x000000ff00000000ull) >> 8) \ + | (((x) & 0x00000000ff000000ull) << 8) \ + | (((x) & 0x0000000000ff0000ull) << 24) \ + | (((x) & 0x000000000000ff00ull) << 40) \ + | (((x) & 0x00000000000000ffull) << 56)) + +# if __WORDSIZE == 64 +# define __bswap_64(x) \ + (__extension__ \ + ({ register unsigned long __v, __x = (x); \ + if (__builtin_constant_p (__x)) \ + __v = __bswap_constant_64 (__x); \ + else \ + __asm__ ("bswap %q0" : "=r" (__v) : "0" (__x)); \ + __v; })) +# else +# define __bswap_64(x) \ + (__extension__ \ + ({ union { __extension__ unsigned long long int __ll; \ + unsigned int __l[2]; } __w, __r; \ + if (__builtin_constant_p (x)) \ + __r.__ll = __bswap_constant_64 (x); \ + else \ + { \ + __w.__ll = (x); \ + __r.__l[0] = __bswap_32 (__w.__l[1]); \ + __r.__l[1] = __bswap_32 (__w.__l[0]); \ + } \ + __r.__ll; })) +# endif +#endif + +#endif /* _BITS_BYTESWAP_H */ |