about summary refs log tree commit diff
path: root/sysdeps/i386/bits/byteswap.h
blob: 354281638515e46eb9ebdfee8332bbed11437cc2 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
/* Macros to swap the order of bytes in 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
   <http://www.gnu.org/licenses/>.  */

#if !defined _BYTESWAP_H && !defined _NETINET_IN_H && !defined _ENDIAN_H
# error "Never use <bits/byteswap.h> directly; include <byteswap.h> instead."
#endif

#ifndef _BITS_BYTESWAP_H
#define _BITS_BYTESWAP_H 1

/* Swap bytes in 16 bit value.  */
#define __bswap_constant_16(x) \
     ((unsigned short int) ((((x) >> 8) & 0xff) | (((x) & 0xff) << 8)))

/* Get __bswap_16.  */
#include <bits/byteswap-16.h>

/* Swap bytes in 32 bit value.  */
#define __bswap_constant_32(x) \
     ((((x) & 0xff000000) >> 24) | (((x) & 0x00ff0000) >>  8) |		      \
      (((x) & 0x0000ff00) <<  8) | (((x) & 0x000000ff) << 24))

#ifdef __GNUC__
# if __GNUC__ >= 2
/* To swap the bytes in a word the i486 processors and up provide the
   `bswap' opcode.  On i386 we have to use three instructions.  */
#  if !defined __i486__ && !defined __pentium__ && !defined __pentiumpro__ \
      && !defined __pentium4__ && !defined __k8__ && !defined __athlon__ \
      && !defined __k6__ && !defined __nocona__ && !defined __core2__ \
      && !defined __geode__ && !defined __amdfam10__
#   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; }))
#  else
#   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; }))
#  endif
# else
#  define __bswap_32(x) \
     (__extension__							      \
      ({ register unsigned int __x = (x); __bswap_constant_32 (__x); }))
# endif
#else
static __inline unsigned int
__bswap_32 (unsigned int __bsx)
{
  return __bswap_constant_32 (__bsx);
}
#endif


#if defined __GNUC__ && __GNUC__ >= 2
/* Swap bytes in 64 bit value.  */
# define __bswap_constant_64(x) \
     (__extension__ ((((x) & 0xff00000000000000ull) >> 56)		      \
		     | (((x) & 0x00ff000000000000ull) >> 40)		      \
		     | (((x) & 0x0000ff0000000000ull) >> 24)		      \
		     | (((x) & 0x000000ff00000000ull) >> 8)		      \
		     | (((x) & 0x00000000ff000000ull) << 8)		      \
		     | (((x) & 0x0000000000ff0000ull) << 24)		      \
		     | (((x) & 0x000000000000ff00ull) << 40)		      \
		     | (((x) & 0x00000000000000ffull) << 56)))

# define __bswap_64(x) \
     (__extension__							      \
      ({ union { __extension__ unsigned long long int __ll;		      \
		 unsigned long 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; }))
#elif __GLIBC_HAVE_LONG_LONG
# 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))

static __inline unsigned long long int
__bswap_64 (unsigned long long int __bsx)
{
  return __bswap_constant_64 (__bsx);
}
#endif

#endif /* _BITS_BYTESWAP_H */