1    	/* Macros to swap the order of bytes in integer values.
2    	   Copyright (C) 1997-2015 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   	#if !defined _BYTESWAP_H && !defined _NETINET_IN_H && !defined _ENDIAN_H
20   	# error "Never use <bits/byteswap.h> directly; include <byteswap.h> instead."
21   	#endif
22   	
23   	#ifndef _BITS_BYTESWAP_H
24   	#define _BITS_BYTESWAP_H 1
25   	
26   	#include <features.h>
27   	#include <bits/types.h>
28   	#include <bits/wordsize.h>
29   	
30   	/* Swap bytes in 16 bit value.  */
31   	#define __bswap_constant_16(x) \
32   	     ((unsigned short int) ((((x) >> 8) & 0xff) | (((x) & 0xff) << 8)))
33   	
34   	/* Get __bswap_16.  */
35   	#include <bits/byteswap-16.h>
36   	
37   	/* Swap bytes in 32 bit value.  */
38   	#define __bswap_constant_32(x) \
39   	     ((((x) & 0xff000000) >> 24) | (((x) & 0x00ff0000) >>  8) |		      \
40   	      (((x) & 0x0000ff00) <<  8) | (((x) & 0x000000ff) << 24))
41   	
42   	#ifdef __GNUC__
43   	# if __GNUC_PREREQ (4, 3)
44   	static __inline unsigned int
45   	__bswap_32 (unsigned int __bsx)
46   	{
47   	  return __builtin_bswap32 (__bsx);
48   	}
49   	# elif __GNUC__ >= 2
50   	#  if __WORDSIZE == 64 || (defined __i486__ || defined __pentium__	      \
51   				   || defined __pentiumpro__ || defined __pentium4__  \
52   				   || defined __k8__ || defined __athlon__	      \
53   				   || defined __k6__ || defined __nocona__	      \
54   				   || defined __core2__ || defined __geode__	      \
55   				   || defined __amdfam10__)
56   	/* To swap the bytes in a word the i486 processors and up provide the
57   	   `bswap' opcode.  On i386 we have to use three instructions.  */
58   	#   define __bswap_32(x) \
59   	      (__extension__							      \
60   	       ({ unsigned int __v, __x = (x);					      \
61   		  if (__builtin_constant_p (__x))				      \
62   		    __v = __bswap_constant_32 (__x);				      \
63   		  else								      \
64   		    __asm__ ("bswap %0" : "=r" (__v) : "0" (__x));		      \
65   		  __v; }))
66   	#  else
67   	#   define __bswap_32(x)						      \
68   	      (__extension__							      \
69   	       ({ unsigned int __v, __x = (x);					      \
70   		  if (__builtin_constant_p (__x))				      \
71   		    __v = __bswap_constant_32 (__x);				      \
72   		  else								      \
73   		    __asm__ ("rorw $8, %w0;"					      \
74   			     "rorl $16, %0;"					      \
75   			     "rorw $8, %w0"					      \
76   			     : "=r" (__v)					      \
77   			     : "0" (__x)					      \
78   			     : "cc");						      \
79   		  __v; }))
80   	#  endif
81   	# else
82   	#  define __bswap_32(x) \
83   	     (__extension__							      \
84   	      ({ unsigned int __x = (x); __bswap_constant_32 (__x); }))
85   	# endif
86   	#else
87   	static __inline unsigned int
88   	__bswap_32 (unsigned int __bsx)
89   	{
90   	  return __bswap_constant_32 (__bsx);
91   	}
92   	#endif
93   	
94   	
95   	#if __GNUC_PREREQ (2, 0)
96   	/* Swap bytes in 64 bit value.  */
97   	# define __bswap_constant_64(x) \
98   	     (__extension__ ((((x) & 0xff00000000000000ull) >> 56)		      \
99   			     | (((x) & 0x00ff000000000000ull) >> 40)		      \
100  			     | (((x) & 0x0000ff0000000000ull) >> 24)		      \
101  			     | (((x) & 0x000000ff00000000ull) >> 8)		      \
102  			     | (((x) & 0x00000000ff000000ull) << 8)		      \
103  			     | (((x) & 0x0000000000ff0000ull) << 24)		      \
104  			     | (((x) & 0x000000000000ff00ull) << 40)		      \
105  			     | (((x) & 0x00000000000000ffull) << 56)))
106  	
107  	# if __GNUC_PREREQ (4, 3)
108  	static __inline __uint64_t
109  	__bswap_64 (__uint64_t __bsx)
110  	{
111  	  return __builtin_bswap64 (__bsx);
112  	}
113  	# elif __WORDSIZE == 64
114  	#  define __bswap_64(x) \
115  	     (__extension__							      \
116  	      ({ __uint64_t __v, __x = (x);					      \
117  		 if (__builtin_constant_p (__x))				      \
118  		   __v = __bswap_constant_64 (__x);				      \
119  		 else								      \
120  		   __asm__ ("bswap %q0" : "=r" (__v) : "0" (__x));		      \
121  		 __v; }))
122  	# else
123  	#  define __bswap_64(x) \
124  	     (__extension__                                                           \
125  	      ({ union { __extension__ __uint64_t __ll;		                      \
126  			 unsigned int __l[2]; } __w, __r;                             \
127  		 if (__builtin_constant_p (x))                                        \
128  		   __r.__ll = __bswap_constant_64 (x);                                \
129  		 else                                                                 \
130  		   {                                                                  \
131  		     __w.__ll = (x);                                                  \
132  		     __r.__l[0] = __bswap_32 (__w.__l[1]);                            \
133  		     __r.__l[1] = __bswap_32 (__w.__l[0]);                            \
134  		   }                                                                  \
135  		 __r.__ll; }))
136  	# endif
137  	#else
138  	# define __bswap_constant_64(x) \
139  	     ((((x) & 0xff00000000000000ull) >> 56)				      \
140  	      | (((x) & 0x00ff000000000000ull) >> 40)				      \
141  	      | (((x) & 0x0000ff0000000000ull) >> 24)				      \
142  	      | (((x) & 0x000000ff00000000ull) >> 8)				      \
143  	      | (((x) & 0x00000000ff000000ull) << 8)				      \
144  	      | (((x) & 0x0000000000ff0000ull) << 24)				      \
145  	      | (((x) & 0x000000000000ff00ull) << 40)				      \
146  	      | (((x) & 0x00000000000000ffull) << 56))
147  	
148  	static __inline __uint64_t
149  	__bswap_64 (__uint64_t __bsx)
150  	{
151  	  return __bswap_constant_64 (__bsx);
152  	}
153  	#endif
154  	
155  	#endif /* _BITS_BYTESWAP_H */
156