xref: /freebsd/sys/amd64/include/endian.h (revision 1e413cf93298b5b97441a21d9a50fdcd0ee9945e)
1 /*-
2  * Copyright (c) 1987, 1991 Regents of the University of California.
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 4. Neither the name of the University nor the names of its contributors
14  *    may be used to endorse or promote products derived from this software
15  *    without specific prior written permission.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  *
29  *	@(#)endian.h	7.8 (Berkeley) 4/3/91
30  * $FreeBSD$
31  */
32 
33 #ifndef _MACHINE_ENDIAN_H_
34 #define	_MACHINE_ENDIAN_H_
35 
36 #include <sys/cdefs.h>
37 #include <sys/_types.h>
38 
39 #ifdef __cplusplus
40 extern "C" {
41 #endif
42 
43 /*
44  * Define the order of 32-bit words in 64-bit words.
45  */
46 #define	_QUAD_HIGHWORD 1
47 #define	_QUAD_LOWWORD 0
48 
49 /*
50  * Definitions for byte order, according to byte significance from low
51  * address to high.
52  */
53 #define	_LITTLE_ENDIAN	1234	/* LSB first: i386, vax */
54 #define	_BIG_ENDIAN	4321	/* MSB first: 68000, ibm, net */
55 #define	_PDP_ENDIAN	3412	/* LSB first in word, MSW first in long */
56 
57 #define	_BYTE_ORDER	_LITTLE_ENDIAN
58 
59 /*
60  * Deprecated variants that don't have enough underscores to be useful in more
61  * strict namespaces.
62  */
63 #if __BSD_VISIBLE
64 #define	LITTLE_ENDIAN	_LITTLE_ENDIAN
65 #define	BIG_ENDIAN	_BIG_ENDIAN
66 #define	PDP_ENDIAN	_PDP_ENDIAN
67 #define	BYTE_ORDER	_BYTE_ORDER
68 #endif
69 
70 #if defined(__GNUCLIKE_ASM) && defined(__GNUCLIKE_BUILTIN_CONSTANT_P)
71 
72 #define __word_swap_int_var(x) \
73 __extension__ ({ register __uint32_t __X = (x); \
74    __asm ("rorl $16, %0" : "+r" (__X)); \
75    __X; })
76 
77 #ifdef __OPTIMIZE__
78 
79 #define	__word_swap_int_const(x) \
80 	((((x) & 0xffff0000) >> 16) | \
81 	 (((x) & 0x0000ffff) << 16))
82 #define	__word_swap_int(x) (__builtin_constant_p(x) ? \
83 	__word_swap_int_const(x) : __word_swap_int_var(x))
84 
85 #else	/* __OPTIMIZE__ */
86 
87 #define	__word_swap_int(x) __word_swap_int_var(x)
88 
89 #endif	/* __OPTIMIZE__ */
90 
91 #define __byte_swap_int_var(x) \
92 __extension__ ({ register __uint32_t __X = (x); \
93    __asm ("bswap %0" : "+r" (__X)); \
94    __X; })
95 
96 #ifdef __OPTIMIZE__
97 
98 #define	__byte_swap_int_const(x) \
99 	((((x) & 0xff000000) >> 24) | \
100 	 (((x) & 0x00ff0000) >>  8) | \
101 	 (((x) & 0x0000ff00) <<  8) | \
102 	 (((x) & 0x000000ff) << 24))
103 #define	__byte_swap_int(x) (__builtin_constant_p(x) ? \
104 	__byte_swap_int_const(x) : __byte_swap_int_var(x))
105 
106 #else	/* __OPTIMIZE__ */
107 
108 #define	__byte_swap_int(x) __byte_swap_int_var(x)
109 
110 #endif	/* __OPTIMIZE__ */
111 
112 #define __byte_swap_long_var(x) \
113 __extension__ ({ register __uint64_t __X = (x); \
114    __asm ("bswap %0" : "+r" (__X)); \
115    __X; })
116 
117 #ifdef __OPTIMIZE__
118 
119 #define	__byte_swap_long_const(x) \
120 	(((x >> 56) | \
121 	 ((x >> 40) & 0xff00) | \
122 	 ((x >> 24) & 0xff0000) | \
123 	 ((x >> 8) & 0xff000000) | \
124 	 ((x << 8) & (0xfful << 32)) | \
125 	 ((x << 24) & (0xfful << 40)) | \
126 	 ((x << 40) & (0xfful << 48)) | \
127 	 ((x << 56))))
128 
129 #define	__byte_swap_long(x) (__builtin_constant_p(x) ? \
130 	__byte_swap_long_const(x) : __byte_swap_long_var(x))
131 
132 #else	/* __OPTIMIZE__ */
133 
134 #define	__byte_swap_long(x) __byte_swap_long_var(x)
135 
136 #endif	/* __OPTIMIZE__ */
137 
138 #define __byte_swap_word_var(x) \
139 __extension__ ({ register __uint16_t __X = (x); \
140    __asm ("xchgb %h0, %b0" : "+Q" (__X)); \
141    __X; })
142 
143 #ifdef __OPTIMIZE__
144 
145 #define	__byte_swap_word_const(x) \
146 	((((x) & 0xff00) >> 8) | \
147 	 (((x) & 0x00ff) << 8))
148 
149 #define	__byte_swap_word(x) (__builtin_constant_p(x) ? \
150 	__byte_swap_word_const(x) : __byte_swap_word_var(x))
151 
152 #else	/* __OPTIMIZE__ */
153 
154 #define	__byte_swap_word(x) __byte_swap_word_var(x)
155 
156 #endif	/* __OPTIMIZE__ */
157 
158 static __inline __uint64_t
159 __bswap64(__uint64_t _x)
160 {
161 
162 	return (__byte_swap_long(_x));
163 }
164 
165 static __inline __uint32_t
166 __bswap32(__uint32_t _x)
167 {
168 
169 	return (__byte_swap_int(_x));
170 }
171 
172 static __inline __uint16_t
173 __bswap16(__uint16_t _x)
174 {
175 
176 	return (__byte_swap_word(_x));
177 }
178 
179 #define	__htonl(x)	__bswap32(x)
180 #define	__htons(x)	__bswap16(x)
181 #define	__ntohl(x)	__bswap32(x)
182 #define	__ntohs(x)	__bswap16(x)
183 
184 #else /* !(__GNUCLIKE_ASM && __GNUCLIKE_BUILTIN_CONSTANT_P) */
185 
186 /*
187  * No optimizations are available for this compiler.  Fall back to
188  * non-optimized functions by defining the constant usually used to prevent
189  * redefinition.
190  */
191 #define	_BYTEORDER_FUNC_DEFINED
192 
193 #endif /* __GNUCLIKE_ASM && __GNUCLIKE_BUILTIN_CONSTANT_P */
194 
195 #ifdef __cplusplus
196 }
197 #endif
198 
199 #endif /* !_MACHINE_ENDIAN_H_ */
200