xref: /freebsd/sys/i386/include/endian.h (revision eacee0ff7ec955b32e09515246bd97b6edcd2b0f)
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  * 3. All advertising materials mentioning features or use of this software
14  *    must display the following acknowledgement:
15  *	This product includes software developed by the University of
16  *	California, Berkeley and its contributors.
17  * 4. Neither the name of the University nor the names of its contributors
18  *    may be used to endorse or promote products derived from this software
19  *    without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  *
33  *	@(#)endian.h	7.8 (Berkeley) 4/3/91
34  * $FreeBSD$
35  */
36 
37 #ifndef _MACHINE_ENDIAN_H_
38 #define	_MACHINE_ENDIAN_H_
39 
40 #include <sys/cdefs.h>
41 #include <machine/ansi.h>
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 #ifndef _POSIX_SOURCE
54 #define	LITTLE_ENDIAN	1234	/* LSB first: i386, vax */
55 #define	BIG_ENDIAN	4321	/* MSB first: 68000, ibm, net */
56 #define	PDP_ENDIAN	3412	/* LSB first in word, MSW first in long */
57 
58 #define	BYTE_ORDER	LITTLE_ENDIAN
59 #endif /* ! _POSIX_SOURCE */
60 
61 #ifdef __GNUC__
62 
63 __BEGIN_DECLS
64 
65 static __inline __uint32_t
66 __htonl(__uint32_t __x)
67 {
68 #if defined(_KERNEL) && (defined(I486_CPU) || defined(I586_CPU) || defined(I686_CPU)) && !defined(I386_CPU)
69 	__asm ("bswap %0" : "+r" (__x));
70 #else
71 	__asm ("xchgb %h0, %b0\n\t"
72 	       "rorl $16, %0\n\t"
73 	       "xchgb %h0, %b0"
74 	       : "+q" (__x));
75 #endif
76 	return __x;
77 }
78 
79 static __inline __uint16_t
80 __htons(__uint16_t __x)
81 {
82 	__asm ("xchgb %h0, %b0" : "+q" (__x));
83 
84 	return __x;
85 }
86 
87 static __inline __uint32_t
88 __ntohl(__uint32_t __x)
89 {
90 
91 	return (__htonl(__x));
92 }
93 
94 static __inline __uint16_t
95 __ntohs(__uint16_t __x)
96 {
97 
98 	return (__htons(__x));
99 }
100 
101 __END_DECLS
102 
103 #endif /* __GNUC__ */
104 
105 #endif /* !_MACHINE_ENDIAN_H_ */
106