xref: /freebsd/sys/i386/include/endian.h (revision a316b26e50bbed7cf655fbba726ab87d8ab7599d)
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  *	from: @(#)endian.h	7.8 (Berkeley) 4/3/91
34  *	$Id: endian.h,v 1.4 1993/12/19 05:14:45 alm Exp $
35  */
36 
37 #ifndef _MACHINE_ENDIAN_H_
38 #define _MACHINE_ENDIAN_H_ 1
39 
40 /*
41  * Define the order of 32-bit words in 64-bit words.
42  */
43 #define	_QUAD_HIGHWORD 1
44 #define	_QUAD_LOWWORD 0
45 
46 /*
47  * Definitions for byte order, according to byte significance from low
48  * address to high.
49  */
50 #define	LITTLE_ENDIAN	1234	/* LSB first: i386, vax */
51 #define	BIG_ENDIAN	4321	/* MSB first: 68000, ibm, net */
52 #define	PDP_ENDIAN	3412	/* LSB first in word, MSW first in long */
53 
54 #define	BYTE_ORDER	LITTLE_ENDIAN
55 
56 #ifndef KERNEL
57 #include <sys/cdefs.h>
58 #endif
59 
60 #define __word_swap_long(x) \
61 ({ register u_long X = (x); \
62    __asm ("rorl $16, %1" \
63 	: "=r" (X) \
64 	: "0" (X)); \
65    X; })
66 #if __GNUC__ >= 2
67 #define __byte_swap_long(x) \
68 ({ register u_long X = (x); \
69    __asm ("xchgb %h1, %b1\n\trorl $16, %1\n\txchgb %h1, %b1" \
70 	: "=q" (X) \
71 	: "0" (X)); \
72    X; })
73 #define __byte_swap_word(x) \
74 ({ register u_short X = (x); \
75    __asm ("xchgb %h1, %b1" \
76 	: "=q" (X) \
77 	: "0" (X)); \
78    X; })
79 #else /* __GNUC__ >= 2 */
80 #define __byte_swap_long(x) \
81 ({ register u_long X = (x); \
82    __asm ("rorw $8, %w1\n\trorl $16, %1\n\trorw $8, %w1" \
83 	: "=r" (X) \
84 	: "0" (X)); \
85    X; })
86 #define __byte_swap_word(x) \
87 ({ register u_short X = (x); \
88    __asm ("rorw $8, %w1" \
89 	: "=r" (X) \
90 	: "0" (X)); \
91    X; })
92 #endif /* __GNUC__ >= 2 */
93 
94 /*
95  * Macros for network/external number representation conversion.
96  */
97 #if BYTE_ORDER == BIG_ENDIAN && !defined(lint)
98 #define	ntohl(x)	(x)
99 #define	ntohs(x)	(x)
100 #define	htonl(x)	(x)
101 #define	htons(x)	(x)
102 
103 #define	NTOHL(x)	(x)
104 #define	NTOHS(x)	(x)
105 #define	HTONL(x)	(x)
106 #define	HTONS(x)	(x)
107 
108 #else
109 
110 #define	ntohl	__byte_swap_long
111 #define	ntohs	__byte_swap_word
112 #define	htonl	__byte_swap_long
113 #define	htons	__byte_swap_word
114 
115 #define	NTOHL(x)	(x) = ntohl((u_long)x)
116 #define	NTOHS(x)	(x) = ntohs((u_short)x)
117 #define	HTONL(x)	(x) = htonl((u_long)x)
118 #define	HTONS(x)	(x) = htons((u_short)x)
119 #endif
120 #endif /* _MACHINE_ENDIAN_H_ */
121