xref: /netbsd-src/sys/arch/i386/include/endian.h (revision cda4f8f6ee55684e8d311b86c99ea59191e6b74f)
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 1.3 1993/05/22 08:00:16 cgd Exp $
35  */
36 
37 /*
38  * Definitions for byte order, according to byte significance from low
39  * address to high.
40  */
41 #define	LITTLE_ENDIAN	1234	/* LSB first: i386, vax */
42 #define	BIG_ENDIAN	4321	/* MSB first: 68000, ibm, net */
43 #define	PDP_ENDIAN	3412	/* LSB first in word, MSW first in long */
44 
45 #define	BYTE_ORDER	LITTLE_ENDIAN
46 
47 #ifndef KERNEL
48 #include <sys/cdefs.h>
49 #endif
50 
51 #define __word_swap_long(x) \
52 ({ register u_long X = (x); \
53    asm ("rorl $16, %1" \
54 	: "=r" (X) \
55 	: "0" (X)); \
56    X; })
57 #if __GNUC__ >= 2
58 #define __byte_swap_long(x) \
59 ({ register u_long X = (x); \
60    asm ("xchgb %h1, %b1\n\trorl $16, %1\n\txchgb %h1, %b1" \
61 	: "=q" (X) \
62 	: "0" (X)); \
63    X; })
64 #define __byte_swap_word(x) \
65 ({ register u_short X = (x); \
66    asm ("xchgb %h1, %b1" \
67 	: "=q" (X) \
68 	: "0" (X)); \
69    X; })
70 #else /* __GNUC__ >= 2 */
71 #define __byte_swap_long(x) \
72 ({ register u_long X = (x); \
73    asm ("rorw $8, %w1\n\trorl $16, %1\n\trorw $8, %w1" \
74 	: "=r" (X) \
75 	: "0" (X)); \
76    X; })
77 #define __byte_swap_word(x) \
78 ({ register u_short X = (x); \
79    asm ("rorw $8, %w1" \
80 	: "=r" (X) \
81 	: "0" (X)); \
82    X; })
83 #endif /* __GNUC__ >= 2 */
84 
85 /*
86  * Macros for network/external number representation conversion.
87  */
88 #if BYTE_ORDER == BIG_ENDIAN && !defined(lint)
89 #define	ntohl(x)	(x)
90 #define	ntohs(x)	(x)
91 #define	htonl(x)	(x)
92 #define	htons(x)	(x)
93 
94 #define	NTOHL(x)	(x)
95 #define	NTOHS(x)	(x)
96 #define	HTONL(x)	(x)
97 #define	HTONS(x)	(x)
98 
99 #else
100 
101 #define	ntohl	__byte_swap_long
102 #define	ntohs	__byte_swap_word
103 #define	htonl	__byte_swap_long
104 #define	htons	__byte_swap_word
105 
106 #define	NTOHL(x)	(x) = ntohl((u_long)x)
107 #define	NTOHS(x)	(x) = ntohs((u_short)x)
108 #define	HTONL(x)	(x) = htonl((u_long)x)
109 #define	HTONS(x)	(x) = htons((u_short)x)
110 #endif
111