xref: /freebsd/sys/i386/include/endian.h (revision 7660b554bc59a07be0431c17e0e33815818baa69)
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 <sys/_types.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 #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 #ifdef __GNUC__
71 
72 #define __word_swap_int(x) \
73 __extension__ ({ register __uint32_t __X = (x); \
74    __asm ("rorl $16, %0" : "+r" (__X)); \
75    __X; })
76 
77 #if defined(_KERNEL) && (defined(I486_CPU) || defined(I586_CPU) || defined(I686_CPU)) && !defined(I386_CPU)
78 
79 #define __byte_swap_int(x) \
80 __extension__ ({ register __uint32_t __X = (x); \
81    __asm ("bswap %0" : "+r" (__X)); \
82    __X; })
83 #else
84 
85 #define __byte_swap_int(x) \
86 __extension__ ({ register __uint32_t __X = (x); \
87    __asm ("xchgb %h0, %b0\n\trorl $16, %0\n\txchgb %h0, %b0" \
88        : "+q" (__X)); \
89    __X; })
90 #endif
91 
92 #define __byte_swap_word(x) \
93 __extension__ ({ register __uint16_t __X = (x); \
94    __asm ("xchgb %h0, %b0" : "+q" (__X)); \
95    __X; })
96 
97 static __inline __uint64_t
98 __bswap64(__uint64_t _x)
99 {
100 
101 	return ((_x >> 56) | ((_x >> 40) & 0xff00) | ((_x >> 24) & 0xff0000) |
102 	    ((_x >> 8) & 0xff000000) | ((_x << 8) & ((__uint64_t)0xff << 32)) |
103 	    ((_x << 24) & ((__uint64_t)0xff << 40)) |
104 	    ((_x << 40) & ((__uint64_t)0xff << 48)) | ((_x << 56)));
105 }
106 
107 static __inline __uint32_t
108 __bswap32(__uint32_t _x)
109 {
110 
111 	return (__byte_swap_int(_x));
112 }
113 
114 static __inline __uint16_t
115 __bswap16(__uint16_t _x)
116 {
117 
118 	return (__byte_swap_word(_x));
119 }
120 
121 #define	__htonl(x)	__bswap32(x)
122 #define	__htons(x)	__bswap16(x)
123 #define	__ntohl(x)	__bswap32(x)
124 #define	__ntohs(x)	__bswap16(x)
125 
126 #else /* !__GNUC__ */
127 
128 /*
129  * No optimizations are available for this compiler.  Fall back to
130  * non-optimized functions by defining the constant usually used to prevent
131  * redefinition.
132  */
133 #define	_BYTEORDER_FUNC_DEFINED
134 
135 #endif /* __GNUC__ */
136 
137 #endif /* !_MACHINE_ENDIAN_H_ */
138