2 * SPDX-License-Identifier: BSD-3-Clause
4 * Copyright (c) 1987, 1991 Regents of the University of California.
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
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14 * documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the University nor the names of its contributors
16 * may be used to endorse or promote products derived from this software
17 * without specific prior written permission.
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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31 * @(#)endian.h 7.8 (Berkeley) 4/3/91
35 #ifndef _MACHINE_ENDIAN_H_
36 #define _MACHINE_ENDIAN_H_
38 #include <sys/cdefs.h>
39 #include <sys/_types.h>
42 * Define the order of 32-bit words in 64-bit words.
44 #define _QUAD_HIGHWORD 1
45 #define _QUAD_LOWWORD 0
48 * Definitions for byte order, according to byte significance from low
51 #define _LITTLE_ENDIAN 1234 /* LSB first: i386, vax */
52 #define _BIG_ENDIAN 4321 /* MSB first: 68000, ibm, net */
53 #define _PDP_ENDIAN 3412 /* LSB first in word, MSW first in long */
55 #define _BYTE_ORDER _LITTLE_ENDIAN
58 * Deprecated variants that don't have enough underscores to be useful in more
62 #define LITTLE_ENDIAN _LITTLE_ENDIAN
63 #define BIG_ENDIAN _BIG_ENDIAN
64 #define PDP_ENDIAN _PDP_ENDIAN
65 #define BYTE_ORDER _BYTE_ORDER
68 #define __bswap16_gen(x) (__uint16_t)((x) << 8 | (x) >> 8)
69 #define __bswap32_gen(x) \
70 (((__uint32_t)__bswap16((x) & 0xffff) << 16) | __bswap16((x) >> 16))
71 #define __bswap64_gen(x) \
72 (((__uint64_t)__bswap32((x) & 0xffffffff) << 32) | __bswap32((x) >> 32))
74 #ifdef __GNUCLIKE_BUILTIN_CONSTANT_P
75 #define __bswap16(x) \
76 ((__uint16_t)(__builtin_constant_p(x) ? \
77 __bswap16_gen((__uint16_t)(x)) : __bswap16_var(x)))
78 #define __bswap32(x) \
79 (__builtin_constant_p(x) ? \
80 __bswap32_gen((__uint32_t)(x)) : __bswap32_var(x))
81 #define __bswap64(x) \
82 (__builtin_constant_p(x) ? \
83 __bswap64_gen((__uint64_t)(x)) : __bswap64_var(x))
85 /* XXX these are broken for use in static initializers. */
86 #define __bswap16(x) __bswap16_var(x)
87 #define __bswap32(x) __bswap32_var(x)
88 #define __bswap64(x) __bswap64_var(x)
91 /* These are defined as functions to avoid multiple evaluation of x. */
93 static __inline __uint16_t
94 __bswap16_var(__uint16_t _x)
97 return (__bswap16_gen(_x));
100 static __inline __uint32_t
101 __bswap32_var(__uint32_t _x)
104 #ifdef __GNUCLIKE_ASM
105 __asm("bswap %0" : "+r" (_x));
108 return (__bswap32_gen(_x));
112 static __inline __uint64_t
113 __bswap64_var(__uint64_t _x)
116 #if defined(__amd64__) && defined(__GNUCLIKE_ASM)
117 __asm("bswap %0" : "+r" (_x));
121 * It is important for the optimizations that the following is not
122 * really generic, but expands to 2 __bswap32_var()'s.
124 return (__bswap64_gen(_x));
128 #define __htonl(x) __bswap32(x)
129 #define __htons(x) __bswap16(x)
130 #define __ntohl(x) __bswap32(x)
131 #define __ntohs(x) __bswap16(x)
133 #endif /* !_MACHINE_ENDIAN_H_ */