byte_swap.h revision 1.3 
1/*	$NetBSD: byte_swap.h,v 1.3 2005/12/28 18:40:13 perry Exp $	*/
2
3/*-
4 * Copyright (c) 1998 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Charles M. Hannum.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 *    notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 *    notice, this list of conditions and the following disclaimer in the
17 *    documentation and/or other materials provided with the distribution.
18 * 3. All advertising materials mentioning features or use of this software
19 *    must display the following acknowledgement:
20 *        This product includes software developed by the NetBSD
21 *        Foundation, Inc. and its contributors.
22 * 4. Neither the name of The NetBSD Foundation nor the names of its
23 *    contributors may be used to endorse or promote products derived
24 *    from this software without specific prior written permission.
25 *
26 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
27 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
28 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
29 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
30 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
31 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
32 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
33 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
34 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
35 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
36 * POSSIBILITY OF SUCH DAMAGE.
37 */
38
39/*
40 * Copy of the i386 version. 64 bit versions may be added later.
41 */
42
43#ifndef _AMD64_BYTE_SWAP_H_
44#define	_AMD64_BYTE_SWAP_H_
45
46#include <sys/types.h>
47
48static __inline u_int32_t __byte_swap_long_variable(u_int32_t);
49static __inline u_int16_t __byte_swap_word_variable(u_int16_t);
50
51static __inline u_int32_t
52__byte_swap_long_variable(u_int32_t x)
53{
54	__asm volatile ( "bswap %1" : "=r" (x) : "0" (x));
55	return (x);
56}
57
58static __inline u_int16_t
59__byte_swap_word_variable(u_int16_t x)
60{
61	__asm volatile ("rorw $8, %w1" : "=r" (x) : "0" (x));
62	return (x);
63}
64
65
66#ifdef __OPTIMIZE__
67
68#define	__byte_swap_long_constant(x) \
69	((((x) & 0xff000000) >> 24) | \
70	 (((x) & 0x00ff0000) >>  8) | \
71	 (((x) & 0x0000ff00) <<  8) | \
72	 (((x) & 0x000000ff) << 24))
73#define	__byte_swap_word_constant(x) \
74	((((x) & 0xff00) >> 8) | \
75	 (((x) & 0x00ff) << 8))
76#define	__byte_swap_long(x) \
77	(__builtin_constant_p((x)) ? \
78	 __byte_swap_long_constant(x) : __byte_swap_long_variable(x))
79#define	__byte_swap_word(x) \
80	(__builtin_constant_p((x)) ? \
81	 __byte_swap_word_constant(x) : __byte_swap_word_variable(x))
82
83#else /* __OPTIMIZE__ */
84
85#define	__byte_swap_long(x)	__byte_swap_long_variable(x)
86#define	__byte_swap_word(x)	__byte_swap_word_variable(x)
87
88#endif /* __OPTIMIZE__ */
89
90#endif /* !_AMD64_BYTE_SWAP_H_ */
91