byte_swap.h revision 1.2 
1/*	$NetBSD: byte_swap.h,v 1.2 2002/08/14 15:08:58 thorpej Exp $	*/
2
3/*-
4 * Copyright (c) 1997, 1999, 2002 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, Neil A. Carson, and Jason R. Thorpe.
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#ifndef _ARM_BYTE_SWAP_H_
40#define	_ARM_BYTE_SWAP_H_
41
42#include <sys/types.h>
43
44static __inline u_int32_t
45__byte_swap_32_variable(u_int32_t v)
46{
47	u_int32_t t1;
48
49	t1 = v ^ ((v << 16) | (v >> 16));
50	t1 &= 0xff00ffff;
51	v = (v >> 8) | (v << 24);
52	v ^= (t1 >> 8);
53
54	return (v);
55}
56
57static __inline u_int16_t
58__byte_swap_16_variable(u_int16_t v)
59{
60
61	__asm __volatile(
62		"mov	%0, %1, ror #8\n"
63		"orr	%0, %0, %0, lsr #16\n"
64		"bic	%0, %0, %0, lsl #16"
65	: "=r" (v)
66	: "0" (v));
67
68	return (v);
69}
70
71#ifdef __OPTIMIZE__
72
73#define __byte_swap_32_constant(x)	\
74	((((x) & 0xff000000) >> 24) |	\
75	 (((x) & 0x00ff0000) >>  8) |	\
76	 (((x) & 0x0000ff00) <<  8) |	\
77	 (((x) & 0x000000ff) << 24))
78
79#define	__byte_swap_16_constant(x)	\
80	((((x) & 0xff00) >> 8) |	\
81	 (((x) & 0x00ff) << 8))
82
83#define	__byte_swap_32(x)		\
84	(__builtin_constant_p((x)) ?	\
85	 __byte_swap_32_constant(x) :	__byte_swap_32_variable(x))
86
87#define	__byte_swap_16(x)		\
88	(__builtin_constant_p((x)) ?	\
89	 __byte_swap_16_constant(x) : __byte_swap_16_variable(x))
90
91#else
92
93#define	__byte_swap_32(x)	__byte_swap_32_variable(x)
94#define	__byte_swap_16(x)	__byte_swap_16_variable(x)
95
96#endif /* __OPTIMIZE__ */
97
98#endif /* _ARM_BYTE_SWAP_H_ */
99