byte_swap.h revision 1.7 
1/*	$NetBSD: byte_swap.h,v 1.7 2008/04/27 18:58:44 matt 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#ifdef __GNUC__
43#include <sys/types.h>
44__BEGIN_DECLS
45
46#define	__BYTE_SWAP_U32_VARIABLE __byte_swap_u32_variable
47static __inline uint32_t
48__byte_swap_u32_variable(uint32_t v)
49{
50#ifdef _ARM_ARCH_6
51	__asm("rev\t%0, %1" : "=r" (v) : "0" (v));
52#else
53	uint32_t t1;
54
55	t1 = v ^ ((v << 16) | (v >> 16));
56	t1 &= 0xff00ffffU;
57	v = (v >> 8) | (v << 24);
58	v ^= (t1 >> 8);
59#endif
60	return (v);
61}
62
63#define	__BYTE_SWAP_U16_VARIABLE __byte_swap_u16_variable
64static __inline uint16_t
65__byte_swap_u16_variable(uint16_t v)
66{
67
68#ifdef _ARM_ARCH_6
69	__asm("rev16\t%0, %1" : "=r" (v) : "0" (v));
70#elif !defined(__thumb__)
71	__asm volatile(
72		"mov	%0, %1, ror #8\n"
73		"orr	%0, %0, %0, lsr #16\n"
74		"bic	%0, %0, %0, lsl #16"
75	: "=r" (v)
76	: "0" (v));
77#else
78	v &= 0xffff;
79	v = (v >> 8) | (v << 8);
80#endif
81
82	return (v);
83}
84
85__END_DECLS
86#endif
87
88
89#endif /* _ARM_BYTE_SWAP_H_ */
90