byte_swap.h revision 1.11 
1/*	$NetBSD: byte_swap.h,v 1.11 2012/07/20 18:53:34 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 *
19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
30 */
31
32#ifndef _ARM_BYTE_SWAP_H_
33#define	_ARM_BYTE_SWAP_H_
34
35#ifdef _LOCORE
36
37#if defined(_ARM_ARCH_6) || defined(_ARM_ARCH_7)
38
39#define	BSWAP16(_src, _dst, _tmp)		\
40	rev16	_dst, _src
41#define	BSWAP32(_src, _dst, _tmp)		\
42	rev	_dst, _src
43
44#else
45
46#define	BSWAP16(_src, _dst, _tmp)		\
47	mov	_tmp, _src, ror #8		;\
48	orr	_tmp, _tmp, _tmp, lsr #16	;\
49	bic	_dst, _tmp, _tmp, lsl #16
50
51#define	BSWAP32(_src, _dst, _tmp)		\
52	eor	_tmp, _src, _src, ror #16	;\
53	bic	_tmp, _tmp, #0x00FF0000		;\
54	mov	_dst, _src, ror #8		;\
55	eor	_dst, _dst, _tmp, lsr #8
56
57#endif
58
59
60#else
61
62#ifdef __GNUC__
63#include <sys/types.h>
64__BEGIN_DECLS
65
66#define	__BYTE_SWAP_U32_VARIABLE __byte_swap_u32_variable
67static __inline uint32_t
68__byte_swap_u32_variable(uint32_t v)
69{
70	uint32_t t1;
71
72#ifdef _ARM_ARCH_6
73	if (!__builtin_constant_p(v)) {
74		__asm("rev\t%0, %1" : "=r" (v) : "0" (v));
75		return v;
76	}
77#endif
78
79	t1 = v ^ ((v << 16) | (v >> 16));
80	t1 &= 0xff00ffffU;
81	v = (v >> 8) | (v << 24);
82	v ^= (t1 >> 8);
83
84	return (v);
85}
86
87#define	__BYTE_SWAP_U16_VARIABLE __byte_swap_u16_variable
88static __inline uint16_t
89__byte_swap_u16_variable(uint16_t v)
90{
91
92#ifdef _ARM_ARCH_6
93	if (!__builtin_constant_p(v)) {
94		__asm("rev16\t%0, %1" : "=r" (v) : "0" (v));
95		return v;
96	}
97#elif !defined(__thumb__)
98	if (!__builtin_constant_p(v)) {
99		__asm volatile(
100			"mov	%0, %1, ror #8\n"
101			"orr	%0, %0, %0, lsr #16\n"
102			"bic	%0, %0, %0, lsl #16"
103		: "=&r" (v)
104		: "0" (v));
105		return (v);
106	}
107#endif
108	v &= 0xffff;
109	v = (v >> 8) | (v << 8);
110
111	return (v);
112}
113
114__END_DECLS
115#endif
116
117#endif	/* _LOCORE */
118
119#endif /* _ARM_BYTE_SWAP_H_ */
120