1/*	$NetBSD: atomic_cas_32.S,v 1.2 2008/08/16 07:12:39 matt Exp $	*/
2/*-
3 * Copyright (c) 2008 The NetBSD Foundation, Inc.
4 * All rights reserved.
5 *
6 * This code is derived from software contributed to The NetBSD Foundation
7 * by Matt Thomas <matt@3am-software.com>
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 *    notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 *    notice, this list of conditions and the following disclaimer in the
16 *    documentation and/or other materials provided with the distribution.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
19 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
20 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
21 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
22 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
23 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
24 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
25 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
26 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
27 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
28 * POSSIBILITY OF SUCH DAMAGE.
29 */
30
31#include "atomic_op_asm.h"
32
33#if defined(_ARM_ARCH_6)
34/*
35 * ARMv6 has load-exclusive/store-exclusive which works for both user
36 * and kernel.
37 */
38ENTRY_NP(_atomic_cas_32)
39	mov	r3, r0			/* we need r0 for return value */
401:
41	ldrex	r0, [r3]		/* load old value */
42	teq	r0, r1			/*   compare? */
43	RETc(ne)			/*     return if different */
44	strex	ip, r2, [r3]		/* store new value */
45	cmp	ip, #0			/*   succeed? */
46	bne	1b			/*     nope, try again. */
47	RET				/*    yes, return. */
48	END(_atomic_cas_32)
49
50ATOMIC_OP_ALIAS(atomic_cas_32,_atomic_cas_32)
51ATOMIC_OP_ALIAS(atomic_cas_uint,_atomic_cas_32)
52ATOMIC_OP_ALIAS(atomic_cas_ulong,_atomic_cas_32)
53ATOMIC_OP_ALIAS(atomic_cas_ptr,_atomic_cas_32)
54STRONG_ALIAS(_atomic_cas_uint,_atomic_cas_32)
55STRONG_ALIAS(_atomic_cas_ulong,_atomic_cas_32)
56STRONG_ALIAS(_atomic_cas_ptr,_atomic_cas_32)
57
58#endif /* _ARCH_ARM_6 */
59