1/* $NetBSD: atomic_cas_16.S,v 1.1 2014/08/10 05:47:35 matt Exp $ */
2
3/*-
4 * Copyright (c) 2014 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Matt Thomas of 3am Software Foundry.
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#include "atomic_op_asm.h"
33
34ENTRY_NP(_atomic_cas_16)
35	mov	x4, x0			/* we need r0 for return value */
361:	ldxrh	w0, [x4]		/* load old value */
37	cmp	w0, w1			/*   compare? */
38	b.ne	2f
39	stxrh	w3, w2, [x4]		/* store new value */
40	cbnz	w3, 1b			/*   succeed? nope, try again. */
41	dmb	st			/* data memory barrier */
422:	ret				/* return. */
43END(_atomic_cas_16)
44
45ATOMIC_OP_ALIAS(atomic_cas_16,_atomic_cas_16)
46STRONG_ALIAS(_atomic_cas_short,_atomic_cas_16)
47STRONG_ALIAS(_atomic_cas_ushort,_atomic_cas_16)
48STRONG_ALIAS(__sync_val_compare_and_swap_2,_atomic_cas_16)
49