xref: /netbsd-src/common/lib/libc/arch/arm/atomic/atomic_swap_64.S (revision 5298fab779741f242bc9edef59c60d92530d14f7)
1/*	$NetBSD: atomic_swap_64.S,v 1.15 2021/08/01 21:58:56 andvar Exp $	*/
2/*-
3 * Copyright (c) 2012 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.
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
33ENTRY_NP(__sync_lock_test_and_set_8)
34	DMB
35	/* FALLTHROUGH */
36
37ENTRY_NP(_atomic_swap_64)
38	push	{r3, r4}		/* save temporary */
39	mov	ip, r0			/* return value will be in r0 */
40#ifndef __ARM_EABI__
41	mov	r3, r2			/* r2 will be overwritten by r1 */
42	mov	r2, r1			/* and r1 will be overwritten by ldrexd */
43#endif
441:	ldrexd	r0, r1, [ip]		/* load old value */
45	strexd	r4, r2, r3, [ip]	/* store new value */
46	cmp	r4, #0			/*   succeed? */
47	bne	1b			/*    no, try again */
48	pop	{r3, r4}		/* restore temporary */
49	RET
50END(_atomic_swap_64)
51END(__sync_lock_test_and_set_8)
52
53
54ATOMIC_OP_ALIAS(atomic_swap_64,_atomic_swap_64)
55CRT_ALIAS(__atomic_exchange_8,_atomic_swap_64)
56
57#if (!defined(_KERNEL) || !defined(_RUMPKERNEL)) && !defined(_STANDALONE)
58ENTRY_NP(__sync_lock_release_8)
59	mov	r2, #0
60	mov	r3, #0
61
62	DMB
63	strd	r2, r3, [r0]
64	RET
65END(__sync_lock_release_8)
66#endif
67