atomic_inc_64.S revision 1.4 
1/*	$NetBSD: atomic_inc_64.S,v 1.4 2013/08/10 18:28:15 matt 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 <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#ifdef _ARM_ARCH_6
34
35ENTRY_NP(_atomic_inc_64)
36	mov	r3, r0			/* need r0 for return value */
371:	ldrexd	r0, [r3]		/* load old value (return value) */
38	adds	LO, LO, #1		/* calculate new value */
39	adc	HI, HI, #0		/* zero means we carried */
40	strexd	ip, r0, [r3]		/* try to store */
41	cmp	ip, #0			/*   succeed? */
42	bne	1b			/*     no, try again? */
43#ifdef _ARM_ARCH_7
44	dmb
45#else
46	mcr	p15, 0, ip, c7, c10, 5	/* data memory barrier */
47#endif
48	mvn	r2, #0			/* r2 = -1 */
49	adds	LO, LO, r2		/* add it */
50	adc	HI, HI, r2		/* add with carry */
51	RET				/* return orig value */
52	END(_atomic_inc_64)
53ATOMIC_OP_ALIAS(atomic_inc_64,_atomic_inc_64)
54
55ENTRY_NP(_atomic_inc_64_nv)
56	mov	r3, r0			/* need r0 for return value */
571:	ldrexd	r0, [r3]		/* load old value */
58	adds	LO, LO, #1		/* calculate new value (return value) */
59	adc	HI, HI, #0		/* fold carry into high */
60	strexd	ip, r0, [r3]		/* try to store */
61	cmp	ip, #0			/*   succeed? */
62	bne	1b			/*     no, try again? */
63#ifdef _ARM_ARCH_7
64	dmb
65#else
66	mcr	p15, 0, ip, c7, c10, 5	/* data memory barrier */
67#endif
68	RET				/* return new value */
69	END(_atomic_inc_64_nv)
70ATOMIC_OP_ALIAS(atomic_inc_64_nv,_atomic_inc_64_nv)
71
72#endif /* _ARM_ARCH_6 */
73