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