/* $NetBSD: sync_bool_compare_and_swap_2.S,v 1.1 2013/11/08 22:42:52 matt Exp $ */ /*- * Copyright (c) 2013 The NetBSD Foundation, Inc. * All rights reserved. * * This code is derived from software contributed to The NetBSD Foundation * by Matt Thomas * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. */ #include "atomic_op_asm.h" #if defined(_ARM_ARCH_6) /* * ARMv6 has load-exclusive/store-exclusive which works for both user * and kernel. */ ENTRY_NP(__sync_bool_compare_and_swap_2) mov ip, r0 /* we need r0 for return value */ movs r0, #0 /* assume failure */ 1: ldrexh r3, [ip] /* load old value */ cmp r3, r1 /* compare? */ #ifdef __thumb__ bne 2f #else RETc(ne) /* return if different */ #endif strexh r0, r2, [ip] /* store new value */ cmp r0, #0 /* succeed? */ bne 1b /* nope, try again. */ movs r0, #1 /* indicate success */ #ifdef _ARM_ARCH_7 dsb /* data synchronization barrier */ #else mcr p15, 0, r3, c7, c10, 4 /* data synchronization barrier */ #endif 2: RET /* return. */ END(__sync_bool_compare_and_swap_2) #endif /* _ARM_ARCH_6 */