1*0a6a1f1dSLionel Sambuc/* $NetBSD: atomic_cas_16.S,v 1.2 2014/03/04 16:15:28 matt Exp $ */ 284d9c625SLionel Sambuc/*- 384d9c625SLionel Sambuc * Copyright (c) 2013 The NetBSD Foundation, Inc. 484d9c625SLionel Sambuc * All rights reserved. 584d9c625SLionel Sambuc * 684d9c625SLionel Sambuc * This code is derived from software contributed to The NetBSD Foundation 784d9c625SLionel Sambuc * by Matt Thomas <matt@3am-software.com> 884d9c625SLionel Sambuc * 984d9c625SLionel Sambuc * Redistribution and use in source and binary forms, with or without 1084d9c625SLionel Sambuc * modification, are permitted provided that the following conditions 1184d9c625SLionel Sambuc * are met: 1284d9c625SLionel Sambuc * 1. Redistributions of source code must retain the above copyright 1384d9c625SLionel Sambuc * notice, this list of conditions and the following disclaimer. 1484d9c625SLionel Sambuc * 2. Redistributions in binary form must reproduce the above copyright 1584d9c625SLionel Sambuc * notice, this list of conditions and the following disclaimer in the 1684d9c625SLionel Sambuc * documentation and/or other materials provided with the distribution. 1784d9c625SLionel Sambuc * 1884d9c625SLionel Sambuc * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 1984d9c625SLionel Sambuc * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 2084d9c625SLionel Sambuc * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 2184d9c625SLionel Sambuc * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 2284d9c625SLionel Sambuc * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 2384d9c625SLionel Sambuc * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 2484d9c625SLionel Sambuc * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 2584d9c625SLionel Sambuc * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 2684d9c625SLionel Sambuc * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 2784d9c625SLionel Sambuc * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 2884d9c625SLionel Sambuc * POSSIBILITY OF SUCH DAMAGE. 2984d9c625SLionel Sambuc */ 3084d9c625SLionel Sambuc 3184d9c625SLionel Sambuc#include "atomic_op_asm.h" 3284d9c625SLionel Sambuc 3384d9c625SLionel Sambuc#if defined(_ARM_ARCH_6) 3484d9c625SLionel Sambuc/* 3584d9c625SLionel Sambuc * ARMv6 has load-exclusive/store-exclusive which works for both user 3684d9c625SLionel Sambuc * and kernel. 3784d9c625SLionel Sambuc */ 3884d9c625SLionel SambucENTRY_NP(_atomic_cas_16) 3984d9c625SLionel Sambuc mov ip, r0 /* we need r0 for return value */ 4084d9c625SLionel Sambuc1: 4184d9c625SLionel Sambuc ldrexh r0, [ip] /* load old value */ 4284d9c625SLionel Sambuc cmp r0, r1 /* compare? */ 4384d9c625SLionel Sambuc#ifdef __thumb__ 4484d9c625SLionel Sambuc bne 2f 4584d9c625SLionel Sambuc#else 4684d9c625SLionel Sambuc RETc(ne) /* return if different */ 4784d9c625SLionel Sambuc#endif 4884d9c625SLionel Sambuc strexh r3, r2, [ip] /* store new value */ 4984d9c625SLionel Sambuc cmp r3, #0 /* succeed? */ 5084d9c625SLionel Sambuc bne 1b /* nope, try again. */ 5184d9c625SLionel Sambuc#ifdef _ARM_ARCH_7 5284d9c625SLionel Sambuc dsb /* data synchronization barrier */ 5384d9c625SLionel Sambuc#else 5484d9c625SLionel Sambuc mcr p15, 0, r3, c7, c10, 4 /* data synchronization barrier */ 5584d9c625SLionel Sambuc#endif 5684d9c625SLionel Sambuc2: RET /* return. */ 5784d9c625SLionel SambucEND(_atomic_cas_16) 5884d9c625SLionel Sambuc 5984d9c625SLionel SambucATOMIC_OP_ALIAS(atomic_cas_16,_atomic_cas_16) 6084d9c625SLionel SambucSTRONG_ALIAS(_atomic_cas_short,_atomic_cas_16) 6184d9c625SLionel SambucSTRONG_ALIAS(_atomic_cas_ushort,_atomic_cas_16) 62*0a6a1f1dSLionel SambucCRT_ALIAS(__sync_val_compare_and_swap_2,_atomic_cas_16) 6384d9c625SLionel Sambuc 6484d9c625SLionel Sambuc#endif /* _ARM_ARCH_6 */ 65