11.9Sskrll/* $NetBSD: atomic_cas_8.S,v 1.9 2021/07/28 07:32:20 skrll Exp $ */ 21.6Smatt 31.1Smatt/*- 41.6Smatt * Copyright (c) 2013 The NetBSD Foundation, Inc. 51.1Smatt * All rights reserved. 61.1Smatt * 71.1Smatt * This code is derived from software contributed to The NetBSD Foundation 81.1Smatt * by Matt Thomas <matt@3am-software.com> 91.1Smatt * 101.1Smatt * Redistribution and use in source and binary forms, with or without 111.1Smatt * modification, are permitted provided that the following conditions 121.1Smatt * are met: 131.1Smatt * 1. Redistributions of source code must retain the above copyright 141.1Smatt * notice, this list of conditions and the following disclaimer. 151.1Smatt * 2. Redistributions in binary form must reproduce the above copyright 161.1Smatt * notice, this list of conditions and the following disclaimer in the 171.1Smatt * documentation and/or other materials provided with the distribution. 181.1Smatt * 191.1Smatt * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 201.1Smatt * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 211.1Smatt * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 221.1Smatt * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 231.1Smatt * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 241.1Smatt * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 251.1Smatt * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 261.1Smatt * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 271.1Smatt * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 281.1Smatt * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 291.1Smatt * POSSIBILITY OF SUCH DAMAGE. 301.1Smatt */ 311.1Smatt 321.2Smatt#include "atomic_op_asm.h" 331.1Smatt 341.2Smatt#if defined(_ARM_ARCH_6) 351.9Sskrll 361.2Smatt/* 371.2Smatt * ARMv6 has load-exclusive/store-exclusive which works for both user 381.2Smatt * and kernel. 391.2Smatt */ 401.2SmattENTRY_NP(_atomic_cas_8) 411.5Smatt mov ip, r0 /* we need r0 for return value */ 421.2Smatt1: 431.5Smatt ldrexb r0, [ip] /* load old value */ 441.5Smatt cmp r0, r1 /* compare? */ 451.5Smatt#ifdef __thumb__ 461.5Smatt bne 2f 471.5Smatt#else 481.2Smatt RETc(ne) /* return if different */ 491.5Smatt#endif 501.5Smatt strexb r3, r2, [ip] /* store new value */ 511.5Smatt cmp r3, #0 /* succeed? */ 521.2Smatt bne 1b /* nope, try again. */ 531.5Smatt2: RET /* return. */ 541.8SskrllEND(_atomic_cas_8) 551.1Smatt 561.2SmattATOMIC_OP_ALIAS(atomic_cas_8,_atomic_cas_8) 571.2SmattSTRONG_ALIAS(_atomic_cas_char,_atomic_cas_8) 581.2SmattSTRONG_ALIAS(_atomic_cas_uchar,_atomic_cas_8) 591.9Sskrll 601.9SskrllENTRY_NP(__sync_val_compare_and_swap_1) 611.9Sskrll push {r4, lr} 621.9Sskrll DMB 631.9Sskrll bl _atomic_cas_8 641.9Sskrll DMB 651.9Sskrll pop {r4, pc} 661.9SskrllEND(__sync_val_compare_and_swap_1) 671.1Smatt 681.4Schs#endif /* _ARM_ARCH_6 */ 69