1/* $NetBSD: atomic_swap_64.S,v 1.2 2012/09/13 00:36:12 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. 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 33ENTRY_NP(_atomic_swap_64) 34 str r4, [sp, #-4]! /* save temporary */ 35 mov r4, r0 /* return value will be in r0 */ 36#ifndef __ARM_EABI__ 37 mov r3, r2 /* r2 will be overwriten by r1 */ 38 mov r2, r1 /* and r1 will be overwritten by ldrexd */ 39#endif 401: 41 ldrexd r0, [r4] /* load old value */ 42 strexd ip, r2, [r4] /* store new value */ 43 cmpne ip, #0 /* succeed? */ 44 bne 1b /* no, try again */ 45#ifdef _ARM_ARCH_7 46 dmb 47#else 48 mcr p15, 0, ip, c7, c10, 5 /* data memory barrier */ 49#endif 50 ldr r4, [sp], #4 /* restore temporary */ 51 RET 52 END(_atomic_swap_64) 53ATOMIC_OP_ALIAS(atomic_swap_64,_atomic_swap_64) 54