1*0a6a1f1dSLionel Sambuc/* $NetBSD: atomic_cas_64.S,v 1.10 2014/03/05 17:20:48 matt Exp $ */ 2f14fb602SLionel Sambuc/*- 3f14fb602SLionel Sambuc * Copyright (c) 2012 The NetBSD Foundation, Inc. 4f14fb602SLionel Sambuc * All rights reserved. 5f14fb602SLionel Sambuc * 6f14fb602SLionel Sambuc * This code is derived from software contributed to The NetBSD Foundation 7f14fb602SLionel Sambuc * by Matt Thomas <matt@3am-software.com> 8f14fb602SLionel Sambuc * 9f14fb602SLionel Sambuc * Redistribution and use in source and binary forms, with or without 10f14fb602SLionel Sambuc * modification, are permitted provided that the following conditions 11f14fb602SLionel Sambuc * are met: 12f14fb602SLionel Sambuc * 1. Redistributions of source code must retain the above copyright 13f14fb602SLionel Sambuc * notice, this list of conditions and the following disclaimer. 14f14fb602SLionel Sambuc * 2. Redistributions in binary form must reproduce the above copyright 15f14fb602SLionel Sambuc * notice, this list of conditions and the following disclaimer in the 16f14fb602SLionel Sambuc * documentation and/or other materials provided with the distribution. 17f14fb602SLionel Sambuc * 18f14fb602SLionel Sambuc * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 19f14fb602SLionel Sambuc * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 20f14fb602SLionel Sambuc * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 21f14fb602SLionel Sambuc * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 22f14fb602SLionel Sambuc * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 23f14fb602SLionel Sambuc * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 24f14fb602SLionel Sambuc * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 25f14fb602SLionel Sambuc * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 26f14fb602SLionel Sambuc * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 27f14fb602SLionel Sambuc * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 28f14fb602SLionel Sambuc * POSSIBILITY OF SUCH DAMAGE. 29f14fb602SLionel Sambuc */ 30f14fb602SLionel Sambuc 31f14fb602SLionel Sambuc#include "atomic_op_asm.h" 32f14fb602SLionel Sambuc 33f14fb602SLionel Sambuc#if defined(_ARM_ARCH_6) 34f14fb602SLionel Sambuc/* 35f14fb602SLionel Sambuc * ARMv6 has load-exclusive/store-exclusive which works for both user 36f14fb602SLionel Sambuc * and kernel. 37f14fb602SLionel Sambuc */ 38f14fb602SLionel SambucENTRY_NP(_atomic_cas_64) 39*0a6a1f1dSLionel Sambuc push {r4-r7} /* save temporaries */ 4084d9c625SLionel Sambuc mov ip, r0 /* we need r0 for return value */ 41f14fb602SLionel Sambuc#ifdef __ARM_EABI__ 42*0a6a1f1dSLionel Sambuc ldrd r4, r5, [sp, #16] /* fetch new value */ 43f14fb602SLionel Sambuc#else 44*0a6a1f1dSLionel Sambuc ldr r5, [sp, #16] /* second word third argument */ 45*0a6a1f1dSLionel Sambuc mov r4, r3 /* first word third argument */ 46f14fb602SLionel Sambuc mov r3, r2 /* r2 will be overwritten by r1 which ... */ 47f14fb602SLionel Sambuc mov r2, r1 /* r1 will be overwritten by ldrexd */ 48f14fb602SLionel Sambuc#endif 49f14fb602SLionel Sambuc1: 5084d9c625SLionel Sambuc ldrexd r0, r1, [ip] /* load current value */ 5184d9c625SLionel Sambuc cmp r0, r2 /* compare to old? 1st half */ 5284d9c625SLionel Sambuc#ifdef __thumb__ 53f14fb602SLionel Sambuc bne 2f /* jump to return if different */ 5484d9c625SLionel Sambuc cmp r1, r3 /* compare to old? 2nd half */ 5584d9c625SLionel Sambuc#else 5684d9c625SLionel Sambuc cmpeq r1, r3 /* compare to old? 2nd half */ 5784d9c625SLionel Sambuc#endif 5884d9c625SLionel Sambuc bne 2f /* jump to return if different */ 5984d9c625SLionel Sambuc strexd r6, r4, r5, [ip] /* store new value */ 6084d9c625SLionel Sambuc cmp r6, #0 /* succeed? */ 61f14fb602SLionel Sambuc bne 1b /* nope, try again. */ 62f14fb602SLionel Sambuc#ifdef _ARM_ARCH_7 63f14fb602SLionel Sambuc dsb 64f14fb602SLionel Sambuc#else 65f14fb602SLionel Sambuc mcr p15, 0, ip, c7, c10, 4 /* data synchronization barrier */ 66f14fb602SLionel Sambuc#endif 67f14fb602SLionel Sambuc2: 68*0a6a1f1dSLionel Sambuc pop {r4-r7} /* restore temporaries */ 69f14fb602SLionel Sambuc RET /* return. */ 70f14fb602SLionel SambucEND(_atomic_cas_64) 71f14fb602SLionel Sambuc 72f14fb602SLionel SambucATOMIC_OP_ALIAS(atomic_cas_64,_atomic_cas_64) 73*0a6a1f1dSLionel SambucCRT_ALIAS(__sync_val_compare_and_swap_8,_atomic_cas_64) 74f14fb602SLionel Sambuc 7584d9c625SLionel Sambuc#endif /* _ARM_ARCH_6 */ 76