/* $NetBSD: atomic_c11_compare_exchange_cas_32.c,v 1.2.20.2 2022/05/17 13:48:45 martin Exp $ */ /*- * Copyright (c) 2007 The NetBSD Foundation, Inc. * All rights reserved. * * This code is derived from software contributed to The NetBSD Foundation * by Martin Husemann. * * 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_namespace.h" #if !defined(_KERNEL) && !defined(_STANDALONE) #include <stdbool.h> #endif #include <sys/atomic.h> bool __atomic_compare_exchange_4(volatile void *, void *, uint32_t, bool, int, int); bool __atomic_compare_exchange_4(volatile void *mem, void *expected, uint32_t desired, bool weak, int success, int failure) { uint32_t * const ep = expected; const uint32_t old = *ep; /* * Ignore the details (weak, memory model on success and failure) * and just do the cas. If we get here the compiler couldn't * do better and it mostly will not matter at all. */ const uint32_t prev = atomic_cas_32(mem, old, desired); if (prev == old) return true; *ep = prev; return false; } |