1 /* $NetBSD: atomic_swap_32_cas.c,v 1.4 2008/04/28 20:22:53 martin Exp $ */ 2 3 /*- 4 * Copyright (c) 2007 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Jason R. Thorpe. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 * POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32 #include "atomic_op_namespace.h" 33 34 #include <sys/atomic.h> 35 36 uint32_t 37 atomic_swap_32(volatile uint32_t *addr, uint32_t new) 38 { 39 uint32_t old; 40 41 do { 42 old = *addr; 43 } while (atomic_cas_32(addr, old, new) != old); 44 45 return (old); 46 } 47 48 #undef atomic_swap_32 49 atomic_op_alias(atomic_swap_32,_atomic_swap_32) 50 #undef atomic_swap_uint 51 atomic_op_alias(atomic_swap_uint,_atomic_swap_32) 52 __strong_alias(_atomic_swap_uint,_atomic_swap_32) 53 #if !defined(_LP64) 54 #undef atomic_swap_ulong 55 atomic_op_alias(atomic_swap_ulong,_atomic_swap_32) 56 __strong_alias(_atomic_swap_ulong,_atomic_swap_32) 57 #undef atomic_swap_ptr 58 atomic_op_alias(atomic_swap_ptr,_atomic_swap_32) 59 __strong_alias(_atomic_swap_ptr,_atomic_swap_32) 60 #endif /* _LP64 */ 61