1 /* $NetBSD: atomic_dec_64_cas.c,v 1.3 2008/04/28 20:22:52 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 #ifdef __HAVE_ATOMIC64_OPS 37 38 void 39 atomic_dec_64(volatile uint64_t *addr) 40 { 41 uint64_t old, new; 42 43 do { 44 old = *addr; 45 new = old - 1; 46 } while (atomic_cas_64(addr, old, new) != old); 47 } 48 49 #undef atomic_dec_64 50 atomic_op_alias(atomic_dec_64,_atomic_dec_64) 51 52 #if defined(_LP64) 53 #undef atomic_dec_ulong 54 atomic_op_alias(atomic_dec_ulong,_atomic_dec_64) 55 __strong_alias(_atomic_dec_ulong,_atomic_dec_64) 56 57 #undef atomic_dec_ptr 58 atomic_op_alias(atomic_dec_ptr,_atomic_dec_64) 59 __strong_alias(_atomic_dec_ptr,_atomic_dec_64) 60 #endif /* _LP64 */ 61 62 #endif 63