1 /* $NetBSD: atomic_sub_16_cas.c,v 1.3 2014/06/23 21:53:45 joerg Exp $ */ 2 3 /*- 4 * Copyright (c) 2014 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 uint16_t fetch_and_sub_2(volatile uint16_t *, uint16_t, ...) 37 asm("__sync_fetch_and_sub_2"); 38 uint16_t sub_and_fetch_2(volatile uint16_t *, uint16_t, ...) 39 asm("__sync_sub_and_fetch_2"); 40 41 uint16_t 42 fetch_and_sub_2(volatile uint16_t *addr, uint16_t val, ...) 43 { 44 uint16_t old, new; 45 46 do { 47 old = *addr; 48 new = old - val; 49 } while (atomic_cas_16(addr, old, new) != old); 50 return old; 51 } 52 53 uint16_t 54 sub_and_fetch_2(volatile uint16_t *addr, uint16_t val, ...) 55 { 56 uint16_t old, new; 57 58 do { 59 old = *addr; 60 new = old - val; 61 } while (atomic_cas_16(addr, old, new) != old); 62 return new; 63 } 64 65 __strong_alias(__atomic_fetch_sub_2,__sync_fetch_and_sub_2) 66