1/* $NetBSD: atomic_dec_32.S,v 1.1 2014/08/10 05:47:35 matt 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 Matt Thomas of 3am Software Foundry. 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_asm.h" 33 34ENTRY_NP(_atomic_dec_32) 351: ldxr w3, [x0] /* load old value (return value) */ 36 sub w3, w3, #1 /* calculate new value */ 37 stxr w2, w3, [x0] /* try to store */ 38 cbnz w2, 1b /* succeed? no, try again? */ 39 dmb st 40 ret /* return new value */ 41END(_atomic_dec_32) 42 43ATOMIC_OP_ALIAS(atomic_dec_32,_atomic_dec_32) 44ATOMIC_OP_ALIAS(atomic_dec_uint,_atomic_dec_32) 45STRONG_ALIAS(_atomic_dec_uint,_atomic_dec_32) 46 47ENTRY_NP(_atomic_dec_32_nv) 48 mov x4, x0 /* need r0 for return value */ 491: ldxr w0, [x4] /* load old value */ 50 sub w0, w0, #1 /* calculate new value (return value) */ 51 stxr w3, w0, [x4] /* try to store */ 52 cbnz w3, 1b /* succeed? no, try again? */ 53 dmb st 54 ret /* return new value */ 55END(_atomic_dec_32_nv) 56 57ATOMIC_OP_ALIAS(atomic_dec_32_nv,_atomic_dec_32_nv) 58ATOMIC_OP_ALIAS(atomic_dec_uint_nv,_atomic_dec_32_nv) 59STRONG_ALIAS(_atomic_dec_uint_nv,_atomic_dec_32_nv) 60