1/* $NetBSD: atomic_dec_32.S,v 1.5 2013/08/11 04:41:17 matt Exp $ */ 2/*- 3 * Copyright (c) 2008 The NetBSD Foundation, Inc. 4 * All rights reserved. 5 * 6 * This code is derived from software contributed to The NetBSD Foundation 7 * by Matt Thomas <matt@3am-software.com> 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 19 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 20 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 21 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 22 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 23 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 24 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 25 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 26 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 27 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 28 * POSSIBILITY OF SUCH DAMAGE. 29 */ 30 31#include "atomic_op_asm.h" 32 33#ifdef _ARM_ARCH_6 34 35ENTRY_NP(_atomic_dec_32) 361: ldrex r3, [r0] /* load old value (return value) */ 37 subs r3, r3, #1 /* calculate new value */ 38 strex r2, r3, [r0] /* try to store */ 39 cmp r2, #0 /* succeed? */ 40 bne 1b /* no, try again? */ 41#ifdef _ARM_ARCH_7 42 dmb 43#else 44 mcr p15, 0, r2, c7, c10, 5 /* data memory barrier */ 45#endif 46 RET /* return new value */ 47END(_atomic_dec_32) 48 49ATOMIC_OP_ALIAS(atomic_dec_32,_atomic_dec_32) 50ATOMIC_OP_ALIAS(atomic_dec_uint,_atomic_dec_32) 51ATOMIC_OP_ALIAS(atomic_dec_ulong,_atomic_dec_32) 52ATOMIC_OP_ALIAS(atomic_dec_ptr,_atomic_dec_32) 53STRONG_ALIAS(_atomic_dec_uint,_atomic_dec_32) 54STRONG_ALIAS(_atomic_dec_ulong,_atomic_dec_32) 55STRONG_ALIAS(_atomic_dec_ptr,_atomic_dec_32) 56 57ENTRY_NP(_atomic_dec_32_nv) 58 mov ip, r0 /* need r0 for return value */ 591: ldrex r0, [ip] /* load old value */ 60 subs r0, r0, #1 /* calculate new value (return value) */ 61 strex r2, r0, [ip] /* try to store */ 62 cmp r2, #0 /* succeed? */ 63 bne 1b /* no, try again? */ 64#ifdef _ARM_ARCH_7 65 dmb 66#else 67 mcr p15, 0, r2, c7, c10, 5 /* data memory barrier */ 68#endif 69 RET /* return new value */ 70END(_atomic_dec_32_nv) 71 72ATOMIC_OP_ALIAS(atomic_dec_32_nv,_atomic_dec_32_nv) 73ATOMIC_OP_ALIAS(atomic_dec_uint_nv,_atomic_dec_32_nv) 74ATOMIC_OP_ALIAS(atomic_dec_ulong_nv,_atomic_dec_32_nv) 75ATOMIC_OP_ALIAS(atomic_dec_ptr_nv,_atomic_dec_32_nv) 76STRONG_ALIAS(_atomic_dec_uint_nv,_atomic_dec_32_nv) 77STRONG_ALIAS(_atomic_dec_ulong_nv,_atomic_dec_32_nv) 78STRONG_ALIAS(_atomic_dec_ptr_nv,_atomic_dec_32_nv) 79 80#endif /* _ARM_ARCH_6 */ 81