1/* $NetBSD: atomic_dec_64.S,v 1.4 2013/08/10 18:45:12 matt Exp $ */ 2/*- 3 * Copyright (c) 2012 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_64) 36 mov r3, r0 /* need r0 for return value */ 371: ldrexd r0, [r3] /* load old value (return value) */ 38 subs LO, LO, #1 /* calculate new value */ 39 sbc HI, HI, #0 /* calculate new value */ 40 strexd r2, r0, [r3] /* try to store */ 41 cmp r2, #0 /* succeed? */ 42 bne 1b /* no, try again? */ 43#ifdef _ARM_ARCH_7 44 dmb 45#else 46 mcr p15, 0, r2, c7, c10, 5 /* data memory barrier */ 47#endif 48 RET 49 END(_atomic_dec_64) 50ATOMIC_OP_ALIAS(atomic_dec_64,_atomic_dec_64) 51 52ENTRY_NP(_atomic_dec_64_nv) 53 mov r3, r0 /* need r0 for return value */ 541: ldrexd r0, [r3] /* load old value */ 55 subs LO, LO, #1 /* calculate new value */ 56 sbc HI, HI, #0 /* calculate new value */ 57 strexd r2, r0, [r3] /* try to store */ 58 cmp r2, #0 /* succeed? */ 59 bne 1b /* no, try again? */ 60#ifdef _ARM_ARCH_7 61 dmb 62#else 63 mcr p15, 0, r2, c7, c10, 5 /* data memory barrier */ 64#endif 65 RET /* return new value */ 66 END(_atomic_dec_64_nv) 67ATOMIC_OP_ALIAS(atomic_dec_64_nv,_atomic_dec_64_nv) 68 69#endif /* _ARM_ARCH_6 */ 70