/* $NetBSD: atomic_dec_64.S,v 1.9 2021/07/28 07:32:20 skrll Exp $ */ /*- * Copyright (c) 2012 The NetBSD Foundation, Inc. * All rights reserved. * * This code is derived from software contributed to The NetBSD Foundation * by Matt Thomas <matt@3am-software.com> * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. */ #include "atomic_op_asm.h" #if defined(_ARM_ARCH_6) ENTRY_NP(_atomic_dec_64_nv) mov ip, r0 /* need r0 for return value */ 1: ldrexd r0, r1, [ip] /* load old value */ subs LO, LO, #1 /* calculate new value */ sbcs HI, HI, #0 /* calculate new value */ strexd r2, r0, r1, [ip] /* try to store */ cmp r2, #0 /* succeed? */ bne 1b /* no, try again? */ RET /* return new value */ END(_atomic_dec_64_nv) STRONG_ALIAS(_atomic_dec_64,_atomic_dec_64_nv) ATOMIC_OP_ALIAS(atomic_dec_64_nv,_atomic_dec_64_nv) ATOMIC_OP_ALIAS(atomic_dec_64,_atomic_dec_64) #endif /* _ARM_ARCH_6 */ |