/* $NetBSD: atomic_cas_64.S,v 1.11.2.1 2021/08/11 17:05:42 martin 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 * * 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) /* * ARMv6 has load-exclusive/store-exclusive which works for both user * and kernel. */ ENTRY_NP(_atomic_cas_64) push {r4-r7} /* save temporaries */ mov ip, r0 /* we need r0 for return value */ #ifdef __ARM_EABI__ ldrd r4, r5, [sp, #16] /* fetch new value */ #else ldr r5, [sp, #16] /* second word third argument */ mov r4, r3 /* first word third argument */ mov r3, r2 /* r2 will be overwritten by r1 which ... */ mov r2, r1 /* r1 will be overwritten by ldrexd */ #endif 1: ldrexd r0, r1, [ip] /* load current value */ cmp r0, r2 /* compare to old? 1st half */ #ifdef __thumb__ bne 2f /* jump to return if different */ cmp r1, r3 /* compare to old? 2nd half */ #else cmpeq r1, r3 /* compare to old? 2nd half */ #endif bne 2f /* jump to return if different */ strexd r6, r4, r5, [ip] /* store new value */ cmp r6, #0 /* succeed? */ bne 1b /* nope, try again. */ 2: pop {r4-r7} /* restore temporaries */ RET /* return. */ END(_atomic_cas_64) ATOMIC_OP_ALIAS(atomic_cas_64,_atomic_cas_64) ATOMIC_OP_ALIAS(atomic_cas_64_ni,_atomic_cas_64) STRONG_ALIAS(_atomic_cas_64_ni,_atomic_cas_64) ENTRY_NP(__sync_val_compare_and_swap_8) push {r4, lr} DMB bl _atomic_cas_64 DMB pop {r4, pc} END(__sync_val_compare_and_swap_8) #endif /* _ARM_ARCH_6 */