52 lines
1.8 KiB
C
52 lines
1.8 KiB
C
/*-
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* Copyright (c) 2001 Daniel Eischen <deischen@FreeBSD.org>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Neither the name of the author nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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#ifndef _ATOMIC_OPS_H_
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#define _ATOMIC_OPS_H_
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/*
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* Atomic swap:
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* Atomic (tmp = *dst, *dst = val), then *res = tmp
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*
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* void atomic_swap_long(long *dst, long val, long *res);
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*/
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static inline void
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atomic_swap_long(long *dst, long val, long *res)
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{
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__asm __volatile(
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"xchgl %2, %1; movl %2, %0"
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: "=m" (*res) : "m" (*dst), "r" (val) : "memory");
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}
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#define atomic_swap_int(d, v, r) \
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atomic_swap_long((long *)(d), (long)(v), (long *)(r))
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#define atomic_swap_ptr atomic_swap_int
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#endif
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