Blame sysdeps/generic/atomic-machine.h

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/* Copyright (C) 2003-2018 Free Software Foundation, Inc.
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   This file is part of the GNU C Library.
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   Contributed by Ulrich Drepper <drepper@redhat.com>, 2003.
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   The GNU C Library is free software; you can redistribute it and/or
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   modify it under the terms of the GNU Lesser General Public
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   License as published by the Free Software Foundation; either
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   version 2.1 of the License, or (at your option) any later version.
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   The GNU C Library is distributed in the hope that it will be useful,
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   but WITHOUT ANY WARRANTY; without even the implied warranty of
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   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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   Lesser General Public License for more details.
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   You should have received a copy of the GNU Lesser General Public
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   License along with the GNU C Library; if not, see
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   <http://www.gnu.org/licenses/>.  */
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#ifndef _ATOMIC_MACHINE_H
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#define _ATOMIC_MACHINE_H	1
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/* We have by default no support for atomic operations.  So define
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   them non-atomic.  If this is a problem somebody will have to come
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   up with real definitions.  */
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/* The only basic operation needed is compare and exchange.  */
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#define atomic_compare_and_exchange_val_acq(mem, newval, oldval) \
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  ({ __typeof (mem) __gmemp = (mem);				      \
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     __typeof (*mem) __gret = *__gmemp;				      \
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     __typeof (*mem) __gnewval = (newval);			      \
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								      \
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     if (__gret == (oldval))					      \
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       *__gmemp = __gnewval;					      \
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     __gret; })
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#define atomic_compare_and_exchange_bool_acq(mem, newval, oldval) \
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  ({ __typeof (mem) __gmemp = (mem);				      \
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     __typeof (*mem) __gnewval = (newval);			      \
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								      \
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     *__gmemp == (oldval) ? (*__gmemp = __gnewval, 0) : 1; })
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#endif	/* atomic-machine.h */