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43 lines
1.7 KiB
C
43 lines
1.7 KiB
C
/* Copyright (C) 2003-2020 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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<https://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 */
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