ca6e601a9d
This uses atomic operations to access lock elision metadata that is accessed concurrently (ie, adapt_count fields). The size of the data is less than a word but accessed only with atomic loads and stores; therefore, we add support for shorter-size atomic load and stores too. * include/atomic.h (__atomic_check_size_ls): New. (atomic_load_relaxed, atomic_load_acquire, atomic_store_relaxed, atomic_store_release): Use it. * sysdeps/x86/elide.h (ACCESS_ONCE): Remove. (elision_adapt, ELIDE_LOCK): Use atomics. * sysdeps/unix/sysv/linux/x86/elision-lock.c (__lll_lock_elision): Use atomics and improve code comments. * sysdeps/unix/sysv/linux/x86/elision-trylock.c (__lll_trylock_elision): Likewise.
822 lines
29 KiB
C
822 lines
29 KiB
C
/* Internal macros for atomic operations for GNU C Library.
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Copyright (C) 2002-2016 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>, 2002.
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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_H
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#define _ATOMIC_H 1
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/* This header defines three types of macros:
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- atomic arithmetic and logic operation on memory. They all
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have the prefix "atomic_".
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- conditionally atomic operations of the same kinds. These
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always behave identical but can be faster when atomicity
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is not really needed since only one thread has access to
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the memory location. In that case the code is slower in
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the multi-thread case. The interfaces have the prefix
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"catomic_".
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- support functions like barriers. They also have the prefix
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"atomic_".
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Architectures must provide a few lowlevel macros (the compare
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and exchange definitions). All others are optional. They
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should only be provided if the architecture has specific
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support for the operation.
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As <atomic.h> macros are usually heavily nested and often use local
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variables to make sure side-effects are evaluated properly, use for
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macro local variables a per-macro unique prefix. This file uses
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__atgN_ prefix where N is different in each macro. */
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#include <stdlib.h>
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#include <atomic-machine.h>
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/* Wrapper macros to call pre_NN_post (mem, ...) where NN is the
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bit width of *MEM. The calling macro puts parens around MEM
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and following args. */
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#define __atomic_val_bysize(pre, post, mem, ...) \
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({ \
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__typeof (*mem) __atg1_result; \
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if (sizeof (*mem) == 1) \
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__atg1_result = pre##_8_##post (mem, __VA_ARGS__); \
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else if (sizeof (*mem) == 2) \
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__atg1_result = pre##_16_##post (mem, __VA_ARGS__); \
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else if (sizeof (*mem) == 4) \
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__atg1_result = pre##_32_##post (mem, __VA_ARGS__); \
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else if (sizeof (*mem) == 8) \
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__atg1_result = pre##_64_##post (mem, __VA_ARGS__); \
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else \
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abort (); \
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__atg1_result; \
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})
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#define __atomic_bool_bysize(pre, post, mem, ...) \
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({ \
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int __atg2_result; \
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if (sizeof (*mem) == 1) \
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__atg2_result = pre##_8_##post (mem, __VA_ARGS__); \
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else if (sizeof (*mem) == 2) \
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__atg2_result = pre##_16_##post (mem, __VA_ARGS__); \
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else if (sizeof (*mem) == 4) \
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__atg2_result = pre##_32_##post (mem, __VA_ARGS__); \
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else if (sizeof (*mem) == 8) \
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__atg2_result = pre##_64_##post (mem, __VA_ARGS__); \
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else \
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abort (); \
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__atg2_result; \
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})
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/* Atomically store NEWVAL in *MEM if *MEM is equal to OLDVAL.
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Return the old *MEM value. */
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#if !defined atomic_compare_and_exchange_val_acq \
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&& defined __arch_compare_and_exchange_val_32_acq
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# define atomic_compare_and_exchange_val_acq(mem, newval, oldval) \
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__atomic_val_bysize (__arch_compare_and_exchange_val,acq, \
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mem, newval, oldval)
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#endif
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#ifndef catomic_compare_and_exchange_val_acq
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# ifdef __arch_c_compare_and_exchange_val_32_acq
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# define catomic_compare_and_exchange_val_acq(mem, newval, oldval) \
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__atomic_val_bysize (__arch_c_compare_and_exchange_val,acq, \
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mem, newval, oldval)
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# else
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# define catomic_compare_and_exchange_val_acq(mem, newval, oldval) \
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atomic_compare_and_exchange_val_acq (mem, newval, oldval)
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# endif
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#endif
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#ifndef catomic_compare_and_exchange_val_rel
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# ifndef atomic_compare_and_exchange_val_rel
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# define catomic_compare_and_exchange_val_rel(mem, newval, oldval) \
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catomic_compare_and_exchange_val_acq (mem, newval, oldval)
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# else
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# define catomic_compare_and_exchange_val_rel(mem, newval, oldval) \
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atomic_compare_and_exchange_val_rel (mem, newval, oldval)
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# endif
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#endif
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#ifndef atomic_compare_and_exchange_val_rel
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# define atomic_compare_and_exchange_val_rel(mem, newval, oldval) \
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atomic_compare_and_exchange_val_acq (mem, newval, oldval)
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#endif
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/* Atomically store NEWVAL in *MEM if *MEM is equal to OLDVAL.
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Return zero if *MEM was changed or non-zero if no exchange happened. */
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#ifndef atomic_compare_and_exchange_bool_acq
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# ifdef __arch_compare_and_exchange_bool_32_acq
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# define atomic_compare_and_exchange_bool_acq(mem, newval, oldval) \
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__atomic_bool_bysize (__arch_compare_and_exchange_bool,acq, \
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mem, newval, oldval)
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# else
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# define atomic_compare_and_exchange_bool_acq(mem, newval, oldval) \
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({ /* Cannot use __oldval here, because macros later in this file might \
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call this macro with __oldval argument. */ \
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__typeof (oldval) __atg3_old = (oldval); \
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atomic_compare_and_exchange_val_acq (mem, newval, __atg3_old) \
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!= __atg3_old; \
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})
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# endif
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#endif
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#ifndef catomic_compare_and_exchange_bool_acq
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# ifdef __arch_c_compare_and_exchange_bool_32_acq
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# define catomic_compare_and_exchange_bool_acq(mem, newval, oldval) \
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__atomic_bool_bysize (__arch_c_compare_and_exchange_bool,acq, \
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mem, newval, oldval)
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# else
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# define catomic_compare_and_exchange_bool_acq(mem, newval, oldval) \
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({ /* Cannot use __oldval here, because macros later in this file might \
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call this macro with __oldval argument. */ \
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__typeof (oldval) __atg4_old = (oldval); \
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catomic_compare_and_exchange_val_acq (mem, newval, __atg4_old) \
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!= __atg4_old; \
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})
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# endif
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#endif
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/* Store NEWVALUE in *MEM and return the old value. */
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#ifndef atomic_exchange_acq
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# define atomic_exchange_acq(mem, newvalue) \
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({ __typeof (*(mem)) __atg5_oldval; \
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__typeof (mem) __atg5_memp = (mem); \
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__typeof (*(mem)) __atg5_value = (newvalue); \
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\
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do \
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__atg5_oldval = *__atg5_memp; \
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while (__builtin_expect \
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(atomic_compare_and_exchange_bool_acq (__atg5_memp, __atg5_value, \
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__atg5_oldval), 0)); \
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\
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__atg5_oldval; })
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#endif
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#ifndef atomic_exchange_rel
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# define atomic_exchange_rel(mem, newvalue) atomic_exchange_acq (mem, newvalue)
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#endif
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/* Add VALUE to *MEM and return the old value of *MEM. */
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#ifndef atomic_exchange_and_add_acq
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# ifdef atomic_exchange_and_add
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# define atomic_exchange_and_add_acq(mem, value) \
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atomic_exchange_and_add (mem, value)
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# else
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# define atomic_exchange_and_add_acq(mem, value) \
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({ __typeof (*(mem)) __atg6_oldval; \
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__typeof (mem) __atg6_memp = (mem); \
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__typeof (*(mem)) __atg6_value = (value); \
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\
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do \
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__atg6_oldval = *__atg6_memp; \
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while (__builtin_expect \
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(atomic_compare_and_exchange_bool_acq (__atg6_memp, \
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__atg6_oldval \
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+ __atg6_value, \
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__atg6_oldval), 0)); \
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\
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__atg6_oldval; })
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# endif
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#endif
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#ifndef atomic_exchange_and_add_rel
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# define atomic_exchange_and_add_rel(mem, value) \
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atomic_exchange_and_add_acq(mem, value)
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#endif
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#ifndef atomic_exchange_and_add
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# define atomic_exchange_and_add(mem, value) \
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atomic_exchange_and_add_acq(mem, value)
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#endif
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#ifndef catomic_exchange_and_add
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# define catomic_exchange_and_add(mem, value) \
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({ __typeof (*(mem)) __atg7_oldv; \
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__typeof (mem) __atg7_memp = (mem); \
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__typeof (*(mem)) __atg7_value = (value); \
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\
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do \
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__atg7_oldv = *__atg7_memp; \
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while (__builtin_expect \
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(catomic_compare_and_exchange_bool_acq (__atg7_memp, \
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__atg7_oldv \
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+ __atg7_value, \
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__atg7_oldv), 0)); \
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\
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__atg7_oldv; })
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#endif
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#ifndef atomic_max
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# define atomic_max(mem, value) \
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do { \
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__typeof (*(mem)) __atg8_oldval; \
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__typeof (mem) __atg8_memp = (mem); \
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__typeof (*(mem)) __atg8_value = (value); \
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do { \
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__atg8_oldval = *__atg8_memp; \
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if (__atg8_oldval >= __atg8_value) \
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break; \
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} while (__builtin_expect \
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(atomic_compare_and_exchange_bool_acq (__atg8_memp, __atg8_value,\
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__atg8_oldval), 0)); \
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} while (0)
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#endif
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#ifndef catomic_max
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# define catomic_max(mem, value) \
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do { \
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__typeof (*(mem)) __atg9_oldv; \
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__typeof (mem) __atg9_memp = (mem); \
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__typeof (*(mem)) __atg9_value = (value); \
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do { \
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__atg9_oldv = *__atg9_memp; \
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if (__atg9_oldv >= __atg9_value) \
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break; \
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} while (__builtin_expect \
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(catomic_compare_and_exchange_bool_acq (__atg9_memp, \
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__atg9_value, \
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__atg9_oldv), 0)); \
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} while (0)
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#endif
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#ifndef atomic_min
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# define atomic_min(mem, value) \
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do { \
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__typeof (*(mem)) __atg10_oldval; \
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__typeof (mem) __atg10_memp = (mem); \
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__typeof (*(mem)) __atg10_value = (value); \
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do { \
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__atg10_oldval = *__atg10_memp; \
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if (__atg10_oldval <= __atg10_value) \
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break; \
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} while (__builtin_expect \
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(atomic_compare_and_exchange_bool_acq (__atg10_memp, \
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__atg10_value, \
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__atg10_oldval), 0)); \
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} while (0)
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#endif
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#ifndef atomic_add
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# define atomic_add(mem, value) (void) atomic_exchange_and_add ((mem), (value))
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#endif
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#ifndef catomic_add
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# define catomic_add(mem, value) \
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(void) catomic_exchange_and_add ((mem), (value))
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#endif
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#ifndef atomic_increment
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# define atomic_increment(mem) atomic_add ((mem), 1)
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#endif
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#ifndef catomic_increment
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# define catomic_increment(mem) catomic_add ((mem), 1)
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#endif
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#ifndef atomic_increment_val
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# define atomic_increment_val(mem) (atomic_exchange_and_add ((mem), 1) + 1)
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#endif
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#ifndef catomic_increment_val
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# define catomic_increment_val(mem) (catomic_exchange_and_add ((mem), 1) + 1)
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#endif
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/* Add one to *MEM and return true iff it's now zero. */
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#ifndef atomic_increment_and_test
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# define atomic_increment_and_test(mem) \
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(atomic_exchange_and_add ((mem), 1) + 1 == 0)
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#endif
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#ifndef atomic_decrement
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# define atomic_decrement(mem) atomic_add ((mem), -1)
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#endif
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#ifndef catomic_decrement
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# define catomic_decrement(mem) catomic_add ((mem), -1)
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#endif
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#ifndef atomic_decrement_val
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# define atomic_decrement_val(mem) (atomic_exchange_and_add ((mem), -1) - 1)
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#endif
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#ifndef catomic_decrement_val
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# define catomic_decrement_val(mem) (catomic_exchange_and_add ((mem), -1) - 1)
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#endif
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/* Subtract 1 from *MEM and return true iff it's now zero. */
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#ifndef atomic_decrement_and_test
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# define atomic_decrement_and_test(mem) \
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(atomic_exchange_and_add ((mem), -1) == 1)
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#endif
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/* Decrement *MEM if it is > 0, and return the old value. */
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#ifndef atomic_decrement_if_positive
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# define atomic_decrement_if_positive(mem) \
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({ __typeof (*(mem)) __atg11_oldval; \
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__typeof (mem) __atg11_memp = (mem); \
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\
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do \
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{ \
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__atg11_oldval = *__atg11_memp; \
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if (__glibc_unlikely (__atg11_oldval <= 0)) \
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break; \
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} \
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while (__builtin_expect \
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(atomic_compare_and_exchange_bool_acq (__atg11_memp, \
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__atg11_oldval - 1, \
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__atg11_oldval), 0)); \
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__atg11_oldval; })
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#endif
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#ifndef atomic_add_negative
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# define atomic_add_negative(mem, value) \
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({ __typeof (value) __atg12_value = (value); \
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atomic_exchange_and_add (mem, __atg12_value) < -__atg12_value; })
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#endif
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#ifndef atomic_add_zero
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# define atomic_add_zero(mem, value) \
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({ __typeof (value) __atg13_value = (value); \
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atomic_exchange_and_add (mem, __atg13_value) == -__atg13_value; })
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#endif
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#ifndef atomic_bit_set
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# define atomic_bit_set(mem, bit) \
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(void) atomic_bit_test_set(mem, bit)
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#endif
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#ifndef atomic_bit_test_set
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# define atomic_bit_test_set(mem, bit) \
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({ __typeof (*(mem)) __atg14_old; \
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__typeof (mem) __atg14_memp = (mem); \
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__typeof (*(mem)) __atg14_mask = ((__typeof (*(mem))) 1 << (bit)); \
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\
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do \
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__atg14_old = (*__atg14_memp); \
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while (__builtin_expect \
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(atomic_compare_and_exchange_bool_acq (__atg14_memp, \
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__atg14_old | __atg14_mask,\
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__atg14_old), 0)); \
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\
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__atg14_old & __atg14_mask; })
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#endif
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/* Atomically *mem &= mask. */
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#ifndef atomic_and
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# define atomic_and(mem, mask) \
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do { \
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__typeof (*(mem)) __atg15_old; \
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__typeof (mem) __atg15_memp = (mem); \
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__typeof (*(mem)) __atg15_mask = (mask); \
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\
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do \
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__atg15_old = (*__atg15_memp); \
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while (__builtin_expect \
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(atomic_compare_and_exchange_bool_acq (__atg15_memp, \
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__atg15_old & __atg15_mask, \
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__atg15_old), 0)); \
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} while (0)
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#endif
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#ifndef catomic_and
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# define catomic_and(mem, mask) \
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do { \
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__typeof (*(mem)) __atg20_old; \
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__typeof (mem) __atg20_memp = (mem); \
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__typeof (*(mem)) __atg20_mask = (mask); \
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\
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do \
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__atg20_old = (*__atg20_memp); \
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while (__builtin_expect \
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(catomic_compare_and_exchange_bool_acq (__atg20_memp, \
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__atg20_old & __atg20_mask,\
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__atg20_old), 0)); \
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} while (0)
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#endif
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/* Atomically *mem &= mask and return the old value of *mem. */
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#ifndef atomic_and_val
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# define atomic_and_val(mem, mask) \
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({ __typeof (*(mem)) __atg16_old; \
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__typeof (mem) __atg16_memp = (mem); \
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__typeof (*(mem)) __atg16_mask = (mask); \
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\
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do \
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__atg16_old = (*__atg16_memp); \
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while (__builtin_expect \
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|
(atomic_compare_and_exchange_bool_acq (__atg16_memp, \
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__atg16_old & __atg16_mask,\
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__atg16_old), 0)); \
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\
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__atg16_old; })
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#endif
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/* Atomically *mem |= mask and return the old value of *mem. */
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#ifndef atomic_or
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|
# define atomic_or(mem, mask) \
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do { \
|
|
__typeof (*(mem)) __atg17_old; \
|
|
__typeof (mem) __atg17_memp = (mem); \
|
|
__typeof (*(mem)) __atg17_mask = (mask); \
|
|
\
|
|
do \
|
|
__atg17_old = (*__atg17_memp); \
|
|
while (__builtin_expect \
|
|
(atomic_compare_and_exchange_bool_acq (__atg17_memp, \
|
|
__atg17_old | __atg17_mask, \
|
|
__atg17_old), 0)); \
|
|
} while (0)
|
|
#endif
|
|
|
|
#ifndef catomic_or
|
|
# define catomic_or(mem, mask) \
|
|
do { \
|
|
__typeof (*(mem)) __atg18_old; \
|
|
__typeof (mem) __atg18_memp = (mem); \
|
|
__typeof (*(mem)) __atg18_mask = (mask); \
|
|
\
|
|
do \
|
|
__atg18_old = (*__atg18_memp); \
|
|
while (__builtin_expect \
|
|
(catomic_compare_and_exchange_bool_acq (__atg18_memp, \
|
|
__atg18_old | __atg18_mask,\
|
|
__atg18_old), 0)); \
|
|
} while (0)
|
|
#endif
|
|
|
|
/* Atomically *mem |= mask and return the old value of *mem. */
|
|
#ifndef atomic_or_val
|
|
# define atomic_or_val(mem, mask) \
|
|
({ __typeof (*(mem)) __atg19_old; \
|
|
__typeof (mem) __atg19_memp = (mem); \
|
|
__typeof (*(mem)) __atg19_mask = (mask); \
|
|
\
|
|
do \
|
|
__atg19_old = (*__atg19_memp); \
|
|
while (__builtin_expect \
|
|
(atomic_compare_and_exchange_bool_acq (__atg19_memp, \
|
|
__atg19_old | __atg19_mask,\
|
|
__atg19_old), 0)); \
|
|
\
|
|
__atg19_old; })
|
|
#endif
|
|
|
|
#ifndef atomic_full_barrier
|
|
# define atomic_full_barrier() __asm ("" ::: "memory")
|
|
#endif
|
|
|
|
|
|
#ifndef atomic_read_barrier
|
|
# define atomic_read_barrier() atomic_full_barrier ()
|
|
#endif
|
|
|
|
|
|
#ifndef atomic_write_barrier
|
|
# define atomic_write_barrier() atomic_full_barrier ()
|
|
#endif
|
|
|
|
|
|
#ifndef atomic_forced_read
|
|
# define atomic_forced_read(x) \
|
|
({ __typeof (x) __x; __asm ("" : "=r" (__x) : "0" (x)); __x; })
|
|
#endif
|
|
|
|
/* This is equal to 1 iff the architecture supports 64b atomic operations. */
|
|
#ifndef __HAVE_64B_ATOMICS
|
|
#error Unable to determine if 64-bit atomics are present.
|
|
#endif
|
|
|
|
/* The following functions are a subset of the atomic operations provided by
|
|
C11. Usually, a function named atomic_OP_MO(args) is equivalent to C11's
|
|
atomic_OP_explicit(args, memory_order_MO); exceptions noted below. */
|
|
|
|
/* Each arch can request to use compiler built-ins for C11 atomics. If it
|
|
does, all atomics will be based on these. */
|
|
#if USE_ATOMIC_COMPILER_BUILTINS
|
|
|
|
/* We require 32b atomic operations; some archs also support 64b atomic
|
|
operations. */
|
|
void __atomic_link_error (void);
|
|
# if __HAVE_64B_ATOMICS == 1
|
|
# define __atomic_check_size(mem) \
|
|
if ((sizeof (*mem) != 4) && (sizeof (*mem) != 8)) \
|
|
__atomic_link_error ();
|
|
# else
|
|
# define __atomic_check_size(mem) \
|
|
if (sizeof (*mem) != 4) \
|
|
__atomic_link_error ();
|
|
# endif
|
|
/* We additionally provide 8b and 16b atomic loads and stores; we do not yet
|
|
need other atomic operations of such sizes, and restricting the support to
|
|
loads and stores makes this easier for archs that do not have native
|
|
support for atomic operations to less-than-word-sized data. */
|
|
# if __HAVE_64B_ATOMICS == 1
|
|
# define __atomic_check_size_ls(mem) \
|
|
if ((sizeof (*mem) != 1) && (sizeof (*mem) != 2) && (sizeof (*mem) != 4) \
|
|
&& (sizeof (*mem) != 8)) \
|
|
__atomic_link_error ();
|
|
# else
|
|
# define __atomic_check_size_ls(mem) \
|
|
if ((sizeof (*mem) != 1) && (sizeof (*mem) != 2) && sizeof (*mem) != 4) \
|
|
__atomic_link_error ();
|
|
# endif
|
|
|
|
# define atomic_thread_fence_acquire() \
|
|
__atomic_thread_fence (__ATOMIC_ACQUIRE)
|
|
# define atomic_thread_fence_release() \
|
|
__atomic_thread_fence (__ATOMIC_RELEASE)
|
|
# define atomic_thread_fence_seq_cst() \
|
|
__atomic_thread_fence (__ATOMIC_SEQ_CST)
|
|
|
|
# define atomic_load_relaxed(mem) \
|
|
({ __atomic_check_size_ls((mem)); \
|
|
__atomic_load_n ((mem), __ATOMIC_RELAXED); })
|
|
# define atomic_load_acquire(mem) \
|
|
({ __atomic_check_size_ls((mem)); \
|
|
__atomic_load_n ((mem), __ATOMIC_ACQUIRE); })
|
|
|
|
# define atomic_store_relaxed(mem, val) \
|
|
do { \
|
|
__atomic_check_size_ls((mem)); \
|
|
__atomic_store_n ((mem), (val), __ATOMIC_RELAXED); \
|
|
} while (0)
|
|
# define atomic_store_release(mem, val) \
|
|
do { \
|
|
__atomic_check_size_ls((mem)); \
|
|
__atomic_store_n ((mem), (val), __ATOMIC_RELEASE); \
|
|
} while (0)
|
|
|
|
/* On failure, this CAS has memory_order_relaxed semantics. */
|
|
# define atomic_compare_exchange_weak_relaxed(mem, expected, desired) \
|
|
({ __atomic_check_size((mem)); \
|
|
__atomic_compare_exchange_n ((mem), (expected), (desired), 1, \
|
|
__ATOMIC_RELAXED, __ATOMIC_RELAXED); })
|
|
# define atomic_compare_exchange_weak_acquire(mem, expected, desired) \
|
|
({ __atomic_check_size((mem)); \
|
|
__atomic_compare_exchange_n ((mem), (expected), (desired), 1, \
|
|
__ATOMIC_ACQUIRE, __ATOMIC_RELAXED); })
|
|
# define atomic_compare_exchange_weak_release(mem, expected, desired) \
|
|
({ __atomic_check_size((mem)); \
|
|
__atomic_compare_exchange_n ((mem), (expected), (desired), 1, \
|
|
__ATOMIC_RELEASE, __ATOMIC_RELAXED); })
|
|
|
|
# define atomic_exchange_relaxed(mem, desired) \
|
|
({ __atomic_check_size((mem)); \
|
|
__atomic_exchange_n ((mem), (desired), __ATOMIC_RELAXED); })
|
|
# define atomic_exchange_acquire(mem, desired) \
|
|
({ __atomic_check_size((mem)); \
|
|
__atomic_exchange_n ((mem), (desired), __ATOMIC_ACQUIRE); })
|
|
# define atomic_exchange_release(mem, desired) \
|
|
({ __atomic_check_size((mem)); \
|
|
__atomic_exchange_n ((mem), (desired), __ATOMIC_RELEASE); })
|
|
|
|
# define atomic_fetch_add_relaxed(mem, operand) \
|
|
({ __atomic_check_size((mem)); \
|
|
__atomic_fetch_add ((mem), (operand), __ATOMIC_RELAXED); })
|
|
# define atomic_fetch_add_acquire(mem, operand) \
|
|
({ __atomic_check_size((mem)); \
|
|
__atomic_fetch_add ((mem), (operand), __ATOMIC_ACQUIRE); })
|
|
# define atomic_fetch_add_release(mem, operand) \
|
|
({ __atomic_check_size((mem)); \
|
|
__atomic_fetch_add ((mem), (operand), __ATOMIC_RELEASE); })
|
|
# define atomic_fetch_add_acq_rel(mem, operand) \
|
|
({ __atomic_check_size((mem)); \
|
|
__atomic_fetch_add ((mem), (operand), __ATOMIC_ACQ_REL); })
|
|
|
|
# define atomic_fetch_and_relaxed(mem, operand) \
|
|
({ __atomic_check_size((mem)); \
|
|
__atomic_fetch_and ((mem), (operand), __ATOMIC_RELAXED); })
|
|
# define atomic_fetch_and_acquire(mem, operand) \
|
|
({ __atomic_check_size((mem)); \
|
|
__atomic_fetch_and ((mem), (operand), __ATOMIC_ACQUIRE); })
|
|
# define atomic_fetch_and_release(mem, operand) \
|
|
({ __atomic_check_size((mem)); \
|
|
__atomic_fetch_and ((mem), (operand), __ATOMIC_RELEASE); })
|
|
|
|
# define atomic_fetch_or_relaxed(mem, operand) \
|
|
({ __atomic_check_size((mem)); \
|
|
__atomic_fetch_or ((mem), (operand), __ATOMIC_RELAXED); })
|
|
# define atomic_fetch_or_acquire(mem, operand) \
|
|
({ __atomic_check_size((mem)); \
|
|
__atomic_fetch_or ((mem), (operand), __ATOMIC_ACQUIRE); })
|
|
# define atomic_fetch_or_release(mem, operand) \
|
|
({ __atomic_check_size((mem)); \
|
|
__atomic_fetch_or ((mem), (operand), __ATOMIC_RELEASE); })
|
|
|
|
# define atomic_fetch_xor_release(mem, operand) \
|
|
({ __atomic_check_size((mem)); \
|
|
__atomic_fetch_xor ((mem), (operand), __ATOMIC_RELEASE); })
|
|
|
|
#else /* !USE_ATOMIC_COMPILER_BUILTINS */
|
|
|
|
/* By default, we assume that read, write, and full barriers are equivalent
|
|
to acquire, release, and seq_cst barriers. Archs for which this does not
|
|
hold have to provide custom definitions of the fences. */
|
|
# ifndef atomic_thread_fence_acquire
|
|
# define atomic_thread_fence_acquire() atomic_read_barrier ()
|
|
# endif
|
|
# ifndef atomic_thread_fence_release
|
|
# define atomic_thread_fence_release() atomic_write_barrier ()
|
|
# endif
|
|
# ifndef atomic_thread_fence_seq_cst
|
|
# define atomic_thread_fence_seq_cst() atomic_full_barrier ()
|
|
# endif
|
|
|
|
# ifndef atomic_load_relaxed
|
|
# define atomic_load_relaxed(mem) \
|
|
({ __typeof (*(mem)) __atg100_val; \
|
|
__asm ("" : "=r" (__atg100_val) : "0" (*(mem))); \
|
|
__atg100_val; })
|
|
# endif
|
|
# ifndef atomic_load_acquire
|
|
# define atomic_load_acquire(mem) \
|
|
({ __typeof (*(mem)) __atg101_val = atomic_load_relaxed (mem); \
|
|
atomic_thread_fence_acquire (); \
|
|
__atg101_val; })
|
|
# endif
|
|
|
|
# ifndef atomic_store_relaxed
|
|
/* XXX Use inline asm here? */
|
|
# define atomic_store_relaxed(mem, val) do { *(mem) = (val); } while (0)
|
|
# endif
|
|
# ifndef atomic_store_release
|
|
# define atomic_store_release(mem, val) \
|
|
do { \
|
|
atomic_thread_fence_release (); \
|
|
atomic_store_relaxed ((mem), (val)); \
|
|
} while (0)
|
|
# endif
|
|
|
|
/* On failure, this CAS has memory_order_relaxed semantics. */
|
|
/* XXX This potentially has one branch more than necessary, but archs
|
|
currently do not define a CAS that returns both the previous value and
|
|
the success flag. */
|
|
# ifndef atomic_compare_exchange_weak_acquire
|
|
# define atomic_compare_exchange_weak_acquire(mem, expected, desired) \
|
|
({ typeof (*(expected)) __atg102_expected = *(expected); \
|
|
*(expected) = \
|
|
atomic_compare_and_exchange_val_acq ((mem), (desired), *(expected)); \
|
|
*(expected) == __atg102_expected; })
|
|
# endif
|
|
# ifndef atomic_compare_exchange_weak_relaxed
|
|
/* XXX Fall back to CAS with acquire MO because archs do not define a weaker
|
|
CAS. */
|
|
# define atomic_compare_exchange_weak_relaxed(mem, expected, desired) \
|
|
atomic_compare_exchange_weak_acquire ((mem), (expected), (desired))
|
|
# endif
|
|
# ifndef atomic_compare_exchange_weak_release
|
|
# define atomic_compare_exchange_weak_release(mem, expected, desired) \
|
|
({ typeof (*(expected)) __atg103_expected = *(expected); \
|
|
*(expected) = \
|
|
atomic_compare_and_exchange_val_rel ((mem), (desired), *(expected)); \
|
|
*(expected) == __atg103_expected; })
|
|
# endif
|
|
|
|
/* XXX Fall back to acquire MO because archs do not define a weaker
|
|
atomic_exchange. */
|
|
# ifndef atomic_exchange_relaxed
|
|
# define atomic_exchange_relaxed(mem, val) \
|
|
atomic_exchange_acq ((mem), (val))
|
|
# endif
|
|
# ifndef atomic_exchange_acquire
|
|
# define atomic_exchange_acquire(mem, val) \
|
|
atomic_exchange_acq ((mem), (val))
|
|
# endif
|
|
# ifndef atomic_exchange_release
|
|
# define atomic_exchange_release(mem, val) \
|
|
atomic_exchange_rel ((mem), (val))
|
|
# endif
|
|
|
|
# ifndef atomic_fetch_add_acquire
|
|
# define atomic_fetch_add_acquire(mem, operand) \
|
|
atomic_exchange_and_add_acq ((mem), (operand))
|
|
# endif
|
|
# ifndef atomic_fetch_add_relaxed
|
|
/* XXX Fall back to acquire MO because the MO semantics of
|
|
atomic_exchange_and_add are not documented; the generic version falls back
|
|
to atomic_exchange_and_add_acq if atomic_exchange_and_add is not defined,
|
|
and vice versa. */
|
|
# define atomic_fetch_add_relaxed(mem, operand) \
|
|
atomic_fetch_add_acquire ((mem), (operand))
|
|
# endif
|
|
# ifndef atomic_fetch_add_release
|
|
# define atomic_fetch_add_release(mem, operand) \
|
|
atomic_exchange_and_add_rel ((mem), (operand))
|
|
# endif
|
|
# ifndef atomic_fetch_add_acq_rel
|
|
# define atomic_fetch_add_acq_rel(mem, operand) \
|
|
({ atomic_thread_fence_release (); \
|
|
atomic_exchange_and_add_acq ((mem), (operand)); })
|
|
# endif
|
|
|
|
/* XXX Fall back to acquire MO because archs do not define a weaker
|
|
atomic_and_val. */
|
|
# ifndef atomic_fetch_and_relaxed
|
|
# define atomic_fetch_and_relaxed(mem, operand) \
|
|
atomic_fetch_and_acquire ((mem), (operand))
|
|
# endif
|
|
/* XXX The default for atomic_and_val has acquire semantics, but this is not
|
|
documented. */
|
|
# ifndef atomic_fetch_and_acquire
|
|
# define atomic_fetch_and_acquire(mem, operand) \
|
|
atomic_and_val ((mem), (operand))
|
|
# endif
|
|
# ifndef atomic_fetch_and_release
|
|
/* XXX This unnecessarily has acquire MO. */
|
|
# define atomic_fetch_and_release(mem, operand) \
|
|
({ atomic_thread_fence_release (); \
|
|
atomic_and_val ((mem), (operand)); })
|
|
# endif
|
|
|
|
/* XXX The default for atomic_or_val has acquire semantics, but this is not
|
|
documented. */
|
|
# ifndef atomic_fetch_or_acquire
|
|
# define atomic_fetch_or_acquire(mem, operand) \
|
|
atomic_or_val ((mem), (operand))
|
|
# endif
|
|
/* XXX Fall back to acquire MO because archs do not define a weaker
|
|
atomic_or_val. */
|
|
# ifndef atomic_fetch_or_relaxed
|
|
# define atomic_fetch_or_relaxed(mem, operand) \
|
|
atomic_fetch_or_acquire ((mem), (operand))
|
|
# endif
|
|
/* XXX Contains an unnecessary acquire MO because archs do not define a weaker
|
|
atomic_or_val. */
|
|
# ifndef atomic_fetch_or_release
|
|
# define atomic_fetch_or_release(mem, operand) \
|
|
({ atomic_thread_fence_release (); \
|
|
atomic_fetch_or_acquire ((mem), (operand)); })
|
|
# endif
|
|
|
|
# ifndef atomic_fetch_xor_release
|
|
/* Failing the atomic_compare_exchange_weak_release reloads the value in
|
|
__atg104_expected, so we need only do the XOR again and retry. */
|
|
# define atomic_fetch_xor_release(mem, operand) \
|
|
({ __typeof (mem) __atg104_memp = (mem); \
|
|
__typeof (*(mem)) __atg104_expected = (*__atg104_memp); \
|
|
__typeof (*(mem)) __atg104_desired; \
|
|
__typeof (*(mem)) __atg104_op = (operand); \
|
|
\
|
|
do \
|
|
__atg104_desired = __atg104_expected ^ __atg104_op; \
|
|
while (__glibc_unlikely \
|
|
(atomic_compare_exchange_weak_release ( \
|
|
__atg104_memp, &__atg104_expected, __atg104_desired) \
|
|
== 0)); \
|
|
__atg104_expected; })
|
|
#endif
|
|
|
|
#endif /* !USE_ATOMIC_COMPILER_BUILTINS */
|
|
|
|
/* This operation does not affect synchronization semantics but can be used
|
|
in the body of a spin loop to potentially improve its efficiency. */
|
|
#ifndef atomic_spin_nop
|
|
# define atomic_spin_nop() do { /* nothing */ } while (0)
|
|
#endif
|
|
|
|
#endif /* atomic.h */
|