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/* Copyright (C) 2003-2025 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#ifndef _ATOMIC_MACHINE_H
#define _ATOMIC_MACHINE_H 1
/* Some macros can be overridden if the architecture requires some specific
atomic operations or provides extra optimizations.
* atomic_max (mem, value): atomically set the maximum value of *mem
and value to *mem. Used on malloc statistics collection.
* atomic_full_barrier: defaults to __atomic_thread_fence (__ATOMIC_SEQ_CST)
* atomic_read_barrier: defaults to __atomic_thread_fence (__ATOMIC_ACQUIRE)
* atomic_write_barrier: defaults to __atomic_thread_fence (__ATOMIC_RELEASE)
* atomic_spin_nop: arch-specific instruction used on pthread spin lock
and adaptive mutexes to optimize spin-wait loops.
*/
#include <bits/wordsize.h>
/* NB: The NPTL semaphore code casts a sem_t to a new_sem and issues a 64-bit
atomic operation for USE_64B_ATOMICS. However, the sem_t has 32-bit
alignment on 32-bit architectures, which prevents using 64-bit atomics even
if the ABI supports it. */
#if __WORDSIZE == 64
# define USE_64B_ATOMICS 1
#else
# define USE_64B_ATOMICS 0
#endif
#endif /* atomic-machine.h */
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