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/* Atomic operations. Pure ARM version.
Copyright (C) 2002-2025 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/>. */
#define __HAVE_64B_ATOMICS 0
#define USE_ATOMIC_COMPILER_BUILTINS 1
#define ATOMIC_EXCHANGE_USES_CAS 1
void __arm_link_error (void);
#ifdef __GCC_HAVE_SYNC_COMPARE_AND_SWAP_4
# define atomic_full_barrier() __sync_synchronize ()
#else
# define atomic_full_barrier() __arm_assisted_full_barrier ()
#endif
/* An OS-specific atomic-machine.h file will define this macro if
the OS can provide something. If not, we'll fail to build
with a compiler that doesn't supply the operation. */
#ifndef __arm_assisted_full_barrier
# define __arm_assisted_full_barrier() __arm_link_error()
#endif
/* Use the atomic builtins provided by GCC in case the backend provides
a pattern to do this efficiently. */
#ifdef __GCC_HAVE_SYNC_COMPARE_AND_SWAP_4
# define atomic_exchange_acq(mem, value) \
__atomic_val_bysize (__arch_exchange, int, mem, value, __ATOMIC_ACQUIRE)
# define atomic_exchange_rel(mem, value) \
__atomic_val_bysize (__arch_exchange, int, mem, value, __ATOMIC_RELEASE)
/* Atomic exchange (without compare). */
# define __arch_exchange_8_int(mem, newval, model) \
(__arm_link_error (), (typeof (*mem)) 0)
# define __arch_exchange_16_int(mem, newval, model) \
(__arm_link_error (), (typeof (*mem)) 0)
# define __arch_exchange_32_int(mem, newval, model) \
__atomic_exchange_n (mem, newval, model)
# define __arch_exchange_64_int(mem, newval, model) \
(__arm_link_error (), (typeof (*mem)) 0)
/* Compare and exchange with "acquire" semantics, ie barrier after. */
# define atomic_compare_and_exchange_bool_acq(mem, new, old) \
__atomic_bool_bysize (__arch_compare_and_exchange_bool, int, \
mem, new, old, __ATOMIC_ACQUIRE)
# define atomic_compare_and_exchange_val_acq(mem, new, old) \
__atomic_val_bysize (__arch_compare_and_exchange_val, int, \
mem, new, old, __ATOMIC_ACQUIRE)
/* Compare and exchange with "release" semantics, ie barrier before. */
# define atomic_compare_and_exchange_val_rel(mem, new, old) \
__atomic_val_bysize (__arch_compare_and_exchange_val, int, \
mem, new, old, __ATOMIC_RELEASE)
/* Compare and exchange.
For all "bool" routines, we return FALSE if exchange successful. */
# define __arch_compare_and_exchange_bool_8_int(mem, newval, oldval, model) \
({__arm_link_error (); 0; })
# define __arch_compare_and_exchange_bool_16_int(mem, newval, oldval, model) \
({__arm_link_error (); 0; })
# define __arch_compare_and_exchange_bool_32_int(mem, newval, oldval, model) \
({ \
typeof (*mem) __oldval = (oldval); \
!__atomic_compare_exchange_n (mem, (void *) &__oldval, newval, 0, \
model, __ATOMIC_RELAXED); \
})
# define __arch_compare_and_exchange_bool_64_int(mem, newval, oldval, model) \
({__arm_link_error (); 0; })
# define __arch_compare_and_exchange_val_8_int(mem, newval, oldval, model) \
({__arm_link_error (); oldval; })
# define __arch_compare_and_exchange_val_16_int(mem, newval, oldval, model) \
({__arm_link_error (); oldval; })
# define __arch_compare_and_exchange_val_32_int(mem, newval, oldval, model) \
({ \
typeof (*mem) __oldval = (oldval); \
__atomic_compare_exchange_n (mem, (void *) &__oldval, newval, 0, \
model, __ATOMIC_RELAXED); \
__oldval; \
})
# define __arch_compare_and_exchange_val_64_int(mem, newval, oldval, model) \
({__arm_link_error (); oldval; })
#else
# define __arch_compare_and_exchange_val_32_acq(mem, newval, oldval) \
__arm_assisted_compare_and_exchange_val_32_acq ((mem), (newval), (oldval))
#endif
#ifndef __GCC_HAVE_SYNC_COMPARE_AND_SWAP_4
/* We don't support atomic operations on any non-word types.
So make them link errors. */
# define __arch_compare_and_exchange_val_8_acq(mem, newval, oldval) \
({ __arm_link_error (); oldval; })
# define __arch_compare_and_exchange_val_16_acq(mem, newval, oldval) \
({ __arm_link_error (); oldval; })
# define __arch_compare_and_exchange_val_64_acq(mem, newval, oldval) \
({ __arm_link_error (); oldval; })
#endif
/* An OS-specific atomic-machine.h file will define this macro if
the OS can provide something. If not, we'll fail to build
with a compiler that doesn't supply the operation. */
#ifndef __arm_assisted_compare_and_exchange_val_32_acq
# define __arm_assisted_compare_and_exchange_val_32_acq(mem, newval, oldval) \
({ __arm_link_error (); oldval; })
#endif
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