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#ifndef SCM_ATOMICS_INTERNAL_H
#define SCM_ATOMICS_INTERNAL_H
/* Copyright (C) 2016
* Free Software Foundation, Inc.
*
* This 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 3 of
* the License, or (at your option) any later version.
*
* This 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 this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301 USA
*/
#include <stdint.h>
#define HAVE_C11_ATOMICS (__STDC_VERSION__ >= 201112L && !defined(__STDC_NO_ATOMICS__))
#if HAVE_C11_ATOMICS
#include <stdatomic.h>
static inline uint32_t
scm_atomic_subtract_uint32 (uint32_t *obj, uint32_t arg)
{
return atomic_fetch_sub (obj, arg);
}
static inline _Bool
scm_atomic_compare_and_swap_uint32 (uint32_t *obj, uint32_t *expected,
uint32_t desired)
{
return atomic_compare_exchange_weak (obj, expected, desired);
}
#else /* HAVE_C11_ATOMICS */
/* Fallback implementation using locks. */
#include "libguile/threads.h"
static scm_i_pthread_mutex_t atomics_lock = SCM_I_PTHREAD_MUTEX_INITIALIZER;
static inline uint32_t
scm_atomic_subtract_uint32 (uint32_t *obj, uint32_t arg)
{
uint32_t ret;
scm_i_pthread_mutex_lock (&atomics_lock);
ret = *obj;
*obj -= arg;
scm_i_pthread_mutex_unlock (&atomics_lock);
return ret;
}
static inline int
scm_atomic_compare_and_swap_uint32 (uint32_t *obj, uint32_t *expected,
uint32_t desired)
{
int ret;
scm_i_pthread_mutex_lock (&atomics_lock);
if (*obj == *expected)
{
*obj = desired;
ret = 1;
}
else
{
*expected = *obj;
ret = 0;
}
scm_i_pthread_mutex_unlock (&atomics_lock);
return ret;
}
#endif /* HAVE_C11_ATOMICS */
#endif /* SCM_ATOMICS_INTERNAL_H */
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