Atomic: More atomic calls

/*

 *	BIRD Library -- Atomic calls

 *

 *	(c) 2019 Maria Matejka <mq@ucw.cz>

 *

 *	Can be freely distributed and used under the terms of the GNU GPL.

 */

#ifndef _BIRD_ATOMIC_H_

#define _BIRD_ATOMIC_H_

/* If we have stdatomic.h, we simply use C11 atomic calls */

#if HAVE_ATOMIC

#include <stdatomic.h>

#else

/* Otherwise, we try to approximate the atomic calls by GCC __sync calls */

#define _Atomic

#define atomic_load(ptr) __sync_val_compare_and_swap(ptr, 0, 0)

#define atomic_fetch_sub(ptr, val) __sync_fetch_and_sub((ptr), (val))

#define atomic_fetch_sub_explicit(ptr, val, memory) __sync_fetch_and_sub((ptr), (val))

#define atomic_exchange(ptr, val) __sync_lock_test_and_set((ptr), (val))

#define atomic_exchange_explicit(ptr, val, memory) atomic_exchange((ptr), (val))

#define atomic_compare_exchange_weak(ptr, desired, wanted) ({ \

    typeof(desired) _desptr = desired; /* save the pointer */ \

    typeof(*_desptr) _old = __sync_val_compare_and_swap(ptr, *_desptr, wanted); /* do the exchange */ \

#define atomic_compare_exchange_strong_explicit(ptr, desired, wanted, success, failure) \

  atomic_compare_exchange_weak(ptr, desired, wanted)

#define ATOMIC_FLAG_INIT  0

typedef u8 atomic_flag;

#define atomic_flag_test_and_set_explicit(ptr, memory) \

  __sync_lock_test_and_set(ptr, 1)

#define atomic_flag_clear_explicit(ptr, memory) \

  __sync_lock_release(ptr)

#endif

#endif