/* Copyright (c) 2021, ARM Limited
 * Copyright (c) 2021, Nokia
 * All rights reserved.
 *
 * SPDX-License-Identifier:     BSD-3-Clause
 */

#ifndef ODP_API_ABI_ATOMIC_GENERIC_H_
#define ODP_API_ABI_ATOMIC_GENERIC_H_

#include <odp/api/atomic.h>

#ifdef __SIZEOF_INT128__

static inline void _odp_atomic_init_u128(odp_atomic_u128_t *atom, odp_u128_t val)
{
	atom->v = val;
}

static inline odp_u128_t _odp_atomic_load_u128(odp_atomic_u128_t *atom)
{
	odp_u128_t val;

	*(__int128_t *)&val = __atomic_load_n((__int128_t *)&atom->v, __ATOMIC_RELAXED);
	return val;
}

static inline void _odp_atomic_store_u128(odp_atomic_u128_t *atom, odp_u128_t val)
{
	__atomic_store_n((__int128_t *)&atom->v, *(__int128_t *)&val, __ATOMIC_RELAXED);
}

static inline int _odp_atomic_cas_u128(odp_atomic_u128_t *atom, odp_u128_t *old_val,
				       odp_u128_t new_val)
{
	return __atomic_compare_exchange_n((__int128_t *)&atom->v, (__int128_t *)old_val,
					   *(__int128_t *)&new_val, 0 /* strong */,
					   __ATOMIC_RELAXED, __ATOMIC_RELAXED);
}

static inline int _odp_atomic_cas_acq_u128(odp_atomic_u128_t *atom, odp_u128_t *old_val,
					   odp_u128_t new_val)
{
	return __atomic_compare_exchange_n((__int128_t *)&atom->v, (__int128_t *)old_val,
					   *(__int128_t *)&new_val, 0 /* strong */,
					   __ATOMIC_ACQUIRE, __ATOMIC_RELAXED);
}

static inline int _odp_atomic_cas_rel_u128(odp_atomic_u128_t *atom, odp_u128_t *old_val,
					   odp_u128_t new_val)
{
	return __atomic_compare_exchange_n((__int128_t *)&atom->v, (__int128_t *)old_val,
					   *(__int128_t *)&new_val, 0 /* strong */,
					   __ATOMIC_RELEASE, __ATOMIC_RELAXED);
}

static inline int _odp_atomic_cas_acq_rel_u128(odp_atomic_u128_t *atom, odp_u128_t *old_val,
					       odp_u128_t new_val)
{
	return __atomic_compare_exchange_n((__int128_t *)&atom->v, (__int128_t *)old_val,
					   *(__int128_t *)&new_val, 0 /* strong */,
					   __ATOMIC_ACQ_REL, __ATOMIC_RELAXED);
}

#else /* Lock-based implementation */

/**
 * @internal
 * 128 bit store operation expression for the ATOMIC_OP macro
 */
#define ATOMIC_STORE_OP_128(new_val) \
({ \
	(_atom)->v = (new_val); \
})

/**
 * @internal
 * 128 bit CAS operation expression for the ATOMIC_OP macro
 */
#define ATOMIC_CAS_OP_128(ret_ptr, old_val, new_val) \
({ \
	int *_ret_ptr = ret_ptr; \
	odp_u128_t *_old_val = old_val; \
	odp_u128_t _new_val = new_val; \
	if (((_atom)->v.u64[0] == (_old_val)->u64[0]) && \
	    ((_atom)->v.u64[1] == (_old_val)->u64[1])) { \
		(_atom)->v = (_new_val); \
		*(_ret_ptr) = 1; \
	} else { \
		*(_ret_ptr) = 0; \
	} \
})

/**
 * @internal
 * Helper macro for lock-based atomic operations on 128-bit integers
 * @param[in,out] atom Pointer to the 128-bit atomic variable
 * @param expr Expression used update the variable.
 * @return The old value of the variable.
 */
#define ATOMIC_OP_128(atom, expr) \
({ \
	odp_u128_t _old_val; \
	odp_atomic_u128_t *_atom = atom; \
	/* Loop while lock is already taken, stop when lock becomes clear */ \
	while (__atomic_test_and_set(&(_atom)->lock, __ATOMIC_ACQUIRE)) \
		(void)0; \
	_old_val = (_atom)->v; \
	(expr); /* Perform whatever update is desired */ \
	__atomic_clear(&(_atom)->lock, __ATOMIC_RELEASE); \
	_old_val; /* Return old value */ \
})

static inline void _odp_atomic_init_u128(odp_atomic_u128_t *atom, odp_u128_t val)
{
	atom->v.u64[0] = val.u64[0];
	atom->v.u64[1] = val.u64[1];
	atom->lock = 0;
}

static inline odp_u128_t _odp_atomic_load_u128(odp_atomic_u128_t *atom)
{
	return ATOMIC_OP_128(atom, (void)0);
}

static inline void _odp_atomic_store_u128(odp_atomic_u128_t *atom, odp_u128_t val)
{
	ATOMIC_OP_128(atom, ATOMIC_STORE_OP_128(val));
}

static inline int _odp_atomic_cas_u128(odp_atomic_u128_t *atom, odp_u128_t *old_val,
				       odp_u128_t new_val)
{
	int ret;

	*old_val = ATOMIC_OP_128(atom, ATOMIC_CAS_OP_128(&ret, old_val, new_val));
	return ret;
}

static inline int _odp_atomic_cas_acq_u128(odp_atomic_u128_t *atom, odp_u128_t *old_val,
					   odp_u128_t new_val)
{
	return _odp_atomic_cas_u128(atom, old_val, new_val);
}

static inline int _odp_atomic_cas_rel_u128(odp_atomic_u128_t *atom, odp_u128_t *old_val,
					   odp_u128_t new_val)
{
	return _odp_atomic_cas_u128(atom, old_val, new_val);
}

static inline int _odp_atomic_cas_acq_rel_u128(odp_atomic_u128_t *atom, odp_u128_t *old_val,
					       odp_u128_t new_val)
{
	return _odp_atomic_cas_u128(atom, old_val, new_val);
}
#endif

#endif