/*
 * Copyright (c) 2014-2020 Josef 'Jeff' Sipek <jeffpc@josefsipek.net>
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

#ifndef __JEFFPC_ATOMIC_H
#define __JEFFPC_ATOMIC_H

#include <stdint.h>

typedef struct {
	volatile uint32_t v;
} atomic_t;

typedef struct {
	volatile uint64_t v;
} atomic64_t;

/*
 * The following implement generic set/read/add/sub/inc/dec operations.
 *
 * WARNING: atomic_set and atomic_read may break on some really quirky
 * architectures.
 */

#define atomic_set(var, val)	((var)->v = (val))
#define atomic_read(var)	((var)->v)

/* The following return the new (modified) value. */
#define atomic_add(var, val)	__sync_add_and_fetch(&(var)->v, (val))
#define atomic_sub(var, val)	__sync_sub_and_fetch(&(var)->v, (val))
#define atomic_inc(var)		atomic_add((var), 1)
#define atomic_dec(var)		atomic_sub((var), 1)

/* The following return the 'before' value.  If == old, then a swap occured. */
#define atomic_cas(var, old, new)	\
		__sync_val_compare_and_swap(&(var)->v, (old), (new))
#define atomic_cas_ptr(var, old, new)	\
		__sync_val_compare_and_swap((var), (old), (new))

#define ATOMIC_INITIALIZER(val)		{ .v = (val) }

#endif