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/*
* Copyright (c) 1991, 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Berkeley Software Design, Inc.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)cdefs.h 8.8 (Berkeley) 1/9/95
*/
#ifndef _UTILS_H_
#define _UTILS_H_
#include <assert.h>
/*
* A regular assert (debug/diagnostic only).
*/
#if defined(DEBUG)
#define ASSERT assert
#else
#define ASSERT(x)
#endif
/*
* Minimum, maximum and rounding macros.
*/
#ifndef MIN
#define MIN(x, y) ((x) < (y) ? (x) : (y))
#endif
#ifndef MAX
#define MAX(x, y) ((x) > (y) ? (x) : (y))
#endif
/*
* Branch prediction macros.
*/
#ifndef __predict_true
#define __predict_true(x) __builtin_expect((x) != 0, 1)
#define __predict_false(x) __builtin_expect((x) != 0, 0)
#endif
/*
* Atomic operations and memory barriers. If C11 API is not available,
* then wrap the GCC builtin routines.
*
* Note: This atomic_compare_exchange_weak does not do the C11 thing of
* filling *(expected) with the actual value, because we don't need
* that here.
*/
#ifndef atomic_compare_exchange_weak
#define atomic_compare_exchange_weak(ptr, expected, desired) \
__sync_bool_compare_and_swap(ptr, *(expected), desired)
#endif
#ifndef atomic_thread_fence
#define memory_order_relaxed __ATOMIC_RELAXED
#define memory_order_acquire __ATOMIC_ACQUIRE
#define memory_order_release __ATOMIC_RELEASE
#define memory_order_seq_cst __ATOMIC_SEQ_CST
#define atomic_thread_fence(m) __atomic_thread_fence(m)
#endif
#ifndef atomic_store_explicit
#define atomic_store_explicit __atomic_store_n
#endif
#ifndef atomic_load_explicit
#define atomic_load_explicit __atomic_load_n
#endif
/*
* Exponential back-off for the spinning paths.
*/
#define SPINLOCK_BACKOFF_MIN 4
#define SPINLOCK_BACKOFF_MAX 128
#if defined(__x86_64__) || defined(__i386__)
#define SPINLOCK_BACKOFF_HOOK __asm volatile("pause" ::: "memory")
#else
#define SPINLOCK_BACKOFF_HOOK
#endif
#define SPINLOCK_BACKOFF(count) \
do { \
for (int __i = (count); __i != 0; __i--) { \
SPINLOCK_BACKOFF_HOOK; \
} \
if ((count) < SPINLOCK_BACKOFF_MAX) \
(count) += (count); \
} while (/* CONSTCOND */ 0);
#endif
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