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: / usr / include / x86_64-linux-gnu / mpi / openmpi / opal /
Filename : prefetch.h
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/*
 * Copyright (c) 2004-2006 The Regents of the University of California.
 *                         All rights reserved.
 * $COPYRIGHT$
 *
 * Additional copyrights may follow
 *
 * $HEADER$
 */

/** @file
 *
 * Compiler-specific prefetch functions
 *
 * A small set of prefetch / prediction interfaces for using compiler
 * directives to improve memory prefetching and branch prediction
 */

#ifndef OPAL_PREFETCH_H
#define OPAL_PREFETCH_H

#if defined(c_plusplus) || defined(__cplusplus)
/* C++ code */

#if OMPI_CXX_HAVE_BUILTIN_EXPECT
#define OPAL_LIKELY(expression) __builtin_expect(!!(expression), 1)
#define OPAL_UNLIKELY(expression) __builtin_expect(!!(expression), 0)
#else
#define OPAL_LIKELY(expression) (expression)
#define OPAL_UNLIKELY(expression) (expression)
#endif

#if OMPI_CXX_HAVE_BUILTIN_PREFETCH
#define OPAL_PREFETCH(address,rw,locality) __builtin_prefetch(address,rw,locality)
#else
#define OPAL_PREFETCH(address,rw,locality)
#endif

#else
/* C code */

#if OPAL_C_HAVE_BUILTIN_EXPECT
#define OPAL_LIKELY(expression) __builtin_expect(!!(expression), 1)
#define OPAL_UNLIKELY(expression) __builtin_expect(!!(expression), 0)
#else
#define OPAL_LIKELY(expression) (expression)
#define OPAL_UNLIKELY(expression) (expression)
#endif

#if OPAL_C_HAVE_BUILTIN_PREFETCH
#define OPAL_PREFETCH(address,rw,locality) __builtin_prefetch(address,rw,locality)
#else
#define OPAL_PREFETCH(address,rw,locality)
#endif

#endif

#endif