compiler_opt.h

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/*
 * $Id$
 * 
 * Copyright (C) 2007 iptelorg GmbH
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

/* 
 * History:
 * --------
 *  2007-05-14  created by andrei
 */

#ifndef __compiler_opt_h
#define __compiler_opt_h

/* likely/unlikely */
#if __GNUC__ >= 3

#define likely(expr)              __builtin_expect(!!(expr), 1)
#define unlikely(expr)            __builtin_expect(!!(expr), 0)

#else /* __GNUC__ */

/* #warning "No compiler optimizations supported try gcc 4.x" */
#define likely(expr) (expr)
#define unlikely(expr) (expr)

#endif /* __GNUC__ */



/* prefetch* */
#if ( __GNUC__ > 3 ) || ( __GNUC__ == 3 && __GNUC_MINOR__ >= 1 )

#define prefetch(addr)            __builtin_prefetch((addr))
#define prefetch_w(addr)          __builtin_prefetch((addr), 1)
#define prefetch_loc_r(addr, loc) __builtin_prefetch((addr), 0, (loc))
#define prefetch_loc_w(addr, loc) __builtin_prefetch((addr), 1, (loc))

#else

#define prefetch(addr)
#define prefetch_w(addr)
#define prefetch_loc_r(addr, loc)
#define prefetch_loc_w(addr, loc)

#endif /* __GNUC__ > 3  || ( __GNUC__ == 3 && __GNUC_MINOR__ >= 1 ) */

#endif