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atomic.h revision 1.1.2.3 
      1 /*	$NetBSD: atomic.h,v 1.1.2.3 2013/07/24 01:55:58 riastradh Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2013 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Taylor R. Campbell.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     29  * POSSIBILITY OF SUCH DAMAGE.
     30  */
     31 
     32 #ifndef _LINUX_ATOMIC_H_
     33 #define _LINUX_ATOMIC_H_
     34 
     35 #include <sys/atomic.h>
     36 
     37 typedef struct {
     38 	int atomic_value;
     39 } atomic_t;
     40 
     41 static inline int
     42 atomic_read(atomic_t *atomic)
     43 {
     44 	return *(volatile int *)&atomic->atomic_value;
     45 }
     46 
     47 static inline void
     48 atomic_set(atomic_t *atomic, int value)
     49 {
     50 	atomic->atomic_value = value;
     51 }
     52 
     53 static inline void
     54 atomic_inc(atomic_t *atomic)
     55 {
     56 	atomic_inc_uint((unsigned int *)&atomic->atomic_value);
     57 }
     58 
     59 static inline int
     60 atomic_dec_and_test(atomic_t *atomic)
     61 {
     62 	return (-1 == (int)atomic_dec_uint_nv(&atomic->atomic_value));
     63 }
     64 
     65 #endif  /* _LINUX_ATOMIC_H_ */
     66