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atomic.h revision 1.1.2.4 
      1 /*	$NetBSD: atomic.h,v 1.1.2.4 2013/07/24 02:02:17 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 	union {
     39 		int au_int;
     40 		unsigned int au_uint;
     41 	} a_u;
     42 } atomic_t;
     43 
     44 static inline int
     45 atomic_read(atomic_t *atomic)
     46 {
     47 	return *(volatile int *)&atomic->a_u.au_int;
     48 }
     49 
     50 static inline void
     51 atomic_set(atomic_t *atomic, int value)
     52 {
     53 	atomic->a_u.au_int = value;
     54 }
     55 
     56 static inline void
     57 atomic_inc(atomic_t *atomic)
     58 {
     59 	atomic_inc_uint(&atomic->a_u.au_uint);
     60 }
     61 
     62 static inline void
     63 atomic_dec(atomic_t *atomic)
     64 {
     65 	atomic_dec_uint(&atomic->a_u.au_uint);
     66 }
     67 
     68 static inline int
     69 atomic_dec_and_test(atomic_t *atomic)
     70 {
     71 	return (-1 == (int)atomic_dec_uint_nv(&atomic->a_u.au_uint));
     72 }
     73 
     74 #endif  /* _LINUX_ATOMIC_H_ */
     75