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atomic.h revision 1.1.2.6 
      1 /*	$NetBSD: atomic.h,v 1.1.2.6 2013/07/24 02:27:38 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 struct atomic {
     38 	union {
     39 		int au_int;
     40 		unsigned int au_uint;
     41 	} a_u;
     42 };
     43 
     44 typedef struct atomic atomic_t;
     45 
     46 static inline int
     47 atomic_read(atomic_t *atomic)
     48 {
     49 	return *(volatile int *)&atomic->a_u.au_int;
     50 }
     51 
     52 static inline void
     53 atomic_set(atomic_t *atomic, int value)
     54 {
     55 	atomic->a_u.au_int = value;
     56 }
     57 
     58 static inline void
     59 atomic_inc(atomic_t *atomic)
     60 {
     61 	atomic_inc_uint(&atomic->a_u.au_uint);
     62 }
     63 
     64 static inline void
     65 atomic_dec(atomic_t *atomic)
     66 {
     67 	atomic_dec_uint(&atomic->a_u.au_uint);
     68 }
     69 
     70 static inline int
     71 atomic_dec_and_test(atomic_t *atomic)
     72 {
     73 	return (-1 == (int)atomic_dec_uint_nv(&atomic->a_u.au_uint));
     74 }
     75 
     76 static inline void
     77 set_bit(unsigned long bit, volatile unsigned long *ptr)
     78 {
     79 	atomic_or_ulong(ptr, (1 << bit));
     80 }
     81 
     82 static inline void
     83 clear_bit(unsigned long bit, volatile unsigned long *ptr)
     84 {
     85 	atomic_and_ulong(ptr, ~(1 << bit));
     86 }
     87 
     88 static inline void
     89 change_bit(unsigned long bit, volatile unsigned long *ptr)
     90 {
     91 	unsigned long v;
     92 
     93 	do v = *ptr; while (atomic_cas_ulong(ptr, v, v ^ (1 << bit)) != v);
     94 }
     95 
     96 static inline unsigned long
     97 test_and_set_bit(unsigned long bit, volatile unsigned long *ptr)
     98 {
     99 	unsigned long v;
    100 
    101 	do v = *ptr; while (atomic_cas_ulong(ptr, v, v | (1 << bit)) != v);
    102 
    103 	return (v & (1 << bit));
    104 }
    105 
    106 static inline unsigned long
    107 test_and_clear_bit(unsigned long bit, volatile unsigned long *ptr)
    108 {
    109 	unsigned long v;
    110 
    111 	do v = *ptr; while (atomic_cas_ulong(ptr, v, v &~ (1 << bit)) != v);
    112 
    113 	return (v & (1 << bit));
    114 }
    115 
    116 static inline unsigned long
    117 test_and_change_bit(unsigned long bit, volatile unsigned long *ptr)
    118 {
    119 	unsigned long v;
    120 
    121 	do v = *ptr; while (atomic_cas_ulong(ptr, v, v ^ (1 << bit)) != v);
    122 
    123 	return (v & (1 << bit));
    124 }
    125 
    126 #endif  /* _LINUX_ATOMIC_H_ */
    127