Subversion Repositories HelenOS

Rev

Rev 2787 | Details | Compare with Previous | Last modification | View Log | RSS feed

Rev Author Line No. Line
2128 jermar 1 
/*
2465 jermar 2 
 * Copyright (c) 2007 Michal Kebrt
2128 jermar 3 
 * All rights reserved.
4 
 *
5 
 * Redistribution and use in source and binary forms, with or without
6 
 * modification, are permitted provided that the following conditions
7 
 * are met:
8 
 *
9 
 * - Redistributions of source code must retain the above copyright
10 
 *   notice, this list of conditions and the following disclaimer.
11 
 * - Redistributions in binary form must reproduce the above copyright
12 
 *   notice, this list of conditions and the following disclaimer in the
13 
 *   documentation and/or other materials provided with the distribution.
14 
 * - The name of the author may not be used to endorse or promote products
15 
 *   derived from this software without specific prior written permission.
16 
 *
17 
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 
 */
28 
 
4377 svoboda 29 
/** @addtogroup arm32
2128 jermar 30 
 * @{
31 
 */
4377 svoboda 32 
/** @file
2465 jermar 33 
 *  @brief Atomic operations.
2128 jermar 34 
 */
35 
 
36 
#ifndef KERN_arm32_ATOMIC_H_
37 
#define KERN_arm32_ATOMIC_H_
38 
 
2465 jermar 39 
/** Atomic addition.
40 
 *
41 
 * @param val Where to add.
42 
 * @param i   Value to be added.
43 
 *
44 
 * @return Value after addition.
4377 svoboda 45 
 *
2465 jermar 46 
 */
47 
static inline long atomic_add(atomic_t *val, int i)
48 
{
49 
    int ret;
50 
    volatile long *mem = &(val->count);
4377 svoboda 51 
 
2465 jermar 52 
    asm volatile (
4377 svoboda 53 
        "1:\n"
54 
            "ldr r2, [%[mem]]\n"
55 
            "add r3, r2, %[i]\n"
56 
            "str r3, %[ret]\n"
57 
            "swp r3, r3, [%[mem]]\n"
58 
            "cmp r3, r2\n"
59 
            "bne 1b\n"
60 
        : [ret] "=m" (ret)
61 
        : [mem] "r" (mem), [i] "r" (i)
2465 jermar 62 
        : "r3", "r2"
63 
    );
4377 svoboda 64 
 
2465 jermar 65 
    return ret;
66 
}
67 
 
68 
/** Atomic increment.
2128 jermar 69 
 *
2465 jermar 70 
 * @param val Variable to be incremented.
71 
 */
72 
static inline void atomic_inc(atomic_t *val)
73 
{
74 
    atomic_add(val, 1);
75 
}
76 
 
77 
/** Atomic decrement.
2128 jermar 78 
 *
2465 jermar 79 
 * @param val Variable to be decremented.
2128 jermar 80 
 */
2465 jermar 81 
static inline void atomic_dec(atomic_t *val) {
82 
    atomic_add(val, -1);
83 
}
84 
 
85 
/** Atomic pre-increment.
86 
 *
87 
 * @param val Variable to be incremented.
88 
 * @return    Value after incrementation.
89 
 */
90 
static inline long atomic_preinc(atomic_t *val)
2128 jermar 91 
{
2465 jermar 92 
    return atomic_add(val, 1);
2128 jermar 93 
}
94 
 
2465 jermar 95 
/** Atomic pre-decrement.
96 
 *
97 
 * @param val Variable to be decremented.
98 
 * @return    Value after decrementation.
99 
 */
100 
static inline long atomic_predec(atomic_t *val)
101 
{
102 
    return atomic_add(val, -1);
103 
}
104 
 
105 
/** Atomic post-increment.
106 
 *
107 
 * @param val Variable to be incremented.
108 
 * @return    Value before incrementation.
109 
 */
110 
static inline long atomic_postinc(atomic_t *val)
111 
{
112 
    return atomic_add(val, 1) - 1;
113 
}
114 
 
115 
/** Atomic post-decrement.
116 
 *
117 
 * @param val Variable to be decremented.
118 
 * @return    Value before decrementation.
119 
 */
120 
static inline long atomic_postdec(atomic_t *val)
121 
{
122 
    return atomic_add(val, -1) + 1;
123 
}
124 
 
2128 jermar 125 
#endif
126 
 
127 
/** @}
128 
 */