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2128 | jermar | 1 | /* |
2174 | kebrt | 2 | * Copyright (c) 2007 Michal Kebrt |
2128 | jermar | 3 | * All rights reserved. |
4 | * |
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5 | * Redistribution and use in source and binary forms, with or without |
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6 | * modification, are permitted provided that the following conditions |
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7 | * are met: |
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8 | * |
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9 | * - Redistributions of source code must retain the above copyright |
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10 | * notice, this list of conditions and the following disclaimer. |
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11 | * - Redistributions in binary form must reproduce the above copyright |
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12 | * notice, this list of conditions and the following disclaimer in the |
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13 | * documentation and/or other materials provided with the distribution. |
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14 | * - The name of the author may not be used to endorse or promote products |
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15 | * derived from this software without specific prior written permission. |
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16 | * |
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17 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
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18 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
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19 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
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20 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
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21 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
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22 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
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23 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
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24 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
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25 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
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26 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
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27 | */ |
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28 | |||
2341 | kebrt | 29 | /** @addtogroup arm32 |
2128 | jermar | 30 | * @{ |
31 | */ |
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2356 | kebrt | 32 | /** @file |
33 | * @brief Atomic operations. |
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2128 | jermar | 34 | */ |
35 | |||
36 | #ifndef KERN_arm32_ATOMIC_H_ |
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37 | #define KERN_arm32_ATOMIC_H_ |
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38 | |||
2313 | kebrt | 39 | /** Atomic addition. |
2128 | jermar | 40 | * |
2356 | kebrt | 41 | * @param val Where to add. |
42 | * @param i Value to be added. |
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2128 | jermar | 43 | * |
44 | * @return Value after addition. |
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45 | */ |
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46 | static inline long atomic_add(atomic_t *val, int i) |
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47 | { |
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2174 | kebrt | 48 | int ret; |
2464 | jermar | 49 | volatile long *mem = &(val->count); |
2174 | kebrt | 50 | |
51 | asm volatile ( |
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2464 | jermar | 52 | "1:\n" |
2195 | kebrt | 53 | "ldr r2, [%1] \n" |
54 | "add r3, r2, %2 \n" |
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55 | "str r3, %0 \n" |
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56 | "swp r3, r3, [%1] \n" |
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57 | "cmp r3, r2 \n" |
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58 | "bne 1b \n" |
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2174 | kebrt | 59 | |
60 | : "=m" (ret) |
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61 | : "r" (mem), "r" (i) |
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62 | : "r3", "r2" |
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63 | ); |
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64 | |||
65 | return ret; |
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2313 | kebrt | 66 | } |
2128 | jermar | 67 | |
2356 | kebrt | 68 | /** Atomic increment. |
69 | * |
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70 | * @param val Variable to be incremented. |
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71 | */ |
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2464 | jermar | 72 | static inline void atomic_inc(atomic_t *val) |
73 | { |
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74 | atomic_add(val, 1); |
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75 | } |
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2356 | kebrt | 76 | |
77 | /** Atomic decrement. |
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78 | * |
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79 | * @param val Variable to be decremented. |
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80 | */ |
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2464 | jermar | 81 | static inline void atomic_dec(atomic_t *val) { |
82 | atomic_add(val, -1); |
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83 | } |
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2313 | kebrt | 84 | |
2356 | kebrt | 85 | /** Atomic pre-increment. |
86 | * |
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87 | * @param val Variable to be incremented. |
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88 | * @return Value after incrementation. |
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89 | */ |
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2464 | jermar | 90 | static inline long atomic_preinc(atomic_t *val) |
91 | { |
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92 | return atomic_add(val, 1); |
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93 | } |
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2356 | kebrt | 94 | |
95 | /** Atomic pre-decrement. |
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96 | * |
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97 | * @param val Variable to be decremented. |
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98 | * @return Value after decrementation. |
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99 | */ |
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2464 | jermar | 100 | static inline long atomic_predec(atomic_t *val) |
101 | { |
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102 | return atomic_add(val, -1); |
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103 | } |
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2313 | kebrt | 104 | |
2356 | kebrt | 105 | /** Atomic post-increment. |
106 | * |
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107 | * @param val Variable to be incremented. |
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108 | * @return Value before incrementation. |
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109 | */ |
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2464 | jermar | 110 | static inline long atomic_postinc(atomic_t *val) |
111 | { |
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112 | return atomic_add(val, 1) - 1; |
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113 | } |
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2356 | kebrt | 114 | |
115 | /** Atomic post-decrement. |
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116 | * |
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117 | * @param val Variable to be decremented. |
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118 | * @return Value before decrementation. |
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119 | */ |
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2464 | jermar | 120 | static inline long atomic_postdec(atomic_t *val) |
121 | { |
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122 | return atomic_add(val, -1) + 1; |
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123 | } |
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2313 | kebrt | 124 | |
2128 | jermar | 125 | #endif |
126 | |||
127 | /** @} |
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128 | */ |