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2128 | jermar | 1 | /* |
2465 | jermar | 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 | |||
29 | /** @addtogroup libcarm32 |
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30 | * @{ |
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31 | */ |
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32 | /** @file |
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2465 | jermar | 33 | * @brief Atomic operations. |
2128 | jermar | 34 | */ |
35 | |||
36 | #ifndef LIBC_arm32_ATOMIC_H_ |
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37 | #define LIBC_arm32_ATOMIC_H_ |
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38 | |||
39 | /** Atomic addition. |
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40 | * |
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2465 | jermar | 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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2465 | jermar | 46 | static inline long atomic_add(atomic_t *val, int i) |
2128 | jermar | 47 | { |
2465 | jermar | 48 | int ret; |
49 | volatile long * mem = &(val->count); |
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50 | |||
51 | asm volatile ( |
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52 | "1: \n" |
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53 | "ldr r2, [%1] \n" |
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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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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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2128 | jermar | 66 | } |
67 | |||
2465 | jermar | 68 | |
69 | /** Atomic increment. |
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70 | * |
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71 | * @param val Variable to be incremented. |
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72 | */ |
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2128 | jermar | 73 | static inline void atomic_inc(atomic_t *val) { atomic_add(val, 1); } |
2465 | jermar | 74 | |
75 | |||
76 | /** Atomic decrement. |
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77 | * |
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78 | * @param val Variable to be decremented. |
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79 | */ |
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2128 | jermar | 80 | static inline void atomic_dec(atomic_t *val) { atomic_add(val, -1); } |
81 | |||
82 | |||
2465 | jermar | 83 | /** Atomic pre-increment. |
84 | * |
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85 | * @param val Variable to be incremented. |
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86 | * @return Value after incrementation. |
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87 | */ |
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88 | static inline long atomic_preinc(atomic_t *val) { return atomic_add(val, 1); } |
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2128 | jermar | 89 | |
2465 | jermar | 90 | |
91 | /** Atomic pre-decrement. |
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92 | * |
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93 | * @param val Variable to be decremented. |
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94 | * @return Value after decrementation. |
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95 | */ |
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96 | static inline long atomic_predec(atomic_t *val) { return atomic_add(val, -1); } |
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97 | |||
98 | |||
99 | /** Atomic post-increment. |
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100 | * |
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101 | * @param val Variable to be incremented. |
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102 | * @return Value before incrementation. |
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103 | */ |
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104 | static inline long atomic_postinc(atomic_t *val) { return atomic_add(val, 1) - 1; } |
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105 | |||
106 | |||
107 | /** Atomic post-decrement. |
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108 | * |
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109 | * @param val Variable to be decremented. |
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110 | * @return Value before decrementation. |
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111 | */ |
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112 | static inline long atomic_postdec(atomic_t *val) { return atomic_add(val, -1) + 1; } |
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113 | |||
114 | |||
2128 | jermar | 115 | #endif |
116 | |||
117 | /** @} |
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118 | */ |