root / prex-0.9.0 / usr / sample / sem / sem.c @ 03e9c04a
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1 | 03e9c04a | Brad Neuman | /*
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2 | * Copyright (c) 2005, Kohsuke Ohtani
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3 | * All rights reserved.
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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 | * 1. Redistributions of source code must retain the above copyright
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9 | * notice, this list of conditions and the following disclaimer.
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10 | * 2. Redistributions in binary form must reproduce the above copyright
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11 | * notice, this list of conditions and the following disclaimer in the
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12 | * documentation and/or other materials provided with the distribution.
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13 | * 3. Neither the name of the author nor the names of any co-contributors
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14 | * may be used to endorse or promote products derived from this software
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15 | * without specific prior written permission.
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16 | *
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17 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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18 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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19 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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20 | * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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21 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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22 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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23 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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24 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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25 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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26 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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27 | * SUCH DAMAGE.
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28 | */
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29 | |||
30 | /*
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31 | * sem.c - sample program for semaphore.
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32 | */
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33 | |||
34 | #include <sys/prex.h> |
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35 | #include <stdio.h> |
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36 | |||
37 | static sem_t sem;
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38 | |||
39 | void
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40 | thread_run(void (*start)(void), void *stack) |
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41 | { |
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42 | thread_t t; |
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43 | |||
44 | if (thread_create(task_self(), &t) != 0) |
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45 | panic("thread_create is failed");
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46 | |||
47 | if (thread_load(t, start, stack) != 0) |
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48 | panic("thread_load is failed");
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49 | |||
50 | if (thread_resume(t) != 0) |
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51 | panic("thread_resume failed");
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52 | |||
53 | return;
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54 | } |
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55 | |||
56 | /*
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57 | * The main routine create 10 copy of this thread. But, since the
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58 | * initial semaphore value is 3, only 3 threads can run at same time.
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59 | */
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60 | static void |
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61 | new_thread(void)
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62 | { |
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63 | thread_t t; |
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64 | |||
65 | t = thread_self(); |
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66 | printf("Start thread=%x\n", (u_int)t);
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67 | thread_yield(); |
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68 | |||
69 | /*
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70 | * Acquire semaphore
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71 | */
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72 | sem_wait(&sem, 0);
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73 | |||
74 | /*
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75 | * Sleep 2000 ms
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76 | */
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77 | printf("Running thread=%x\n", (u_int)t);
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78 | timer_sleep(2000, 0); |
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79 | |||
80 | /*
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81 | * Release semaphore
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82 | */
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83 | sem_post(&sem); |
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84 | |||
85 | printf("End thread=%x\n", (u_int)t);
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86 | thread_terminate(t); |
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87 | } |
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88 | |||
89 | int
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90 | main(int argc, char *argv[]) |
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91 | { |
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92 | static char stack[10][1024]; |
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93 | int i;
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94 | |||
95 | printf("Semaphore sample program\n");
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96 | |||
97 | /*
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98 | * Initialize semaphore with initial count 3
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99 | */
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100 | sem_init(&sem, 3);
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101 | |||
102 | /*
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103 | * Boost the priority of this thread
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104 | */
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105 | thread_setpri(thread_self(), 100);
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106 | |||
107 | /*
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108 | * Create 10 threads
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109 | */
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110 | for (i = 0; i < 10; i++) |
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111 | thread_run(new_thread, stack[i]+1024);
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112 | |||
113 | /*
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114 | * Wait...
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115 | */
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116 | thread_suspend(thread_self()); |
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117 | |||
118 | return 0; |
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119 | } |