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annotate packages/kernel/current/tests/kphilo.c @ 208:e0c0827131d1 ecos
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| author | jlarmour |
|---|---|
| date | Mon, 20 May 2002 22:19:26 +0000 |
| parents | bf00f99aec69 |
| children | d2c90368aeef |
| rev | line source |
|---|---|
| 0 | 1 //========================================================================== |
| 2 // | |
| 3 // kphilo.c | |
| 4 // | |
| 5 // A test of the dining philosophers problem | |
| 6 // | |
| 7 //========================================================================== | |
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8 //####ECOSGPLCOPYRIGHTBEGIN#### |
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9 // ------------------------------------------- |
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10 // This file is part of eCos, the Embedded Configurable Operating System. |
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11 // Copyright (C) 1998, 1999, 2000, 2001, 2002 Red Hat, Inc. |
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12 // |
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13 // eCos is free software; you can redistribute it and/or modify it under |
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14 // the terms of the GNU General Public License as published by the Free |
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15 // Software Foundation; either version 2 or (at your option) any later version. |
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16 // |
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17 // eCos is distributed in the hope that it will be useful, but WITHOUT ANY |
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18 // WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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19 // FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
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20 // for more details. |
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21 // |
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22 // You should have received a copy of the GNU General Public License along |
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23 // with eCos; if not, write to the Free Software Foundation, Inc., |
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24 // 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA. |
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25 // |
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26 // As a special exception, if other files instantiate templates or use macros |
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27 // or inline functions from this file, or you compile this file and link it |
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28 // with other works to produce a work based on this file, this file does not |
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29 // by itself cause the resulting work to be covered by the GNU General Public |
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30 // License. However the source code for this file must still be made available |
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31 // in accordance with section (3) of the GNU General Public License. |
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32 // |
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33 // This exception does not invalidate any other reasons why a work based on |
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34 // this file might be covered by the GNU General Public License. |
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35 // |
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36 // Alternative licenses for eCos may be arranged by contacting Red Hat, Inc. |
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37 // at http://sources.redhat.com/ecos/ecos-license |
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38 // ------------------------------------------- |
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39 //####ECOSGPLCOPYRIGHTEND#### |
| 0 | 40 //========================================================================== |
| 41 //#####DESCRIPTIONBEGIN#### | |
| 42 // | |
| 43 // Author(s): dsm | |
| 44 // Contributors: dsm | |
| 45 // Date: 1998-02-24 | |
| 46 // Description: A test of the dining philosophers problem | |
| 47 //####DESCRIPTIONEND#### | |
| 48 // | |
| 49 | |
| 50 #include <cyg/kernel/kapi.h> | |
| 51 | |
| 52 #include <cyg/infra/cyg_ass.h> | |
| 53 #include <cyg/kernel/diag.h> | |
| 54 | |
| 55 // ------------------------------------------------------------------------- | |
| 56 // Data for the philosophers problem | |
| 57 | |
| 58 #define PHILOSOPHERS 15 // number of philosophers | |
| 59 #define STACKSIZE (2*1024) // size of thread stack | |
| 60 | |
| 61 // array of stacks for philosopher threads | |
| 62 char thread_stack[PHILOSOPHERS][STACKSIZE]; | |
| 63 | |
| 64 // array of threads. | |
| 65 cyg_thread thread[PHILOSOPHERS]; | |
| 66 | |
| 67 cyg_handle_t thread_handle[PHILOSOPHERS]; | |
| 68 | |
| 69 // array of chopsticks | |
| 70 cyg_sem_t chopstick[PHILOSOPHERS]; | |
| 71 | |
| 72 cyg_ucount32 data_index; | |
| 73 | |
| 74 // ------------------------------------------------------------------------- | |
| 75 // State recording and display | |
| 76 | |
| 77 static char pstate[PHILOSOPHERS+1]; // state vector showing what each | |
| 78 // philosopher is doing | |
| 79 | |
| 80 cyg_mutex_t state_mutex; | |
| 81 | |
| 82 #ifdef CYG_HAL_MN10300_MN103002 | |
| 83 static cyg_count8 eaters = 0; | |
| 84 #endif | |
| 85 | |
| 86 void change_state(int id, char newstate) | |
| 87 { | |
| 88 cyg_mutex_lock(&state_mutex); | |
| 89 | |
| 90 #ifdef CYG_HAL_MN10300_MN103002 | |
| 91 if( pstate[id] == 'E' ) eaters--; | |
| 92 if( newstate == 'E' ) eaters++; | |
| 93 // led(eaters); | |
| 94 #endif | |
| 95 | |
| 96 pstate[id] = newstate; | |
| 97 | |
| 98 diag_write_string(pstate); | |
| 99 #if 0 | |
| 100 diag_write_char(' '); | |
| 101 diag_write_dec(Cyg_Scheduler::get_thread_switches()); | |
| 102 #endif | |
| 103 diag_write_char('\n'); | |
| 104 | |
| 105 cyg_mutex_unlock(&state_mutex); | |
| 106 | |
| 107 } | |
| 108 | |
| 109 char get_state( int id) | |
| 110 { | |
| 111 char s; | |
| 112 cyg_mutex_lock(&state_mutex); | |
| 113 | |
| 114 s = pstate[id]; | |
| 115 | |
| 116 cyg_mutex_unlock(&state_mutex); | |
| 117 | |
| 118 return s; | |
| 119 } | |
| 120 | |
| 121 // ------------------------------------------------------------------------- | |
| 122 // Thread to behave like a philosopher | |
| 123 | |
| 124 void Philosopher( cyg_addrword_t vid ) | |
| 125 { | |
| 126 cyg_uint32 id = (cyg_uint32)vid; | |
| 127 cyg_sem_t *first_stick = &chopstick[id]; | |
| 128 cyg_sem_t *second_stick = &chopstick[(id+1)%PHILOSOPHERS]; | |
| 129 #ifdef CYGPKG_INFRA_DEBUG | |
| 130 int left_philo = ((id==0)?PHILOSOPHERS:id)-1; | |
| 131 int right_philo = (id==PHILOSOPHERS-1)?0:(id+1); | |
| 132 #endif | |
| 133 | |
| 134 CYG_ASSERT( id >= 0 && id < PHILOSOPHERS, "Bad id"); | |
| 135 | |
| 136 // Deadlock avoidance. The easiest way to make the philosophers | |
| 137 // behave is to make each pick up the lowest numbered stick | |
| 138 // first. This is how it works out anyway for all the philosophers | |
| 139 // except the last, who must have his sticks swapped. | |
| 140 | |
| 141 if( id == PHILOSOPHERS-1 ) | |
| 142 { | |
| 143 cyg_sem_t *t = first_stick; | |
| 144 first_stick = second_stick; | |
| 145 second_stick = t; | |
| 146 } | |
| 147 | |
| 148 for(;;) | |
| 149 { | |
| 150 cyg_ucount32 val; | |
| 151 | |
| 152 // The following variable is shared by all philosophers. | |
| 153 // It is incremented unprotected, but this does not matter | |
| 154 // since it is only present to introduce a little variability | |
| 155 // into the think and eat times. | |
| 156 | |
| 157 static volatile int cycle = 0; | |
| 158 | |
| 159 // Think for a bit | |
| 160 | |
| 161 cyg_thread_delay((id+cycle++)%12); // Cogito ergo sum... | |
| 162 | |
| 163 // I am now hungry, try to get the chopsticks | |
| 164 | |
| 165 change_state(id,'H'); | |
| 166 | |
| 167 // Get the first stick | |
| 168 cyg_semaphore_wait(first_stick); | |
| 169 | |
| 170 // Get the second stick | |
| 171 cyg_semaphore_wait(second_stick); | |
| 172 | |
| 173 // Got them, now eat | |
| 174 | |
| 175 change_state(id,'E'); | |
| 176 | |
| 177 // Check that the world is as I think it is... | |
| 178 cyg_semaphore_peek( first_stick, &val); | |
| 179 CYG_ASSERT( val == 0, "Not got first stick"); | |
| 180 cyg_semaphore_peek( second_stick, &val); | |
| 181 CYG_ASSERT( val == 0, "Not got second stick"); | |
| 182 CYG_ASSERT( get_state(left_philo) != 'E', "Left neighbour also eating!!"); | |
| 183 CYG_ASSERT( get_state(right_philo) != 'E', "Right neighbour also eating!!"); | |
| 184 | |
| 185 cyg_thread_delay((id+cycle++)%6); // munch munch | |
| 186 | |
| 187 // Finished eating, put down sticks. | |
| 188 | |
| 189 change_state(id,'T'); | |
| 190 | |
| 191 cyg_semaphore_post( first_stick ); | |
| 192 cyg_semaphore_post( second_stick ); | |
| 193 | |
| 194 } | |
| 195 } | |
| 196 | |
| 197 // ------------------------------------------------------------------------- | |
| 198 | |
| 199 externC void | |
| 200 cyg_start( void ) | |
| 201 { | |
| 202 int i; | |
| 203 | |
| 204 diag_init(); | |
| 205 | |
| 206 diag_write_string("Philosophers\n"); | |
| 207 diag_write_string("Started\n"); | |
| 208 | |
| 209 // Zero last element in state so it acts like | |
| 210 // a string. | |
| 211 pstate[PHILOSOPHERS] = 0; | |
| 212 | |
| 213 #if 1 | |
| 214 for( i = 0; i < PHILOSOPHERS; i++ ) | |
| 215 { | |
| 216 change_state(i,'T'); // starting state | |
| 217 | |
| 218 cyg_thread_create(4, Philosopher, (cyg_addrword_t)i, "philosopher", | |
| 219 (void *)(&thread_stack[i]), STACKSIZE, | |
| 220 &thread_handle[i], &thread[i]); | |
| 221 | |
| 222 // resume it | |
| 223 cyg_thread_resume(thread_handle[i]); | |
| 224 | |
| 225 // and make the matching chopstick present | |
| 226 cyg_semaphore_init( &chopstick[i], 1); | |
| 227 } | |
| 228 #endif | |
| 229 | |
| 230 // Get the world going | |
| 231 cyg_scheduler_start(); | |
| 232 | |
| 233 } | |
| 234 | |
| 235 // ------------------------------------------------------------------------- | |
| 236 // EOF kphilo.c |