Mercurial > ecos

comparison packages/kernel/current/tests/kphilo.c @ 0:3111d98ba7b3 ecos-v1_1-release

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
Initial commit of eCos version 1.1
author jlarmour
date Tue, 11 May 1999 11:16:07 +0000
parents
children 443894e2e912
comparison
equal deleted inserted replaced
-1:000000000000 0:3111d98ba7b3
1 //==========================================================================
2 //
3 // kphilo.c
4 //
5 // A test of the dining philosophers problem
6 //
7 //==========================================================================
8 //####COPYRIGHTBEGIN####
9 //
10 // -------------------------------------------
11 // The contents of this file are subject to the Cygnus eCos Public License
12 // Version 1.0 (the "License"); you may not use this file except in
13 // compliance with the License. You may obtain a copy of the License at
14 // http://sourceware.cygnus.com/ecos
15 //
16 // Software distributed under the License is distributed on an "AS IS"
17 // basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See the
18 // License for the specific language governing rights and limitations under
19 // the License.
20 //
21 // The Original Code is eCos - Embedded Cygnus Operating System, released
22 // September 30, 1998.
23 //
24 // The Initial Developer of the Original Code is Cygnus. Portions created
25 // by Cygnus are Copyright (C) 1998 Cygnus Solutions. All Rights Reserved.
26 // -------------------------------------------
27 //
28 //####COPYRIGHTEND####
29 //==========================================================================
30 //#####DESCRIPTIONBEGIN####
31 //
32 // Author(s): dsm
33 // Contributors: dsm
34 // Date: 1998-02-24
35 // Description: A test of the dining philosophers problem
36 //####DESCRIPTIONEND####
37 //
38
39 #include <cyg/kernel/kapi.h>
40
41 #include <cyg/infra/cyg_ass.h>
42 #include <cyg/kernel/diag.h>
43
44 // -------------------------------------------------------------------------
45 // Data for the philosophers problem
46
47 #define PHILOSOPHERS 15 // number of philosophers
48 #define STACKSIZE (2*1024) // size of thread stack
49
50 // array of stacks for philosopher threads
51 char thread_stack[PHILOSOPHERS][STACKSIZE];
52
53 // array of threads.
54 cyg_thread thread[PHILOSOPHERS];
55
56 cyg_handle_t thread_handle[PHILOSOPHERS];
57
58 // array of chopsticks
59 cyg_sem_t chopstick[PHILOSOPHERS];
60
61 cyg_ucount32 data_index;
62
63 // -------------------------------------------------------------------------
64 // State recording and display
65
66 static char pstate[PHILOSOPHERS+1]; // state vector showing what each
67 // philosopher is doing
68
69 cyg_mutex_t state_mutex;
70
71 #ifdef CYG_HAL_MN10300_MN103002
72 static cyg_count8 eaters = 0;
73 #endif
74
75 void change_state(int id, char newstate)
76 {
77 cyg_mutex_lock(&state_mutex);
78
79 #ifdef CYG_HAL_MN10300_MN103002
80 if( pstate[id] == 'E' ) eaters--;
81 if( newstate == 'E' ) eaters++;
82 // led(eaters);
83 #endif
84
85 pstate[id] = newstate;
86
87 diag_write_string(pstate);
88 #if 0
89 diag_write_char(' ');
90 diag_write_dec(Cyg_Scheduler::get_thread_switches());
91 #endif
92 diag_write_char('\n');
93
94 cyg_mutex_unlock(&state_mutex);
95
96 }
97
98 char get_state( int id)
99 {
100 char s;
101 cyg_mutex_lock(&state_mutex);
102
103 s = pstate[id];
104
105 cyg_mutex_unlock(&state_mutex);
106
107 return s;
108 }
109
110 // -------------------------------------------------------------------------
111 // Thread to behave like a philosopher
112
113 void Philosopher( cyg_addrword_t vid )
114 {
115 cyg_uint32 id = (cyg_uint32)vid;
116 cyg_sem_t *first_stick = &chopstick[id];
117 cyg_sem_t *second_stick = &chopstick[(id+1)%PHILOSOPHERS];
118 #ifdef CYGPKG_INFRA_DEBUG
119 int left_philo = ((id==0)?PHILOSOPHERS:id)-1;
120 int right_philo = (id==PHILOSOPHERS-1)?0:(id+1);
121 #endif
122
123 CYG_ASSERT( id >= 0 && id < PHILOSOPHERS, "Bad id");
124
125 // Deadlock avoidance. The easiest way to make the philosophers
126 // behave is to make each pick up the lowest numbered stick
127 // first. This is how it works out anyway for all the philosophers
128 // except the last, who must have his sticks swapped.
129
130 if( id == PHILOSOPHERS-1 )
131 {
132 cyg_sem_t *t = first_stick;
133 first_stick = second_stick;
134 second_stick = t;
135 }
136
137 for(;;)
138 {
139 cyg_ucount32 val;
140
141 // The following variable is shared by all philosophers.
142 // It is incremented unprotected, but this does not matter
143 // since it is only present to introduce a little variability
144 // into the think and eat times.
145
146 static volatile int cycle = 0;
147
148 // Think for a bit
149
150 cyg_thread_delay((id+cycle++)%12); // Cogito ergo sum...
151
152 // I am now hungry, try to get the chopsticks
153
154 change_state(id,'H');
155
156 // Get the first stick
157 cyg_semaphore_wait(first_stick);
158
159 // Get the second stick
160 cyg_semaphore_wait(second_stick);
161
162 // Got them, now eat
163
164 change_state(id,'E');
165
166 // Check that the world is as I think it is...
167 cyg_semaphore_peek( first_stick, &val);
168 CYG_ASSERT( val == 0, "Not got first stick");
169 cyg_semaphore_peek( second_stick, &val);
170 CYG_ASSERT( val == 0, "Not got second stick");
171 CYG_ASSERT( get_state(left_philo) != 'E', "Left neighbour also eating!!");
172 CYG_ASSERT( get_state(right_philo) != 'E', "Right neighbour also eating!!");
173
174 cyg_thread_delay((id+cycle++)%6); // munch munch
175
176 // Finished eating, put down sticks.
177
178 change_state(id,'T');
179
180 cyg_semaphore_post( first_stick );
181 cyg_semaphore_post( second_stick );
182
183 }
184 }
185
186 // -------------------------------------------------------------------------
187
188 externC void
189 cyg_start( void )
190 {
191 int i;
192
193 diag_init();
194
195 diag_write_string("Philosophers\n");
196 diag_write_string("Started\n");
197
198 // Zero last element in state so it acts like
199 // a string.
200 pstate[PHILOSOPHERS] = 0;
201
202 #if 1
203 for( i = 0; i < PHILOSOPHERS; i++ )
204 {
205 change_state(i,'T'); // starting state
206
207 cyg_thread_create(4, Philosopher, (cyg_addrword_t)i, "philosopher",
208 (void *)(&thread_stack[i]), STACKSIZE,
209 &thread_handle[i], &thread[i]);
210
211 // resume it
212 cyg_thread_resume(thread_handle[i]);
213
214 // and make the matching chopstick present
215 cyg_semaphore_init( &chopstick[i], 1);
216 }
217 #endif
218
219 // Get the world going
220 cyg_scheduler_start();
221
222 }
223
224 // -------------------------------------------------------------------------
225 // EOF kphilo.c