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[/] [openrisc/] [trunk/] [rtos/] [ecos-2.0/] [packages/] [kernel/] [v2_0/] [tests/] [kphilo.c] - Rev 608
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//========================================================================== // // kphilo.c // // A test of the dining philosophers problem // //========================================================================== //####ECOSGPLCOPYRIGHTBEGIN#### // ------------------------------------------- // This file is part of eCos, the Embedded Configurable Operating System. // Copyright (C) 1998, 1999, 2000, 2001, 2002 Red Hat, Inc. // // eCos is free software; you can redistribute it and/or modify it under // the terms of the GNU General Public License as published by the Free // Software Foundation; either version 2 or (at your option) any later version. // // eCos is distributed in the hope that it will be useful, but WITHOUT ANY // WARRANTY; without even the implied warranty of MERCHANTABILITY or // FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License // for more details. // // You should have received a copy of the GNU General Public License along // with eCos; if not, write to the Free Software Foundation, Inc., // 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA. // // As a special exception, if other files instantiate templates or use macros // or inline functions from this file, or you compile this file and link it // with other works to produce a work based on this file, this file does not // by itself cause the resulting work to be covered by the GNU General Public // License. However the source code for this file must still be made available // in accordance with section (3) of the GNU General Public License. // // This exception does not invalidate any other reasons why a work based on // this file might be covered by the GNU General Public License. // // Alternative licenses for eCos may be arranged by contacting Red Hat, Inc. // at http://sources.redhat.com/ecos/ecos-license/ // ------------------------------------------- //####ECOSGPLCOPYRIGHTEND#### //========================================================================== //#####DESCRIPTIONBEGIN#### // // Author(s): dsm // Contributors: dsm // Date: 1998-02-24 // Description: A test of the dining philosophers problem //####DESCRIPTIONEND#### // #include <cyg/kernel/kapi.h> #include <cyg/infra/cyg_ass.h> #include <cyg/kernel/diag.h> // ------------------------------------------------------------------------- // Data for the philosophers problem #define PHILOSOPHERS 15 // number of philosophers #define STACKSIZE (2*1024) // size of thread stack // array of stacks for philosopher threads char thread_stack[PHILOSOPHERS][STACKSIZE]; // array of threads. cyg_thread thread[PHILOSOPHERS]; cyg_handle_t thread_handle[PHILOSOPHERS]; // array of chopsticks cyg_sem_t chopstick[PHILOSOPHERS]; cyg_ucount32 data_index; // ------------------------------------------------------------------------- // State recording and display static char pstate[PHILOSOPHERS+1]; // state vector showing what each // philosopher is doing cyg_mutex_t state_mutex; #ifdef CYG_HAL_MN10300_MN103002 static cyg_count8 eaters = 0; #endif void change_state(int id, char newstate) { cyg_mutex_lock(&state_mutex); #ifdef CYG_HAL_MN10300_MN103002 if( pstate[id] == 'E' ) eaters--; if( newstate == 'E' ) eaters++; // led(eaters); #endif pstate[id] = newstate; diag_write_string(pstate); #if 0 diag_write_char(' '); diag_write_dec(Cyg_Scheduler::get_thread_switches()); #endif diag_write_char('\n'); cyg_mutex_unlock(&state_mutex); } char get_state( int id) { char s; cyg_mutex_lock(&state_mutex); s = pstate[id]; cyg_mutex_unlock(&state_mutex); return s; } // ------------------------------------------------------------------------- // Thread to behave like a philosopher void Philosopher( cyg_addrword_t vid ) { cyg_uint32 id = (cyg_uint32)vid; cyg_sem_t *first_stick = &chopstick[id]; cyg_sem_t *second_stick = &chopstick[(id+1)%PHILOSOPHERS]; #ifdef CYGPKG_INFRA_DEBUG int left_philo = ((id==0)?PHILOSOPHERS:id)-1; int right_philo = (id==PHILOSOPHERS-1)?0:(id+1); #endif CYG_ASSERT( id >= 0 && id < PHILOSOPHERS, "Bad id"); // Deadlock avoidance. The easiest way to make the philosophers // behave is to make each pick up the lowest numbered stick // first. This is how it works out anyway for all the philosophers // except the last, who must have his sticks swapped. if( id == PHILOSOPHERS-1 ) { cyg_sem_t *t = first_stick; first_stick = second_stick; second_stick = t; } for(;;) { cyg_ucount32 val; // The following variable is shared by all philosophers. // It is incremented unprotected, but this does not matter // since it is only present to introduce a little variability // into the think and eat times. static volatile int cycle = 0; // Think for a bit cyg_thread_delay((id+cycle++)%12); // Cogito ergo sum... // I am now hungry, try to get the chopsticks change_state(id,'H'); // Get the first stick cyg_semaphore_wait(first_stick); // Get the second stick cyg_semaphore_wait(second_stick); // Got them, now eat change_state(id,'E'); // Check that the world is as I think it is... cyg_semaphore_peek( first_stick, &val); CYG_ASSERT( val == 0, "Not got first stick"); cyg_semaphore_peek( second_stick, &val); CYG_ASSERT( val == 0, "Not got second stick"); CYG_ASSERT( get_state(left_philo) != 'E', "Left neighbour also eating!!"); CYG_ASSERT( get_state(right_philo) != 'E', "Right neighbour also eating!!"); cyg_thread_delay((id+cycle++)%6); // munch munch // Finished eating, put down sticks. change_state(id,'T'); cyg_semaphore_post( first_stick ); cyg_semaphore_post( second_stick ); } } // ------------------------------------------------------------------------- externC void cyg_start( void ) { int i; diag_init(); diag_write_string("Philosophers\n"); diag_write_string("Started\n"); // Zero last element in state so it acts like // a string. pstate[PHILOSOPHERS] = 0; #if 1 for( i = 0; i < PHILOSOPHERS; i++ ) { change_state(i,'T'); // starting state cyg_thread_create(4, Philosopher, (cyg_addrword_t)i, "philosopher", (void *)(&thread_stack[i]), STACKSIZE, &thread_handle[i], &thread[i]); // resume it cyg_thread_resume(thread_handle[i]); // and make the matching chopstick present cyg_semaphore_init( &chopstick[i], 1); } #endif // Get the world going cyg_scheduler_start(); } // ------------------------------------------------------------------------- // EOF kphilo.c
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