zephyr/doc/doxygen/phil_task_commented.c

122 lines
3.6 KiB
C

/** @file
* @brief An implementation of a solution to the dining philosophers problem
* for both the nano- and microkernel.
*
* This particular implementation uses 6 fibers or tasks of
* different priority, semaphores and timers. The implementation demostrates
* fibers and semaphores in the nanokernel and tasks and timers in the
* microkernel.
*/
/*
* Copyright (c) 2012-2014 Wind River Systems, Inc.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1) Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* 2) Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* 3) Neither the name of Wind River Systems nor the names of its contributors
* may be used to endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#ifdef CONFIG_NANOKERNEL
#include <nanokernel.h>
#include "phil.h"
#else
#include <zephyr.h>
#include "phil.h"
#endif
#define DEMO_DESCRIPTION \
"\x1b[2J\x1b[15;1H" \
"Demo Description\n" \
"----------------\n" \
"An implementation of a solution to the Dining Philosophers problem\n" \
"(a classic multi-thread synchronization problem). This particular\n" \
"implementation demonstrates the usage of multiple (6) %s\n" \
"of differing priorities and the %s semaphores and timers."
#ifdef CONFIG_NANOKERNEL
#define STSIZE 1024
extern void philEntry (void); //!< External function.
char philStack[N_PHILOSOPHERS][STSIZE];//!< Declares a global stack of size 1024.
struct nano_sem forks[N_PHILOSOPHERS];//!< Declares global semaphore forks for the number of philosophers.
#endif /* CONFIG_NANOKERNEL */
#ifdef CONFIG_NANOKERNEL
/**
* @brief The nanokernel entry point.
*
* Actions:
* -# Starts one fiber per philosopher.
* -# Waits forever.
* @return Does not return.
*/
int main (void)
{
int i;
PRINTF (DEMO_DESCRIPTION, "fibers", "nanokernel");
for (i = 0; i < N_PHILOSOPHERS; i++)
{
nano_sem_init (&forks[i]);
nano_task_sem_give (&forks[i]);
}
/* A1 */
for (i = 0; i < N_PHILOSOPHERS; i++)
task_fiber_start (&philStack[i][0], STSIZE,
(nano_fiber_entry_t) philEntry, 0, 0, 6, 0);
/* A2 */
while (1)
{
extern void nano_cpu_idle (void);
nano_cpu_idle ();
}
}
#else
/**
* @brief Starts the dining philosophers demo of the microkernel.
*
* This function starts the dining philosophers demo and
* then waits forever.
* @return Does not return.
*/
void philDemo(void) {
PRINTF(DEMO_DESCRIPTION, "tasks", "microkernel");
task_group_start(PHI);
while (1) {
task_sleep(10000);
}
}
#endif