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/* main.c - Hello World demo */
/*
* Copyright (c) 2012-2014 Wind River Systems, Inc.
*
* SPDX-License-Identifier: Apache-2.0
*/
#include <zephyr.h>
#include <misc/printk.h>
/*
* The hello world demo has two threads that utilize semaphores and sleeping
* to take turns printing a greeting message at a controlled rate. The demo
* shows both the static and dynamic approaches for spawning a thread; a real
* world application would likely use the static approach for both threads.
*/
/* size of stack area used by each thread */
#define STACKSIZE 1024
/* scheduling priority used by each thread */
#define PRIORITY 7
/* delay between greetings (in ms) */
#define SLEEPTIME 500
/*
* @param my_name thread identification string
* @param my_sem thread's own semaphore
* @param other_sem other thread's semaphore
*/
void helloLoop(const char *my_name,
struct k_sem *my_sem, struct k_sem *other_sem)
{
while (1) {
/* take my semaphore */
k_sem_take(my_sem, K_FOREVER);
/* say "hello" */
printk("%s: Hello World from %s!\n", my_name, CONFIG_ARCH);
/* wait a while, then let other thread have a turn */
k_sleep(SLEEPTIME);
k_sem_give(other_sem);
}
}
/* define semaphores */
K_SEM_DEFINE(threadA_sem, 1, 1); /* starts off "available" */
K_SEM_DEFINE(threadB_sem, 0, 1); /* starts off "not available" */
/* threadB is a dynamic thread that is spawned by threadA */
void threadB(void *dummy1, void *dummy2, void *dummy3)
{
ARG_UNUSED(dummy1);
ARG_UNUSED(dummy2);
ARG_UNUSED(dummy3);
/* invoke routine to ping-pong hello messages with threadA */
helloLoop(__func__, &threadB_sem, &threadA_sem);
}
char __noinit __stack threadB_stack_area[STACKSIZE];
/* threadA is a static thread that is spawned automatically */
void threadA(void *dummy1, void *dummy2, void *dummy3)
{
ARG_UNUSED(dummy1);
ARG_UNUSED(dummy2);
ARG_UNUSED(dummy3);
/* spawn threadB */
k_thread_spawn(threadB_stack_area, STACKSIZE, threadB, NULL, NULL, NULL,
PRIORITY, 0, K_NO_WAIT);
/* invoke routine to ping-pong hello messages with threadB */
helloLoop(__func__, &threadA_sem, &threadB_sem);
}
K_THREAD_DEFINE(threadA_id, STACKSIZE, threadA, NULL, NULL, NULL,
PRIORITY, 0, K_NO_WAIT);