/* hello.c - Hello World demo */ /* * Copyright (c) 2012-2014 Wind River Systems, Inc. * * SPDX-License-Identifier: Apache-2.0 */ #include #include /* * Microkernel version of hello world demo has two tasks that utilize * semaphores and sleeps to take turns printing a greeting message at * a controlled rate. */ /* specify delay between greetings (in ms); compute equivalent in ticks */ #define SLEEPTIME 500 #define SLEEPTICKS (SLEEPTIME * sys_clock_ticks_per_sec / 1000) /* * * @param taskname task identification string * @param mySem task's own semaphore * @param otherSem other task's semaphore * */ void helloLoop(const char *taskname, ksem_t mySem, ksem_t otherSem) { while (1) { task_sem_take(mySem, TICKS_UNLIMITED); /* say "hello" */ printk("%s: Hello World from %s!\n", taskname, CONFIG_ARCH); /* wait a while, then let other task have a turn */ task_sleep(SLEEPTICKS); task_sem_give(otherSem); } } void taskA(void) { /* taskA gives its own semaphore, allowing it to say hello right away */ task_sem_give(TASKASEM); /* invoke routine that allows task to ping-pong hello messages with taskB */ helloLoop(__func__, TASKASEM, TASKBSEM); } void taskB(void) { /* invoke routine that allows task to ping-pong hello messages with taskA */ helloLoop(__func__, TASKBSEM, TASKASEM); }