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