mbed_example / Mbed OS mbed-os-example-critical-section

Example to demonstrate CriticalSection API usage

main.cpp@0:a88acbffd78b, 2017-10-23 (annotated)

Committer:
deepikabhavnani
Date:
Mon Oct 23 21:11:16 2017 +0000
Revision:
0:a88acbffd78b
CriticalSection API example

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deepikabhavnani 0:a88acbffd78b 1 /*
deepikabhavnani 0:a88acbffd78b 2 * Copyright (c) 2016-2016, ARM Limited, All Rights Reserved
deepikabhavnani 0:a88acbffd78b 3 * SPDX-License-Identifier: Apache-2.0
deepikabhavnani 0:a88acbffd78b 4 *
deepikabhavnani 0:a88acbffd78b 5 * Licensed under the Apache License, Version 2.0 (the "License"); you may
deepikabhavnani 0:a88acbffd78b 6 * not use this file except in compliance with the License.
deepikabhavnani 0:a88acbffd78b 7 * You may obtain a copy of the License at
deepikabhavnani 0:a88acbffd78b 8 *
deepikabhavnani 0:a88acbffd78b 9 * http://www.apache.org/licenses/LICENSE-2.0
deepikabhavnani 0:a88acbffd78b 10 *
deepikabhavnani 0:a88acbffd78b 11 * Unless required by applicable law or agreed to in writing, software
deepikabhavnani 0:a88acbffd78b 12 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
deepikabhavnani 0:a88acbffd78b 13 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
deepikabhavnani 0:a88acbffd78b 14 * See the License for the specific language governing permissions and
deepikabhavnani 0:a88acbffd78b 15 * limitations under the License.
deepikabhavnani 0:a88acbffd78b 16 */
deepikabhavnani 0:a88acbffd78b 17 #include "rtos/Thread.h"
deepikabhavnani 0:a88acbffd78b 18 #include "mbed.h"
deepikabhavnani 0:a88acbffd78b 19 #include "rtos/rtos_idle.h"
deepikabhavnani 0:a88acbffd78b 20 #include "platform/mbed_critical.h"
deepikabhavnani 0:a88acbffd78b 21
deepikabhavnani 0:a88acbffd78b 22 #define USE_CRITICAL_SECTION_LOCK 1 // Set 0 to see race condition
deepikabhavnani 0:a88acbffd78b 23 // Note: Might require few runs to see race condition
deepikabhavnani 0:a88acbffd78b 24
deepikabhavnani 0:a88acbffd78b 25 #define THREAD_CNT 8
deepikabhavnani 0:a88acbffd78b 26
deepikabhavnani 0:a88acbffd78b 27 int32_t value = 100000;
deepikabhavnani 0:a88acbffd78b 28 volatile int32_t count = 0;
deepikabhavnani 0:a88acbffd78b 29
deepikabhavnani 0:a88acbffd78b 30 void increment(void) {
deepikabhavnani 0:a88acbffd78b 31 for (int i = 0; i < value; i++) {
deepikabhavnani 0:a88acbffd78b 32 #if (USE_CRITICAL_SECTION_LOCK == 1)
deepikabhavnani 0:a88acbffd78b 33 CriticalSectionLock lock;
deepikabhavnani 0:a88acbffd78b 34 #endif
deepikabhavnani 0:a88acbffd78b 35 count += 1;
deepikabhavnani 0:a88acbffd78b 36 }
deepikabhavnani 0:a88acbffd78b 37 }
deepikabhavnani 0:a88acbffd78b 38
deepikabhavnani 0:a88acbffd78b 39 int get_count(void) {
deepikabhavnani 0:a88acbffd78b 40 if (count == (value * THREAD_CNT)) {
deepikabhavnani 0:a88acbffd78b 41 printf("No Race condition\n");
deepikabhavnani 0:a88acbffd78b 42 } else {
deepikabhavnani 0:a88acbffd78b 43 printf("Race condition\n");
deepikabhavnani 0:a88acbffd78b 44 }
deepikabhavnani 0:a88acbffd78b 45 return count;
deepikabhavnani 0:a88acbffd78b 46 }
deepikabhavnani 0:a88acbffd78b 47
deepikabhavnani 0:a88acbffd78b 48 int main()
deepikabhavnani 0:a88acbffd78b 49 {
deepikabhavnani 0:a88acbffd78b 50 Thread counter_thread[THREAD_CNT];
deepikabhavnani 0:a88acbffd78b 51
deepikabhavnani 0:a88acbffd78b 52 for (int i = 0; i < THREAD_CNT; i++) {
deepikabhavnani 0:a88acbffd78b 53 counter_thread[i].start(callback(increment));
deepikabhavnani 0:a88acbffd78b 54 }
deepikabhavnani 0:a88acbffd78b 55
deepikabhavnani 0:a88acbffd78b 56 // Wait for the threads to finish
deepikabhavnani 0:a88acbffd78b 57 for (int i = 0; i < THREAD_CNT; i++) {
deepikabhavnani 0:a88acbffd78b 58 counter_thread[i].join();
deepikabhavnani 0:a88acbffd78b 59 }
deepikabhavnani 0:a88acbffd78b 60 printf ("Counter = %d\n", get_count());
deepikabhavnani 0:a88acbffd78b 61 }