Stage-1 Students SoCEM / Mbed OS Task614-mbedos54

Demonstrates data corruption due to a race condition updated for mbed os 5.4

main.cpp@2:7e77fec81f7d, 2017-03-30 (annotated)

Committer:
noutram
Date:
Thu Mar 30 14:12:06 2017 +0000
Revision:
2:7e77fec81f7d
Parent:
1:8c6ec9de7688 
Updated for mbed os 5.4

Who changed what in which revision?

UserRevisionLine numberNew contents of line
noutram 0:f916cefba2f4 1 #include "mbed.h"
noutram 0:f916cefba2f4 2
noutram 0:f916cefba2f4 3 #define RED_DONE 1
noutram 0:f916cefba2f4 4 #define YELLOW_DONE 2
noutram 0:f916cefba2f4 5
noutram 0:f916cefba2f4 6
noutram 0:f916cefba2f4 7 //Function declarations
noutram 2:7e77fec81f7d 8 void countUP();
noutram 2:7e77fec81f7d 9 void countDOWN();
noutram 0:f916cefba2f4 10
noutram 0:f916cefba2f4 11 //Digital outputs
noutram 0:f916cefba2f4 12 DigitalOut onBoardLED(LED1);
noutram 0:f916cefba2f4 13 DigitalOut redLED(D7);
noutram 0:f916cefba2f4 14 DigitalOut yellowLED(D6);
noutram 0:f916cefba2f4 15 DigitalOut greenLED(D5);
noutram 0:f916cefba2f4 16
noutram 0:f916cefba2f4 17 //Digital inputs
noutram 0:f916cefba2f4 18 DigitalIn onBoardSwitch(USER_BUTTON);
noutram 0:f916cefba2f4 19 DigitalIn SW1(D4);
noutram 0:f916cefba2f4 20 DigitalIn SW2(D3);
noutram 0:f916cefba2f4 21
noutram 0:f916cefba2f4 22 //Thread ID for the Main function (CMSIS API)
noutram 0:f916cefba2f4 23 osThreadId tidMain;
noutram 0:f916cefba2f4 24
noutram 0:f916cefba2f4 25 //Stared mutable state
noutram 0:f916cefba2f4 26 volatile long long count = 0;
noutram 0:f916cefba2f4 27
noutram 0:f916cefba2f4 28 //Threads
noutram 2:7e77fec81f7d 29 void countUP()
noutram 0:f916cefba2f4 30 {
noutram 0:f916cefba2f4 31 redLED = 1;
noutram 0:f916cefba2f4 32
noutram 0:f916cefba2f4 33 for (unsigned int n=0; n<10000; n++) {
noutram 0:f916cefba2f4 34 count++;
noutram 0:f916cefba2f4 35 count++;
noutram 0:f916cefba2f4 36 count++;
noutram 0:f916cefba2f4 37 count++;
noutram 0:f916cefba2f4 38 count++;
noutram 0:f916cefba2f4 39 count++;
noutram 0:f916cefba2f4 40 count++;
noutram 0:f916cefba2f4 41 count++;
noutram 0:f916cefba2f4 42 count++;
noutram 0:f916cefba2f4 43 count++;
noutram 0:f916cefba2f4 44 }
noutram 0:f916cefba2f4 45
noutram 0:f916cefba2f4 46 redLED = 0;
noutram 0:f916cefba2f4 47 osSignalSet(tidMain, RED_DONE); //Signal main thread we are done
noutram 0:f916cefba2f4 48 }
noutram 0:f916cefba2f4 49
noutram 2:7e77fec81f7d 50 void countDOWN()
noutram 0:f916cefba2f4 51 {
noutram 0:f916cefba2f4 52 yellowLED = 1;
noutram 0:f916cefba2f4 53
noutram 0:f916cefba2f4 54 for (unsigned int n=0; n<10000; n++) {
noutram 0:f916cefba2f4 55 count--;
noutram 0:f916cefba2f4 56 count--;
noutram 0:f916cefba2f4 57 count--;
noutram 0:f916cefba2f4 58 count--;
noutram 0:f916cefba2f4 59 count--;
noutram 0:f916cefba2f4 60 count--;
noutram 0:f916cefba2f4 61 count--;
noutram 0:f916cefba2f4 62 count--;
noutram 0:f916cefba2f4 63 count--;
noutram 0:f916cefba2f4 64 count--;
noutram 0:f916cefba2f4 65 }
noutram 0:f916cefba2f4 66
noutram 0:f916cefba2f4 67 osSignalSet(tidMain, YELLOW_DONE); //Signal main thread we are done
noutram 0:f916cefba2f4 68 yellowLED = 0;
noutram 0:f916cefba2f4 69 }
noutram 0:f916cefba2f4 70
noutram 0:f916cefba2f4 71
noutram 0:f916cefba2f4 72 //Main thread
noutram 0:f916cefba2f4 73 int main() {
noutram 2:7e77fec81f7d 74 Thread t1, t2;
noutram 2:7e77fec81f7d 75
noutram 0:f916cefba2f4 76 redLED = 0;
noutram 0:f916cefba2f4 77 yellowLED = 0;
noutram 0:f916cefba2f4 78 greenLED = 1;
noutram 0:f916cefba2f4 79
noutram 0:f916cefba2f4 80 //Main thread ID
noutram 0:f916cefba2f4 81 tidMain = Thread::gettid();
noutram 0:f916cefba2f4 82
noutram 0:f916cefba2f4 83 //Press the switch to run concurrently
noutram 0:f916cefba2f4 84 if (onBoardSwitch == 1) {
noutram 0:f916cefba2f4 85 printf("Running sequntially\n");
noutram 2:7e77fec81f7d 86 countUP();
noutram 2:7e77fec81f7d 87 countDOWN();
noutram 0:f916cefba2f4 88 } else {
noutram 0:f916cefba2f4 89 printf("Running concurrently\n");
noutram 2:7e77fec81f7d 90 t1.start(countUP);
noutram 2:7e77fec81f7d 91 t2.start(countDOWN);
noutram 0:f916cefba2f4 92
noutram 0:f916cefba2f4 93 //Wait for the ALL_ON signal
noutram 0:f916cefba2f4 94 Thread::signal_wait(RED_DONE,osWaitForever);
noutram 0:f916cefba2f4 95 Thread::signal_wait(YELLOW_DONE,osWaitForever);
noutram 0:f916cefba2f4 96 }
noutram 0:f916cefba2f4 97
noutram 0:f916cefba2f4 98 printf("Final result = %lld\n", count);
noutram 0:f916cefba2f4 99 if (count == 0) {
noutram 0:f916cefba2f4 100 greenLED = 0;
noutram 0:f916cefba2f4 101 }
noutram 0:f916cefba2f4 102 while(true);
noutram 0:f916cefba2f4 103 }