main.cpp

00001 #include "mbed.h"
00002 
00003 #define RED_DONE 1
00004 #define YELLOW_DONE 2
00005 
00006 
00007 //Function declarations
00008 void countUP();
00009 void countDOWN();
00010 
00011 //Digital outputs
00012 DigitalOut onBoardLED(LED1);
00013 DigitalOut redLED(D7);
00014 DigitalOut yellowLED(D6);
00015 DigitalOut greenLED(D5);
00016 
00017 //Digital inputs
00018 DigitalIn  onBoardSwitch(USER_BUTTON);
00019 DigitalIn  SW1(D4);
00020 DigitalIn  SW2(D3);
00021 
00022 //MUTEX Lock
00023 Mutex *countLock;
00024 
00025 //Thread ID for the Main function (CMSIS API)
00026 osThreadId tidMain;
00027 
00028 //Stared mutable state
00029 volatile long long count = 0;
00030 
00031 //Threads
00032 void countUP()
00033 {
00034     redLED = 1;
00035     
00036     for (unsigned int n=0; n<10000; n++) {
00037         //Take lock
00038         countLock->lock();
00039         
00040         //Critical section(s)
00041         count++;
00042         count++;        
00043         count++;
00044         count++;    
00045         count++;
00046         count++; 
00047         count++;
00048         count++;
00049         count++;
00050         count++;   
00051         
00052         //Release lock
00053         countLock->unlock();
00054     }
00055     
00056     redLED = 0;
00057     osSignalSet(tidMain, RED_DONE);  //Signal main thread we are done
00058 }
00059 
00060 void countDOWN()
00061 {
00062     yellowLED = 1;
00063     
00064     for (unsigned int n=0; n<10000; n++) {
00065         //Take lock
00066         countLock->lock();
00067         
00068         //Critical section(s)        
00069         count--;
00070         count--;        
00071         count--;
00072         count--;    
00073         count--;
00074         count--; 
00075         count--;
00076         count--;
00077         count--;
00078         count--;    
00079         
00080         //Release lock
00081         countLock->unlock();                   
00082     }   
00083     
00084     osSignalSet(tidMain, YELLOW_DONE); //Signal main thread we are done
00085     yellowLED = 0;
00086 }
00087 
00088 
00089 //Main thread
00090 int main() {
00091     Thread t1;           
00092     Thread t2;        
00093     
00094     redLED    = 0;
00095     yellowLED = 0;
00096     greenLED  = 1;
00097     
00098     //Main thread ID
00099     tidMain = Thread::gettid();  
00100     
00101     //Create lock
00102     countLock = new Mutex();
00103     
00104     //Press the switch to run concurrently
00105     if (onBoardSwitch == 1) {
00106         printf("Running sequntially\n");
00107         countUP();
00108         countDOWN();        
00109     } else {
00110         printf("Running concurrently\n");
00111         t1.start(countUP);           
00112         t2.start(countDOWN);    
00113   
00114         //Wait for the ALL_ON signal
00115         Thread::signal_wait(RED_DONE,osWaitForever);
00116         Thread::signal_wait(YELLOW_DONE,osWaitForever);        
00117     }
00118 
00119     printf("Final result = %lld\n", count);
00120     if (count == 0) {
00121         greenLED = 0;
00122     }
00123     
00124     //Tidy
00125     delete countLock;
00126     
00127     while(true);
00128 }