Revision 5:31707531f715, committed 2016-03-09

Comitter:

noutram

Date:

Wed Mar 09 17:55:53 2016 +0000

Parent:

4:dae8898e55fe

Child:

6:2e463846b575

Commit message:

Solution to 6.1.7 - by changing the sequence in which the locks are taken.

Changed in this revision

--- a/main.cpp	Wed Mar 09 17:18:55 2016 +0000
+++ b/main.cpp	Wed Mar 09 17:55:53 2016 +0000
@@ -33,6 +33,7 @@
 {
     pc.printf("Entering thread 1\n");
     while (true) {
+        yellowLED = 1;
         
         //Start critical section
         lock1.lock();
@@ -40,19 +41,18 @@
         sw1Count++;
         printf("\nCount1 = %lu", sw1Count);
         
-        //Thread::wait(1); //1ms
-        
-        if (SW1 == 1) {
-            yellowLED = 1;
-            lock2.lock();
-            sw2Count--;
-            lock2.unlock();  
-            yellowLED = 0; 
-        }
+        Thread::wait(1); //1ms
         
         //End critical section
         lock1.unlock();
+                
+        if (SW1 == 1) {
+            lock2.lock();
+            sw2Count--;
+            lock2.unlock();   
+        }
         
+        yellowLED = 0;
         Thread::wait(DELAY);       
     }
 }
@@ -61,6 +61,7 @@
 {
     pc.printf("Entering thread 2\n");  
     while (true) {
+        redLED = 1;
         
         //Start critical section
         lock2.lock();
@@ -68,19 +69,20 @@
         sw2Count++;
         printf("\nCount2 = %lu", sw2Count);
         
-        //Thread::wait(1);  //1ms
+        Thread::wait(1);  //1ms
         
-        if (SW2 == 1) {
-            redLED = 1; 
+        //End critical section
+        lock2.unlock();
+        
+        if (SW2 == 1) { 
             lock1.lock();
             sw1Count--;
             lock1.unlock();  
-            redLED = 0;
         }  
-        //End critical section
-        lock2.unlock();
+
+        redLED = 0;
+        Thread::wait(DELAY); 
         
-        Thread::wait(DELAY); 
     } 
 }