Improving comments and legibility on Os_Internal_Arch.c for the CortexM4 port.

Author: glpuga

src/cortexM4/Os_Internal_Arch.c

@@ -93,22 +93,36 @@ TaskType WaitingTask = INVALID_TASK;
 
 void ReturnHook_Arch(void)
 {
-   /* Tasks shouldn't return here... */
-   while(1) osekpause();
+   /*
+    * Tasks shouldn't return here...
+    *
+    * This is a security net for runaway tasks that reach the end of
+    * their main body code without terminating their execution
+    * properly using TerminateTask or something of the kind.
+    *
+    * */
 
+   while(1)
+   {
+      osekpause();
+   }
 }
 
 
 
 void CheckTerminatingTask_Arch(void)
 {
+   /*
+    * If there is task being terminated, destroy its context information and
+    * reset its state so that the next time that the task is activated it
+    * starts its execution on the first instruction of the task body.
+    * */
+
    if(TerminatingTask != INVALID_TASK)
    {
-//      int i;
-//      for(i=0; i<TasksConst[TerminatingTask].StackSize/4; i++)
-//         ((uint32 *)TasksConst[TerminatingTask].StackPtr)[i] = 0;
       InitStack_Arch(TerminatingTask);
    }
+
    TerminatingTask = INVALID_TASK;
 }
 
@@ -117,7 +131,6 @@ void CheckTerminatingTask_Arch(void)
 /* Task Stack Initialization */
 void InitStack_Arch(uint8 TaskID)
 {
-
    uint32_t *taskStackRegionPtr;
    int32_t taskStackSizeWords;
 
@@ -243,23 +256,32 @@ void InitStack_Arch(uint8 TaskID)
 /* Periodic Interrupt Timer, included in all Cortex-M4 processors */
 void SysTick_Handler(void)
 {
-   /* store the calling context in a variable */
+   /* Store the calling context in a variable. */
    ContextType actualContext = GetCallingContext();
-   /* set isr 2 context */
+
+   /* Set ISR2 context. */
    SetActualContext(CONTEXT_ISR2);
 
 #if (ALARMS_COUNT != 0)
-   /* counter increment */
-   static CounterIncrementType CounterIncrement = 1;
-   (void)CounterIncrement; /* TODO remove me */
 
-   /* increment the disable interrupt conter to avoid enable the interrupts */
+   /* Counter increment. */
+   static CounterIncrementType CounterIncrement = 1; /* TODO remove me. */
+
+   (void)CounterIncrement; /* This avoids a compiler warning because the variable is not being used. */
+
+   /*
+    * Enter critical section.
+    * */
    IntSecure_Start();
 
-   /* call counter interrupt handler */
+   /*
+    * The the RTOS counter increment handler.
+    * */
    CounterIncrement = IncrementCounter(0, 1 /* CounterIncrement */); /* TODO FIXME */
 
-   /* set the disable interrupt counter back */
+   /*
+    * Exit the critical section.
+    * */
    IntSecure_End();
 
 #endif /* #if (ALARMS_COUNT != 0) */
@@ -268,13 +290,19 @@ void SysTick_Handler(void)
    SetActualContext(actualContext);
 
 #if (NON_PREEMPTIVE == OSEK_DISABLE)
-   /* check if the actual task is preemptive */
+
+   /*
+    * Check if the currently active task is preemptive;
+    * if it is, call schedule().
+    * */
+
    if ( ( CONTEXT_TASK == actualContext ) &&
-        ( TasksConst[GetRunningTask()].ConstFlags.Preemtive ) )
+         ( TasksConst[GetRunningTask()].ConstFlags.Preemtive ) )
    {
-      /* this shall force a call to the scheduler */
+      /* This shall force a call to the scheduler. */
       PostIsr2_Arch(isr);
    }
+
 #endif /* #if (NON_PREEMPTIVE == OSEK_DISABLE) */
 }