Demo/Common: fix divide by zero possibility and non-used return values (FreeRTOS#1370)

* Demo/Common: fix divide by zero possibility and non-used return values

- In TimerDemo.c fix possible divide by zero in
  "xMaxBlockTimeUsedByTheseTests / xCycleFrequency".
- Move this code in TimerDemo.c into if-clause where it is
  actually used.
- In Minimal/StreamBufferDemo.c and Minimal/TaskNotify.c avoid
  unused return values.

Signed-off-by: Florian La Roche <[email protected]>
Co-authored-by: Kody Stribrny <[email protected]>

Author: laroche

FreeRTOS/Demo/Common/Minimal/StreamBufferDemo.c

@@ -560,7 +560,7 @@ static void prvSingleTaskTests( StreamBufferHandle_t xStreamBuffer )
     /* Ensure data was written as expected even when there was an attempt to
      * write more than was available.  This also tries to read more bytes than are
      * available. */
-    xReturned = xStreamBufferReceive( xStreamBuffer, ( void * ) pucFullBuffer, xFullBufferSize, xMinimalBlockTime );
+    xStreamBufferReceive( xStreamBuffer, ( void * ) pucFullBuffer, xFullBufferSize, xMinimalBlockTime );
     prvCheckExpectedState( memcmp( ( const void * ) pucFullBuffer, ( const void * ) pc54ByteString, sbSTREAM_BUFFER_LENGTH_BYTES ) == 0 );
     prvCheckExpectedState( xStreamBufferIsFull( xStreamBuffer ) == pdFALSE );
     prvCheckExpectedState( xStreamBufferIsEmpty( xStreamBuffer ) == pdTRUE );

FreeRTOS/Demo/Common/Minimal/TaskNotify.c

@@ -242,6 +242,7 @@ static void prvSingleTaskTests( void )
     configASSERT( xReturned == pdPASS );
     ( void ) xReturned; /* In case configASSERT() is not defined. */
     xReturned = xTaskNotifyWait( notifyUINT32_MAX, 0, &ulNotifiedValue, 0 );
+    configASSERT( xReturned == pdPASS );
     configASSERT( ulNotifiedValue == ulSecondNotifiedValueConst );
     ( void ) ulNotifiedValue; /* In case configASSERT() is not defined. */
 

FreeRTOS/Demo/Common/Minimal/TimerDemo.c

@@ -230,8 +230,10 @@ static void prvTimerTestTask( void * pvParameters )
 BaseType_t xAreTimerDemoTasksStillRunning( TickType_t xCycleFrequency )
 {
     static uint32_t ulLastLoopCounter = 0UL;
-    TickType_t xMaxBlockTimeUsedByTheseTests, xLoopCounterIncrementTimeMax;
     static TickType_t xIterationsWithoutCounterIncrement = ( TickType_t ) 0, xLastCycleFrequency;
+    TickType_t xMaxBlockTimeUsedByTheseTests, xLoopCounterIncrementTimeMax;
+
+    configASSERT( xCycleFrequency != 0UL );
 
     if( xLastCycleFrequency != xCycleFrequency )
     {
@@ -241,17 +243,17 @@ BaseType_t xAreTimerDemoTasksStillRunning( TickType_t xCycleFrequency )
         xLastCycleFrequency = xCycleFrequency;
     }
 
-    /* Calculate the maximum number of times that it is permissible for this
-     * function to be called without ulLoopCounter being incremented.  This is
-     * necessary because the tests in this file block for extended periods, and the
-     * block period might be longer than the time between calls to this function. */
-    xMaxBlockTimeUsedByTheseTests = ( ( TickType_t ) configTIMER_QUEUE_LENGTH ) * xBasePeriod;
-    xLoopCounterIncrementTimeMax = ( xMaxBlockTimeUsedByTheseTests / xCycleFrequency ) + 1;
-
     /* If the demo task is still running then the loop counter is expected to
      * have incremented every xLoopCounterIncrementTimeMax calls. */
     if( ulLastLoopCounter == ulLoopCounter )
     {
+        /* Calculate the maximum number of times that it is permissible for this
+         * function to be called without ulLoopCounter being incremented.  This is
+         * necessary because the tests in this file block for extended periods, and the
+         * block period might be longer than the time between calls to this function. */
+        xMaxBlockTimeUsedByTheseTests = ( ( TickType_t ) configTIMER_QUEUE_LENGTH ) * xBasePeriod;
+        xLoopCounterIncrementTimeMax = ( xMaxBlockTimeUsedByTheseTests / xCycleFrequency ) + 1;
+
         xIterationsWithoutCounterIncrement++;
 
         if( xIterationsWithoutCounterIncrement > xLoopCounterIncrementTimeMax )