text: /*
      FreeRTOS V7.0.0 - Copyright (C) 2011 Real Time Engineers Ltd.
  	
  
      ***************************************************************************
       *                                                                       *
       *    FreeRTOS tutorial books are available in pdf and paperback.        *
       *    Complete, revised, and edited pdf reference manuals are also       *
       *    available.                                                         *
       *                                                                       *
       *    Purchasing FreeRTOS documentation will not only help you, by       *
       *    ensuring you get running as quickly as possible and with an        *
       *    in-depth knowledge of how to use FreeRTOS, it will also help       *
       *    the FreeRTOS project to continue with its mission of providing     *
       *    professional grade, cross platform, de facto standard solutions    *
       *    for microcontrollers - completely free of charge!                  *
       *                                                                       *
       *    >>> See http://www.FreeRTOS.org/Documentation for details. <<<     *
       *                                                                       *
       *    Thank you for using FreeRTOS, and thank you for your support!      *
       *                                                                       *
      ***************************************************************************
  
  
      This file is part of the FreeRTOS distribution.
  
      FreeRTOS is free software; you can redistribute it and/or modify it under
      the terms of the GNU General Public License (version 2) as published by the
      Free Software Foundation AND MODIFIED BY the FreeRTOS exception.
      >>>NOTE<<< The modification to the GPL is included to allow you to
      distribute a combined work that includes FreeRTOS without being obliged to
      provide the source code for proprietary components outside of the FreeRTOS
      kernel.  FreeRTOS is distributed in the hope that it will be useful, but
      WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
      or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
      more details. You should have received a copy of the GNU General Public
      License and the FreeRTOS license exception along with FreeRTOS; if not it
      can be viewed here: http://www.freertos.org/a00114.html and also obtained
      by writing to Richard Barry, contact details for whom are available on the
      FreeRTOS WEB site.
  
      1 tab == 4 spaces!
  
      http://www.FreeRTOS.org - Documentation, latest information, license and
      contact details.
  
      http://www.SafeRTOS.com - A version that is certified for use in safety
      critical systems.
  
      http://www.OpenRTOS.com - Commercial support, development, porting,
      licensing and training services.
  */
  
  /*
   * This is a version of BlockTim.c that uses the light weight API.
   *
   * This file contains some test scenarios that ensure tasks do not exit queue
   * send or receive functions prematurely.  A description of the tests is
   * included within the code.
   */
  
  /* Kernel includes. */
  #include "FreeRTOS.h"
  #include "task.h"
  #include "queue.h"
  
  /* Demo includes. */
  #include "AltBlock.h"
  
  /* Task priorities. */
  #define bktPRIMARY_PRIORITY			( 3 )
  #define bktSECONDARY_PRIORITY		( 2 )
  
  /* Task behaviour. */
  #define bktQUEUE_LENGTH				( 5 )
  #define bktSHORT_WAIT				( ( ( portTickType ) 20 ) / portTICK_RATE_MS )
  #define bktPRIMARY_BLOCK_TIME		( 10 )
  #define bktALLOWABLE_MARGIN			( 12 )
  #define bktTIME_TO_BLOCK			( 175 )
  #define bktDONT_BLOCK				( ( portTickType ) 0 )
  #define bktRUN_INDICATOR			( ( unsigned portBASE_TYPE ) 0x55 )
  
  /* The queue on which the tasks block. */
  static xQueueHandle xTestQueue;
  
  /* Handle to the secondary task is required by the primary task for calls
  to vTaskSuspend/Resume(). */
  static xTaskHandle xSecondary;
  
  /* Used to ensure that tasks are still executing without error. */
  static portBASE_TYPE xPrimaryCycles = 0, xSecondaryCycles = 0;
  static portBASE_TYPE xErrorOccurred = pdFALSE;
  
  /* Provides a simple mechanism for the primary task to know when the
  secondary task has executed. */
  static volatile unsigned portBASE_TYPE xRunIndicator;
  
  /* The two test tasks.  Their behaviour is commented within the files. */
  static void vPrimaryBlockTimeTestTask( void *pvParameters );
  static void vSecondaryBlockTimeTestTask( void *pvParameters );
  
  /*-----------------------------------------------------------*/
  
  void vCreateAltBlockTimeTasks( void )
  {
  	/* Create the queue on which the two tasks block. */
      xTestQueue = xQueueCreate( bktQUEUE_LENGTH, sizeof( portBASE_TYPE ) );
  
  	/* vQueueAddToRegistry() adds the queue to the queue registry, if one is
  	in use.  The queue registry is provided as a means for kernel aware 
  	debuggers to locate queues and has no purpose if a kernel aware debugger
  	is not being used.  The call to vQueueAddToRegistry() will be removed
  	by the pre-processor if configQUEUE_REGISTRY_SIZE is not defined or is 
  	defined to be less than 1. */
  	vQueueAddToRegistry( xTestQueue, ( signed portCHAR * ) "AltBlockQueue" );
  
  
  	/* Create the two test tasks. */
  	xTaskCreate( vPrimaryBlockTimeTestTask, ( signed portCHAR * )"FBTest1", configMINIMAL_STACK_SIZE, NULL, bktPRIMARY_PRIORITY, NULL );
  	xTaskCreate( vSecondaryBlockTimeTestTask, ( signed portCHAR * )"FBTest2", configMINIMAL_STACK_SIZE, NULL, bktSECONDARY_PRIORITY, &xSecondary );
  }
  /*-----------------------------------------------------------*/
  
  static void vPrimaryBlockTimeTestTask( void *pvParameters )
  {
  portBASE_TYPE xItem, xData;
  portTickType xTimeWhenBlocking;
  portTickType xTimeToBlock, xBlockedTime;
  
  	#ifdef USE_STDIO
  	void vPrintDisplayMessage( const portCHAR * const * ppcMessageToSend );
  	
  		const portCHAR * const pcTaskStartMsg = "Alt primary block time test started.\r\n";
  
  		/* Queue a message for printing to say the task has started. */
  		vPrintDisplayMessage( &pcTaskStartMsg );
  	#endif
  
  	( void ) pvParameters;
  
  	for( ;; )
  	{
  		/*********************************************************************
          Test 1
  
          Simple block time wakeup test on queue receives. */
  		for( xItem = 0; xItem < bktQUEUE_LENGTH; xItem++ )
  		{
  			/* The queue is empty. Attempt to read from the queue using a block
  			time.  When we wake, ensure the delta in time is as expected. */
  			xTimeToBlock = bktPRIMARY_BLOCK_TIME << xItem;
  
  			/* A critical section is used to minimise the jitter in the time
  			measurements. */
  			portENTER_CRITICAL();
  			{
  				xTimeWhenBlocking = xTaskGetTickCount();
  				
  				/* We should unblock after xTimeToBlock having not received
  				anything on the queue. */
  				if( xQueueAltReceive( xTestQueue, &xData, xTimeToBlock ) != errQUEUE_EMPTY )
  				{
  					xErrorOccurred = pdTRUE;
  				}
  
  				/* How long were we blocked for? */
  				xBlockedTime = xTaskGetTickCount() - xTimeWhenBlocking;
  			}
  			portEXIT_CRITICAL();
  
  			if( xBlockedTime < xTimeToBlock )
  			{
  				/* Should not have blocked for less than we requested. */
  				xErrorOccurred = pdTRUE;
  			}
  
  			if( xBlockedTime > ( xTimeToBlock + bktALLOWABLE_MARGIN ) )
  			{
  				/* Should not have blocked for longer than we requested,
  				although we would not necessarily run as soon as we were
  				unblocked so a margin is allowed. */
  				xErrorOccurred = pdTRUE;
  			}
  		}
  
  
  		#if configUSE_PREEMPTION == 0
  			taskYIELD();
  		#endif
  
  
  		/*********************************************************************
          Test 2
  
          Simple block time wakeup test on queue sends.
  
  		First fill the queue.  It should be empty so all sends should pass. */
  		for( xItem = 0; xItem < bktQUEUE_LENGTH; xItem++ )
  		{
  			if( xQueueAltSendToBack( xTestQueue, &xItem, bktDONT_BLOCK ) != pdPASS )
  			{
  				xErrorOccurred = pdTRUE;
  			}
  		}
  
  		for( xItem = 0; xItem < bktQUEUE_LENGTH; xItem++ )
  		{
  			/* The queue is full. Attempt to write to the queue using a block
  			time.  When we wake, ensure the delta in time is as expected. */
  			xTimeToBlock = bktPRIMARY_BLOCK_TIME << xItem;
  
  			portENTER_CRITICAL();
  			{
  				xTimeWhenBlocking = xTaskGetTickCount();
  				
  				/* We should unblock after xTimeToBlock having not received
  				anything on the queue. */
  				if( xQueueAltSendToBack( xTestQueue, &xItem, xTimeToBlock ) != errQUEUE_FULL )
  				{
  					xErrorOccurred = pdTRUE;
  				}
  
  				/* How long were we blocked for? */
  				xBlockedTime = xTaskGetTickCount() - xTimeWhenBlocking;
  			}
  			portEXIT_CRITICAL();
  
  			if( xBlockedTime < xTimeToBlock )
  			{
  				/* Should not have blocked for less than we requested. */
  				xErrorOccurred = pdTRUE;
  			}
  
  			if( xBlockedTime > ( xTimeToBlock + bktALLOWABLE_MARGIN ) )
  			{
  				/* Should not have blocked for longer than we requested,
  				although we would not necessarily run as soon as we were
  				unblocked so a margin is allowed. */
  				xErrorOccurred = pdTRUE;
  			}
  		}
  
  		#if configUSE_PREEMPTION == 0
  			taskYIELD();
  		#endif
  
  		
  		/*********************************************************************
          Test 3
  
  		Wake the other task, it will block attempting to post to the queue.
  		When we read from the queue the other task will wake, but before it
  		can run we will post to the queue again.  When the other task runs it
  		will find the queue still full, even though it was woken.  It should
  		recognise that its block time has not expired and return to block for
  		the remains of its block time.
  
  		Wake the other task so it blocks attempting to post to the already
  		full queue. */
  		xRunIndicator = 0;
  		vTaskResume( xSecondary );
  
  		/* We need to wait a little to ensure the other task executes. */
  		while( xRunIndicator != bktRUN_INDICATOR )
  		{
  			/* The other task has not yet executed. */
  			vTaskDelay( bktSHORT_WAIT );
  		}
  		/* Make sure the other task is blocked on the queue. */
  		vTaskDelay( bktSHORT_WAIT );
  		xRunIndicator = 0;
  
  		for( xItem = 0; xItem < bktQUEUE_LENGTH; xItem++ )
  		{
  			/* Now when we make space on the queue the other task should wake
  			but not execute as this task has higher priority. */				
  			if( xQueueAltReceive( xTestQueue, &xData, bktDONT_BLOCK ) != pdPASS )
  			{
  				xErrorOccurred = pdTRUE;
  			}
  
  			/* Now fill the queue again before the other task gets a chance to
  			execute.  If the other task had executed we would find the queue
  			full ourselves, and the other task have set xRunIndicator. */
  			if( xQueueAltSendToBack( xTestQueue, &xItem, bktDONT_BLOCK ) != pdPASS )
  			{
  				xErrorOccurred = pdTRUE;
  			}
  
  			if( xRunIndicator == bktRUN_INDICATOR )
  			{
  				/* The other task should not have executed. */
  				xErrorOccurred = pdTRUE;
  			}
  
  			/* Raise the priority of the other task so it executes and blocks
  			on the queue again. */
  			vTaskPrioritySet( xSecondary, bktPRIMARY_PRIORITY + 2 );
  
  			/* The other task should now have re-blocked without exiting the
  			queue function. */
  			if( xRunIndicator == bktRUN_INDICATOR )
  			{
  				/* The other task should not have executed outside of the
  				queue function. */
  				xErrorOccurred = pdTRUE;
  			}
  
  			/* Set the priority back down. */
  			vTaskPrioritySet( xSecondary, bktSECONDARY_PRIORITY );			
  		}
  
  		/* Let the other task timeout.  When it unblockes it will check that it
  		unblocked at the correct time, then suspend itself. */
  		while( xRunIndicator != bktRUN_INDICATOR )
  		{
  			vTaskDelay( bktSHORT_WAIT );
  		}
  		vTaskDelay( bktSHORT_WAIT );
  		xRunIndicator = 0;
  
  		#if configUSE_PREEMPTION == 0
  			taskYIELD();
  		#endif
  
  		/*********************************************************************
          Test 4
  
  		As per test 3 - but with the send and receive the other way around.
  		The other task blocks attempting to read from the queue.
  
  		Empty the queue.  We should find that it is full. */
  		for( xItem = 0; xItem < bktQUEUE_LENGTH; xItem++ )
  		{
  			if( xQueueAltReceive( xTestQueue, &xData, bktDONT_BLOCK ) != pdPASS )
  			{
  				xErrorOccurred = pdTRUE;
  			}
  		}
  		
  		/* Wake the other task so it blocks attempting to read from  the
  		already	empty queue. */
  		vTaskResume( xSecondary );
  
  		/* We need to wait a little to ensure the other task executes. */
  		while( xRunIndicator != bktRUN_INDICATOR )
  		{
  			vTaskDelay( bktSHORT_WAIT );
  		}
  		vTaskDelay( bktSHORT_WAIT );
  		xRunIndicator = 0;
  
  		for( xItem = 0; xItem < bktQUEUE_LENGTH; xItem++ )
  		{
  			/* Now when we place an item on the queue the other task should
  			wake but not execute as this task has higher priority. */				
  			if( xQueueAltSendToBack( xTestQueue, &xItem, bktDONT_BLOCK ) != pdPASS )
  			{
  				xErrorOccurred = pdTRUE;
  			}
  
  			/* Now empty the queue again before the other task gets a chance to
  			execute.  If the other task had executed we would find the queue
  			empty ourselves, and the other task would be suspended. */
  			if( xQueueAltReceive( xTestQueue, &xData, bktDONT_BLOCK ) != pdPASS )
  			{
  				xErrorOccurred = pdTRUE;
  			}
  
  			if( xRunIndicator == bktRUN_INDICATOR )
  			{
  				/* The other task should not have executed. */
  				xErrorOccurred = pdTRUE;
  			}
  
  			/* Raise the priority of the other task so it executes and blocks
  			on the queue again. */
  			vTaskPrioritySet( xSecondary, bktPRIMARY_PRIORITY + 2 );
  
  			/* The other task should now have re-blocked without exiting the
  			queue function. */
  			if( xRunIndicator == bktRUN_INDICATOR )
  			{
  				/* The other task should not have executed outside of the
  				queue function. */
  				xErrorOccurred = pdTRUE;
  			}
  			vTaskPrioritySet( xSecondary, bktSECONDARY_PRIORITY );			
  		}
  
  		/* Let the other task timeout.  When it unblockes it will check that it
  		unblocked at the correct time, then suspend itself. */
  		while( xRunIndicator != bktRUN_INDICATOR )
  		{
  			vTaskDelay( bktSHORT_WAIT );
  		}
  		vTaskDelay( bktSHORT_WAIT );
  
  		xPrimaryCycles++;
  	}
  }
  /*-----------------------------------------------------------*/
  
  static void vSecondaryBlockTimeTestTask( void *pvParameters )
  {
  portTickType xTimeWhenBlocking, xBlockedTime;
  portBASE_TYPE xData;
  
  	#ifdef USE_STDIO
  	void vPrintDisplayMessage( const portCHAR * const * ppcMessageToSend );
  	
  		const portCHAR * const pcTaskStartMsg = "Alt secondary block time test started.\r\n";
  
  		/* Queue a message for printing to say the task has started. */
  		vPrintDisplayMessage( &pcTaskStartMsg );
  	#endif
  
  	( void ) pvParameters;
  
  	for( ;; )
  	{
  		/*********************************************************************
          Test 1 and 2
  
  		This task does does not participate in these tests. */
  		vTaskSuspend( NULL );
  
  		/*********************************************************************
          Test 3
  
  		The first thing we do is attempt to read from the queue.  It should be
  		full so we block.  Note the time before we block so we can check the
  		wake time is as per that expected. */
  		portENTER_CRITICAL();
  		{
  			xTimeWhenBlocking = xTaskGetTickCount();
  			
  			/* We should unblock after bktTIME_TO_BLOCK having not received
  			anything on the queue. */
  			xData = 0;
  			xRunIndicator = bktRUN_INDICATOR;
  			if( xQueueAltSendToBack( xTestQueue, &xData, bktTIME_TO_BLOCK ) != errQUEUE_FULL )
  			{
  				xErrorOccurred = pdTRUE;
  			}
  
  			/* How long were we inside the send function? */
  			xBlockedTime = xTaskGetTickCount() - xTimeWhenBlocking;
  		}
  		portEXIT_CRITICAL();
  
  		/* We should not have blocked for less time than bktTIME_TO_BLOCK. */
  		if( xBlockedTime < bktTIME_TO_BLOCK )
  		{
  			xErrorOccurred = pdTRUE;
  		}
  
  		/* We should of not blocked for much longer than bktALLOWABLE_MARGIN
  		either.  A margin is permitted as we would not necessarily run as
  		soon as we unblocked. */
  		if( xBlockedTime > ( bktTIME_TO_BLOCK + bktALLOWABLE_MARGIN ) )
  		{
  			xErrorOccurred = pdTRUE;
  		}
  
  		/* Suspend ready for test 3. */
  		xRunIndicator = bktRUN_INDICATOR;
  		vTaskSuspend( NULL );
  
  		/*********************************************************************
          Test 4
  
  		As per test three, but with the send and receive reversed. */
  		portENTER_CRITICAL();
  		{
  			xTimeWhenBlocking = xTaskGetTickCount();
  			
  			/* We should unblock after bktTIME_TO_BLOCK having not received
  			anything on the queue. */
  			xRunIndicator = bktRUN_INDICATOR;
  			if( xQueueAltReceive( xTestQueue, &xData, bktTIME_TO_BLOCK ) != errQUEUE_EMPTY )
  			{
  				xErrorOccurred = pdTRUE;
  			}
  
  			xBlockedTime = xTaskGetTickCount() - xTimeWhenBlocking;
  		}
  		portEXIT_CRITICAL();
  
  		/* We should not have blocked for less time than bktTIME_TO_BLOCK. */
  		if( xBlockedTime < bktTIME_TO_BLOCK )
  		{
  			xErrorOccurred = pdTRUE;
  		}
  
  		/* We should of not blocked for much longer than bktALLOWABLE_MARGIN
  		either.  A margin is permitted as we would not necessarily run as soon
  		as we unblocked. */
  		if( xBlockedTime > ( bktTIME_TO_BLOCK + bktALLOWABLE_MARGIN ) )
  		{
  			xErrorOccurred = pdTRUE;
  		}
  
  		xRunIndicator = bktRUN_INDICATOR;
  
  		xSecondaryCycles++;
  	}
  }
  /*-----------------------------------------------------------*/
  
  portBASE_TYPE xAreAltBlockTimeTestTasksStillRunning( void )
  {
  static portBASE_TYPE xLastPrimaryCycleCount = 0, xLastSecondaryCycleCount = 0;
  portBASE_TYPE xReturn = pdPASS;
  
  	/* Have both tasks performed at least one cycle since this function was
  	last called? */
  	if( xPrimaryCycles == xLastPrimaryCycleCount )
  	{
  		xReturn = pdFAIL;
  	}
  
  	if( xSecondaryCycles == xLastSecondaryCycleCount )
  	{
  		xReturn = pdFAIL;
  	}
  
  	if( xErrorOccurred == pdTRUE )
  	{
  		xReturn = pdFAIL;
  	}
  
  	xLastSecondaryCycleCount = xSecondaryCycles;
  	xLastPrimaryCycleCount = xPrimaryCycles;
  
  	return xReturn;
  }
  