Demo/Common/Minimal/AltBlock.c - third_party/github/FreeRTOS/FreeRTOS-Kernel - Git at Google

 /*
 	FreeRTOS V5.4.0 - Copyright (C) 2003-2009 Richard Barry.

 	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 exception 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.
 	Alternative commercial license and support terms are also available upon
 	request.  See the licensing section of http://www.FreeRTOS.org for full
 	license details.

 	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 along
 	with FreeRTOS; if not, write to the Free Software Foundation, Inc., 59
 	Temple Place, Suite 330, Boston, MA  02111-1307  USA.


 	***************************************************************************
 	*                                                                         *
 	* Looking for a quick start?  Then check out the FreeRTOS eBook!          *
 	* See http://www.FreeRTOS.org/Documentation for details                   *
 	*                                                                         *
 	***************************************************************************

 	1 tab == 4 spaces!

 	Please ensure to read the configuration and relevant port sections of the
 	online documentation.

 	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;
 }
	/*
	FreeRTOS V5.4.0 - Copyright (C) 2003-2009 Richard Barry.

	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 exception 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.
	Alternative commercial license and support terms are also available upon
	request. See the licensing section of http://www.FreeRTOS.org for full
	license details.

	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 along
	with FreeRTOS; if not, write to the Free Software Foundation, Inc., 59
	Temple Place, Suite 330, Boston, MA 02111-1307 USA.


	***************************************************************************
	* *
	* Looking for a quick start? Then check out the FreeRTOS eBook! *
	* See http://www.FreeRTOS.org/Documentation for details *
	* *
	***************************************************************************

	1 tab == 4 spaces!

	Please ensure to read the configuration and relevant port sections of the
	online documentation.

	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;
	}