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

 /*
     FreeRTOS V7.5.0 - Copyright (C) 2013 Real Time Engineers Ltd.

     VISIT http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.

     ***************************************************************************
      *                                                                       *
      *    FreeRTOS provides completely free yet professionally developed,    *
      *    robust, strictly quality controlled, supported, and cross          *
      *    platform software that has become a de facto standard.             *
      *                                                                       *
      *    Help yourself get started quickly and support the FreeRTOS         *
      *    project by purchasing a FreeRTOS tutorial book, reference          *
      *    manual, or both from: http://www.FreeRTOS.org/Documentation        *
      *                                                                       *
      *    Thank you!                                                         *
      *                                                                       *
     ***************************************************************************

     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.  Full license text is available from the following
     link: http://www.freertos.org/a00114.html

     1 tab == 4 spaces!

     ***************************************************************************
      *                                                                       *
      *    Having a problem?  Start by reading the FAQ "My application does   *
      *    not run, what could be wrong?"                                     *
      *                                                                       *
      *    http://www.FreeRTOS.org/FAQHelp.html                               *
      *                                                                       *
     ***************************************************************************

     http://www.FreeRTOS.org - Documentation, books, training, latest versions,
     license and Real Time Engineers Ltd. contact details.

     http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
     including FreeRTOS+Trace - an indispensable productivity tool, a DOS
     compatible FAT file system, and our tiny thread aware UDP/IP stack.

     http://www.OpenRTOS.com - Real Time Engineers ltd license FreeRTOS to High
     Integrity Systems to sell under the OpenRTOS brand.  Low cost OpenRTOS
     licenses offer ticketed support, indemnification and middleware.

     http://www.SafeRTOS.com - High Integrity Systems also provide a safety
     engineered and independently SIL3 certified version for use in safety and
     mission critical applications that require provable dependability.

     1 tab == 4 spaces!
 */

 /*
  * Creates eight tasks, each of which loops continuously performing a floating
  * point calculation.
  *
  * All the tasks run at the idle priority and never block or yield.  This causes
  * all eight tasks to time slice with the idle task.  Running at the idle
  * priority means that these tasks will get pre-empted any time another task is
  * ready to run or a time slice occurs.  More often than not the pre-emption
  * will occur mid calculation, creating a good test of the schedulers context
  * switch mechanism - a calculation producing an unexpected result could be a
  * symptom of a corruption in the context of a task.
  */

 #include <stdlib.h>
 #include <math.h>

 /* Scheduler include files. */
 #include "FreeRTOS.h"
 #include "task.h"

 /* Demo program include files. */
 #include "flop.h"

 #define mathSTACK_SIZE		configMINIMAL_STACK_SIZE
 #define mathNUMBER_OF_TASKS  ( 4 )

 /* Four tasks, each of which performs a different floating point calculation.
 Each of the four is created twice. */
 static portTASK_FUNCTION_PROTO( vCompetingMathTask1, pvParameters );
 static portTASK_FUNCTION_PROTO( vCompetingMathTask2, pvParameters );
 static portTASK_FUNCTION_PROTO( vCompetingMathTask3, pvParameters );
 static portTASK_FUNCTION_PROTO( vCompetingMathTask4, pvParameters );

 /* These variables are used to check that all the tasks are still running.  If a
 task gets a calculation wrong it will stop setting its check variable. */
 static volatile unsigned short usTaskCheck[ mathNUMBER_OF_TASKS ] = { ( unsigned short ) 0 };

 /*-----------------------------------------------------------*/

 void vStartMathTasks( unsigned portBASE_TYPE uxPriority )
 {
 	xTaskCreate( vCompetingMathTask1, ( signed char * ) "Math1", mathSTACK_SIZE, ( void * ) &( usTaskCheck[ 0 ] ), uxPriority, NULL );
 	xTaskCreate( vCompetingMathTask2, ( signed char * ) "Math2", mathSTACK_SIZE, ( void * ) &( usTaskCheck[ 1 ] ), uxPriority, NULL );
 	xTaskCreate( vCompetingMathTask3, ( signed char * ) "Math3", mathSTACK_SIZE, ( void * ) &( usTaskCheck[ 2 ] ), uxPriority, NULL );
 	xTaskCreate( vCompetingMathTask4, ( signed char * ) "Math4", mathSTACK_SIZE, ( void * ) &( usTaskCheck[ 3 ] ), uxPriority, NULL );
 }
 /*-----------------------------------------------------------*/

 static portTASK_FUNCTION( vCompetingMathTask1, pvParameters )
 {
 volatile portDOUBLE d1, d2, d3, d4;
 volatile unsigned short *pusTaskCheckVariable;
 volatile portDOUBLE dAnswer;
 short sError = pdFALSE;

 	/* Some ports require that tasks that use a hardware floating point unit
 	tell the kernel that they require a floating point context before any
 	floating point instructions are executed. */
 	portTASK_USES_FLOATING_POINT();

 	d1 = 123.4567;
 	d2 = 2345.6789;
 	d3 = -918.222;

 	dAnswer = ( d1 + d2 ) * d3;

 	/* The variable this task increments to show it is still running is passed in
 	as the parameter. */
 	pusTaskCheckVariable = ( unsigned short * ) pvParameters;

 	/* Keep performing a calculation and checking the result against a constant. */
 	for(;;)
 	{
 		d1 = 123.4567;
 		d2 = 2345.6789;
 		d3 = -918.222;

 		d4 = ( d1 + d2 ) * d3;

 		#if configUSE_PREEMPTION == 0
 			taskYIELD();
 		#endif

 		/* If the calculation does not match the expected constant, stop the
 		increment of the check variable. */
 		if( fabs( d4 - dAnswer ) > 0.001 )
 		{
 			sError = pdTRUE;
 		}

 		if( sError == pdFALSE )
 		{
 			/* If the calculation has always been correct then set set the check
 			variable.  The check variable will get set to pdFALSE each time
 			xAreMathsTaskStillRunning() is executed. */
 			( *pusTaskCheckVariable ) = pdTRUE;
 		}

 		#if configUSE_PREEMPTION == 0
 			taskYIELD();
 		#endif

 	}
 }
 /*-----------------------------------------------------------*/

 static portTASK_FUNCTION( vCompetingMathTask2, pvParameters )
 {
 volatile portDOUBLE d1, d2, d3, d4;
 volatile unsigned short *pusTaskCheckVariable;
 volatile portDOUBLE dAnswer;
 short sError = pdFALSE;

 	/* Some ports require that tasks that use a hardware floating point unit
 	tell the kernel that they require a floating point context before any
 	floating point instructions are executed. */
 	portTASK_USES_FLOATING_POINT();

 	d1 = -389.38;
 	d2 = 32498.2;
 	d3 = -2.0001;

 	dAnswer = ( d1 / d2 ) * d3;


 	/* The variable this task increments to show it is still running is passed in
 	as the parameter. */
 	pusTaskCheckVariable = ( unsigned short * ) pvParameters;

 	/* Keep performing a calculation and checking the result against a constant. */
 	for( ;; )
 	{
 		d1 = -389.38;
 		d2 = 32498.2;
 		d3 = -2.0001;

 		d4 = ( d1 / d2 ) * d3;

 		#if configUSE_PREEMPTION == 0
 			taskYIELD();
 		#endif

 		/* If the calculation does not match the expected constant, stop the
 		increment of the check variable. */
 		if( fabs( d4 - dAnswer ) > 0.001 )
 		{
 			sError = pdTRUE;
 		}

 		if( sError == pdFALSE )
 		{
 			/* If the calculation has always been correct then set set the check
 			variable.  The check variable will get set to pdFALSE each time
 			xAreMathsTaskStillRunning() is executed. */
 			( *pusTaskCheckVariable ) = pdTRUE;
 		}

 		#if configUSE_PREEMPTION == 0
 			taskYIELD();
 		#endif
 	}
 }
 /*-----------------------------------------------------------*/

 static portTASK_FUNCTION( vCompetingMathTask3, pvParameters )
 {
 volatile portDOUBLE *pdArray, dTotal1, dTotal2, dDifference;
 volatile unsigned short *pusTaskCheckVariable;
 const size_t xArraySize = 10;
 size_t xPosition;
 short sError = pdFALSE;

 	/* Some ports require that tasks that use a hardware floating point unit
 	tell the kernel that they require a floating point context before any
 	floating point instructions are executed. */
 	portTASK_USES_FLOATING_POINT();

 	/* The variable this task increments to show it is still running is passed in
 	as the parameter. */
 	pusTaskCheckVariable = ( unsigned short * ) pvParameters;

 	pdArray = ( portDOUBLE * ) pvPortMalloc( xArraySize * sizeof( portDOUBLE ) );

 	/* Keep filling an array, keeping a running total of the values placed in the
 	array.  Then run through the array adding up all the values.  If the two totals
 	do not match, stop the check variable from incrementing. */
 	for( ;; )
 	{
 		dTotal1 = 0.0;
 		dTotal2 = 0.0;

 		for( xPosition = 0; xPosition < xArraySize; xPosition++ )
 		{
 			pdArray[ xPosition ] = ( portDOUBLE ) xPosition + 5.5;
 			dTotal1 += ( portDOUBLE ) xPosition + 5.5;
 		}

 		#if configUSE_PREEMPTION == 0
 			taskYIELD();
 		#endif

 		for( xPosition = 0; xPosition < xArraySize; xPosition++ )
 		{
 			dTotal2 += pdArray[ xPosition ];
 		}

 		dDifference = dTotal1 - dTotal2;
 		if( fabs( dDifference ) > 0.001 )
 		{
 			sError = pdTRUE;
 		}

 		#if configUSE_PREEMPTION == 0
 			taskYIELD();
 		#endif

 		if( sError == pdFALSE )
 		{
 			/* If the calculation has always been correct then set set the check
 			variable.  The check variable will get set to pdFALSE each time
 			xAreMathsTaskStillRunning() is executed. */
 			( *pusTaskCheckVariable ) = pdTRUE;
 		}
 	}
 }
 /*-----------------------------------------------------------*/

 static portTASK_FUNCTION( vCompetingMathTask4, pvParameters )
 {
 volatile portDOUBLE *pdArray, dTotal1, dTotal2, dDifference;
 volatile unsigned short *pusTaskCheckVariable;
 const size_t xArraySize = 10;
 size_t xPosition;
 short sError = pdFALSE;

 	/* Some ports require that tasks that use a hardware floating point unit
 	tell the kernel that they require a floating point context before any
 	floating point instructions are executed. */
 	portTASK_USES_FLOATING_POINT();

 	/* The variable this task increments to show it is still running is passed in
 	as the parameter. */
 	pusTaskCheckVariable = ( unsigned short * ) pvParameters;

 	pdArray = ( portDOUBLE * ) pvPortMalloc( xArraySize * sizeof( portDOUBLE ) );

 	/* Keep filling an array, keeping a running total of the values placed in the
 	array.  Then run through the array adding up all the values.  If the two totals
 	do not match, stop the check variable from incrementing. */
 	for( ;; )
 	{
 		dTotal1 = 0.0;
 		dTotal2 = 0.0;

 		for( xPosition = 0; xPosition < xArraySize; xPosition++ )
 		{
 			pdArray[ xPosition ] = ( portDOUBLE ) xPosition * 12.123;
 			dTotal1 += ( portDOUBLE ) xPosition * 12.123;
 		}

 		#if configUSE_PREEMPTION == 0
 			taskYIELD();
 		#endif

 		for( xPosition = 0; xPosition < xArraySize; xPosition++ )
 		{
 			dTotal2 += pdArray[ xPosition ];
 		}

 		dDifference = dTotal1 - dTotal2;
 		if( fabs( dDifference ) > 0.001 )
 		{
 			sError = pdTRUE;
 		}

 		#if configUSE_PREEMPTION == 0
 			taskYIELD();
 		#endif

 		if( sError == pdFALSE )
 		{
 			/* If the calculation has always been correct then set set the check
 			variable.  The check variable will get set to pdFALSE each time
 			xAreMathsTaskStillRunning() is executed. */
 			( *pusTaskCheckVariable ) = pdTRUE;
 		}
 	}
 }
 /*-----------------------------------------------------------*/

 /* This is called to check that all the created tasks are still running. */
 portBASE_TYPE xAreMathsTaskStillRunning( void )
 {
 portBASE_TYPE xReturn = pdPASS, xTask;

 	/* Check the maths tasks are still running by ensuring their check variables
 	have been set to pdPASS. */
 	for( xTask = 0; xTask < mathNUMBER_OF_TASKS; xTask++ )
 	{
 		if( usTaskCheck[ xTask ] != pdTRUE )
 		{
 			/* The check has not been set so the associated task has either
 			stalled or detected an error. */
 			xReturn = pdFAIL;
 		}
 		else
 		{
 			/* Reset the variable so it can be checked again the next time this
 			function is executed. */
 			usTaskCheck[ xTask ] = pdFALSE;
 		}
 	}

 	return xReturn;
 }
	/*
	FreeRTOS V7.5.0 - Copyright (C) 2013 Real Time Engineers Ltd.

	VISIT http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.

	***************************************************************************
	* *
	* FreeRTOS provides completely free yet professionally developed, *
	* robust, strictly quality controlled, supported, and cross *
	* platform software that has become a de facto standard. *
	* *
	* Help yourself get started quickly and support the FreeRTOS *
	* project by purchasing a FreeRTOS tutorial book, reference *
	* manual, or both from: http://www.FreeRTOS.org/Documentation *
	* *
	* Thank you! *
	* *
	***************************************************************************

	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. Full license text is available from the following
	link: http://www.freertos.org/a00114.html

	1 tab == 4 spaces!

	***************************************************************************
	* *
	* Having a problem? Start by reading the FAQ "My application does *
	* not run, what could be wrong?" *
	* *
	* http://www.FreeRTOS.org/FAQHelp.html *
	* *
	***************************************************************************

	http://www.FreeRTOS.org - Documentation, books, training, latest versions,
	license and Real Time Engineers Ltd. contact details.

	http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
	including FreeRTOS+Trace - an indispensable productivity tool, a DOS
	compatible FAT file system, and our tiny thread aware UDP/IP stack.

	http://www.OpenRTOS.com - Real Time Engineers ltd license FreeRTOS to High
	Integrity Systems to sell under the OpenRTOS brand. Low cost OpenRTOS
	licenses offer ticketed support, indemnification and middleware.

	http://www.SafeRTOS.com - High Integrity Systems also provide a safety
	engineered and independently SIL3 certified version for use in safety and
	mission critical applications that require provable dependability.

	1 tab == 4 spaces!
	*/

	/*
	* Creates eight tasks, each of which loops continuously performing a floating
	* point calculation.
	*
	* All the tasks run at the idle priority and never block or yield. This causes
	* all eight tasks to time slice with the idle task. Running at the idle
	* priority means that these tasks will get pre-empted any time another task is
	* ready to run or a time slice occurs. More often than not the pre-emption
	* will occur mid calculation, creating a good test of the schedulers context
	* switch mechanism - a calculation producing an unexpected result could be a
	* symptom of a corruption in the context of a task.
	*/

	#include <stdlib.h>
	#include <math.h>

	/* Scheduler include files. */
	#include "FreeRTOS.h"
	#include "task.h"

	/* Demo program include files. */
	#include "flop.h"

	#define mathSTACK_SIZE configMINIMAL_STACK_SIZE
	#define mathNUMBER_OF_TASKS ( 4 )

	/* Four tasks, each of which performs a different floating point calculation.
	Each of the four is created twice. */
	static portTASK_FUNCTION_PROTO( vCompetingMathTask1, pvParameters );
	static portTASK_FUNCTION_PROTO( vCompetingMathTask2, pvParameters );
	static portTASK_FUNCTION_PROTO( vCompetingMathTask3, pvParameters );
	static portTASK_FUNCTION_PROTO( vCompetingMathTask4, pvParameters );

	/* These variables are used to check that all the tasks are still running. If a
	task gets a calculation wrong it will stop setting its check variable. */
	static volatile unsigned short usTaskCheck[ mathNUMBER_OF_TASKS ] = { ( unsigned short ) 0 };

	/-----------------------------------------------------------/

	void vStartMathTasks( unsigned portBASE_TYPE uxPriority )
	{
	xTaskCreate( vCompetingMathTask1, ( signed char * ) "Math1", mathSTACK_SIZE, ( void * ) &( usTaskCheck[ 0 ] ), uxPriority, NULL );
	xTaskCreate( vCompetingMathTask2, ( signed char * ) "Math2", mathSTACK_SIZE, ( void * ) &( usTaskCheck[ 1 ] ), uxPriority, NULL );
	xTaskCreate( vCompetingMathTask3, ( signed char * ) "Math3", mathSTACK_SIZE, ( void * ) &( usTaskCheck[ 2 ] ), uxPriority, NULL );
	xTaskCreate( vCompetingMathTask4, ( signed char * ) "Math4", mathSTACK_SIZE, ( void * ) &( usTaskCheck[ 3 ] ), uxPriority, NULL );
	}
	/-----------------------------------------------------------/

	static portTASK_FUNCTION( vCompetingMathTask1, pvParameters )
	{
	volatile portDOUBLE d1, d2, d3, d4;
	volatile unsigned short *pusTaskCheckVariable;
	volatile portDOUBLE dAnswer;
	short sError = pdFALSE;

	/* Some ports require that tasks that use a hardware floating point unit
	tell the kernel that they require a floating point context before any
	floating point instructions are executed. */
	portTASK_USES_FLOATING_POINT();

	d1 = 123.4567;
	d2 = 2345.6789;
	d3 = -918.222;

	dAnswer = ( d1 + d2 ) * d3;

	/* The variable this task increments to show it is still running is passed in
	as the parameter. */
	pusTaskCheckVariable = ( unsigned short * ) pvParameters;

	/* Keep performing a calculation and checking the result against a constant. */
	for(;;)
	{
	d1 = 123.4567;
	d2 = 2345.6789;
	d3 = -918.222;

	d4 = ( d1 + d2 ) * d3;

	#if configUSE_PREEMPTION == 0
	taskYIELD();
	#endif

	/* If the calculation does not match the expected constant, stop the
	increment of the check variable. */
	if( fabs( d4 - dAnswer ) > 0.001 )
	{
	sError = pdTRUE;
	}

	if( sError == pdFALSE )
	{
	/* If the calculation has always been correct then set set the check
	variable. The check variable will get set to pdFALSE each time
	xAreMathsTaskStillRunning() is executed. */
	( *pusTaskCheckVariable ) = pdTRUE;
	}

	#if configUSE_PREEMPTION == 0
	taskYIELD();
	#endif

	}
	}
	/-----------------------------------------------------------/

	static portTASK_FUNCTION( vCompetingMathTask2, pvParameters )
	{
	volatile portDOUBLE d1, d2, d3, d4;
	volatile unsigned short *pusTaskCheckVariable;
	volatile portDOUBLE dAnswer;
	short sError = pdFALSE;

	/* Some ports require that tasks that use a hardware floating point unit
	tell the kernel that they require a floating point context before any
	floating point instructions are executed. */
	portTASK_USES_FLOATING_POINT();

	d1 = -389.38;
	d2 = 32498.2;
	d3 = -2.0001;

	dAnswer = ( d1 / d2 ) * d3;


	/* The variable this task increments to show it is still running is passed in
	as the parameter. */
	pusTaskCheckVariable = ( unsigned short * ) pvParameters;

	/* Keep performing a calculation and checking the result against a constant. */
	for( ;; )
	{
	d1 = -389.38;
	d2 = 32498.2;
	d3 = -2.0001;

	d4 = ( d1 / d2 ) * d3;

	#if configUSE_PREEMPTION == 0
	taskYIELD();
	#endif

	/* If the calculation does not match the expected constant, stop the
	increment of the check variable. */
	if( fabs( d4 - dAnswer ) > 0.001 )
	{
	sError = pdTRUE;
	}

	if( sError == pdFALSE )
	{
	/* If the calculation has always been correct then set set the check
	variable. The check variable will get set to pdFALSE each time
	xAreMathsTaskStillRunning() is executed. */
	( *pusTaskCheckVariable ) = pdTRUE;
	}

	#if configUSE_PREEMPTION == 0
	taskYIELD();
	#endif
	}
	}
	/-----------------------------------------------------------/

	static portTASK_FUNCTION( vCompetingMathTask3, pvParameters )
	{
	volatile portDOUBLE *pdArray, dTotal1, dTotal2, dDifference;
	volatile unsigned short *pusTaskCheckVariable;
	const size_t xArraySize = 10;
	size_t xPosition;
	short sError = pdFALSE;

	/* Some ports require that tasks that use a hardware floating point unit
	tell the kernel that they require a floating point context before any
	floating point instructions are executed. */
	portTASK_USES_FLOATING_POINT();

	/* The variable this task increments to show it is still running is passed in
	as the parameter. */
	pusTaskCheckVariable = ( unsigned short * ) pvParameters;

	pdArray = ( portDOUBLE * ) pvPortMalloc( xArraySize * sizeof( portDOUBLE ) );

	/* Keep filling an array, keeping a running total of the values placed in the
	array. Then run through the array adding up all the values. If the two totals
	do not match, stop the check variable from incrementing. */
	for( ;; )
	{
	dTotal1 = 0.0;
	dTotal2 = 0.0;

	for( xPosition = 0; xPosition < xArraySize; xPosition++ )
	{
	pdArray[ xPosition ] = ( portDOUBLE ) xPosition + 5.5;
	dTotal1 += ( portDOUBLE ) xPosition + 5.5;
	}

	#if configUSE_PREEMPTION == 0
	taskYIELD();
	#endif

	for( xPosition = 0; xPosition < xArraySize; xPosition++ )
	{
	dTotal2 += pdArray[ xPosition ];
	}

	dDifference = dTotal1 - dTotal2;
	if( fabs( dDifference ) > 0.001 )
	{
	sError = pdTRUE;
	}

	#if configUSE_PREEMPTION == 0
	taskYIELD();
	#endif

	if( sError == pdFALSE )
	{
	/* If the calculation has always been correct then set set the check
	variable. The check variable will get set to pdFALSE each time
	xAreMathsTaskStillRunning() is executed. */
	( *pusTaskCheckVariable ) = pdTRUE;
	}
	}
	}
	/-----------------------------------------------------------/

	static portTASK_FUNCTION( vCompetingMathTask4, pvParameters )
	{
	volatile portDOUBLE *pdArray, dTotal1, dTotal2, dDifference;
	volatile unsigned short *pusTaskCheckVariable;
	const size_t xArraySize = 10;
	size_t xPosition;
	short sError = pdFALSE;

	/* Some ports require that tasks that use a hardware floating point unit
	tell the kernel that they require a floating point context before any
	floating point instructions are executed. */
	portTASK_USES_FLOATING_POINT();

	/* The variable this task increments to show it is still running is passed in
	as the parameter. */
	pusTaskCheckVariable = ( unsigned short * ) pvParameters;

	pdArray = ( portDOUBLE * ) pvPortMalloc( xArraySize * sizeof( portDOUBLE ) );

	/* Keep filling an array, keeping a running total of the values placed in the
	array. Then run through the array adding up all the values. If the two totals
	do not match, stop the check variable from incrementing. */
	for( ;; )
	{
	dTotal1 = 0.0;
	dTotal2 = 0.0;

	for( xPosition = 0; xPosition < xArraySize; xPosition++ )
	{
	pdArray[ xPosition ] = ( portDOUBLE ) xPosition * 12.123;
	dTotal1 += ( portDOUBLE ) xPosition * 12.123;
	}

	#if configUSE_PREEMPTION == 0
	taskYIELD();
	#endif

	for( xPosition = 0; xPosition < xArraySize; xPosition++ )
	{
	dTotal2 += pdArray[ xPosition ];
	}

	dDifference = dTotal1 - dTotal2;
	if( fabs( dDifference ) > 0.001 )
	{
	sError = pdTRUE;
	}

	#if configUSE_PREEMPTION == 0
	taskYIELD();
	#endif

	if( sError == pdFALSE )
	{
	/* If the calculation has always been correct then set set the check
	variable. The check variable will get set to pdFALSE each time
	xAreMathsTaskStillRunning() is executed. */
	( *pusTaskCheckVariable ) = pdTRUE;
	}
	}
	}
	/-----------------------------------------------------------/

	/* This is called to check that all the created tasks are still running. */
	portBASE_TYPE xAreMathsTaskStillRunning( void )
	{
	portBASE_TYPE xReturn = pdPASS, xTask;

	/* Check the maths tasks are still running by ensuring their check variables
	have been set to pdPASS. */
	for( xTask = 0; xTask < mathNUMBER_OF_TASKS; xTask++ )
	{
	if( usTaskCheck[ xTask ] != pdTRUE )
	{
	/* The check has not been set so the associated task has either
	stalled or detected an error. */
	xReturn = pdFAIL;
	}
	else
	{
	/* Reset the variable so it can be checked again the next time this
	function is executed. */
	usTaskCheck[ xTask ] = pdFALSE;
	}
	}

	return xReturn;
	}