/*
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    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.

    ***************************************************************************
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    ***************************************************************************

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    link: http://www.freertos.org/a00114.html

    ***************************************************************************
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*/

/*
 * 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.
 */

/* Standard includes. */
#include <stdlib.h>
#include <math.h>

/* Scheduler include files. */
#include "FreeRTOS.h"
#include "task.h"

/* Demo program include files. */
#include "flop.h"

#ifndef mathSTACK_SIZE
	#define mathSTACK_SIZE		configMINIMAL_STACK_SIZE
#endif

#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 uint16_t usTaskCheck[ mathNUMBER_OF_TASKS ] = { ( uint16_t ) 0 };

/*-----------------------------------------------------------*/

void vStartMathTasks( UBaseType_t uxPriority )
{
	xTaskCreate( vCompetingMathTask1, "Math1", mathSTACK_SIZE, ( void * ) &( usTaskCheck[ 0 ] ), uxPriority, NULL );
	xTaskCreate( vCompetingMathTask2, "Math2", mathSTACK_SIZE, ( void * ) &( usTaskCheck[ 1 ] ), uxPriority, NULL );
	xTaskCreate( vCompetingMathTask3, "Math3", mathSTACK_SIZE, ( void * ) &( usTaskCheck[ 2 ] ), uxPriority, NULL );
	xTaskCreate( vCompetingMathTask4, "Math4", mathSTACK_SIZE, ( void * ) &( usTaskCheck[ 3 ] ), uxPriority, NULL );
}
/*-----------------------------------------------------------*/

static portTASK_FUNCTION( vCompetingMathTask1, pvParameters )
{
volatile portDOUBLE d1, d2, d3, d4;
volatile uint16_t *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 = ( uint16_t * ) 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 uint16_t *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 = ( uint16_t * ) 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 uint16_t *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 = ( uint16_t * ) 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 uint16_t *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 = ( uint16_t * ) 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. */
BaseType_t xAreMathsTaskStillRunning( void )
{
BaseType_t 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;
}