/*
    FreeRTOS V6.0.3 - Copyright (C) 2010 Real Time Engineers Ltd.

    ***************************************************************************
    *                                                                         *
    * If you are:                                                             *
    *                                                                         *
    *    + New to FreeRTOS,                                                   *
    *    + Wanting to learn FreeRTOS or multitasking in general quickly       *
    *    + Looking for basic training,                                        *
    *    + Wanting to improve your FreeRTOS skills and productivity           *
    *                                                                         *
    * then take a look at the FreeRTOS eBook                                  *
    *                                                                         *
    *        "Using the FreeRTOS Real Time Kernel - a Practical Guide"        *
    *                  http://www.FreeRTOS.org/Documentation                  *
    *                                                                         *
    * A pdf reference manual is also available.  Both are usually delivered   *
    * to your inbox within 20 minutes to two hours when purchased between 8am *
    * and 8pm GMT (although please allow up to 24 hours in case of            *
    * exceptional circumstances).  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 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.
    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.
*/

/*
 * Creates eight tasks, each of which loops continuously performing an (emulated) 
 * 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  ( 8 )

/* 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 incrementing 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 );
	xTaskCreate( vCompetingMathTask1, ( signed char * ) "Math5", mathSTACK_SIZE, ( void * ) &( usTaskCheck[ 4 ] ), uxPriority, NULL );
	xTaskCreate( vCompetingMathTask2, ( signed char * ) "Math6", mathSTACK_SIZE, ( void * ) &( usTaskCheck[ 5 ] ), uxPriority, NULL );
	xTaskCreate( vCompetingMathTask3, ( signed char * ) "Math7", mathSTACK_SIZE, ( void * ) &( usTaskCheck[ 6 ] ), uxPriority, NULL );
	xTaskCreate( vCompetingMathTask4, ( signed char * ) "Math8", mathSTACK_SIZE, ( void * ) &( usTaskCheck[ 7 ] ), uxPriority, NULL );
}
/*-----------------------------------------------------------*/

static portTASK_FUNCTION( vCompetingMathTask1, pvParameters )
{
volatile portDOUBLE d1, d2, d3, d4;
volatile unsigned short *pusTaskCheckVariable;
volatile portDOUBLE dAnswer;
short sError = pdFALSE;

	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, increment the check 
			variable so we know this task is still running okay. */
			( *pusTaskCheckVariable )++;
		}

		#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;

	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, increment the check 
			variable so we know
			this task is still running okay. */
			( *pusTaskCheckVariable )++;
		}

		#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;

	/* 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, increment the check 
			variable so we know	this task is still running okay. */
			( *pusTaskCheckVariable )++;
		}
	}
}
/*-----------------------------------------------------------*/

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;

	/* 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, increment the check 
			variable so we know	this task is still running okay. */
			( *pusTaskCheckVariable )++;
		}
	}
}				 
/*-----------------------------------------------------------*/

/* This is called to check that all the created tasks are still running. */
portBASE_TYPE xAreMathsTaskStillRunning( void )
{
/* Keep a history of the check variables so we know if they have been incremented 
since the last call. */
static unsigned short usLastTaskCheck[ mathNUMBER_OF_TASKS ] = { ( unsigned short ) 0 };
portBASE_TYPE xReturn = pdTRUE, xTask;

	/* Check the maths tasks are still running by ensuring their check variables 
	are still incrementing. */
	for( xTask = 0; xTask < mathNUMBER_OF_TASKS; xTask++ )
	{
		if( usTaskCheck[ xTask ] == usLastTaskCheck[ xTask ] )
		{
			/* The check has not incremented so an error exists. */
			xReturn = pdFALSE;
		}

		usLastTaskCheck[ xTask ] = usTaskCheck[ xTask ];
	}

	return xReturn;
}