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[/] [openrisc/] [trunk/] [rtos/] [freertos-6.1.1/] [Demo/] [Common/] [Minimal/] [semtest.c] - Blame information for rev 609

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1 606 jeremybenn
/*
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    FreeRTOS V6.1.1 - Copyright (C) 2011 Real Time Engineers Ltd.
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    ***************************************************************************
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    *                                                                         *
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    * If you are:                                                             *
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    *                                                                         *
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    *    + New to FreeRTOS,                                                   *
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    *    + Wanting to learn FreeRTOS or multitasking in general quickly       *
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    *    + Looking for basic training,                                        *
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    *    + Wanting to improve your FreeRTOS skills and productivity           *
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    *                                                                         *
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    * then take a look at the FreeRTOS books - available as PDF or paperback  *
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    *                                                                         *
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    *        "Using the FreeRTOS Real Time Kernel - a Practical Guide"        *
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    *                  http://www.FreeRTOS.org/Documentation                  *
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    *                                                                         *
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    * A pdf reference manual is also available.  Both are usually delivered   *
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    * to your inbox within 20 minutes to two hours when purchased between 8am *
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    * and 8pm GMT (although please allow up to 24 hours in case of            *
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    * exceptional circumstances).  Thank you for your support!                *
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    *                                                                         *
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    ***************************************************************************
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    This file is part of the FreeRTOS distribution.
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    FreeRTOS is free software; you can redistribute it and/or modify it under
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    the terms of the GNU General Public License (version 2) as published by the
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    Free Software Foundation AND MODIFIED BY the FreeRTOS exception.
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    ***NOTE*** The exception to the GPL is included to allow you to distribute
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    a combined work that includes FreeRTOS without being obliged to provide the
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    source code for proprietary components outside of the FreeRTOS kernel.
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    FreeRTOS is distributed in the hope that it will be useful, but WITHOUT
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    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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    FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
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    more details. You should have received a copy of the GNU General Public
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    License and the FreeRTOS license exception along with FreeRTOS; if not it
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    can be viewed here: http://www.freertos.org/a00114.html and also obtained
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    by writing to Richard Barry, contact details for whom are available on the
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    FreeRTOS WEB site.
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    1 tab == 4 spaces!
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    http://www.FreeRTOS.org - Documentation, latest information, license and
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    contact details.
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    http://www.SafeRTOS.com - A version that is certified for use in safety
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    critical systems.
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    http://www.OpenRTOS.com - Commercial support, development, porting,
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    licensing and training services.
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*/
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/*
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 * Creates two sets of two tasks.  The tasks within a set share a variable, access
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 * to which is guarded by a semaphore.
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 *
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 * Each task starts by attempting to obtain the semaphore.  On obtaining a
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 * semaphore a task checks to ensure that the guarded variable has an expected
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 * value.  It then clears the variable to zero before counting it back up to the
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 * expected value in increments of 1.  After each increment the variable is checked
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 * to ensure it contains the value to which it was just set. When the starting
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 * value is again reached the task releases the semaphore giving the other task in
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 * the set a chance to do exactly the same thing.  The starting value is high
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 * enough to ensure that a tick is likely to occur during the incrementing loop.
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 *
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 * An error is flagged if at any time during the process a shared variable is
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 * found to have a value other than that expected.  Such an occurrence would
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 * suggest an error in the mutual exclusion mechanism by which access to the
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 * variable is restricted.
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 *
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 * The first set of two tasks poll their semaphore.  The second set use blocking
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 * calls.
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 *
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 */
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#include <stdlib.h>
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/* Scheduler include files. */
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#include "FreeRTOS.h"
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#include "task.h"
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#include "semphr.h"
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/* Demo app include files. */
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#include "semtest.h"
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/* The value to which the shared variables are counted. */
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#define semtstBLOCKING_EXPECTED_VALUE           ( ( unsigned long ) 0xfff )
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#define semtstNON_BLOCKING_EXPECTED_VALUE       ( ( unsigned long ) 0xff  )
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#define semtstSTACK_SIZE                        configMINIMAL_STACK_SIZE
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#define semtstNUM_TASKS                         ( 4 )
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#define semtstDELAY_FACTOR                      ( ( portTickType ) 10 )
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/* The task function as described at the top of the file. */
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static portTASK_FUNCTION_PROTO( prvSemaphoreTest, pvParameters );
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/* Structure used to pass parameters to each task. */
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typedef struct SEMAPHORE_PARAMETERS
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{
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        xSemaphoreHandle xSemaphore;
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        volatile unsigned long *pulSharedVariable;
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        portTickType xBlockTime;
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} xSemaphoreParameters;
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/* Variables used to check that all the tasks are still running without errors. */
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static volatile short sCheckVariables[ semtstNUM_TASKS ] = { 0 };
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static volatile short sNextCheckVariable = 0;
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/*-----------------------------------------------------------*/
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void vStartSemaphoreTasks( unsigned portBASE_TYPE uxPriority )
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{
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xSemaphoreParameters *pxFirstSemaphoreParameters, *pxSecondSemaphoreParameters;
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const portTickType xBlockTime = ( portTickType ) 100;
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        /* Create the structure used to pass parameters to the first two tasks. */
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        pxFirstSemaphoreParameters = ( xSemaphoreParameters * ) pvPortMalloc( sizeof( xSemaphoreParameters ) );
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        if( pxFirstSemaphoreParameters != NULL )
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        {
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                /* Create the semaphore used by the first two tasks. */
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                vSemaphoreCreateBinary( pxFirstSemaphoreParameters->xSemaphore );
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                if( pxFirstSemaphoreParameters->xSemaphore != NULL )
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                {
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                        /* Create the variable which is to be shared by the first two tasks. */
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                        pxFirstSemaphoreParameters->pulSharedVariable = ( unsigned long * ) pvPortMalloc( sizeof( unsigned long ) );
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                        /* Initialise the share variable to the value the tasks expect. */
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                        *( pxFirstSemaphoreParameters->pulSharedVariable ) = semtstNON_BLOCKING_EXPECTED_VALUE;
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                        /* The first two tasks do not block on semaphore calls. */
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                        pxFirstSemaphoreParameters->xBlockTime = ( portTickType ) 0;
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                        /* Spawn the first two tasks.  As they poll they operate at the idle priority. */
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                        xTaskCreate( prvSemaphoreTest, ( signed char * ) "PolSEM1", semtstSTACK_SIZE, ( void * ) pxFirstSemaphoreParameters, tskIDLE_PRIORITY, ( xTaskHandle * ) NULL );
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                        xTaskCreate( prvSemaphoreTest, ( signed char * ) "PolSEM2", semtstSTACK_SIZE, ( void * ) pxFirstSemaphoreParameters, tskIDLE_PRIORITY, ( xTaskHandle * ) NULL );
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                }
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        }
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        /* Do exactly the same to create the second set of tasks, only this time
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        provide a block time for the semaphore calls. */
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        pxSecondSemaphoreParameters = ( xSemaphoreParameters * ) pvPortMalloc( sizeof( xSemaphoreParameters ) );
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        if( pxSecondSemaphoreParameters != NULL )
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        {
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                vSemaphoreCreateBinary( pxSecondSemaphoreParameters->xSemaphore );
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                if( pxSecondSemaphoreParameters->xSemaphore != NULL )
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                {
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                        pxSecondSemaphoreParameters->pulSharedVariable = ( unsigned long * ) pvPortMalloc( sizeof( unsigned long ) );
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                        *( pxSecondSemaphoreParameters->pulSharedVariable ) = semtstBLOCKING_EXPECTED_VALUE;
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                        pxSecondSemaphoreParameters->xBlockTime = xBlockTime / portTICK_RATE_MS;
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                        xTaskCreate( prvSemaphoreTest, ( signed char * ) "BlkSEM1", semtstSTACK_SIZE, ( void * ) pxSecondSemaphoreParameters, uxPriority, ( xTaskHandle * ) NULL );
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                        xTaskCreate( prvSemaphoreTest, ( signed char * ) "BlkSEM2", semtstSTACK_SIZE, ( void * ) pxSecondSemaphoreParameters, uxPriority, ( xTaskHandle * ) NULL );
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                }
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        }
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        /* vQueueAddToRegistry() adds the semaphore to the registry, if one is
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        in use.  The registry is provided as a means for kernel aware
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        debuggers to locate semaphores and has no purpose if a kernel aware debugger
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        is not being used.  The call to vQueueAddToRegistry() will be removed
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        by the pre-processor if configQUEUE_REGISTRY_SIZE is not defined or is
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        defined to be less than 1. */
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        vQueueAddToRegistry( ( xQueueHandle ) pxFirstSemaphoreParameters->xSemaphore, ( signed char * ) "Counting_Sem_1" );
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        vQueueAddToRegistry( ( xQueueHandle ) pxSecondSemaphoreParameters->xSemaphore, ( signed char * ) "Counting_Sem_2" );
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}
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/*-----------------------------------------------------------*/
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static portTASK_FUNCTION( prvSemaphoreTest, pvParameters )
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{
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xSemaphoreParameters *pxParameters;
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volatile unsigned long *pulSharedVariable, ulExpectedValue;
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unsigned long ulCounter;
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short sError = pdFALSE, sCheckVariableToUse;
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        /* See which check variable to use.  sNextCheckVariable is not semaphore
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        protected! */
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        portENTER_CRITICAL();
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                sCheckVariableToUse = sNextCheckVariable;
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                sNextCheckVariable++;
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        portEXIT_CRITICAL();
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        /* A structure is passed in as the parameter.  This contains the shared
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        variable being guarded. */
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        pxParameters = ( xSemaphoreParameters * ) pvParameters;
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        pulSharedVariable = pxParameters->pulSharedVariable;
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        /* If we are blocking we use a much higher count to ensure loads of context
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        switches occur during the count. */
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        if( pxParameters->xBlockTime > ( portTickType ) 0 )
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        {
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                ulExpectedValue = semtstBLOCKING_EXPECTED_VALUE;
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        }
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        else
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        {
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                ulExpectedValue = semtstNON_BLOCKING_EXPECTED_VALUE;
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        }
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        for( ;; )
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        {
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                /* Try to obtain the semaphore. */
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                if( xSemaphoreTake( pxParameters->xSemaphore, pxParameters->xBlockTime ) == pdPASS )
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                {
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                        /* We have the semaphore and so expect any other tasks using the
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                        shared variable to have left it in the state we expect to find
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                        it. */
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                        if( *pulSharedVariable != ulExpectedValue )
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                        {
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                                sError = pdTRUE;
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                        }
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                        /* Clear the variable, then count it back up to the expected value
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                        before releasing the semaphore.  Would expect a context switch or
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                        two during this time. */
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                        for( ulCounter = ( unsigned long ) 0; ulCounter <= ulExpectedValue; ulCounter++ )
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                        {
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                                *pulSharedVariable = ulCounter;
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                                if( *pulSharedVariable != ulCounter )
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                                {
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                                        sError = pdTRUE;
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                                }
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                        }
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                        /* Release the semaphore, and if no errors have occurred increment the check
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                        variable. */
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                        if(     xSemaphoreGive( pxParameters->xSemaphore ) == pdFALSE )
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                        {
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                                sError = pdTRUE;
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                        }
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                        if( sError == pdFALSE )
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                        {
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                                if( sCheckVariableToUse < semtstNUM_TASKS )
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                                {
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                                        ( sCheckVariables[ sCheckVariableToUse ] )++;
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                                }
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                        }
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                        /* If we have a block time then we are running at a priority higher
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                        than the idle priority.  This task takes a long time to complete
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                        a cycle (deliberately so to test the guarding) so will be starving
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                        out lower priority tasks.  Block for some time to allow give lower
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                        priority tasks some processor time. */
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                        vTaskDelay( pxParameters->xBlockTime * semtstDELAY_FACTOR );
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                }
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                else
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                {
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                        if( pxParameters->xBlockTime == ( portTickType ) 0 )
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                        {
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                                /* We have not got the semaphore yet, so no point using the
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                                processor.  We are not blocking when attempting to obtain the
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                                semaphore. */
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                                taskYIELD();
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                        }
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                }
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        }
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}
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/*-----------------------------------------------------------*/
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/* This is called to check that all the created tasks are still running. */
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portBASE_TYPE xAreSemaphoreTasksStillRunning( void )
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{
268
static short sLastCheckVariables[ semtstNUM_TASKS ] = { 0 };
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portBASE_TYPE xTask, xReturn = pdTRUE;
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        for( xTask = 0; xTask < semtstNUM_TASKS; xTask++ )
272
        {
273
                if( sLastCheckVariables[ xTask ] == sCheckVariables[ xTask ] )
274
                {
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                        xReturn = pdFALSE;
276
                }
277
 
278
                sLastCheckVariables[ xTask ] = sCheckVariables[ xTask ];
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        }
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        return xReturn;
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}
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