291 lines
10 KiB
C
291 lines
10 KiB
C
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/*
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* FreeRTOS V202212.00
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* Copyright (C) 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy of
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* this software and associated documentation files (the "Software"), to deal in
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* the Software without restriction, including without limitation the rights to
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* use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
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* the Software, and to permit persons to whom the Software is furnished to do so,
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* subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in all
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* copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
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* FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
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* COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
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* IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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*
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* https://www.FreeRTOS.org
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* https://github.com/FreeRTOS
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*
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*/
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/*
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* Simple demonstration of the usage of counting semaphore.
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*/
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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 program include files. */
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#include "countsem.h"
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/* The maximum count value that the semaphore used for the demo can hold. */
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#define countMAX_COUNT_VALUE ( 200 )
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/* Constants used to indicate whether or not the semaphore should have been
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* created with its maximum count value, or its minimum count value. These
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* numbers are used to ensure that the pointers passed in as the task parameters
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* are valid. */
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#define countSTART_AT_MAX_COUNT ( 0xaa )
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#define countSTART_AT_ZERO ( 0x55 )
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/* Two tasks are created for the test. One uses a semaphore created with its
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* count value set to the maximum, and one with the count value set to zero. */
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#define countNUM_TEST_TASKS ( 2 )
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#define countDONT_BLOCK ( 0 )
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/*-----------------------------------------------------------*/
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/* Flag that will be latched to pdTRUE should any unexpected behaviour be
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* detected in any of the tasks. */
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static volatile BaseType_t xErrorDetected = pdFALSE;
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/*-----------------------------------------------------------*/
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/*
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* The demo task. This simply counts the semaphore up to its maximum value,
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* the counts it back down again. The result of each semaphore 'give' and
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* 'take' is inspected, with an error being flagged if it is found not to be
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* the expected result.
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*/
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static void prvCountingSemaphoreTask( void * pvParameters );
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/*
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* Utility function to increment the semaphore count value up from zero to
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* countMAX_COUNT_VALUE.
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*/
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static void prvIncrementSemaphoreCount( SemaphoreHandle_t xSemaphore,
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volatile UBaseType_t * puxLoopCounter );
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/*
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* Utility function to decrement the semaphore count value up from
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* countMAX_COUNT_VALUE to zero.
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*/
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static void prvDecrementSemaphoreCount( SemaphoreHandle_t xSemaphore,
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volatile UBaseType_t * puxLoopCounter );
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/*-----------------------------------------------------------*/
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/* The structure that is passed into the task as the task parameter. */
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typedef struct COUNT_SEM_STRUCT
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{
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/* The semaphore to be used for the demo. */
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SemaphoreHandle_t xSemaphore;
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/* Set to countSTART_AT_MAX_COUNT if the semaphore should be created with
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* its count value set to its max count value, or countSTART_AT_ZERO if it
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* should have been created with its count value set to 0. */
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UBaseType_t uxExpectedStartCount;
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/* Incremented on each cycle of the demo task. Used to detect a stalled
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* task. */
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volatile UBaseType_t uxLoopCounter;
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} xCountSemStruct;
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/* Two structures are defined, one is passed to each test task. */
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static xCountSemStruct xParameters[ countNUM_TEST_TASKS ];
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/*-----------------------------------------------------------*/
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void vStartCountingSemaphoreTasks( void )
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{
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/* Create the semaphores that we are going to use for the test/demo. The
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* first should be created such that it starts at its maximum count value,
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* the second should be created such that it starts with a count value of zero. */
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xParameters[ 0 ].xSemaphore = xSemaphoreCreateCounting( countMAX_COUNT_VALUE, countMAX_COUNT_VALUE );
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xParameters[ 0 ].uxExpectedStartCount = countSTART_AT_MAX_COUNT;
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xParameters[ 0 ].uxLoopCounter = 0;
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xParameters[ 1 ].xSemaphore = xSemaphoreCreateCounting( countMAX_COUNT_VALUE, 0 );
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xParameters[ 1 ].uxExpectedStartCount = 0;
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xParameters[ 1 ].uxLoopCounter = 0;
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/* Were the semaphores created? */
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if( ( xParameters[ 0 ].xSemaphore != NULL ) || ( xParameters[ 1 ].xSemaphore != NULL ) )
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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
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* debugger is not being used. The call to vQueueAddToRegistry() will be
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* removed by the pre-processor if configQUEUE_REGISTRY_SIZE is not
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* defined or is defined to be less than 1. */
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vQueueAddToRegistry( ( QueueHandle_t ) xParameters[ 0 ].xSemaphore, "Counting_Sem_1" );
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vQueueAddToRegistry( ( QueueHandle_t ) xParameters[ 1 ].xSemaphore, "Counting_Sem_2" );
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/* Create the demo tasks, passing in the semaphore to use as the parameter. */
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xTaskCreate( prvCountingSemaphoreTask, "CNT1", configMINIMAL_STACK_SIZE, ( void * ) &( xParameters[ 0 ] ), tskIDLE_PRIORITY, NULL );
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xTaskCreate( prvCountingSemaphoreTask, "CNT2", configMINIMAL_STACK_SIZE, ( void * ) &( xParameters[ 1 ] ), tskIDLE_PRIORITY, NULL );
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}
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}
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/*-----------------------------------------------------------*/
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static void prvDecrementSemaphoreCount( SemaphoreHandle_t xSemaphore,
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volatile UBaseType_t * puxLoopCounter )
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{
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UBaseType_t ux;
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/* If the semaphore count is at its maximum then we should not be able to
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* 'give' the semaphore. */
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if( xSemaphoreGive( xSemaphore ) == pdPASS )
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{
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xErrorDetected = pdTRUE;
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}
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/* We should be able to 'take' the semaphore countMAX_COUNT_VALUE times. */
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for( ux = 0; ux < countMAX_COUNT_VALUE; ux++ )
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{
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configASSERT( uxSemaphoreGetCount( xSemaphore ) == ( countMAX_COUNT_VALUE - ux ) );
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if( xSemaphoreTake( xSemaphore, countDONT_BLOCK ) != pdPASS )
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{
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/* We expected to be able to take the semaphore. */
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xErrorDetected = pdTRUE;
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}
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( *puxLoopCounter )++;
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}
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#if configUSE_PREEMPTION == 0
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taskYIELD();
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#endif
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/* If the semaphore count is zero then we should not be able to 'take'
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* the semaphore. */
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configASSERT( uxSemaphoreGetCount( xSemaphore ) == 0 );
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if( xSemaphoreTake( xSemaphore, countDONT_BLOCK ) == pdPASS )
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{
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xErrorDetected = pdTRUE;
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}
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}
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/*-----------------------------------------------------------*/
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static void prvIncrementSemaphoreCount( SemaphoreHandle_t xSemaphore,
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volatile UBaseType_t * puxLoopCounter )
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{
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UBaseType_t ux;
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/* If the semaphore count is zero then we should not be able to 'take'
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* the semaphore. */
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if( xSemaphoreTake( xSemaphore, countDONT_BLOCK ) == pdPASS )
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{
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xErrorDetected = pdTRUE;
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}
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/* We should be able to 'give' the semaphore countMAX_COUNT_VALUE times. */
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for( ux = 0; ux < countMAX_COUNT_VALUE; ux++ )
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{
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configASSERT( uxSemaphoreGetCount( xSemaphore ) == ux );
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if( xSemaphoreGive( xSemaphore ) != pdPASS )
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{
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/* We expected to be able to take the semaphore. */
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xErrorDetected = pdTRUE;
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}
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( *puxLoopCounter )++;
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}
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#if configUSE_PREEMPTION == 0
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taskYIELD();
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#endif
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/* If the semaphore count is at its maximum then we should not be able to
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* 'give' the semaphore. */
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if( xSemaphoreGive( xSemaphore ) == pdPASS )
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{
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xErrorDetected = pdTRUE;
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}
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}
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/*-----------------------------------------------------------*/
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static void prvCountingSemaphoreTask( void * pvParameters )
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{
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xCountSemStruct * pxParameter;
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#ifdef USE_STDIO
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void vPrintDisplayMessage( const char * const * ppcMessageToSend );
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const char * const pcTaskStartMsg = "Counting semaphore demo started.\r\n";
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/* Queue a message for printing to say the task has started. */
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vPrintDisplayMessage( &pcTaskStartMsg );
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#endif
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/* The semaphore to be used was passed as the parameter. */
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pxParameter = ( xCountSemStruct * ) pvParameters;
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/* Did we expect to find the semaphore already at its max count value, or
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* at zero? */
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if( pxParameter->uxExpectedStartCount == countSTART_AT_MAX_COUNT )
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{
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prvDecrementSemaphoreCount( pxParameter->xSemaphore, &( pxParameter->uxLoopCounter ) );
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}
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/* Now we expect the semaphore count to be 0, so this time there is an
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* error if we can take the semaphore. */
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if( xSemaphoreTake( pxParameter->xSemaphore, 0 ) == pdPASS )
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{
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xErrorDetected = pdTRUE;
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}
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for( ; ; )
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{
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prvIncrementSemaphoreCount( pxParameter->xSemaphore, &( pxParameter->uxLoopCounter ) );
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prvDecrementSemaphoreCount( pxParameter->xSemaphore, &( pxParameter->uxLoopCounter ) );
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}
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}
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/*-----------------------------------------------------------*/
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BaseType_t xAreCountingSemaphoreTasksStillRunning( void )
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{
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static UBaseType_t uxLastCount0 = 0, uxLastCount1 = 0;
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BaseType_t xReturn = pdPASS;
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/* Return fail if any 'give' or 'take' did not result in the expected
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* behaviour. */
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if( xErrorDetected != pdFALSE )
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{
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xReturn = pdFAIL;
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}
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/* Return fail if either task is not still incrementing its loop counter. */
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if( uxLastCount0 == xParameters[ 0 ].uxLoopCounter )
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{
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xReturn = pdFAIL;
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}
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else
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{
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uxLastCount0 = xParameters[ 0 ].uxLoopCounter;
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}
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if( uxLastCount1 == xParameters[ 1 ].uxLoopCounter )
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{
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xReturn = pdFAIL;
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}
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else
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{
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uxLastCount1 = xParameters[ 1 ].uxLoopCounter;
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}
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return xReturn;
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}
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