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192 lines
8.3 KiB
C
192 lines
8.3 KiB
C
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/*
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FreeRTOS V6.0.4 - Copyright (C) 2010 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 eBook *
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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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#include <stdlib.h>
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#include "FreeRTOS.h"
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#include "list.h"
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/*-----------------------------------------------------------
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* PUBLIC LIST API documented in list.h
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*----------------------------------------------------------*/
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void vListInitialise( xList *pxList )
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{
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/* The list structure contains a list item which is used to mark the
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end of the list. To initialise the list the list end is inserted
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as the only list entry. */
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pxList->pxIndex = ( xListItem * ) &( pxList->xListEnd );
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/* The list end value is the highest possible value in the list to
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ensure it remains at the end of the list. */
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pxList->xListEnd.xItemValue = portMAX_DELAY;
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/* The list end next and previous pointers point to itself so we know
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when the list is empty. */
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pxList->xListEnd.pxNext = ( xListItem * ) &( pxList->xListEnd );
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pxList->xListEnd.pxPrevious = ( xListItem * ) &( pxList->xListEnd );
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pxList->uxNumberOfItems = 0;
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}
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/*-----------------------------------------------------------*/
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void vListInitialiseItem( xListItem *pxItem )
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{
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/* Make sure the list item is not recorded as being on a list. */
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pxItem->pvContainer = NULL;
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}
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/*-----------------------------------------------------------*/
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void vListInsertEnd( xList *pxList, xListItem *pxNewListItem )
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{
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volatile xListItem * pxIndex;
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/* Insert a new list item into pxList, but rather than sort the list,
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makes the new list item the last item to be removed by a call to
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pvListGetOwnerOfNextEntry. This means it has to be the item pointed to by
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the pxIndex member. */
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pxIndex = pxList->pxIndex;
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pxNewListItem->pxNext = pxIndex->pxNext;
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pxNewListItem->pxPrevious = pxList->pxIndex;
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pxIndex->pxNext->pxPrevious = ( volatile xListItem * ) pxNewListItem;
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pxIndex->pxNext = ( volatile xListItem * ) pxNewListItem;
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pxList->pxIndex = ( volatile xListItem * ) pxNewListItem;
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/* Remember which list the item is in. */
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pxNewListItem->pvContainer = ( void * ) pxList;
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( pxList->uxNumberOfItems )++;
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}
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/*-----------------------------------------------------------*/
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void vListInsert( xList *pxList, xListItem *pxNewListItem )
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{
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volatile xListItem *pxIterator;
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portTickType xValueOfInsertion;
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/* Insert the new list item into the list, sorted in ulListItem order. */
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xValueOfInsertion = pxNewListItem->xItemValue;
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/* If the list already contains a list item with the same item value then
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the new list item should be placed after it. This ensures that TCB's which
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are stored in ready lists (all of which have the same ulListItem value)
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get an equal share of the CPU. However, if the xItemValue is the same as
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the back marker the iteration loop below will not end. This means we need
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to guard against this by checking the value first and modifying the
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algorithm slightly if necessary. */
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if( xValueOfInsertion == portMAX_DELAY )
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{
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pxIterator = pxList->xListEnd.pxPrevious;
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}
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else
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{
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/* *** NOTE ***********************************************************
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If you find your application is crashing here then likely causes are:
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1) Stack overflow -
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see http://www.freertos.org/Stacks-and-stack-overflow-checking.html
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2) Incorrect interrupt priority assignment, especially on Cortex M3
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parts where numerically high priority values denote low actual
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interrupt priories, which can seem counter intuitive. See
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configMAX_SYSCALL_INTERRUPT_PRIORITY on http://www.freertos.org/a00110.html
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3) Calling an API function from within a critical section or when
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the scheduler is suspended.
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4) Using a queue or semaphore before it has been initialised or
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before the scheduler has been started (are interrupts firing
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before vTaskStartScheduler() has been called?).
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See http://www.freertos.org/FAQHelp.html for more tips.
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**********************************************************************/
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for( pxIterator = ( xListItem * ) &( pxList->xListEnd ); pxIterator->pxNext->xItemValue <= xValueOfInsertion; pxIterator = pxIterator->pxNext )
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{
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/* There is nothing to do here, we are just iterating to the
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wanted insertion position. */
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}
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}
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pxNewListItem->pxNext = pxIterator->pxNext;
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pxNewListItem->pxNext->pxPrevious = ( volatile xListItem * ) pxNewListItem;
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pxNewListItem->pxPrevious = pxIterator;
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pxIterator->pxNext = ( volatile xListItem * ) pxNewListItem;
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/* Remember which list the item is in. This allows fast removal of the
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item later. */
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pxNewListItem->pvContainer = ( void * ) pxList;
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( pxList->uxNumberOfItems )++;
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}
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/*-----------------------------------------------------------*/
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void vListRemove( xListItem *pxItemToRemove )
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{
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xList * pxList;
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pxItemToRemove->pxNext->pxPrevious = pxItemToRemove->pxPrevious;
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pxItemToRemove->pxPrevious->pxNext = pxItemToRemove->pxNext;
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/* The list item knows which list it is in. Obtain the list from the list
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item. */
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pxList = ( xList * ) pxItemToRemove->pvContainer;
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/* Make sure the index is left pointing to a valid item. */
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if( pxList->pxIndex == pxItemToRemove )
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{
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pxList->pxIndex = pxItemToRemove->pxPrevious;
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}
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pxItemToRemove->pvContainer = NULL;
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( pxList->uxNumberOfItems )--;
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}
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/*-----------------------------------------------------------*/
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