text: /*
      FreeRTOS V7.4.0 - Copyright (C) 2013 Real Time Engineers Ltd.
  
      FEATURES AND PORTS ARE ADDED TO FREERTOS ALL THE TIME.  PLEASE VISIT
      http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.
  
      ***************************************************************************
       *                                                                       *
       *    FreeRTOS tutorial books are available in pdf and paperback.        *
       *    Complete, revised, and edited pdf reference manuals are also       *
       *    available.                                                         *
       *                                                                       *
       *    Purchasing FreeRTOS documentation will not only help you, by       *
       *    ensuring you get running as quickly as possible and with an        *
       *    in-depth knowledge of how to use FreeRTOS, it will also help       *
       *    the FreeRTOS project to continue with its mission of providing     *
       *    professional grade, cross platform, de facto standard solutions    *
       *    for microcontrollers - completely free of charge!                  *
       *                                                                       *
       *    >>> See http://www.FreeRTOS.org/Documentation for details. <<<     *
       *                                                                       *
       *    Thank you for using FreeRTOS, and 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 modification 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 itcan be
      viewed here: http://www.freertos.org/a00114.html and also obtained by
      writing to Real Time Engineers Ltd., contact details for whom are available
      on the FreeRTOS WEB site.
  
      1 tab == 4 spaces!
  
      ***************************************************************************
       *                                                                       *
       *    Having a problem?  Start by reading the FAQ "My application does   *
       *    not run, what could be wrong?"                                     *
       *                                                                       *
       *    http://www.FreeRTOS.org/FAQHelp.html                               *
       *                                                                       *
      ***************************************************************************
  
  
      http://www.FreeRTOS.org - Documentation, books, training, latest versions, 
      license and Real Time Engineers Ltd. contact details.
  
      http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
      including FreeRTOS+Trace - an indispensable productivity tool, and our new
      fully thread aware and reentrant UDP/IP stack.
  
      http://www.OpenRTOS.com - Real Time Engineers ltd license FreeRTOS to High 
      Integrity Systems, who sell the code with commercial support, 
      indemnification and middleware, under the OpenRTOS brand.
      
      http://www.SafeRTOS.com - High Integrity Systems also provide a safety 
      engineered and independently SIL3 certified version for use in safety and 
      mission critical applications that require provable dependability.
  */
  
  
  #include <stdlib.h>
  #include "FreeRTOS.h"
  #include "list.h"
  
  /*-----------------------------------------------------------
   * PUBLIC LIST API documented in list.h
   *----------------------------------------------------------*/
  
  void vListInitialise( xList *pxList )
  {
  	/* The list structure contains a list item which is used to mark the
  	end of the list.  To initialise the list the list end is inserted
  	as the only list entry. */
  	pxList->pxIndex = ( xListItem * ) &( pxList->xListEnd );
  
  	/* The list end value is the highest possible value in the list to
  	ensure it remains at the end of the list. */
  	pxList->xListEnd.xItemValue = portMAX_DELAY;
  
  	/* The list end next and previous pointers point to itself so we know
  	when the list is empty. */
  	pxList->xListEnd.pxNext = ( xListItem * ) &( pxList->xListEnd );
  	pxList->xListEnd.pxPrevious = ( xListItem * ) &( pxList->xListEnd );
  
  	pxList->uxNumberOfItems = ( unsigned portBASE_TYPE ) 0U;
  }
  /*-----------------------------------------------------------*/
  
  void vListInitialiseItem( xListItem *pxItem )
  {
  	/* Make sure the list item is not recorded as being on a list. */
  	pxItem->pvContainer = NULL;
  }
  /*-----------------------------------------------------------*/
  
  void vListInsertEnd( xList *pxList, xListItem *pxNewListItem )
  {
  volatile xListItem * pxIndex;
  
  	/* Insert a new list item into pxList, but rather than sort the list,
  	makes the new list item the last item to be removed by a call to
  	pvListGetOwnerOfNextEntry.  This means it has to be the item pointed to by
  	the pxIndex member. */
  	pxIndex = pxList->pxIndex;
  
  	pxNewListItem->pxNext = pxIndex->pxNext;
  	pxNewListItem->pxPrevious = pxList->pxIndex;
  	pxIndex->pxNext->pxPrevious = ( volatile xListItem * ) pxNewListItem;
  	pxIndex->pxNext = ( volatile xListItem * ) pxNewListItem;
  	pxList->pxIndex = ( volatile xListItem * ) pxNewListItem;
  
  	/* Remember which list the item is in. */
  	pxNewListItem->pvContainer = ( void * ) pxList;
  
  	( pxList->uxNumberOfItems )++;
  }
  /*-----------------------------------------------------------*/
  
  void vListInsert( xList *pxList, xListItem *pxNewListItem )
  {
  volatile xListItem *pxIterator;
  portTickType xValueOfInsertion;
  
  	/* Insert the new list item into the list, sorted in ulListItem order. */
  	xValueOfInsertion = pxNewListItem->xItemValue;
  
  	/* If the list already contains a list item with the same item value then
  	the new list item should be placed after it.  This ensures that TCB's which
  	are stored in ready lists (all of which have the same ulListItem value)
  	get an equal share of the CPU.  However, if the xItemValue is the same as
  	the back marker the iteration loop below will not end.  This means we need
  	to guard against this by checking the value first and modifying the
  	algorithm slightly if necessary. */
  	if( xValueOfInsertion == portMAX_DELAY )
  	{
  		pxIterator = pxList->xListEnd.pxPrevious;
  	}
  	else
  	{
  		/* *** NOTE ***********************************************************
  		If you find your application is crashing here then likely causes are:
  			1) Stack overflow -
  			   see http://www.freertos.org/Stacks-and-stack-overflow-checking.html
  			2) Incorrect interrupt priority assignment, especially on Cortex-M3
  			   parts where numerically high priority values denote low actual
  			   interrupt priories, which can seem counter intuitive.  See
  			   configMAX_SYSCALL_INTERRUPT_PRIORITY on http://www.freertos.org/a00110.html
  			3) Calling an API function from within a critical section or when
  			   the scheduler is suspended.
  			4) Using a queue or semaphore before it has been initialised or
  			   before the scheduler has been started (are interrupts firing
  			   before vTaskStartScheduler() has been called?).
  		See http://www.freertos.org/FAQHelp.html for more tips.
  		**********************************************************************/
  
  		for( pxIterator = ( xListItem * ) &( pxList->xListEnd ); pxIterator->pxNext->xItemValue <= xValueOfInsertion; pxIterator = pxIterator->pxNext )
  		{
  			/* There is nothing to do here, we are just iterating to the
  			wanted insertion position. */
  		}
  	}
  
  	pxNewListItem->pxNext = pxIterator->pxNext;
  	pxNewListItem->pxNext->pxPrevious = ( volatile xListItem * ) pxNewListItem;
  	pxNewListItem->pxPrevious = pxIterator;
  	pxIterator->pxNext = ( volatile xListItem * ) pxNewListItem;
  
  	/* Remember which list the item is in.  This allows fast removal of the
  	item later. */
  	pxNewListItem->pvContainer = ( void * ) pxList;
  
  	( pxList->uxNumberOfItems )++;
  }
  /*-----------------------------------------------------------*/
  
  unsigned portBASE_TYPE uxListRemove( xListItem *pxItemToRemove )
  {
  xList * pxList;
  
  	pxItemToRemove->pxNext->pxPrevious = pxItemToRemove->pxPrevious;
  	pxItemToRemove->pxPrevious->pxNext = pxItemToRemove->pxNext;
  
  	/* The list item knows which list it is in.  Obtain the list from the list
  	item. */
  	pxList = ( xList * ) pxItemToRemove->pvContainer;
  
  	/* Make sure the index is left pointing to a valid item. */
  	if( pxList->pxIndex == pxItemToRemove )
  	{
  		pxList->pxIndex = pxItemToRemove->pxPrevious;
  	}
  
  	pxItemToRemove->pvContainer = NULL;
  	( pxList->uxNumberOfItems )--;
  
  	return pxList->uxNumberOfItems;
  }
  /*-----------------------------------------------------------*/
  
  