2 FreeRTOS V7.0.2 - Copyright (C) 2011 Real Time Engineers Ltd.
5 ***************************************************************************
7 * FreeRTOS tutorial books are available in pdf and paperback. *
8 * Complete, revised, and edited pdf reference manuals are also *
11 * Purchasing FreeRTOS documentation will not only help you, by *
12 * ensuring you get running as quickly as possible and with an *
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14 * the FreeRTOS project to continue with its mission of providing *
15 * professional grade, cross platform, de facto standard solutions *
16 * for microcontrollers - completely free of charge! *
18 * >>> See http://www.FreeRTOS.org/Documentation for details. <<< *
20 * Thank you for using FreeRTOS, and thank you for your support! *
22 ***************************************************************************
25 This file is part of the FreeRTOS distribution.
27 FreeRTOS is free software; you can redistribute it and/or modify it under
28 the terms of the GNU General Public License (version 2) as published by the
29 Free Software Foundation AND MODIFIED BY the FreeRTOS exception.
30 >>>NOTE<<< The modification to the GPL is included to allow you to
31 distribute a combined work that includes FreeRTOS without being obliged to
32 provide the source code for proprietary components outside of the FreeRTOS
33 kernel. FreeRTOS is distributed in the hope that it will be useful, but
34 WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
35 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
36 more details. You should have received a copy of the GNU General Public
37 License and the FreeRTOS license exception along with FreeRTOS; if not it
38 can be viewed here: http://www.freertos.org/a00114.html and also obtained
39 by writing to Richard Barry, contact details for whom are available on the
44 http://www.FreeRTOS.org - Documentation, latest information, license and
47 http://www.SafeRTOS.com - A version that is certified for use in safety
50 http://www.OpenRTOS.com - Commercial support, development, porting,
51 licensing and training services.
56 #include "os/FreeRTOS.h"
59 /*-----------------------------------------------------------
60 * PUBLIC LIST API documented in list.h
61 *----------------------------------------------------------*/
63 void vListInitialise( xList *pxList )
65 /* The list structure contains a list item which is used to mark the
66 end of the list. To initialise the list the list end is inserted
67 as the only list entry. */
68 pxList->pxIndex = ( xListItem * ) &( pxList->xListEnd );
70 /* The list end value is the highest possible value in the list to
71 ensure it remains at the end of the list. */
72 pxList->xListEnd.xItemValue = portMAX_DELAY;
74 /* The list end next and previous pointers point to itself so we know
75 when the list is empty. */
76 pxList->xListEnd.pxNext = ( xListItem * ) &( pxList->xListEnd );
77 pxList->xListEnd.pxPrevious = ( xListItem * ) &( pxList->xListEnd );
79 pxList->uxNumberOfItems = ( unsigned portBASE_TYPE ) 0U;
81 /*-----------------------------------------------------------*/
83 void vListInitialiseItem( xListItem *pxItem )
85 /* Make sure the list item is not recorded as being on a list. */
86 pxItem->pvContainer = NULL;
88 /*-----------------------------------------------------------*/
90 void vListInsertEnd( xList *pxList, xListItem *pxNewListItem )
92 volatile xListItem * pxIndex;
94 /* Insert a new list item into pxList, but rather than sort the list,
95 makes the new list item the last item to be removed by a call to
96 pvListGetOwnerOfNextEntry. This means it has to be the item pointed to by
97 the pxIndex member. */
98 pxIndex = pxList->pxIndex;
100 pxNewListItem->pxNext = pxIndex->pxNext;
101 pxNewListItem->pxPrevious = pxList->pxIndex;
102 pxIndex->pxNext->pxPrevious = ( volatile xListItem * ) pxNewListItem;
103 pxIndex->pxNext = ( volatile xListItem * ) pxNewListItem;
104 pxList->pxIndex = ( volatile xListItem * ) pxNewListItem;
106 /* Remember which list the item is in. */
107 pxNewListItem->pvContainer = ( void * ) pxList;
109 ( pxList->uxNumberOfItems )++;
111 /*-----------------------------------------------------------*/
113 void vListInsert( xList *pxList, xListItem *pxNewListItem )
115 volatile xListItem *pxIterator;
116 portTickType xValueOfInsertion;
118 /* Insert the new list item into the list, sorted in ulListItem order. */
119 xValueOfInsertion = pxNewListItem->xItemValue;
121 /* If the list already contains a list item with the same item value then
122 the new list item should be placed after it. This ensures that TCB's which
123 are stored in ready lists (all of which have the same ulListItem value)
124 get an equal share of the CPU. However, if the xItemValue is the same as
125 the back marker the iteration loop below will not end. This means we need
126 to guard against this by checking the value first and modifying the
127 algorithm slightly if necessary. */
128 if( xValueOfInsertion == portMAX_DELAY )
130 pxIterator = pxList->xListEnd.pxPrevious;
134 /* *** NOTE ***********************************************************
135 If you find your application is crashing here then likely causes are:
137 see http://www.freertos.org/Stacks-and-stack-overflow-checking.html
138 2) Incorrect interrupt priority assignment, especially on Cortex-M3
139 parts where numerically high priority values denote low actual
140 interrupt priories, which can seem counter intuitive. See
141 configMAX_SYSCALL_INTERRUPT_PRIORITY on http://www.freertos.org/a00110.html
142 3) Calling an API function from within a critical section or when
143 the scheduler is suspended.
144 4) Using a queue or semaphore before it has been initialised or
145 before the scheduler has been started (are interrupts firing
146 before vTaskStartScheduler() has been called?).
147 See http://www.freertos.org/FAQHelp.html for more tips.
148 **********************************************************************/
150 for( pxIterator = ( xListItem * ) &( pxList->xListEnd ); pxIterator->pxNext->xItemValue <= xValueOfInsertion; pxIterator = pxIterator->pxNext )
152 /* There is nothing to do here, we are just iterating to the
153 wanted insertion position. */
157 pxNewListItem->pxNext = pxIterator->pxNext;
158 pxNewListItem->pxNext->pxPrevious = ( volatile xListItem * ) pxNewListItem;
159 pxNewListItem->pxPrevious = pxIterator;
160 pxIterator->pxNext = ( volatile xListItem * ) pxNewListItem;
162 /* Remember which list the item is in. This allows fast removal of the
164 pxNewListItem->pvContainer = ( void * ) pxList;
166 ( pxList->uxNumberOfItems )++;
168 /*-----------------------------------------------------------*/
170 void vListRemove( xListItem *pxItemToRemove )
174 pxItemToRemove->pxNext->pxPrevious = pxItemToRemove->pxPrevious;
175 pxItemToRemove->pxPrevious->pxNext = pxItemToRemove->pxNext;
177 /* The list item knows which list it is in. Obtain the list from the list
179 pxList = ( xList * ) pxItemToRemove->pvContainer;
181 /* Make sure the index is left pointing to a valid item. */
182 if( pxList->pxIndex == pxItemToRemove )
184 pxList->pxIndex = pxItemToRemove->pxPrevious;
187 pxItemToRemove->pvContainer = NULL;
188 ( pxList->uxNumberOfItems )--;
190 /*-----------------------------------------------------------*/