2 FreeRTOS.org V4.0.4 - Copyright (C) 2003-2006 Richard Barry.
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4 This file is part of the FreeRTOS.org distribution.
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6 FreeRTOS.org is free software; you can redistribute it and/or modify
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7 it under the terms of the GNU General Public License as published by
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8 the Free Software Foundation; either version 2 of the License, or
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9 (at your option) any later version.
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11 FreeRTOS.org is distributed in the hope that it will be useful,
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12 but WITHOUT ANY WARRANTY; without even the implied warranty of
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13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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14 GNU General Public License for more details.
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16 You should have received a copy of the GNU General Public License
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17 along with FreeRTOS.org; if not, write to the Free Software
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18 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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20 A special exception to the GPL can be applied should you wish to distribute
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21 a combined work that includes FreeRTOS.org, without being obliged to provide
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22 the source code for any proprietary components. See the licensing section
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23 of http://www.FreeRTOS.org for full details of how and when the exception
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26 ***************************************************************************
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27 See http://www.FreeRTOS.org for documentation, latest information, license
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28 and contact details. Please ensure to read the configuration and relevant
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29 port sections of the online documentation.
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30 ***************************************************************************
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36 + Call to portRESTORE_CONTEXT has been removed. The first context
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37 switch is now performed within sPortStartScheduler().
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41 + More use of 8bit data types.
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42 + Function name prefixes changed where the data type returned has changed.
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43 + configUSE_TRACE_FACILITY is no longer defined by default.
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47 + Introduced ucTopReadyPriority. This tracks the highest priority ready
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48 queue that contains a valid TCB and thus makes the context switch
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51 + prvAddTaskToReadyQueue() has been made a macro.
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55 + Added conditional compilation directives.
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57 + Rearranged function order.
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58 + Creating a task now causes a context switch if the task being created
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59 has a higher priority than the calling task - assuming the kernel is
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61 + vTaskDelete() now only causes a context switch if the calling task is
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62 the task being deleted.
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66 + Allow the type of the tick count to be 16 or 32 bits.
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67 + Introduce xPendingReadyList feature to allow the time interrupts have to
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68 be disabled to be minimised.
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69 + Remove the #if( INCLUDE_vTaskSuspendAll ) statements. vTaskSuspendAll()
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70 is now always included as it is used by the scheduler itself.
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74 + Bug fix - pxCurrentTCB is now initialised before the call to
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75 prvInitializeTaskLists(). Previously pxCurrentTCB could be accessed
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80 + Change to where lStackSize is declared within sTaskCreate() to prevent
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81 compiler warnings with 8051 port.
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85 + Explicit use of 'signed' qualifier on portCHAR types added.
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86 + Changed odd calculation of initial pxTopOfStack value when
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87 portSTACK_GROWTH < 0.
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88 + Removed pcVersionNumber definition.
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92 + cTaskResumeAll() modified to ensure it can be called prior to the task
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93 lists being initialised.
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97 + Added API function vTaskDelayUntil().
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98 + Added INCLUDE_vTaskDelay conditional compilation.
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100 Changes from V2.6.0
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102 + Updated the vWriteTraceToBuffer macro to always be 4 byte aligned so it
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103 can be used on ARM architectures.
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104 + tskMAX_TASK_NAME_LEN definition replaced with the port specific
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105 configMAX_TASK_NAME_LEN definition.
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106 + Removed the call to strcpy when copying across the task name into the
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108 + Added ucTasksDeleted variable to prevent vTaskSuspendAll() being called
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109 too often in the idle task.
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111 Changes between V3.0.0 and V2.6.1
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113 + When resuming the scheduler a yield is performed if either a tick has
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114 been missed, or a task is moved from the pending ready list into a ready
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115 list. Previously a yield was not performed on this second condition.
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116 + Introduced the type portBASE_TYPE. This necessitates several API
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118 + Removed the sUsingPreemption variable. The constant defined in
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119 portmacro.h is now used directly.
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120 + The idle task can now include an optional hook function - and no longer
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121 completes its time slice if other tasks with equal priority to it are
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123 + See the FreeRTOS.org documentation for more information on V2.x.x to
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124 V3.x.x modifications.
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126 Changes from V3.1.1
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128 + Modified vTaskPrioritySet() and vTaskResume() to allow these functions to
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129 be called while the scheduler is suspended.
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130 + Corrected the task ordering within event lists.
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132 Changes from V3.2.0
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134 + Added function xTaskGetCurrentTaskHandle().
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136 Changes from V3.2.4
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138 + Changed the volatile declarations on some variables to reflect the
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139 changes to the list definitions.
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140 + Changed the order of the TCB definition so there is commonality between
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141 the task control block and a co-routine control block.
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142 + Allow the scheduler to be started even if no tasks other than the idle
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143 task has been created. This allows co-routines to run even when no tasks
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145 + The need for a context switch is now signalled if a task woken by an
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146 event has a priority greater or equal to the currently running task.
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147 Previously this was only greater than.
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149 Changes from V4.0.0
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151 + Added the xMissedYield handling.
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153 Changes from V4.0.1
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155 + The function vTaskList() now suspends the scheduler rather than disabling
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156 interrupts during the creation of the task list.
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157 + Allow a task to delete itself by passing in its own handle. Previously
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158 this could only be done by passing in NULL.
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159 + The tick hook function is now called only within a tick isr. Previously
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160 it was also called when the tick function was called during the scheduler
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163 Changes from V4.0.3
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165 + Extra checks have been placed in vTaskPrioritySet() to avoid unnecessary
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168 Changed from V4.0.4
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170 + Bug fix: The 'value' of the event list item is updated when the priority
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171 of a task is changed. Previously only the priority of the TCB itself was
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173 + When resuming a task a check is first made to see if the task is actually
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175 + vTaskPrioritySet() and vTaskResume() no longer use the event list item.
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176 This has not been necessary since V4.0.1 when the xMissedYield handling
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181 #include <stdlib.h>
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182 #include <string.h>
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184 #include "FreeRTOS.h"
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188 * Macro to define the amount of stack available to the idle task.
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190 #define tskIDLE_STACK_SIZE configMINIMAL_STACK_SIZE
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194 * Default a definitions for backwards compatibility with old
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195 * portmacro.h files.
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197 #ifndef configMAX_TASK_NAME_LEN
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198 #define configMAX_TASK_NAME_LEN 16
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201 #ifndef INCLUDE_xTaskGetCurrentTaskHandle
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202 #define INCLUDE_xTaskGetCurrentTaskHandle 0
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205 #ifndef configIDLE_SHOULD_YIELD
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206 #define configIDLE_SHOULD_YIELD 1
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209 #if configMAX_TASK_NAME_LEN < 1
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210 #undef configMAX_TASK_NAME_LEN
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211 #define configMAX_TASK_NAME_LEN 1
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216 * Task control block. A task control block (TCB) is allocated to each task,
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217 * and stores the context of the task.
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219 typedef struct tskTaskControlBlock
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221 volatile portSTACK_TYPE *pxTopOfStack; /*< Points to the location of the last item placed on the tasks stack. THIS MUST BE THE FIRST MEMBER OF THE STRUCT. */
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222 xListItem xGenericListItem; /*< List item used to place the TCB in ready and blocked queues. */
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223 xListItem xEventListItem; /*< List item used to place the TCB in event lists. */
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224 unsigned portBASE_TYPE uxPriority; /*< The priority of the task where 0 is the lowest priority. */
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225 portSTACK_TYPE *pxStack; /*< Points to the start of the stack. */
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226 unsigned portBASE_TYPE uxTCBNumber; /*< This is used for tracing the scheduler and making debugging easier only. */
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227 signed portCHAR pcTaskName[ configMAX_TASK_NAME_LEN ];/*< Descriptive name given to the task when created. Facilitates debugging only. */
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228 unsigned portSHORT usStackDepth; /*< Total depth of the stack (when empty). This is defined as the number of variables the stack can hold, not the number of bytes. */
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233 tskTCB * volatile pxCurrentTCB = NULL;
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235 /* Lists for ready and blocked tasks. --------------------*/
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237 static xList pxReadyTasksLists[ configMAX_PRIORITIES ]; /*< Prioritised ready tasks. */
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238 static xList xDelayedTaskList1; /*< Delayed tasks. */
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239 static xList xDelayedTaskList2; /*< Delayed tasks (two lists are used - one for delays that have overflowed the current tick count. */
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240 static xList * volatile pxDelayedTaskList; /*< Points to the delayed task list currently being used. */
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241 static xList * volatile pxOverflowDelayedTaskList; /*< Points to the delayed task list currently being used to hold tasks that have overflowed the current tick count. */
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242 static xList xPendingReadyList; /*< Tasks that have been readied while the scheduler was suspended. They will be moved to the ready queue when the scheduler is resumed. */
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244 #if ( INCLUDE_vTaskDelete == 1 )
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246 static volatile xList xTasksWaitingTermination; /*< Tasks that have been deleted - but the their memory not yet freed. */
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247 static volatile unsigned portBASE_TYPE uxTasksDeleted = ( unsigned portBASE_TYPE ) 0;
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251 #if ( INCLUDE_vTaskSuspend == 1 )
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253 static xList xSuspendedTaskList; /*< Tasks that are currently suspended. */
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257 /* File private variables. --------------------------------*/
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258 static volatile unsigned portBASE_TYPE uxCurrentNumberOfTasks = ( unsigned portBASE_TYPE ) 0;
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259 static volatile portTickType xTickCount = ( portTickType ) 0;
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260 static unsigned portBASE_TYPE uxTopUsedPriority = tskIDLE_PRIORITY;
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261 static volatile unsigned portBASE_TYPE uxTopReadyPriority = tskIDLE_PRIORITY;
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262 static volatile signed portBASE_TYPE xSchedulerRunning = pdFALSE;
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263 static volatile unsigned portBASE_TYPE uxSchedulerSuspended = ( unsigned portBASE_TYPE ) pdFALSE;
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264 static volatile unsigned portBASE_TYPE uxMissedTicks = ( unsigned portBASE_TYPE ) 0;
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265 static volatile portBASE_TYPE xMissedYield = ( portBASE_TYPE ) pdFALSE;
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267 /* Debugging and trace facilities private variables and macros. ------------*/
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270 * The value used to fill the stack of a task when the task is created. This
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271 * is used purely for checking the high water mark for tasks.
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273 #define tskSTACK_FILL_BYTE ( 0xa5 )
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276 * Macros used by vListTask to indicate which state a task is in.
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278 #define tskBLOCKED_CHAR ( ( signed portCHAR ) 'B' )
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279 #define tskREADY_CHAR ( ( signed portCHAR ) 'R' )
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280 #define tskDELETED_CHAR ( ( signed portCHAR ) 'D' )
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281 #define tskSUSPENDED_CHAR ( ( signed portCHAR ) 'S' )
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284 * Macros and private variables used by the trace facility.
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286 #if ( configUSE_TRACE_FACILITY == 1 )
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288 #define tskSIZE_OF_EACH_TRACE_LINE ( ( unsigned portLONG ) ( sizeof( unsigned portLONG ) + sizeof( unsigned portLONG ) ) )
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289 static volatile signed portCHAR * volatile pcTraceBuffer;
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290 static signed portCHAR *pcTraceBufferStart;
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291 static signed portCHAR *pcTraceBufferEnd;
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292 static signed portBASE_TYPE xTracing = pdFALSE;
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297 * Macro that writes a trace of scheduler activity to a buffer. This trace
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298 * shows which task is running when and is very useful as a debugging tool.
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299 * As this macro is called each context switch it is a good idea to undefine
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300 * it if not using the facility.
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302 #if ( configUSE_TRACE_FACILITY == 1 )
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304 #define vWriteTraceToBuffer() \
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308 static unsigned portBASE_TYPE uxPreviousTask = 255; \
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310 if( uxPreviousTask != pxCurrentTCB->uxTCBNumber ) \
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312 if( ( pcTraceBuffer + tskSIZE_OF_EACH_TRACE_LINE ) < pcTraceBufferEnd ) \
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314 uxPreviousTask = pxCurrentTCB->uxTCBNumber; \
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315 *( unsigned portLONG * ) pcTraceBuffer = ( unsigned portLONG ) xTickCount; \
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316 pcTraceBuffer += sizeof( unsigned portLONG ); \
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317 *( unsigned portLONG * ) pcTraceBuffer = ( unsigned portLONG ) uxPreviousTask; \
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318 pcTraceBuffer += sizeof( unsigned portLONG ); \
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322 xTracing = pdFALSE; \
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330 #define vWriteTraceToBuffer()
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336 * Place the task represented by pxTCB into the appropriate ready queue for
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337 * the task. It is inserted at the end of the list. One quirk of this is
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338 * that if the task being inserted is at the same priority as the currently
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339 * executing task, then it will only be rescheduled after the currently
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340 * executing task has been rescheduled.
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342 #define prvAddTaskToReadyQueue( pxTCB ) \
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344 if( pxTCB->uxPriority > uxTopReadyPriority ) \
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346 uxTopReadyPriority = pxTCB->uxPriority; \
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348 vListInsertEnd( ( xList * ) &( pxReadyTasksLists[ pxTCB->uxPriority ] ), &( pxTCB->xGenericListItem ) ); \
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352 * Macro that looks at the list of tasks that are currently delayed to see if
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353 * any require waking.
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355 * Tasks are stored in the queue in the order of their wake time - meaning
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356 * once one tasks has been found whose timer has not expired we need not look
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357 * any further down the list.
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359 #define prvCheckDelayedTasks() \
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361 register tskTCB *pxTCB; \
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363 while( ( pxTCB = ( tskTCB * ) listGET_OWNER_OF_HEAD_ENTRY( pxDelayedTaskList ) ) != NULL ) \
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365 if( xTickCount < listGET_LIST_ITEM_VALUE( &( pxTCB->xGenericListItem ) ) ) \
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369 vListRemove( &( pxTCB->xGenericListItem ) ); \
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370 /* Is the task waiting on an event also? */ \
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371 if( pxTCB->xEventListItem.pvContainer ) \
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373 vListRemove( &( pxTCB->xEventListItem ) ); \
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375 prvAddTaskToReadyQueue( pxTCB ); \
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380 * Several functions take an xTaskHandle parameter that can optionally be NULL,
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381 * where NULL is used to indicate that the handle of the currently executing
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382 * task should be used in place of the parameter. This macro simply checks to
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383 * see if the parameter is NULL and returns a pointer to the appropriate TCB.
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385 #define prvGetTCBFromHandle( pxHandle ) ( ( pxHandle == NULL ) ? ( tskTCB * ) pxCurrentTCB : ( tskTCB * ) pxHandle )
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388 /* File private functions. --------------------------------*/
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391 * Utility to ready a TCB for a given task. Mainly just copies the parameters
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392 * into the TCB structure.
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394 static void prvInitialiseTCBVariables( tskTCB *pxTCB, unsigned portSHORT usStackDepth, const signed portCHAR * const pcName, unsigned portBASE_TYPE uxPriority );
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397 * Utility to ready all the lists used by the scheduler. This is called
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398 * automatically upon the creation of the first task.
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400 static void prvInitialiseTaskLists( void );
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403 * The idle task, which as all tasks is implemented as a never ending loop.
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404 * The idle task is automatically created and added to the ready lists upon
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405 * creation of the first user task.
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407 * The portTASK_FUNCTION_PROTO() macro is used to allow port/compiler specific
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408 * language extensions. The equivalent prototype for this function is:
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410 * void prvIdleTask( void *pvParameters );
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413 static portTASK_FUNCTION_PROTO( prvIdleTask, pvParameters );
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416 * Utility to free all memory allocated by the scheduler to hold a TCB,
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417 * including the stack pointed to by the TCB.
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419 * This does not free memory allocated by the task itself (i.e. memory
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420 * allocated by calls to pvPortMalloc from within the tasks application code).
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422 #if ( ( INCLUDE_vTaskDelete == 1 ) || ( INCLUDE_vTaskCleanUpResources == 1 ) )
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423 static void prvDeleteTCB( tskTCB *pxTCB );
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427 * Used only by the idle task. This checks to see if anything has been placed
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428 * in the list of tasks waiting to be deleted. If so the task is cleaned up
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429 * and its TCB deleted.
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431 static void prvCheckTasksWaitingTermination( void );
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434 * Allocates memory from the heap for a TCB and associated stack. Checks the
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435 * allocation was successful.
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437 static tskTCB *prvAllocateTCBAndStack( unsigned portSHORT usStackDepth );
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440 * Called from vTaskList. vListTasks details all the tasks currently under
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441 * control of the scheduler. The tasks may be in one of a number of lists.
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442 * prvListTaskWithinSingleList accepts a list and details the tasks from
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443 * within just that list.
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445 * THIS FUNCTION IS INTENDED FOR DEBUGGING ONLY, AND SHOULD NOT BE CALLED FROM
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446 * NORMAL APPLICATION CODE.
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448 #if ( configUSE_TRACE_FACILITY == 1 )
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450 static void prvListTaskWithinSingleList( signed portCHAR *pcWriteBuffer, xList *pxList, signed portCHAR cStatus );
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455 * When a task is created, the stack of the task is filled with a known value.
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456 * This function determines the 'high water mark' of the task stack by
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457 * determining how much of the stack remains at the original preset value.
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459 #if ( configUSE_TRACE_FACILITY == 1 )
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461 unsigned portSHORT usTaskCheckFreeStackSpace( const unsigned portCHAR *pucStackByte );
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471 /*-----------------------------------------------------------
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472 * TASK CREATION API documented in task.h
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473 *----------------------------------------------------------*/
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475 signed portBASE_TYPE xTaskCreate( pdTASK_CODE pvTaskCode, const signed portCHAR * const pcName, unsigned portSHORT usStackDepth, void *pvParameters, unsigned portBASE_TYPE uxPriority, xTaskHandle *pxCreatedTask )
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477 signed portBASE_TYPE xReturn;
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479 static unsigned portBASE_TYPE uxTaskNumber = 0; /*lint !e956 Static is deliberate - this is guarded before use. */
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481 /* Allocate the memory required by the TCB and stack for the new task.
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482 checking that the allocation was successful. */
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483 pxNewTCB = prvAllocateTCBAndStack( usStackDepth );
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485 if( pxNewTCB != NULL )
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487 portSTACK_TYPE *pxTopOfStack;
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489 /* Setup the newly allocated TCB with the initial state of the task. */
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490 prvInitialiseTCBVariables( pxNewTCB, usStackDepth, pcName, uxPriority );
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492 /* Calculate the top of stack address. This depends on whether the
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493 stack grows from high memory to low (as per the 80x86) or visa versa.
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494 portSTACK_GROWTH is used to make the result positive or negative as
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495 required by the port. */
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496 #if portSTACK_GROWTH < 0
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498 pxTopOfStack = pxNewTCB->pxStack + ( pxNewTCB->usStackDepth - 1 );
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502 pxTopOfStack = pxNewTCB->pxStack;
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506 /* Initialize the TCB stack to look as if the task was already running,
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507 but had been interrupted by the scheduler. The return address is set
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508 to the start of the task function. Once the stack has been initialised
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509 the top of stack variable is updated. */
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510 pxNewTCB->pxTopOfStack = pxPortInitialiseStack( pxTopOfStack, pvTaskCode, pvParameters );
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512 /* We are going to manipulate the task queues to add this task to a
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513 ready list, so must make sure no interrupts occur. */
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514 portENTER_CRITICAL();
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516 uxCurrentNumberOfTasks++;
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517 if( uxCurrentNumberOfTasks == ( unsigned portBASE_TYPE ) 1 )
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519 /* As this is the first task it must also be the current task. */
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520 pxCurrentTCB = pxNewTCB;
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522 /* This is the first task to be created so do the preliminary
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523 initialisation required. We will not recover if this call
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524 fails, but we will report the failure. */
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525 prvInitialiseTaskLists();
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529 /* If the scheduler is not already running, make this task the
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530 current task if it is the highest priority task to be created
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532 if( xSchedulerRunning == pdFALSE )
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534 if( pxCurrentTCB->uxPriority <= uxPriority )
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536 pxCurrentTCB = pxNewTCB;
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541 /* Remember the top priority to make context switching faster. Use
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542 the priority in pxNewTCB as this has been capped to a valid value. */
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543 if( pxNewTCB->uxPriority > uxTopUsedPriority )
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545 uxTopUsedPriority = pxNewTCB->uxPriority;
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548 /* Add a counter into the TCB for tracing only. */
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549 pxNewTCB->uxTCBNumber = uxTaskNumber;
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552 prvAddTaskToReadyQueue( pxNewTCB );
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556 portEXIT_CRITICAL();
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560 xReturn = errCOULD_NOT_ALLOCATE_REQUIRED_MEMORY;
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563 if( xReturn == pdPASS )
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565 if( ( void * ) pxCreatedTask != NULL )
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567 /* Pass the TCB out - in an anonymous way. The calling function/
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568 task can use this as a handle to delete the task later if
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570 *pxCreatedTask = ( xTaskHandle ) pxNewTCB;
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573 if( xSchedulerRunning != pdFALSE )
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575 /* If the created task is of a higher priority than the current task
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576 then it should run now. */
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577 if( pxCurrentTCB->uxPriority < uxPriority )
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586 /*-----------------------------------------------------------*/
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588 #if ( INCLUDE_vTaskDelete == 1 )
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590 void vTaskDelete( xTaskHandle pxTaskToDelete )
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594 taskENTER_CRITICAL();
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596 /* Ensure a yield is performed if the current task is being
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598 if( pxTaskToDelete == pxCurrentTCB )
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600 pxTaskToDelete = NULL;
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603 /* If null is passed in here then we are deleting ourselves. */
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604 pxTCB = prvGetTCBFromHandle( pxTaskToDelete );
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606 /* Remove task from the ready list and place in the termination list.
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607 This will stop the task from be scheduled. The idle task will check
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608 the termination list and free up any memory allocated by the
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609 scheduler for the TCB and stack. */
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610 vListRemove( &( pxTCB->xGenericListItem ) );
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612 /* Is the task waiting on an event also? */
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613 if( pxTCB->xEventListItem.pvContainer )
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615 vListRemove( &( pxTCB->xEventListItem ) );
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618 vListInsertEnd( ( xList * ) &xTasksWaitingTermination, &( pxTCB->xGenericListItem ) );
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620 /* Increment the ucTasksDeleted variable so the idle task knows
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621 there is a task that has been deleted and that it should therefore
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622 check the xTasksWaitingTermination list. */
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625 taskEXIT_CRITICAL();
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627 /* Force a reschedule if we have just deleted the current task. */
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628 if( xSchedulerRunning != pdFALSE )
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630 if( ( void * ) pxTaskToDelete == NULL )
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644 /*-----------------------------------------------------------
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645 * TASK CONTROL API documented in task.h
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646 *----------------------------------------------------------*/
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648 #if ( INCLUDE_vTaskDelayUntil == 1 )
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650 void vTaskDelayUntil( portTickType *pxPreviousWakeTime, portTickType xTimeIncrement )
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652 portTickType xTimeToWake;
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653 portBASE_TYPE xAlreadyYielded, xShouldDelay = pdFALSE;
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657 /* Generate the tick time at which the task wants to wake. */
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658 xTimeToWake = *pxPreviousWakeTime + xTimeIncrement;
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660 if( xTickCount < *pxPreviousWakeTime )
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662 /* The tick count has overflowed since this function was
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663 lasted called. In this case the only time we should ever
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664 actually delay is if the wake time has also overflowed,
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665 and the wake time is greater than the tick time. When this
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666 is the case it is as if neither time had overflowed. */
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667 if( ( xTimeToWake < *pxPreviousWakeTime ) && ( xTimeToWake > xTickCount ) )
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669 xShouldDelay = pdTRUE;
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674 /* The tick time has not overflowed. In this case we will
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675 delay if either the wake time has overflowed, and/or the
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676 tick time is less than the wake time. */
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677 if( ( xTimeToWake < *pxPreviousWakeTime ) || ( xTimeToWake > xTickCount ) )
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679 xShouldDelay = pdTRUE;
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683 /* Update the wake time ready for the next call. */
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684 *pxPreviousWakeTime = xTimeToWake;
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688 /* We must remove ourselves from the ready list before adding
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689 ourselves to the blocked list as the same list item is used for
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691 vListRemove( ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
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693 /* The list item will be inserted in wake time order. */
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694 listSET_LIST_ITEM_VALUE( &( pxCurrentTCB->xGenericListItem ), xTimeToWake );
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696 if( xTimeToWake < xTickCount )
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698 /* Wake time has overflowed. Place this item in the
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700 vListInsert( ( xList * ) pxOverflowDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
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704 /* The wake time has not overflowed, so we can use the
\r
705 current block list. */
\r
706 vListInsert( ( xList * ) pxDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
\r
710 xAlreadyYielded = xTaskResumeAll();
\r
712 /* Force a reschedule if xTaskResumeAll has not already done so, we may
\r
713 have put ourselves to sleep. */
\r
714 if( !xAlreadyYielded )
\r
721 /*-----------------------------------------------------------*/
\r
723 #if ( INCLUDE_vTaskDelay == 1 )
\r
725 void vTaskDelay( portTickType xTicksToDelay )
\r
727 portTickType xTimeToWake;
\r
728 signed portBASE_TYPE xAlreadyYielded = pdFALSE;
\r
730 /* A delay time of zero just forces a reschedule. */
\r
731 if( xTicksToDelay > ( portTickType ) 0 )
\r
735 /* A task that is removed from the event list while the
\r
736 scheduler is suspended will not get placed in the ready
\r
737 list or removed from the blocked list until the scheduler
\r
740 This task cannot be in an event list as it is the currently
\r
743 /* Calculate the time to wake - this may overflow but this is
\r
745 xTimeToWake = xTickCount + xTicksToDelay;
\r
747 /* We must remove ourselves from the ready list before adding
\r
748 ourselves to the blocked list as the same list item is used for
\r
750 vListRemove( ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
\r
752 /* The list item will be inserted in wake time order. */
\r
753 listSET_LIST_ITEM_VALUE( &( pxCurrentTCB->xGenericListItem ), xTimeToWake );
\r
755 if( xTimeToWake < xTickCount )
\r
757 /* Wake time has overflowed. Place this item in the
\r
759 vListInsert( ( xList * ) pxOverflowDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
\r
763 /* The wake time has not overflowed, so we can use the
\r
764 current block list. */
\r
765 vListInsert( ( xList * ) pxDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
\r
768 xAlreadyYielded = xTaskResumeAll();
\r
771 /* Force a reschedule if xTaskResumeAll has not already done so, we may
\r
772 have put ourselves to sleep. */
\r
773 if( !xAlreadyYielded )
\r
780 /*-----------------------------------------------------------*/
\r
782 #if ( INCLUDE_uxTaskPriorityGet == 1 )
\r
784 unsigned portBASE_TYPE uxTaskPriorityGet( xTaskHandle pxTask )
\r
787 unsigned portBASE_TYPE uxReturn;
\r
789 taskENTER_CRITICAL();
\r
791 /* If null is passed in here then we are changing the
\r
792 priority of the calling function. */
\r
793 pxTCB = prvGetTCBFromHandle( pxTask );
\r
794 uxReturn = pxTCB->uxPriority;
\r
796 taskEXIT_CRITICAL();
\r
802 /*-----------------------------------------------------------*/
\r
804 #if ( INCLUDE_vTaskPrioritySet == 1 )
\r
806 void vTaskPrioritySet( xTaskHandle pxTask, unsigned portBASE_TYPE uxNewPriority )
\r
809 unsigned portBASE_TYPE uxCurrentPriority, xYieldRequired = pdFALSE;
\r
811 /* Ensure the new priority is valid. */
\r
812 if( uxNewPriority >= configMAX_PRIORITIES )
\r
814 uxNewPriority = configMAX_PRIORITIES - 1;
\r
817 taskENTER_CRITICAL();
\r
819 /* If null is passed in here then we are changing the
\r
820 priority of the calling function. */
\r
821 pxTCB = prvGetTCBFromHandle( pxTask );
\r
822 uxCurrentPriority = pxTCB->uxPriority;
\r
824 if( uxCurrentPriority != uxNewPriority )
\r
826 /* The priority change may have readied a task of higher
\r
827 priority than the calling task. */
\r
828 if( uxNewPriority > pxCurrentTCB->uxPriority )
\r
830 if( pxTask != NULL )
\r
832 /* The priority of another task is being raised. If we
\r
833 were raising the priority of the currently running task
\r
834 there would be no need to switch as it must have already
\r
835 been the highest priority task. */
\r
836 xYieldRequired = pdTRUE;
\r
839 else if( pxTask == NULL )
\r
841 /* Setting our own priority down means there may now be another
\r
842 task of higher priority that is ready to execute. */
\r
843 xYieldRequired = pdTRUE;
\r
846 pxTCB->uxPriority = uxNewPriority;
\r
847 listSET_LIST_ITEM_VALUE( &( pxTCB->xEventListItem ), configMAX_PRIORITIES - ( portTickType ) uxNewPriority );
\r
849 /* If the task is in the blocked or suspended list we need do
\r
850 nothing more than change it's priority variable. However, if
\r
851 the task is in a ready list it needs to be removed and placed
\r
852 in the queue appropriate to its new priority. */
\r
853 if( listIS_CONTAINED_WITHIN( &( pxReadyTasksLists[ uxCurrentPriority ] ), &( pxTCB->xGenericListItem ) ) )
\r
855 /* The task is currently in its ready list - remove before adding
\r
856 it to it's new ready list. As we are in a critical section we
\r
857 can do this even if the scheduler is suspended. */
\r
858 vListRemove( &( pxTCB->xGenericListItem ) );
\r
859 prvAddTaskToReadyQueue( pxTCB );
\r
862 if( xYieldRequired == pdTRUE )
\r
868 taskEXIT_CRITICAL();
\r
872 /*-----------------------------------------------------------*/
\r
874 #if ( INCLUDE_vTaskSuspend == 1 )
\r
876 void vTaskSuspend( xTaskHandle pxTaskToSuspend )
\r
880 taskENTER_CRITICAL();
\r
882 /* Ensure a yield is performed if the current task is being
\r
884 if( pxTaskToSuspend == pxCurrentTCB )
\r
886 pxTaskToSuspend = NULL;
\r
889 /* If null is passed in here then we are suspending ourselves. */
\r
890 pxTCB = prvGetTCBFromHandle( pxTaskToSuspend );
\r
892 /* Remove task from the ready/delayed list and place in the suspended list. */
\r
893 vListRemove( &( pxTCB->xGenericListItem ) );
\r
895 /* Is the task waiting on an event also? */
\r
896 if( pxTCB->xEventListItem.pvContainer )
\r
898 vListRemove( &( pxTCB->xEventListItem ) );
\r
901 vListInsertEnd( ( xList * ) &xSuspendedTaskList, &( pxTCB->xGenericListItem ) );
\r
903 taskEXIT_CRITICAL();
\r
905 /* We may have just suspended the current task. */
\r
906 if( ( void * ) pxTaskToSuspend == NULL )
\r
913 /*-----------------------------------------------------------*/
\r
915 #if ( INCLUDE_vTaskSuspend == 1 )
\r
917 void vTaskResume( xTaskHandle pxTaskToResume )
\r
921 /* Remove the task from whichever list it is currently in, and place
\r
922 it in the ready list. */
\r
923 pxTCB = ( tskTCB * ) pxTaskToResume;
\r
925 /* The parameter cannot be NULL as it is impossible to resume the
\r
926 currently executing task. */
\r
927 if( pxTCB != NULL )
\r
929 taskENTER_CRITICAL();
\r
931 /* Is the task we are attempting to resume actually suspended? */
\r
932 if( listIS_CONTAINED_WITHIN( &xSuspendedTaskList, &( pxTCB->xGenericListItem ) ) != pdFALSE )
\r
934 /* As we are in a critical section we can access the ready
\r
935 lists even if the scheduler is suspended. */
\r
936 vListRemove( &( pxTCB->xGenericListItem ) );
\r
937 prvAddTaskToReadyQueue( pxTCB );
\r
939 /* We may have just resumed a higher priority task. */
\r
940 if( pxTCB->uxPriority >= pxCurrentTCB->uxPriority )
\r
942 /* This yield may not cause the task just resumed to run, but
\r
943 will leave the lists in the correct state for the next yield. */
\r
948 taskEXIT_CRITICAL();
\r
954 /*-----------------------------------------------------------*/
\r
956 #if ( INCLUDE_vTaskResumeFromISR == 1 )
\r
958 portBASE_TYPE xTaskResumeFromISR( xTaskHandle pxTaskToResume )
\r
960 portBASE_TYPE xYieldRequired;
\r
962 /* Is the task we are attempting to resume actually suspended? */
\r
963 if( listIS_CONTAINED_WITHIN( &xSuspendedTaskList, &( pxTaskToResume->xGenericListItem ) ) != pdFALSE )
\r
965 if( uxSchedulerSuspended == ( unsigned portBASE_TYPE ) pdFALSE )
\r
967 xYieldRequired = ( pxTaskToResume->uxPriority >= pxCurrentTCB->uxPriority );
\r
968 vListRemove( &( pxTaskToResume->xGenericListItem ) );
\r
969 prvAddTaskToReadyQueue( pxTaskToResume );
\r
973 /* We cannot access the delayed or ready lists, so will hold this
\r
974 task pending until the scheduler is resumed, at which point a
\r
975 yield will be preformed if necessary. */
\r
976 xYieldRequired = pdFALSE;
\r
977 vListInsertEnd( ( xList * ) &( xPendingReadyList ), &( pxTaskToResume->xEventListItem ) );
\r
982 xYieldRequired = pdFALSE;
\r
985 return xYieldRequired;
\r
993 /*-----------------------------------------------------------
\r
994 * PUBLIC SCHEDULER CONTROL documented in task.h
\r
995 *----------------------------------------------------------*/
\r
998 void vTaskStartScheduler( void )
\r
1000 portBASE_TYPE xReturn;
\r
1002 /* Add the idle task at the lowest priority. */
\r
1003 xReturn = xTaskCreate( prvIdleTask, ( signed portCHAR * ) "IDLE", tskIDLE_STACK_SIZE, ( void * ) NULL, tskIDLE_PRIORITY, ( xTaskHandle * ) NULL );
\r
1005 if( xReturn == pdPASS )
\r
1007 /* Interrupts are turned off here, to ensure a tick does not occur
\r
1008 before or during the call to xPortStartScheduler(). The stacks of
\r
1009 the created tasks contain a status word with interrupts switched on
\r
1010 so interrupts will automatically get re-enabled when the first task
\r
1013 STEPPING THROUGH HERE USING A DEBUGGER CAN CAUSE BIG PROBLEMS IF THE
\r
1014 DEBUGGER ALLOWS INTERRUPTS TO BE PROCESSED. */
\r
1015 portDISABLE_INTERRUPTS();
\r
1017 xSchedulerRunning = pdTRUE;
\r
1018 xTickCount = ( portTickType ) 0;
\r
1020 /* Setting up the timer tick is hardware specific and thus in the
\r
1021 portable interface. */
\r
1022 if( xPortStartScheduler() )
\r
1024 /* Should not reach here as if the scheduler is running the
\r
1025 function will not return. */
\r
1029 /* Should only reach here if a task calls xTaskEndScheduler(). */
\r
1033 /*-----------------------------------------------------------*/
\r
1035 void vTaskEndScheduler( void )
\r
1037 /* Stop the scheduler interrupts and call the portable scheduler end
\r
1038 routine so the original ISRs can be restored if necessary. The port
\r
1039 layer must ensure interrupts enable bit is left in the correct state. */
\r
1040 portDISABLE_INTERRUPTS();
\r
1041 xSchedulerRunning = pdFALSE;
\r
1042 vPortEndScheduler();
\r
1044 /*----------------------------------------------------------*/
\r
1046 void vTaskSuspendAll( void )
\r
1048 portENTER_CRITICAL();
\r
1049 ++uxSchedulerSuspended;
\r
1050 portEXIT_CRITICAL();
\r
1052 /*----------------------------------------------------------*/
\r
1054 signed portBASE_TYPE xTaskResumeAll( void )
\r
1056 register tskTCB *pxTCB;
\r
1057 signed portBASE_TYPE xAlreadyYielded = pdFALSE;
\r
1059 /* It is possible that an ISR caused a task to be removed from an event
\r
1060 list while the scheduler was suspended. If this was the case then the
\r
1061 removed task will have been added to the xPendingReadyList. Once the
\r
1062 scheduler has been resumed it is safe to move all the pending ready
\r
1063 tasks from this list into their appropriate ready list. */
\r
1064 portENTER_CRITICAL();
\r
1066 --uxSchedulerSuspended;
\r
1068 if( uxSchedulerSuspended == ( unsigned portBASE_TYPE ) pdFALSE )
\r
1070 if( uxCurrentNumberOfTasks > ( unsigned portBASE_TYPE ) 0 )
\r
1072 portBASE_TYPE xYieldRequired = pdFALSE;
\r
1074 /* Move any readied tasks from the pending list into the
\r
1075 appropriate ready list. */
\r
1076 while( ( pxTCB = ( tskTCB * ) listGET_OWNER_OF_HEAD_ENTRY( ( ( xList * ) &xPendingReadyList ) ) ) != NULL )
\r
1078 vListRemove( &( pxTCB->xEventListItem ) );
\r
1079 vListRemove( &( pxTCB->xGenericListItem ) );
\r
1080 prvAddTaskToReadyQueue( pxTCB );
\r
1082 /* If we have moved a task that has a priority higher than
\r
1083 the current task then we should yield. */
\r
1084 if( pxTCB->uxPriority >= pxCurrentTCB->uxPriority )
\r
1086 xYieldRequired = pdTRUE;
\r
1090 /* If any ticks occurred while the scheduler was suspended then
\r
1091 they should be processed now. This ensures the tick count does not
\r
1092 slip, and that any delayed tasks are resumed at the correct time. */
\r
1093 if( uxMissedTicks > ( unsigned portBASE_TYPE ) 0 )
\r
1095 while( uxMissedTicks > ( unsigned portBASE_TYPE ) 0 )
\r
1097 vTaskIncrementTick();
\r
1101 /* As we have processed some ticks it is appropriate to yield
\r
1102 to ensure the highest priority task that is ready to run is
\r
1103 the task actually running. */
\r
1104 xYieldRequired = pdTRUE;
\r
1107 if( ( xYieldRequired == pdTRUE ) || ( xMissedYield == pdTRUE ) )
\r
1109 xAlreadyYielded = pdTRUE;
\r
1110 xMissedYield = pdFALSE;
\r
1116 portEXIT_CRITICAL();
\r
1118 return xAlreadyYielded;
\r
1126 /*-----------------------------------------------------------
\r
1127 * PUBLIC TASK UTILITIES documented in task.h
\r
1128 *----------------------------------------------------------*/
\r
1132 portTickType xTaskGetTickCount( void )
\r
1134 portTickType xTicks;
\r
1136 /* Critical section required if running on a 16 bit processor. */
\r
1137 taskENTER_CRITICAL();
\r
1139 xTicks = xTickCount;
\r
1141 taskEXIT_CRITICAL();
\r
1145 /*-----------------------------------------------------------*/
\r
1147 unsigned portBASE_TYPE uxTaskGetNumberOfTasks( void )
\r
1149 unsigned portBASE_TYPE uxNumberOfTasks;
\r
1151 taskENTER_CRITICAL();
\r
1152 uxNumberOfTasks = uxCurrentNumberOfTasks;
\r
1153 taskEXIT_CRITICAL();
\r
1155 return uxNumberOfTasks;
\r
1157 /*-----------------------------------------------------------*/
\r
1159 #if ( ( configUSE_TRACE_FACILITY == 1 ) && ( INCLUDE_vTaskDelete == 1 ) && ( INCLUDE_vTaskSuspend == 1 ) )
\r
1161 void vTaskList( signed portCHAR *pcWriteBuffer )
\r
1163 unsigned portBASE_TYPE uxQueue;
\r
1165 /* This is a VERY costly function that should be used for debug only.
\r
1166 It leaves interrupts disabled for a LONG time. */
\r
1168 vTaskSuspendAll();
\r
1170 /* Run through all the lists that could potentially contain a TCB and
\r
1171 report the task name, state and stack high water mark. */
\r
1173 pcWriteBuffer[ 0 ] = ( signed portCHAR ) 0x00;
\r
1174 strcat( ( portCHAR * ) pcWriteBuffer, ( const portCHAR * ) "\r\n" );
\r
1176 uxQueue = uxTopUsedPriority + 1;
\r
1182 if( !listLIST_IS_EMPTY( &( pxReadyTasksLists[ uxQueue ] ) ) )
\r
1184 prvListTaskWithinSingleList( pcWriteBuffer, ( xList * ) &( pxReadyTasksLists[ uxQueue ] ), tskREADY_CHAR );
\r
1186 }while( uxQueue > ( unsigned portSHORT ) tskIDLE_PRIORITY );
\r
1188 if( !listLIST_IS_EMPTY( pxDelayedTaskList ) )
\r
1190 prvListTaskWithinSingleList( pcWriteBuffer, ( xList * ) pxDelayedTaskList, tskBLOCKED_CHAR );
\r
1193 if( !listLIST_IS_EMPTY( pxOverflowDelayedTaskList ) )
\r
1195 prvListTaskWithinSingleList( pcWriteBuffer, ( xList * ) pxOverflowDelayedTaskList, tskBLOCKED_CHAR );
\r
1198 if( !listLIST_IS_EMPTY( &xTasksWaitingTermination ) )
\r
1200 prvListTaskWithinSingleList( pcWriteBuffer, ( xList * ) &xTasksWaitingTermination, tskDELETED_CHAR );
\r
1203 if( !listLIST_IS_EMPTY( &xSuspendedTaskList ) )
\r
1205 prvListTaskWithinSingleList( pcWriteBuffer, ( xList * ) &xSuspendedTaskList, tskSUSPENDED_CHAR );
\r
1212 /*----------------------------------------------------------*/
\r
1214 #if ( configUSE_TRACE_FACILITY == 1 )
\r
1216 void vTaskStartTrace( signed portCHAR * pcBuffer, unsigned portLONG ulBufferSize )
\r
1218 portENTER_CRITICAL();
\r
1220 pcTraceBuffer = ( volatile signed portCHAR * volatile )pcBuffer;
\r
1221 pcTraceBufferStart = pcBuffer;
\r
1222 pcTraceBufferEnd = pcBuffer + ( ulBufferSize - tskSIZE_OF_EACH_TRACE_LINE );
\r
1223 xTracing = pdTRUE;
\r
1225 portEXIT_CRITICAL();
\r
1229 /*----------------------------------------------------------*/
\r
1231 #if ( configUSE_TRACE_FACILITY == 1 )
\r
1233 unsigned portLONG ulTaskEndTrace( void )
\r
1235 unsigned portLONG ulBufferLength;
\r
1237 portENTER_CRITICAL();
\r
1238 xTracing = pdFALSE;
\r
1239 portEXIT_CRITICAL();
\r
1241 ulBufferLength = ( unsigned portLONG ) ( pcTraceBuffer - pcTraceBufferStart );
\r
1243 return ulBufferLength;
\r
1250 /*-----------------------------------------------------------
\r
1251 * SCHEDULER INTERNALS AVAILABLE FOR PORTING PURPOSES
\r
1252 * documented in task.h
\r
1253 *----------------------------------------------------------*/
\r
1256 inline void vTaskIncrementTick( void )
\r
1258 /* Called by the portable layer each time a tick interrupt occurs.
\r
1259 Increments the tick then checks to see if the new tick value will cause any
\r
1260 tasks to be unblocked. */
\r
1261 if( uxSchedulerSuspended == ( unsigned portBASE_TYPE ) pdFALSE )
\r
1264 if( xTickCount == ( portTickType ) 0 )
\r
1268 /* Tick count has overflowed so we need to swap the delay lists.
\r
1269 If there are any items in pxDelayedTaskList here then there is
\r
1271 pxTemp = pxDelayedTaskList;
\r
1272 pxDelayedTaskList = pxOverflowDelayedTaskList;
\r
1273 pxOverflowDelayedTaskList = pxTemp;
\r
1276 /* See if this tick has made a timeout expire. */
\r
1277 prvCheckDelayedTasks();
\r
1283 /* The tick hook gets called at regular intervals, even if the
\r
1284 scheduler is locked. */
\r
1285 #if ( configUSE_TICK_HOOK == 1 )
\r
1287 extern void vApplicationTickHook( void );
\r
1289 vApplicationTickHook();
\r
1294 #if ( configUSE_TICK_HOOK == 1 )
\r
1296 extern void vApplicationTickHook( void );
\r
1298 /* Guard against the tick hook being called when the missed tick
\r
1299 count is being unwound (when the scheduler is being unlocked. */
\r
1300 if( uxMissedTicks == 0 )
\r
1302 vApplicationTickHook();
\r
1307 /*-----------------------------------------------------------*/
\r
1309 #if ( ( INCLUDE_vTaskCleanUpResources == 1 ) && ( INCLUDE_vTaskSuspend == 1 ) )
\r
1311 void vTaskCleanUpResources( void )
\r
1313 unsigned portSHORT usQueue;
\r
1314 volatile tskTCB *pxTCB;
\r
1316 usQueue = ( unsigned portSHORT ) uxTopUsedPriority + ( unsigned portSHORT ) 1;
\r
1318 /* Remove any TCB's from the ready queues. */
\r
1323 while( !listLIST_IS_EMPTY( &( pxReadyTasksLists[ usQueue ] ) ) )
\r
1325 listGET_OWNER_OF_NEXT_ENTRY( pxTCB, &( pxReadyTasksLists[ usQueue ] ) );
\r
1326 vListRemove( ( xListItem * ) &( pxTCB->xGenericListItem ) );
\r
1328 prvDeleteTCB( ( tskTCB * ) pxTCB );
\r
1330 }while( usQueue > ( unsigned portSHORT ) tskIDLE_PRIORITY );
\r
1332 /* Remove any TCB's from the delayed queue. */
\r
1333 while( !listLIST_IS_EMPTY( &xDelayedTaskList1 ) )
\r
1335 listGET_OWNER_OF_NEXT_ENTRY( pxTCB, &xDelayedTaskList1 );
\r
1336 vListRemove( ( xListItem * ) &( pxTCB->xGenericListItem ) );
\r
1338 prvDeleteTCB( ( tskTCB * ) pxTCB );
\r
1341 /* Remove any TCB's from the overflow delayed queue. */
\r
1342 while( !listLIST_IS_EMPTY( &xDelayedTaskList2 ) )
\r
1344 listGET_OWNER_OF_NEXT_ENTRY( pxTCB, &xDelayedTaskList2 );
\r
1345 vListRemove( ( xListItem * ) &( pxTCB->xGenericListItem ) );
\r
1347 prvDeleteTCB( ( tskTCB * ) pxTCB );
\r
1350 while( !listLIST_IS_EMPTY( &xSuspendedTaskList ) )
\r
1352 listGET_OWNER_OF_NEXT_ENTRY( pxTCB, &xSuspendedTaskList );
\r
1353 vListRemove( ( xListItem * ) &( pxTCB->xGenericListItem ) );
\r
1355 prvDeleteTCB( ( tskTCB * ) pxTCB );
\r
1358 while( !listLIST_IS_EMPTY( &xPendingReadyList ) )
\r
1360 listGET_OWNER_OF_NEXT_ENTRY( pxTCB, &xPendingReadyList );
\r
1361 vListRemove( ( xListItem * ) &( pxTCB->xGenericListItem ) );
\r
1363 prvDeleteTCB( ( tskTCB * ) pxTCB );
\r
1368 /*-----------------------------------------------------------*/
\r
1370 void vTaskSwitchContext( void )
\r
1372 if( uxSchedulerSuspended != ( unsigned portBASE_TYPE ) pdFALSE )
\r
1374 /* The scheduler is currently suspended - do not allow a context
\r
1376 xMissedYield = pdTRUE;
\r
1380 /* Find the highest priority queue that contains ready tasks. */
\r
1381 while( listLIST_IS_EMPTY( &( pxReadyTasksLists[ uxTopReadyPriority ] ) ) )
\r
1383 --uxTopReadyPriority;
\r
1386 /* listGET_OWNER_OF_NEXT_ENTRY walks through the list, so the tasks of the
\r
1387 same priority get an equal share of the processor time. */
\r
1388 listGET_OWNER_OF_NEXT_ENTRY( pxCurrentTCB, &( pxReadyTasksLists[ uxTopReadyPriority ] ) );
\r
1389 vWriteTraceToBuffer();
\r
1391 /*-----------------------------------------------------------*/
\r
1393 void vTaskPlaceOnEventList( xList *pxEventList, portTickType xTicksToWait )
\r
1395 portTickType xTimeToWake;
\r
1397 /* THIS FUNCTION MUST BE CALLED WITH INTERRUPTS DISABLED OR THE
\r
1398 SCHEDULER SUSPENDED. */
\r
1400 /* Place the event list item of the TCB in the appropriate event list.
\r
1401 This is placed in the list in priority order so the highest priority task
\r
1402 is the first to be woken by the event. */
\r
1403 vListInsert( ( xList * ) pxEventList, ( xListItem * ) &( pxCurrentTCB->xEventListItem ) );
\r
1405 /* Calculate the time at which the task should be woken if the event does
\r
1406 not occur. This may overflow but this doesn't matter. */
\r
1407 xTimeToWake = xTickCount + xTicksToWait;
\r
1409 /* We must remove ourselves from the ready list before adding ourselves
\r
1410 to the blocked list as the same list item is used for both lists. We have
\r
1411 exclusive access to the ready lists as the scheduler is locked. */
\r
1412 vListRemove( ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
\r
1414 listSET_LIST_ITEM_VALUE( &( pxCurrentTCB->xGenericListItem ), xTimeToWake );
\r
1416 if( xTimeToWake < xTickCount )
\r
1418 /* Wake time has overflowed. Place this item in the overflow list. */
\r
1419 vListInsert( ( xList * ) pxOverflowDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
\r
1423 /* The wake time has not overflowed, so we can use the current block list. */
\r
1424 vListInsert( ( xList * ) pxDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
\r
1427 /*-----------------------------------------------------------*/
\r
1429 signed portBASE_TYPE xTaskRemoveFromEventList( const xList *pxEventList )
\r
1431 tskTCB *pxUnblockedTCB;
\r
1432 portBASE_TYPE xReturn;
\r
1434 /* THIS FUNCTION MUST BE CALLED WITH INTERRUPTS DISABLED OR THE
\r
1435 SCHEDULER SUSPENDED. It can also be called from within an ISR. */
\r
1437 /* The event list is sorted in priority order, so we can remove the
\r
1438 first in the list, remove the TCB from the delayed list, and add
\r
1439 it to the ready list.
\r
1441 If an event is for a queue that is locked then this function will never
\r
1442 get called - the lock count on the queue will get modified instead. This
\r
1443 means we can always expect exclusive access to the event list here. */
\r
1444 pxUnblockedTCB = ( tskTCB * ) listGET_OWNER_OF_HEAD_ENTRY( pxEventList );
\r
1445 vListRemove( &( pxUnblockedTCB->xEventListItem ) );
\r
1447 if( uxSchedulerSuspended == ( unsigned portBASE_TYPE ) pdFALSE )
\r
1449 vListRemove( &( pxUnblockedTCB->xGenericListItem ) );
\r
1450 prvAddTaskToReadyQueue( pxUnblockedTCB );
\r
1454 /* We cannot access the delayed or ready lists, so will hold this
\r
1455 task pending until the scheduler is resumed. */
\r
1456 vListInsertEnd( ( xList * ) &( xPendingReadyList ), &( pxUnblockedTCB->xEventListItem ) );
\r
1459 if( pxUnblockedTCB->uxPriority >= pxCurrentTCB->uxPriority )
\r
1461 /* Return true if the task removed from the event list has
\r
1462 a higher priority than the calling task. This allows
\r
1463 the calling task to know if it should force a context
\r
1469 xReturn = pdFALSE;
\r
1480 * -----------------------------------------------------------
\r
1482 * ----------------------------------------------------------
\r
1484 * The portTASK_FUNCTION() macro is used to allow port/compiler specific
\r
1485 * language extensions. The equivalent prototype for this function is:
\r
1487 * void prvIdleTask( void *pvParameters );
\r
1490 static portTASK_FUNCTION( prvIdleTask, pvParameters )
\r
1492 /* Stop warnings. */
\r
1493 ( void ) pvParameters;
\r
1497 /* See if any tasks have been deleted. */
\r
1498 prvCheckTasksWaitingTermination();
\r
1500 #if ( configUSE_PREEMPTION == 0 )
\r
1502 /* If we are not using preemption we keep forcing a task switch to
\r
1503 see if any other task has become available. If we are using
\r
1504 preemption we don't need to do this as any task becoming available
\r
1505 will automatically get the processor anyway. */
\r
1510 #if ( ( configUSE_PREEMPTION == 1 ) && ( configIDLE_SHOULD_YIELD == 1 ) )
\r
1512 /* When using preemption tasks of equal priority will be
\r
1513 timesliced. If a task that is sharing the idle priority is ready
\r
1514 to run then the idle task should yield before the end of the
\r
1517 A critical region is not required here as we are just reading from
\r
1518 the list, and an occasional incorrect value will not matter. If
\r
1519 the ready list at the idle priority contains more than one task
\r
1520 then a task other than the idle task is ready to execute. */
\r
1521 if( listCURRENT_LIST_LENGTH( &( pxReadyTasksLists[ tskIDLE_PRIORITY ] ) ) > ( unsigned portBASE_TYPE ) 1 )
\r
1528 #if ( configUSE_IDLE_HOOK == 1 )
\r
1530 extern void vApplicationIdleHook( void );
\r
1532 /* Call the user defined function from within the idle task. This
\r
1533 allows the application designer to add background functionality
\r
1534 without the overhead of a separate task.
\r
1535 NOTE: vApplicationIdleHook() MUST NOT, UNDER ANY CIRCUMSTANCES,
\r
1536 CALL A FUNCTION THAT MIGHT BLOCK. */
\r
1537 vApplicationIdleHook();
\r
1541 } /*lint !e715 pvParameters is not accessed but all task functions require the same prototype. */
\r
1549 /*-----------------------------------------------------------
\r
1550 * File private functions documented at the top of the file.
\r
1551 *----------------------------------------------------------*/
\r
1555 static void prvInitialiseTCBVariables( tskTCB *pxTCB, unsigned portSHORT usStackDepth, const signed portCHAR * const pcName, unsigned portBASE_TYPE uxPriority )
\r
1557 pxTCB->usStackDepth = usStackDepth;
\r
1559 /* Store the function name in the TCB. */
\r
1560 strncpy( ( char * ) pxTCB->pcTaskName, ( const char * ) pcName, ( unsigned portSHORT ) configMAX_TASK_NAME_LEN );
\r
1561 pxTCB->pcTaskName[ ( unsigned portSHORT ) configMAX_TASK_NAME_LEN - ( unsigned portSHORT ) 1 ] = '\0';
\r
1563 /* This is used as an array index so must ensure it's not too large. */
\r
1564 if( uxPriority >= configMAX_PRIORITIES )
\r
1566 uxPriority = configMAX_PRIORITIES - 1;
\r
1569 pxTCB->uxPriority = uxPriority;
\r
1571 vListInitialiseItem( &( pxTCB->xGenericListItem ) );
\r
1572 vListInitialiseItem( &( pxTCB->xEventListItem ) );
\r
1574 /* Set the pxTCB as a link back from the xListItem. This is so we can get
\r
1575 back to the containing TCB from a generic item in a list. */
\r
1576 listSET_LIST_ITEM_OWNER( &( pxTCB->xGenericListItem ), pxTCB );
\r
1578 /* Event lists are always in priority order. */
\r
1579 listSET_LIST_ITEM_VALUE( &( pxTCB->xEventListItem ), configMAX_PRIORITIES - ( portTickType ) uxPriority );
\r
1580 listSET_LIST_ITEM_OWNER( &( pxTCB->xEventListItem ), pxTCB );
\r
1582 /*-----------------------------------------------------------*/
\r
1584 static void prvInitialiseTaskLists( void )
\r
1586 unsigned portBASE_TYPE uxPriority;
\r
1588 for( uxPriority = 0; uxPriority < configMAX_PRIORITIES; uxPriority++ )
\r
1590 vListInitialise( ( xList * ) &( pxReadyTasksLists[ uxPriority ] ) );
\r
1593 vListInitialise( ( xList * ) &xDelayedTaskList1 );
\r
1594 vListInitialise( ( xList * ) &xDelayedTaskList2 );
\r
1595 vListInitialise( ( xList * ) &xPendingReadyList );
\r
1597 #if ( INCLUDE_vTaskDelete == 1 )
\r
1599 vListInitialise( ( xList * ) &xTasksWaitingTermination );
\r
1603 #if ( INCLUDE_vTaskSuspend == 1 )
\r
1605 vListInitialise( ( xList * ) &xSuspendedTaskList );
\r
1609 /* Start with pxDelayedTaskList using list1 and the pxOverflowDelayedTaskList
\r
1611 pxDelayedTaskList = &xDelayedTaskList1;
\r
1612 pxOverflowDelayedTaskList = &xDelayedTaskList2;
\r
1614 /*-----------------------------------------------------------*/
\r
1616 static void prvCheckTasksWaitingTermination( void )
\r
1618 #if ( INCLUDE_vTaskDelete == 1 )
\r
1620 portBASE_TYPE xListIsEmpty;
\r
1622 /* ucTasksDeleted is used to prevent vTaskSuspendAll() being called
\r
1623 too often in the idle task. */
\r
1624 if( uxTasksDeleted > ( unsigned portBASE_TYPE ) 0 )
\r
1626 vTaskSuspendAll();
\r
1627 xListIsEmpty = listLIST_IS_EMPTY( &xTasksWaitingTermination );
\r
1630 if( !xListIsEmpty )
\r
1634 portENTER_CRITICAL();
\r
1636 pxTCB = ( tskTCB * ) listGET_OWNER_OF_HEAD_ENTRY( ( ( xList * ) &xTasksWaitingTermination ) );
\r
1637 vListRemove( &( pxTCB->xGenericListItem ) );
\r
1638 --uxCurrentNumberOfTasks;
\r
1641 portEXIT_CRITICAL();
\r
1643 prvDeleteTCB( pxTCB );
\r
1649 /*-----------------------------------------------------------*/
\r
1651 static tskTCB *prvAllocateTCBAndStack( unsigned portSHORT usStackDepth )
\r
1655 /* Allocate space for the TCB. Where the memory comes from depends on
\r
1656 the implementation of the port malloc function. */
\r
1657 pxNewTCB = ( tskTCB * ) pvPortMalloc( sizeof( tskTCB ) );
\r
1659 if( pxNewTCB != NULL )
\r
1661 /* Allocate space for the stack used by the task being created.
\r
1662 The base of the stack memory stored in the TCB so the task can
\r
1663 be deleted later if required. */
\r
1664 pxNewTCB->pxStack = ( portSTACK_TYPE * ) pvPortMalloc( ( ( size_t )usStackDepth ) * sizeof( portSTACK_TYPE ) );
\r
1666 if( pxNewTCB->pxStack == NULL )
\r
1668 /* Could not allocate the stack. Delete the allocated TCB. */
\r
1669 vPortFree( pxNewTCB );
\r
1674 /* Just to help debugging. */
\r
1675 memset( pxNewTCB->pxStack, tskSTACK_FILL_BYTE, usStackDepth * sizeof( portSTACK_TYPE ) );
\r
1681 /*-----------------------------------------------------------*/
\r
1683 #if ( configUSE_TRACE_FACILITY == 1 )
\r
1685 static void prvListTaskWithinSingleList( signed portCHAR *pcWriteBuffer, xList *pxList, signed portCHAR cStatus )
\r
1687 volatile tskTCB *pxNextTCB, *pxFirstTCB;
\r
1688 static portCHAR pcStatusString[ 50 ];
\r
1689 unsigned portSHORT usStackRemaining;
\r
1691 /* Write the details of all the TCB's in pxList into the buffer. */
\r
1692 listGET_OWNER_OF_NEXT_ENTRY( pxFirstTCB, pxList );
\r
1695 listGET_OWNER_OF_NEXT_ENTRY( pxNextTCB, pxList );
\r
1696 usStackRemaining = usTaskCheckFreeStackSpace( ( unsigned portCHAR * ) pxNextTCB->pxStack );
\r
1697 sprintf( pcStatusString, ( portCHAR * ) "%s\t\t%c\t%u\t%u\t%u\r\n", pxNextTCB->pcTaskName, cStatus, ( unsigned int ) pxNextTCB->uxPriority, usStackRemaining, ( unsigned int ) pxNextTCB->uxTCBNumber );
\r
1698 strcat( ( portCHAR * ) pcWriteBuffer, ( portCHAR * ) pcStatusString );
\r
1700 } while( pxNextTCB != pxFirstTCB );
\r
1704 /*-----------------------------------------------------------*/
\r
1706 #if ( configUSE_TRACE_FACILITY == 1 )
\r
1707 unsigned portSHORT usTaskCheckFreeStackSpace( const unsigned portCHAR *pucStackByte )
\r
1709 register unsigned portSHORT usCount = 0;
\r
1711 while( *pucStackByte == tskSTACK_FILL_BYTE )
\r
1713 pucStackByte -= portSTACK_GROWTH;
\r
1717 usCount /= sizeof( portSTACK_TYPE );
\r
1722 /*-----------------------------------------------------------*/
\r
1726 #if ( ( INCLUDE_vTaskDelete == 1 ) || ( INCLUDE_vTaskCleanUpResources == 1 ) )
\r
1728 static void prvDeleteTCB( tskTCB *pxTCB )
\r
1730 /* Free up the memory allocated by the scheduler for the task. It is up to
\r
1731 the task to free any memory allocated at the application level. */
\r
1732 vPortFree( pxTCB->pxStack );
\r
1733 vPortFree( pxTCB );
\r
1739 /*-----------------------------------------------------------*/
\r
1741 #if ( INCLUDE_xTaskGetCurrentTaskHandle == 1 )
\r
1743 xTaskHandle xTaskGetCurrentTaskHandle( void )
\r
1745 xTaskHandle xReturn;
\r
1747 portENTER_CRITICAL();
\r
1749 xReturn = ( xTaskHandle ) pxCurrentTCB;
\r
1751 portEXIT_CRITICAL();
\r