2 FreeRTOS.org V4.2.1 - Copyright (C) 2003-2007 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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31 Also see http://www.SafeRTOS.com for an IEC 61508 compliant version, along
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32 with development and support options.
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33 ***************************************************************************
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39 + Call to portRESTORE_CONTEXT has been removed. The first context
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40 switch is now performed within sPortStartScheduler().
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44 + More use of 8bit data types.
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45 + Function name prefixes changed where the data type returned has changed.
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46 + configUSE_TRACE_FACILITY is no longer defined by default.
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50 + Introduced ucTopReadyPriority. This tracks the highest priority ready
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51 queue that contains a valid TCB and thus makes the context switch
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54 + prvAddTaskToReadyQueue() has been made a macro.
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58 + Added conditional compilation directives.
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60 + Rearranged function order.
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61 + Creating a task now causes a context switch if the task being created
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62 has a higher priority than the calling task - assuming the kernel is
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64 + vTaskDelete() now only causes a context switch if the calling task is
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65 the task being deleted.
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69 + Allow the type of the tick count to be 16 or 32 bits.
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70 + Introduce xPendingReadyList feature to allow the time interrupts have to
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71 be disabled to be minimised.
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72 + Remove the #if( INCLUDE_vTaskSuspendAll ) statements. vTaskSuspendAll()
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73 is now always included as it is used by the scheduler itself.
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77 + Bug fix - pxCurrentTCB is now initialised before the call to
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78 prvInitializeTaskLists(). Previously pxCurrentTCB could be accessed
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83 + Change to where lStackSize is declared within sTaskCreate() to prevent
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84 compiler warnings with 8051 port.
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88 + Explicit use of 'signed' qualifier on portCHAR types added.
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89 + Changed odd calculation of initial pxTopOfStack value when
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90 portSTACK_GROWTH < 0.
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91 + Removed pcVersionNumber definition.
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95 + cTaskResumeAll() modified to ensure it can be called prior to the task
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96 lists being initialised.
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100 + Added API function vTaskDelayUntil().
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101 + Added INCLUDE_vTaskDelay conditional compilation.
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103 Changes from V2.6.0
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105 + Updated the vWriteTraceToBuffer macro to always be 4 byte aligned so it
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106 can be used on ARM architectures.
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107 + tskMAX_TASK_NAME_LEN definition replaced with the port specific
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108 configMAX_TASK_NAME_LEN definition.
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109 + Removed the call to strcpy when copying across the task name into the
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111 + Added ucTasksDeleted variable to prevent vTaskSuspendAll() being called
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112 too often in the idle task.
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114 Changes between V3.0.0 and V2.6.1
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116 + When resuming the scheduler a yield is performed if either a tick has
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117 been missed, or a task is moved from the pending ready list into a ready
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118 list. Previously a yield was not performed on this second condition.
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119 + Introduced the type portBASE_TYPE. This necessitates several API
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121 + Removed the sUsingPreemption variable. The constant defined in
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122 portmacro.h is now used directly.
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123 + The idle task can now include an optional hook function - and no longer
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124 completes its time slice if other tasks with equal priority to it are
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126 + See the FreeRTOS.org documentation for more information on V2.x.x to
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127 V3.x.x modifications.
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129 Changes from V3.1.1
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131 + Modified vTaskPrioritySet() and vTaskResume() to allow these functions to
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132 be called while the scheduler is suspended.
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133 + Corrected the task ordering within event lists.
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135 Changes from V3.2.0
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137 + Added function xTaskGetCurrentTaskHandle().
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139 Changes from V3.2.4
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141 + Changed the volatile declarations on some variables to reflect the
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142 changes to the list definitions.
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143 + Changed the order of the TCB definition so there is commonality between
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144 the task control block and a co-routine control block.
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145 + Allow the scheduler to be started even if no tasks other than the idle
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146 task has been created. This allows co-routines to run even when no tasks
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148 + The need for a context switch is now signalled if a task woken by an
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149 event has a priority greater or equal to the currently running task.
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150 Previously this was only greater than.
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152 Changes from V4.0.0
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154 + Added the xMissedYield handling.
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156 Changes from V4.0.1
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158 + The function vTaskList() now suspends the scheduler rather than disabling
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159 interrupts during the creation of the task list.
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160 + Allow a task to delete itself by passing in its own handle. Previously
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161 this could only be done by passing in NULL.
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162 + The tick hook function is now called only within a tick isr. Previously
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163 it was also called when the tick function was called during the scheduler
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166 Changes from V4.0.3
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168 + Extra checks have been placed in vTaskPrioritySet() to avoid unnecessary
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171 Changed from V4.0.4
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173 + Bug fix: The 'value' of the event list item is updated when the priority
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174 of a task is changed. Previously only the priority of the TCB itself was
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176 + When resuming a task a check is first made to see if the task is actually
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178 + vTaskPrioritySet() and vTaskResume() no longer use the event list item.
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179 This has not been necessary since V4.0.1 when the xMissedYield handling
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181 + Implement xTaskResumeFromISR().
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183 Changes from V4.0.5
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185 + Added utility functions and xOverflowCount variable to facilitate the
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188 Changes from V4.1.2
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190 + Tasks that block on events with a timeout of portMAX_DELAY are now
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191 blocked indefinitely if configINCLUDE_vTaskSuspend is defined.
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192 Previously portMAX_DELAY was just the longest block time possible.
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194 Changes from V4.1.3
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196 + Very small change made to xTaskCheckForTimeout() as a result of the
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197 SafeRTOS testing. This corrects the case where the function can return an
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198 invalid value - but only in an extremely unlikely scenario.
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202 #include <stdlib.h>
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203 #include <string.h>
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205 #include "FreeRTOS.h"
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209 * Macro to define the amount of stack available to the idle task.
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211 #define tskIDLE_STACK_SIZE configMINIMAL_STACK_SIZE
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215 * Default a definitions for backwards compatibility with old
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216 * portmacro.h files.
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218 #ifndef configMAX_TASK_NAME_LEN
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219 #define configMAX_TASK_NAME_LEN 16
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222 #ifndef INCLUDE_xTaskGetCurrentTaskHandle
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223 #define INCLUDE_xTaskGetCurrentTaskHandle 0
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226 #ifndef configIDLE_SHOULD_YIELD
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227 #define configIDLE_SHOULD_YIELD 1
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230 #if configMAX_TASK_NAME_LEN < 1
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231 #undef configMAX_TASK_NAME_LEN
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232 #define configMAX_TASK_NAME_LEN 1
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235 #ifndef INCLUDE_xTaskResumeFromISR
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236 #define INCLUDE_xTaskResumeFromISR 1
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240 * Task control block. A task control block (TCB) is allocated to each task,
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241 * and stores the context of the task.
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243 typedef struct tskTaskControlBlock
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245 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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246 xListItem xGenericListItem; /*< List item used to place the TCB in ready and blocked queues. */
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247 xListItem xEventListItem; /*< List item used to place the TCB in event lists. */
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248 unsigned portBASE_TYPE uxPriority; /*< The priority of the task where 0 is the lowest priority. */
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249 portSTACK_TYPE *pxStack; /*< Points to the start of the stack. */
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250 unsigned portBASE_TYPE uxTCBNumber; /*< This is used for tracing the scheduler and making debugging easier only. */
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251 signed portCHAR pcTaskName[ configMAX_TASK_NAME_LEN ];/*< Descriptive name given to the task when created. Facilitates debugging only. */
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252 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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257 tskTCB * volatile pxCurrentTCB = NULL;
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259 /* Lists for ready and blocked tasks. --------------------*/
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261 static xList pxReadyTasksLists[ configMAX_PRIORITIES ]; /*< Prioritised ready tasks. */
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262 static xList xDelayedTaskList1; /*< Delayed tasks. */
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263 static xList xDelayedTaskList2; /*< Delayed tasks (two lists are used - one for delays that have overflowed the current tick count. */
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264 static xList * volatile pxDelayedTaskList; /*< Points to the delayed task list currently being used. */
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265 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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266 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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268 #if ( INCLUDE_vTaskDelete == 1 )
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270 static volatile xList xTasksWaitingTermination; /*< Tasks that have been deleted - but the their memory not yet freed. */
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271 static volatile unsigned portBASE_TYPE uxTasksDeleted = ( unsigned portBASE_TYPE ) 0;
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275 #if ( INCLUDE_vTaskSuspend == 1 )
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277 static xList xSuspendedTaskList; /*< Tasks that are currently suspended. */
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281 /* File private variables. --------------------------------*/
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282 static volatile unsigned portBASE_TYPE uxCurrentNumberOfTasks = ( unsigned portBASE_TYPE ) 0;
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283 static volatile portTickType xTickCount = ( portTickType ) 0;
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284 static unsigned portBASE_TYPE uxTopUsedPriority = tskIDLE_PRIORITY;
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285 static volatile unsigned portBASE_TYPE uxTopReadyPriority = tskIDLE_PRIORITY;
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286 static volatile signed portBASE_TYPE xSchedulerRunning = pdFALSE;
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287 static volatile unsigned portBASE_TYPE uxSchedulerSuspended = ( unsigned portBASE_TYPE ) pdFALSE;
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288 static volatile unsigned portBASE_TYPE uxMissedTicks = ( unsigned portBASE_TYPE ) 0;
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289 static volatile portBASE_TYPE xMissedYield = ( portBASE_TYPE ) pdFALSE;
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290 static volatile portBASE_TYPE xNumOfOverflows = ( portBASE_TYPE ) 0;
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291 /* Debugging and trace facilities private variables and macros. ------------*/
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294 * The value used to fill the stack of a task when the task is created. This
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295 * is used purely for checking the high water mark for tasks.
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297 #define tskSTACK_FILL_BYTE ( 0xa5 )
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300 * Macros used by vListTask to indicate which state a task is in.
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302 #define tskBLOCKED_CHAR ( ( signed portCHAR ) 'B' )
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303 #define tskREADY_CHAR ( ( signed portCHAR ) 'R' )
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304 #define tskDELETED_CHAR ( ( signed portCHAR ) 'D' )
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305 #define tskSUSPENDED_CHAR ( ( signed portCHAR ) 'S' )
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308 * Macros and private variables used by the trace facility.
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310 #if ( configUSE_TRACE_FACILITY == 1 )
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312 #define tskSIZE_OF_EACH_TRACE_LINE ( ( unsigned portLONG ) ( sizeof( unsigned portLONG ) + sizeof( unsigned portLONG ) ) )
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313 static volatile signed portCHAR * volatile pcTraceBuffer;
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314 static signed portCHAR *pcTraceBufferStart;
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315 static signed portCHAR *pcTraceBufferEnd;
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316 static signed portBASE_TYPE xTracing = pdFALSE;
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321 * Macro that writes a trace of scheduler activity to a buffer. This trace
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322 * shows which task is running when and is very useful as a debugging tool.
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323 * As this macro is called each context switch it is a good idea to undefine
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324 * it if not using the facility.
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326 #if ( configUSE_TRACE_FACILITY == 1 )
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328 #define vWriteTraceToBuffer() \
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332 static unsigned portBASE_TYPE uxPreviousTask = 255; \
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334 if( uxPreviousTask != pxCurrentTCB->uxTCBNumber ) \
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336 if( ( pcTraceBuffer + tskSIZE_OF_EACH_TRACE_LINE ) < pcTraceBufferEnd ) \
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338 uxPreviousTask = pxCurrentTCB->uxTCBNumber; \
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339 *( unsigned portLONG * ) pcTraceBuffer = ( unsigned portLONG ) xTickCount; \
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340 pcTraceBuffer += sizeof( unsigned portLONG ); \
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341 *( unsigned portLONG * ) pcTraceBuffer = ( unsigned portLONG ) uxPreviousTask; \
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342 pcTraceBuffer += sizeof( unsigned portLONG ); \
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346 xTracing = pdFALSE; \
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354 #define vWriteTraceToBuffer()
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360 * Place the task represented by pxTCB into the appropriate ready queue for
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361 * the task. It is inserted at the end of the list. One quirk of this is
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362 * that if the task being inserted is at the same priority as the currently
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363 * executing task, then it will only be rescheduled after the currently
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364 * executing task has been rescheduled.
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366 #define prvAddTaskToReadyQueue( pxTCB ) \
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368 if( pxTCB->uxPriority > uxTopReadyPriority ) \
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370 uxTopReadyPriority = pxTCB->uxPriority; \
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372 vListInsertEnd( ( xList * ) &( pxReadyTasksLists[ pxTCB->uxPriority ] ), &( pxTCB->xGenericListItem ) ); \
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376 * Macro that looks at the list of tasks that are currently delayed to see if
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377 * any require waking.
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379 * Tasks are stored in the queue in the order of their wake time - meaning
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380 * once one tasks has been found whose timer has not expired we need not look
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381 * any further down the list.
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383 #define prvCheckDelayedTasks() \
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385 register tskTCB *pxTCB; \
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387 while( ( pxTCB = ( tskTCB * ) listGET_OWNER_OF_HEAD_ENTRY( pxDelayedTaskList ) ) != NULL ) \
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389 if( xTickCount < listGET_LIST_ITEM_VALUE( &( pxTCB->xGenericListItem ) ) ) \
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393 vListRemove( &( pxTCB->xGenericListItem ) ); \
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394 /* Is the task waiting on an event also? */ \
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395 if( pxTCB->xEventListItem.pvContainer ) \
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397 vListRemove( &( pxTCB->xEventListItem ) ); \
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399 prvAddTaskToReadyQueue( pxTCB ); \
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404 * Several functions take an xTaskHandle parameter that can optionally be NULL,
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405 * where NULL is used to indicate that the handle of the currently executing
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406 * task should be used in place of the parameter. This macro simply checks to
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407 * see if the parameter is NULL and returns a pointer to the appropriate TCB.
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409 #define prvGetTCBFromHandle( pxHandle ) ( ( pxHandle == NULL ) ? ( tskTCB * ) pxCurrentTCB : ( tskTCB * ) pxHandle )
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412 /* File private functions. --------------------------------*/
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415 * Utility to ready a TCB for a given task. Mainly just copies the parameters
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416 * into the TCB structure.
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418 static void prvInitialiseTCBVariables( tskTCB *pxTCB, unsigned portSHORT usStackDepth, const signed portCHAR * const pcName, unsigned portBASE_TYPE uxPriority );
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421 * Utility to ready all the lists used by the scheduler. This is called
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422 * automatically upon the creation of the first task.
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424 static void prvInitialiseTaskLists( void );
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427 * The idle task, which as all tasks is implemented as a never ending loop.
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428 * The idle task is automatically created and added to the ready lists upon
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429 * creation of the first user task.
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431 * The portTASK_FUNCTION_PROTO() macro is used to allow port/compiler specific
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432 * language extensions. The equivalent prototype for this function is:
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434 * void prvIdleTask( void *pvParameters );
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437 static portTASK_FUNCTION_PROTO( prvIdleTask, pvParameters );
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440 * Utility to free all memory allocated by the scheduler to hold a TCB,
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441 * including the stack pointed to by the TCB.
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443 * This does not free memory allocated by the task itself (i.e. memory
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444 * allocated by calls to pvPortMalloc from within the tasks application code).
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446 #if ( ( INCLUDE_vTaskDelete == 1 ) || ( INCLUDE_vTaskCleanUpResources == 1 ) )
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447 static void prvDeleteTCB( tskTCB *pxTCB );
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451 * Used only by the idle task. This checks to see if anything has been placed
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452 * in the list of tasks waiting to be deleted. If so the task is cleaned up
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453 * and its TCB deleted.
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455 static void prvCheckTasksWaitingTermination( void );
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458 * Allocates memory from the heap for a TCB and associated stack. Checks the
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459 * allocation was successful.
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461 static tskTCB *prvAllocateTCBAndStack( unsigned portSHORT usStackDepth );
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464 * Called from vTaskList. vListTasks details all the tasks currently under
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465 * control of the scheduler. The tasks may be in one of a number of lists.
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466 * prvListTaskWithinSingleList accepts a list and details the tasks from
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467 * within just that list.
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469 * THIS FUNCTION IS INTENDED FOR DEBUGGING ONLY, AND SHOULD NOT BE CALLED FROM
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470 * NORMAL APPLICATION CODE.
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472 #if ( configUSE_TRACE_FACILITY == 1 )
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474 static void prvListTaskWithinSingleList( signed portCHAR *pcWriteBuffer, xList *pxList, signed portCHAR cStatus );
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479 * When a task is created, the stack of the task is filled with a known value.
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480 * This function determines the 'high water mark' of the task stack by
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481 * determining how much of the stack remains at the original preset value.
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483 #if ( configUSE_TRACE_FACILITY == 1 )
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485 unsigned portSHORT usTaskCheckFreeStackSpace( const unsigned portCHAR *pucStackByte );
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495 /*-----------------------------------------------------------
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496 * TASK CREATION API documented in task.h
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497 *----------------------------------------------------------*/
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499 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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501 signed portBASE_TYPE xReturn;
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503 static unsigned portBASE_TYPE uxTaskNumber = 0; /*lint !e956 Static is deliberate - this is guarded before use. */
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505 /* Allocate the memory required by the TCB and stack for the new task.
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506 checking that the allocation was successful. */
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507 pxNewTCB = prvAllocateTCBAndStack( usStackDepth );
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509 if( pxNewTCB != NULL )
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511 portSTACK_TYPE *pxTopOfStack;
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513 /* Setup the newly allocated TCB with the initial state of the task. */
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514 prvInitialiseTCBVariables( pxNewTCB, usStackDepth, pcName, uxPriority );
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516 /* Calculate the top of stack address. This depends on whether the
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517 stack grows from high memory to low (as per the 80x86) or visa versa.
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518 portSTACK_GROWTH is used to make the result positive or negative as
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519 required by the port. */
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520 #if portSTACK_GROWTH < 0
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522 pxTopOfStack = pxNewTCB->pxStack + ( pxNewTCB->usStackDepth - 1 );
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526 pxTopOfStack = pxNewTCB->pxStack;
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530 /* Initialize the TCB stack to look as if the task was already running,
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531 but had been interrupted by the scheduler. The return address is set
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532 to the start of the task function. Once the stack has been initialised
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533 the top of stack variable is updated. */
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534 pxNewTCB->pxTopOfStack = pxPortInitialiseStack( pxTopOfStack, pvTaskCode, pvParameters );
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536 /* We are going to manipulate the task queues to add this task to a
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537 ready list, so must make sure no interrupts occur. */
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538 portENTER_CRITICAL();
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540 uxCurrentNumberOfTasks++;
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541 if( uxCurrentNumberOfTasks == ( unsigned portBASE_TYPE ) 1 )
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543 /* As this is the first task it must also be the current task. */
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544 pxCurrentTCB = pxNewTCB;
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546 /* This is the first task to be created so do the preliminary
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547 initialisation required. We will not recover if this call
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548 fails, but we will report the failure. */
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549 prvInitialiseTaskLists();
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553 /* If the scheduler is not already running, make this task the
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554 current task if it is the highest priority task to be created
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556 if( xSchedulerRunning == pdFALSE )
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558 if( pxCurrentTCB->uxPriority <= uxPriority )
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560 pxCurrentTCB = pxNewTCB;
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565 /* Remember the top priority to make context switching faster. Use
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566 the priority in pxNewTCB as this has been capped to a valid value. */
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567 if( pxNewTCB->uxPriority > uxTopUsedPriority )
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569 uxTopUsedPriority = pxNewTCB->uxPriority;
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572 /* Add a counter into the TCB for tracing only. */
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573 pxNewTCB->uxTCBNumber = uxTaskNumber;
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576 prvAddTaskToReadyQueue( pxNewTCB );
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580 portEXIT_CRITICAL();
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584 xReturn = errCOULD_NOT_ALLOCATE_REQUIRED_MEMORY;
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587 if( xReturn == pdPASS )
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589 if( ( void * ) pxCreatedTask != NULL )
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591 /* Pass the TCB out - in an anonymous way. The calling function/
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592 task can use this as a handle to delete the task later if
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594 *pxCreatedTask = ( xTaskHandle ) pxNewTCB;
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597 if( xSchedulerRunning != pdFALSE )
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599 /* If the created task is of a higher priority than the current task
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600 then it should run now. */
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601 if( pxCurrentTCB->uxPriority < uxPriority )
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610 /*-----------------------------------------------------------*/
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612 #if ( INCLUDE_vTaskDelete == 1 )
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614 void vTaskDelete( xTaskHandle pxTaskToDelete )
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618 taskENTER_CRITICAL();
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620 /* Ensure a yield is performed if the current task is being
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622 if( pxTaskToDelete == pxCurrentTCB )
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624 pxTaskToDelete = NULL;
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627 /* If null is passed in here then we are deleting ourselves. */
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628 pxTCB = prvGetTCBFromHandle( pxTaskToDelete );
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630 /* Remove task from the ready list and place in the termination list.
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631 This will stop the task from be scheduled. The idle task will check
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632 the termination list and free up any memory allocated by the
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633 scheduler for the TCB and stack. */
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634 vListRemove( &( pxTCB->xGenericListItem ) );
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636 /* Is the task waiting on an event also? */
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637 if( pxTCB->xEventListItem.pvContainer )
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639 vListRemove( &( pxTCB->xEventListItem ) );
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642 vListInsertEnd( ( xList * ) &xTasksWaitingTermination, &( pxTCB->xGenericListItem ) );
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644 /* Increment the ucTasksDeleted variable so the idle task knows
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645 there is a task that has been deleted and that it should therefore
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646 check the xTasksWaitingTermination list. */
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649 taskEXIT_CRITICAL();
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651 /* Force a reschedule if we have just deleted the current task. */
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652 if( xSchedulerRunning != pdFALSE )
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654 if( ( void * ) pxTaskToDelete == NULL )
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668 /*-----------------------------------------------------------
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669 * TASK CONTROL API documented in task.h
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670 *----------------------------------------------------------*/
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672 #if ( INCLUDE_vTaskDelayUntil == 1 )
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674 void vTaskDelayUntil( portTickType *pxPreviousWakeTime, portTickType xTimeIncrement )
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676 portTickType xTimeToWake;
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677 portBASE_TYPE xAlreadyYielded, xShouldDelay = pdFALSE;
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681 /* Generate the tick time at which the task wants to wake. */
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682 xTimeToWake = *pxPreviousWakeTime + xTimeIncrement;
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684 if( xTickCount < *pxPreviousWakeTime )
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686 /* The tick count has overflowed since this function was
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687 lasted called. In this case the only time we should ever
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688 actually delay is if the wake time has also overflowed,
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689 and the wake time is greater than the tick time. When this
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690 is the case it is as if neither time had overflowed. */
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691 if( ( xTimeToWake < *pxPreviousWakeTime ) && ( xTimeToWake > xTickCount ) )
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693 xShouldDelay = pdTRUE;
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698 /* The tick time has not overflowed. In this case we will
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699 delay if either the wake time has overflowed, and/or the
\r
700 tick time is less than the wake time. */
\r
701 if( ( xTimeToWake < *pxPreviousWakeTime ) || ( xTimeToWake > xTickCount ) )
\r
703 xShouldDelay = pdTRUE;
\r
707 /* Update the wake time ready for the next call. */
\r
708 *pxPreviousWakeTime = xTimeToWake;
\r
712 /* We must remove ourselves from the ready list before adding
\r
713 ourselves to the blocked list as the same list item is used for
\r
715 vListRemove( ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
\r
717 /* The list item will be inserted in wake time order. */
\r
718 listSET_LIST_ITEM_VALUE( &( pxCurrentTCB->xGenericListItem ), xTimeToWake );
\r
720 if( xTimeToWake < xTickCount )
\r
722 /* Wake time has overflowed. Place this item in the
\r
724 vListInsert( ( xList * ) pxOverflowDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
\r
728 /* The wake time has not overflowed, so we can use the
\r
729 current block list. */
\r
730 vListInsert( ( xList * ) pxDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
\r
734 xAlreadyYielded = xTaskResumeAll();
\r
736 /* Force a reschedule if xTaskResumeAll has not already done so, we may
\r
737 have put ourselves to sleep. */
\r
738 if( !xAlreadyYielded )
\r
745 /*-----------------------------------------------------------*/
\r
747 #if ( INCLUDE_vTaskDelay == 1 )
\r
749 void vTaskDelay( portTickType xTicksToDelay )
\r
751 portTickType xTimeToWake;
\r
752 signed portBASE_TYPE xAlreadyYielded = pdFALSE;
\r
754 /* A delay time of zero just forces a reschedule. */
\r
755 if( xTicksToDelay > ( portTickType ) 0 )
\r
759 /* A task that is removed from the event list while the
\r
760 scheduler is suspended will not get placed in the ready
\r
761 list or removed from the blocked list until the scheduler
\r
764 This task cannot be in an event list as it is the currently
\r
767 /* Calculate the time to wake - this may overflow but this is
\r
769 xTimeToWake = xTickCount + xTicksToDelay;
\r
771 /* We must remove ourselves from the ready list before adding
\r
772 ourselves to the blocked list as the same list item is used for
\r
774 vListRemove( ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
\r
776 /* The list item will be inserted in wake time order. */
\r
777 listSET_LIST_ITEM_VALUE( &( pxCurrentTCB->xGenericListItem ), xTimeToWake );
\r
779 if( xTimeToWake < xTickCount )
\r
781 /* Wake time has overflowed. Place this item in the
\r
783 vListInsert( ( xList * ) pxOverflowDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
\r
787 /* The wake time has not overflowed, so we can use the
\r
788 current block list. */
\r
789 vListInsert( ( xList * ) pxDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
\r
792 xAlreadyYielded = xTaskResumeAll();
\r
795 /* Force a reschedule if xTaskResumeAll has not already done so, we may
\r
796 have put ourselves to sleep. */
\r
797 if( !xAlreadyYielded )
\r
804 /*-----------------------------------------------------------*/
\r
806 #if ( INCLUDE_uxTaskPriorityGet == 1 )
\r
808 unsigned portBASE_TYPE uxTaskPriorityGet( xTaskHandle pxTask )
\r
811 unsigned portBASE_TYPE uxReturn;
\r
813 taskENTER_CRITICAL();
\r
815 /* If null is passed in here then we are changing the
\r
816 priority of the calling function. */
\r
817 pxTCB = prvGetTCBFromHandle( pxTask );
\r
818 uxReturn = pxTCB->uxPriority;
\r
820 taskEXIT_CRITICAL();
\r
826 /*-----------------------------------------------------------*/
\r
828 #if ( INCLUDE_vTaskPrioritySet == 1 )
\r
830 void vTaskPrioritySet( xTaskHandle pxTask, unsigned portBASE_TYPE uxNewPriority )
\r
833 unsigned portBASE_TYPE uxCurrentPriority, xYieldRequired = pdFALSE;
\r
835 /* Ensure the new priority is valid. */
\r
836 if( uxNewPriority >= configMAX_PRIORITIES )
\r
838 uxNewPriority = configMAX_PRIORITIES - 1;
\r
841 taskENTER_CRITICAL();
\r
843 /* If null is passed in here then we are changing the
\r
844 priority of the calling function. */
\r
845 pxTCB = prvGetTCBFromHandle( pxTask );
\r
846 uxCurrentPriority = pxTCB->uxPriority;
\r
848 if( uxCurrentPriority != uxNewPriority )
\r
850 /* The priority change may have readied a task of higher
\r
851 priority than the calling task. */
\r
852 if( uxNewPriority > pxCurrentTCB->uxPriority )
\r
854 if( pxTask != NULL )
\r
856 /* The priority of another task is being raised. If we
\r
857 were raising the priority of the currently running task
\r
858 there would be no need to switch as it must have already
\r
859 been the highest priority task. */
\r
860 xYieldRequired = pdTRUE;
\r
863 else if( pxTask == NULL )
\r
865 /* Setting our own priority down means there may now be another
\r
866 task of higher priority that is ready to execute. */
\r
867 xYieldRequired = pdTRUE;
\r
870 pxTCB->uxPriority = uxNewPriority;
\r
871 listSET_LIST_ITEM_VALUE( &( pxTCB->xEventListItem ), configMAX_PRIORITIES - ( portTickType ) uxNewPriority );
\r
873 /* If the task is in the blocked or suspended list we need do
\r
874 nothing more than change it's priority variable. However, if
\r
875 the task is in a ready list it needs to be removed and placed
\r
876 in the queue appropriate to its new priority. */
\r
877 if( listIS_CONTAINED_WITHIN( &( pxReadyTasksLists[ uxCurrentPriority ] ), &( pxTCB->xGenericListItem ) ) )
\r
879 /* The task is currently in its ready list - remove before adding
\r
880 it to it's new ready list. As we are in a critical section we
\r
881 can do this even if the scheduler is suspended. */
\r
882 vListRemove( &( pxTCB->xGenericListItem ) );
\r
883 prvAddTaskToReadyQueue( pxTCB );
\r
886 if( xYieldRequired == pdTRUE )
\r
892 taskEXIT_CRITICAL();
\r
896 /*-----------------------------------------------------------*/
\r
898 #if ( INCLUDE_vTaskSuspend == 1 )
\r
900 void vTaskSuspend( xTaskHandle pxTaskToSuspend )
\r
904 taskENTER_CRITICAL();
\r
906 /* Ensure a yield is performed if the current task is being
\r
908 if( pxTaskToSuspend == pxCurrentTCB )
\r
910 pxTaskToSuspend = NULL;
\r
913 /* If null is passed in here then we are suspending ourselves. */
\r
914 pxTCB = prvGetTCBFromHandle( pxTaskToSuspend );
\r
916 /* Remove task from the ready/delayed list and place in the suspended list. */
\r
917 vListRemove( &( pxTCB->xGenericListItem ) );
\r
919 /* Is the task waiting on an event also? */
\r
920 if( pxTCB->xEventListItem.pvContainer )
\r
922 vListRemove( &( pxTCB->xEventListItem ) );
\r
925 vListInsertEnd( ( xList * ) &xSuspendedTaskList, &( pxTCB->xGenericListItem ) );
\r
927 taskEXIT_CRITICAL();
\r
929 /* We may have just suspended the current task. */
\r
930 if( ( void * ) pxTaskToSuspend == NULL )
\r
937 /*-----------------------------------------------------------*/
\r
939 #if ( INCLUDE_vTaskSuspend == 1 )
\r
941 void vTaskResume( xTaskHandle pxTaskToResume )
\r
945 /* Remove the task from whichever list it is currently in, and place
\r
946 it in the ready list. */
\r
947 pxTCB = ( tskTCB * ) pxTaskToResume;
\r
949 /* The parameter cannot be NULL as it is impossible to resume the
\r
950 currently executing task. */
\r
951 if( pxTCB != NULL )
\r
953 taskENTER_CRITICAL();
\r
955 /* Is the task we are attempting to resume actually suspended? */
\r
956 if( listIS_CONTAINED_WITHIN( &xSuspendedTaskList, &( pxTCB->xGenericListItem ) ) != pdFALSE )
\r
958 /* Has the task already been resumed from within an ISR? */
\r
959 if( listIS_CONTAINED_WITHIN( &xPendingReadyList, &( pxTCB->xEventListItem ) ) != pdTRUE )
\r
961 /* As we are in a critical section we can access the ready
\r
962 lists even if the scheduler is suspended. */
\r
963 vListRemove( &( pxTCB->xGenericListItem ) );
\r
964 prvAddTaskToReadyQueue( pxTCB );
\r
966 /* We may have just resumed a higher priority task. */
\r
967 if( pxTCB->uxPriority >= pxCurrentTCB->uxPriority )
\r
969 /* This yield may not cause the task just resumed to run, but
\r
970 will leave the lists in the correct state for the next yield. */
\r
976 taskEXIT_CRITICAL();
\r
982 /*-----------------------------------------------------------*/
\r
984 #if ( ( INCLUDE_xTaskResumeFromISR == 1 ) && ( INCLUDE_vTaskSuspend == 1 ) )
\r
986 portBASE_TYPE xTaskResumeFromISR( xTaskHandle pxTaskToResume )
\r
988 portBASE_TYPE xYieldRequired = pdFALSE;
\r
991 pxTCB = ( tskTCB * ) pxTaskToResume;
\r
993 /* Is the task we are attempting to resume actually suspended? */
\r
994 if( listIS_CONTAINED_WITHIN( &xSuspendedTaskList, &( pxTCB->xGenericListItem ) ) != pdFALSE )
\r
996 /* Has the task already been resumed from within an ISR? */
\r
997 if( listIS_CONTAINED_WITHIN( &xPendingReadyList, &( pxTCB->xEventListItem ) ) != pdTRUE )
\r
999 if( uxSchedulerSuspended == ( unsigned portBASE_TYPE ) pdFALSE )
\r
1001 xYieldRequired = ( pxTCB->uxPriority >= pxCurrentTCB->uxPriority );
\r
1002 vListRemove( &( pxTCB->xGenericListItem ) );
\r
1003 prvAddTaskToReadyQueue( pxTCB );
\r
1007 /* We cannot access the delayed or ready lists, so will hold this
\r
1008 task pending until the scheduler is resumed, at which point a
\r
1009 yield will be preformed if necessary. */
\r
1010 vListInsertEnd( ( xList * ) &( xPendingReadyList ), &( pxTCB->xEventListItem ) );
\r
1015 return xYieldRequired;
\r
1023 /*-----------------------------------------------------------
\r
1024 * PUBLIC SCHEDULER CONTROL documented in task.h
\r
1025 *----------------------------------------------------------*/
\r
1028 void vTaskStartScheduler( void )
\r
1030 portBASE_TYPE xReturn;
\r
1032 /* Add the idle task at the lowest priority. */
\r
1033 xReturn = xTaskCreate( prvIdleTask, ( signed portCHAR * ) "IDLE", tskIDLE_STACK_SIZE, ( void * ) NULL, tskIDLE_PRIORITY, ( xTaskHandle * ) NULL );
\r
1035 if( xReturn == pdPASS )
\r
1037 /* Interrupts are turned off here, to ensure a tick does not occur
\r
1038 before or during the call to xPortStartScheduler(). The stacks of
\r
1039 the created tasks contain a status word with interrupts switched on
\r
1040 so interrupts will automatically get re-enabled when the first task
\r
1043 STEPPING THROUGH HERE USING A DEBUGGER CAN CAUSE BIG PROBLEMS IF THE
\r
1044 DEBUGGER ALLOWS INTERRUPTS TO BE PROCESSED. */
\r
1045 portDISABLE_INTERRUPTS();
\r
1047 xSchedulerRunning = pdTRUE;
\r
1048 xTickCount = ( portTickType ) 0;
\r
1050 /* Setting up the timer tick is hardware specific and thus in the
\r
1051 portable interface. */
\r
1052 if( xPortStartScheduler() )
\r
1054 /* Should not reach here as if the scheduler is running the
\r
1055 function will not return. */
\r
1059 /* Should only reach here if a task calls xTaskEndScheduler(). */
\r
1063 /*-----------------------------------------------------------*/
\r
1065 void vTaskEndScheduler( void )
\r
1067 /* Stop the scheduler interrupts and call the portable scheduler end
\r
1068 routine so the original ISRs can be restored if necessary. The port
\r
1069 layer must ensure interrupts enable bit is left in the correct state. */
\r
1070 portDISABLE_INTERRUPTS();
\r
1071 xSchedulerRunning = pdFALSE;
\r
1072 vPortEndScheduler();
\r
1074 /*----------------------------------------------------------*/
\r
1076 void vTaskSuspendAll( void )
\r
1078 portENTER_CRITICAL();
\r
1079 ++uxSchedulerSuspended;
\r
1080 portEXIT_CRITICAL();
\r
1082 /*----------------------------------------------------------*/
\r
1084 signed portBASE_TYPE xTaskResumeAll( void )
\r
1086 register tskTCB *pxTCB;
\r
1087 signed portBASE_TYPE xAlreadyYielded = pdFALSE;
\r
1089 /* It is possible that an ISR caused a task to be removed from an event
\r
1090 list while the scheduler was suspended. If this was the case then the
\r
1091 removed task will have been added to the xPendingReadyList. Once the
\r
1092 scheduler has been resumed it is safe to move all the pending ready
\r
1093 tasks from this list into their appropriate ready list. */
\r
1094 portENTER_CRITICAL();
\r
1096 --uxSchedulerSuspended;
\r
1098 if( uxSchedulerSuspended == ( unsigned portBASE_TYPE ) pdFALSE )
\r
1100 if( uxCurrentNumberOfTasks > ( unsigned portBASE_TYPE ) 0 )
\r
1102 portBASE_TYPE xYieldRequired = pdFALSE;
\r
1104 /* Move any readied tasks from the pending list into the
\r
1105 appropriate ready list. */
\r
1106 while( ( pxTCB = ( tskTCB * ) listGET_OWNER_OF_HEAD_ENTRY( ( ( xList * ) &xPendingReadyList ) ) ) != NULL )
\r
1108 vListRemove( &( pxTCB->xEventListItem ) );
\r
1109 vListRemove( &( pxTCB->xGenericListItem ) );
\r
1110 prvAddTaskToReadyQueue( pxTCB );
\r
1112 /* If we have moved a task that has a priority higher than
\r
1113 the current task then we should yield. */
\r
1114 if( pxTCB->uxPriority >= pxCurrentTCB->uxPriority )
\r
1116 xYieldRequired = pdTRUE;
\r
1120 /* If any ticks occurred while the scheduler was suspended then
\r
1121 they should be processed now. This ensures the tick count does not
\r
1122 slip, and that any delayed tasks are resumed at the correct time. */
\r
1123 if( uxMissedTicks > ( unsigned portBASE_TYPE ) 0 )
\r
1125 while( uxMissedTicks > ( unsigned portBASE_TYPE ) 0 )
\r
1127 vTaskIncrementTick();
\r
1131 /* As we have processed some ticks it is appropriate to yield
\r
1132 to ensure the highest priority task that is ready to run is
\r
1133 the task actually running. */
\r
1134 xYieldRequired = pdTRUE;
\r
1137 if( ( xYieldRequired == pdTRUE ) || ( xMissedYield == pdTRUE ) )
\r
1139 xAlreadyYielded = pdTRUE;
\r
1140 xMissedYield = pdFALSE;
\r
1146 portEXIT_CRITICAL();
\r
1148 return xAlreadyYielded;
\r
1156 /*-----------------------------------------------------------
\r
1157 * PUBLIC TASK UTILITIES documented in task.h
\r
1158 *----------------------------------------------------------*/
\r
1162 portTickType xTaskGetTickCount( void )
\r
1164 portTickType xTicks;
\r
1166 /* Critical section required if running on a 16 bit processor. */
\r
1167 taskENTER_CRITICAL();
\r
1169 xTicks = xTickCount;
\r
1171 taskEXIT_CRITICAL();
\r
1175 /*-----------------------------------------------------------*/
\r
1177 unsigned portBASE_TYPE uxTaskGetNumberOfTasks( void )
\r
1179 unsigned portBASE_TYPE uxNumberOfTasks;
\r
1181 taskENTER_CRITICAL();
\r
1182 uxNumberOfTasks = uxCurrentNumberOfTasks;
\r
1183 taskEXIT_CRITICAL();
\r
1185 return uxNumberOfTasks;
\r
1187 /*-----------------------------------------------------------*/
\r
1189 #if ( ( configUSE_TRACE_FACILITY == 1 ) && ( INCLUDE_vTaskDelete == 1 ) && ( INCLUDE_vTaskSuspend == 1 ) )
\r
1191 void vTaskList( signed portCHAR *pcWriteBuffer )
\r
1193 unsigned portBASE_TYPE uxQueue;
\r
1195 /* This is a VERY costly function that should be used for debug only.
\r
1196 It leaves interrupts disabled for a LONG time. */
\r
1198 vTaskSuspendAll();
\r
1200 /* Run through all the lists that could potentially contain a TCB and
\r
1201 report the task name, state and stack high water mark. */
\r
1203 pcWriteBuffer[ 0 ] = ( signed portCHAR ) 0x00;
\r
1204 strcat( ( portCHAR * ) pcWriteBuffer, ( const portCHAR * ) "\r\n" );
\r
1206 uxQueue = uxTopUsedPriority + 1;
\r
1212 if( !listLIST_IS_EMPTY( &( pxReadyTasksLists[ uxQueue ] ) ) )
\r
1214 prvListTaskWithinSingleList( pcWriteBuffer, ( xList * ) &( pxReadyTasksLists[ uxQueue ] ), tskREADY_CHAR );
\r
1216 }while( uxQueue > ( unsigned portSHORT ) tskIDLE_PRIORITY );
\r
1218 if( !listLIST_IS_EMPTY( pxDelayedTaskList ) )
\r
1220 prvListTaskWithinSingleList( pcWriteBuffer, ( xList * ) pxDelayedTaskList, tskBLOCKED_CHAR );
\r
1223 if( !listLIST_IS_EMPTY( pxOverflowDelayedTaskList ) )
\r
1225 prvListTaskWithinSingleList( pcWriteBuffer, ( xList * ) pxOverflowDelayedTaskList, tskBLOCKED_CHAR );
\r
1228 if( !listLIST_IS_EMPTY( &xTasksWaitingTermination ) )
\r
1230 prvListTaskWithinSingleList( pcWriteBuffer, ( xList * ) &xTasksWaitingTermination, tskDELETED_CHAR );
\r
1233 if( !listLIST_IS_EMPTY( &xSuspendedTaskList ) )
\r
1235 prvListTaskWithinSingleList( pcWriteBuffer, ( xList * ) &xSuspendedTaskList, tskSUSPENDED_CHAR );
\r
1242 /*----------------------------------------------------------*/
\r
1244 #if ( configUSE_TRACE_FACILITY == 1 )
\r
1246 void vTaskStartTrace( signed portCHAR * pcBuffer, unsigned portLONG ulBufferSize )
\r
1248 portENTER_CRITICAL();
\r
1250 pcTraceBuffer = ( volatile signed portCHAR * volatile )pcBuffer;
\r
1251 pcTraceBufferStart = pcBuffer;
\r
1252 pcTraceBufferEnd = pcBuffer + ( ulBufferSize - tskSIZE_OF_EACH_TRACE_LINE );
\r
1253 xTracing = pdTRUE;
\r
1255 portEXIT_CRITICAL();
\r
1259 /*----------------------------------------------------------*/
\r
1261 #if ( configUSE_TRACE_FACILITY == 1 )
\r
1263 unsigned portLONG ulTaskEndTrace( void )
\r
1265 unsigned portLONG ulBufferLength;
\r
1267 portENTER_CRITICAL();
\r
1268 xTracing = pdFALSE;
\r
1269 portEXIT_CRITICAL();
\r
1271 ulBufferLength = ( unsigned portLONG ) ( pcTraceBuffer - pcTraceBufferStart );
\r
1273 return ulBufferLength;
\r
1280 /*-----------------------------------------------------------
\r
1281 * SCHEDULER INTERNALS AVAILABLE FOR PORTING PURPOSES
\r
1282 * documented in task.h
\r
1283 *----------------------------------------------------------*/
\r
1286 inline void vTaskIncrementTick( void )
\r
1288 /* Called by the portable layer each time a tick interrupt occurs.
\r
1289 Increments the tick then checks to see if the new tick value will cause any
\r
1290 tasks to be unblocked. */
\r
1291 if( uxSchedulerSuspended == ( unsigned portBASE_TYPE ) pdFALSE )
\r
1294 if( xTickCount == ( portTickType ) 0 )
\r
1298 /* Tick count has overflowed so we need to swap the delay lists.
\r
1299 If there are any items in pxDelayedTaskList here then there is
\r
1301 pxTemp = pxDelayedTaskList;
\r
1302 pxDelayedTaskList = pxOverflowDelayedTaskList;
\r
1303 pxOverflowDelayedTaskList = pxTemp;
\r
1304 xNumOfOverflows++;
\r
1307 /* See if this tick has made a timeout expire. */
\r
1308 prvCheckDelayedTasks();
\r
1314 /* The tick hook gets called at regular intervals, even if the
\r
1315 scheduler is locked. */
\r
1316 #if ( configUSE_TICK_HOOK == 1 )
\r
1318 extern void vApplicationTickHook( void );
\r
1320 vApplicationTickHook();
\r
1325 #if ( configUSE_TICK_HOOK == 1 )
\r
1327 extern void vApplicationTickHook( void );
\r
1329 /* Guard against the tick hook being called when the missed tick
\r
1330 count is being unwound (when the scheduler is being unlocked. */
\r
1331 if( uxMissedTicks == 0 )
\r
1333 vApplicationTickHook();
\r
1338 /*-----------------------------------------------------------*/
\r
1340 #if ( ( INCLUDE_vTaskCleanUpResources == 1 ) && ( INCLUDE_vTaskSuspend == 1 ) )
\r
1342 void vTaskCleanUpResources( void )
\r
1344 unsigned portSHORT usQueue;
\r
1345 volatile tskTCB *pxTCB;
\r
1347 usQueue = ( unsigned portSHORT ) uxTopUsedPriority + ( unsigned portSHORT ) 1;
\r
1349 /* Remove any TCB's from the ready queues. */
\r
1354 while( !listLIST_IS_EMPTY( &( pxReadyTasksLists[ usQueue ] ) ) )
\r
1356 listGET_OWNER_OF_NEXT_ENTRY( pxTCB, &( pxReadyTasksLists[ usQueue ] ) );
\r
1357 vListRemove( ( xListItem * ) &( pxTCB->xGenericListItem ) );
\r
1359 prvDeleteTCB( ( tskTCB * ) pxTCB );
\r
1361 }while( usQueue > ( unsigned portSHORT ) tskIDLE_PRIORITY );
\r
1363 /* Remove any TCB's from the delayed queue. */
\r
1364 while( !listLIST_IS_EMPTY( &xDelayedTaskList1 ) )
\r
1366 listGET_OWNER_OF_NEXT_ENTRY( pxTCB, &xDelayedTaskList1 );
\r
1367 vListRemove( ( xListItem * ) &( pxTCB->xGenericListItem ) );
\r
1369 prvDeleteTCB( ( tskTCB * ) pxTCB );
\r
1372 /* Remove any TCB's from the overflow delayed queue. */
\r
1373 while( !listLIST_IS_EMPTY( &xDelayedTaskList2 ) )
\r
1375 listGET_OWNER_OF_NEXT_ENTRY( pxTCB, &xDelayedTaskList2 );
\r
1376 vListRemove( ( xListItem * ) &( pxTCB->xGenericListItem ) );
\r
1378 prvDeleteTCB( ( tskTCB * ) pxTCB );
\r
1381 while( !listLIST_IS_EMPTY( &xSuspendedTaskList ) )
\r
1383 listGET_OWNER_OF_NEXT_ENTRY( pxTCB, &xSuspendedTaskList );
\r
1384 vListRemove( ( xListItem * ) &( pxTCB->xGenericListItem ) );
\r
1386 prvDeleteTCB( ( tskTCB * ) pxTCB );
\r
1389 while( !listLIST_IS_EMPTY( &xPendingReadyList ) )
\r
1391 listGET_OWNER_OF_NEXT_ENTRY( pxTCB, &xPendingReadyList );
\r
1392 vListRemove( ( xListItem * ) &( pxTCB->xGenericListItem ) );
\r
1394 prvDeleteTCB( ( tskTCB * ) pxTCB );
\r
1399 /*-----------------------------------------------------------*/
\r
1401 void vTaskSwitchContext( void )
\r
1403 if( uxSchedulerSuspended != ( unsigned portBASE_TYPE ) pdFALSE )
\r
1405 /* The scheduler is currently suspended - do not allow a context
\r
1407 xMissedYield = pdTRUE;
\r
1411 /* Find the highest priority queue that contains ready tasks. */
\r
1412 while( listLIST_IS_EMPTY( &( pxReadyTasksLists[ uxTopReadyPriority ] ) ) )
\r
1414 --uxTopReadyPriority;
\r
1417 /* listGET_OWNER_OF_NEXT_ENTRY walks through the list, so the tasks of the
\r
1418 same priority get an equal share of the processor time. */
\r
1419 listGET_OWNER_OF_NEXT_ENTRY( pxCurrentTCB, &( pxReadyTasksLists[ uxTopReadyPriority ] ) );
\r
1420 vWriteTraceToBuffer();
\r
1422 /*-----------------------------------------------------------*/
\r
1424 void vTaskPlaceOnEventList( xList *pxEventList, portTickType xTicksToWait )
\r
1426 portTickType xTimeToWake;
\r
1428 /* THIS FUNCTION MUST BE CALLED WITH INTERRUPTS DISABLED OR THE
\r
1429 SCHEDULER SUSPENDED. */
\r
1431 /* Place the event list item of the TCB in the appropriate event list.
\r
1432 This is placed in the list in priority order so the highest priority task
\r
1433 is the first to be woken by the event. */
\r
1434 vListInsert( ( xList * ) pxEventList, ( xListItem * ) &( pxCurrentTCB->xEventListItem ) );
\r
1436 /* We must remove ourselves from the ready list before adding ourselves
\r
1437 to the blocked list as the same list item is used for both lists. We have
\r
1438 exclusive access to the ready lists as the scheduler is locked. */
\r
1439 vListRemove( ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
\r
1442 #if ( INCLUDE_vTaskSuspend == 1 )
\r
1444 if( xTicksToWait == portMAX_DELAY )
\r
1446 /* Add ourselves to the suspended task list instead of a delayed task
\r
1447 list to ensure we are not woken by a timing event. We will block
\r
1449 vListInsertEnd( ( xList * ) &xSuspendedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
\r
1453 /* Calculate the time at which the task should be woken if the event does
\r
1454 not occur. This may overflow but this doesn't matter. */
\r
1455 xTimeToWake = xTickCount + xTicksToWait;
\r
1457 listSET_LIST_ITEM_VALUE( &( pxCurrentTCB->xGenericListItem ), xTimeToWake );
\r
1459 if( xTimeToWake < xTickCount )
\r
1461 /* Wake time has overflowed. Place this item in the overflow list. */
\r
1462 vListInsert( ( xList * ) pxOverflowDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
\r
1466 /* The wake time has not overflowed, so we can use the current block list. */
\r
1467 vListInsert( ( xList * ) pxDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
\r
1473 /* Calculate the time at which the task should be woken if the event does
\r
1474 not occur. This may overflow but this doesn't matter. */
\r
1475 xTimeToWake = xTickCount + xTicksToWait;
\r
1477 listSET_LIST_ITEM_VALUE( &( pxCurrentTCB->xGenericListItem ), xTimeToWake );
\r
1479 if( xTimeToWake < xTickCount )
\r
1481 /* Wake time has overflowed. Place this item in the overflow list. */
\r
1482 vListInsert( ( xList * ) pxOverflowDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
\r
1486 /* The wake time has not overflowed, so we can use the current block list. */
\r
1487 vListInsert( ( xList * ) pxDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
\r
1492 /*-----------------------------------------------------------*/
\r
1494 signed portBASE_TYPE xTaskRemoveFromEventList( const xList *pxEventList )
\r
1496 tskTCB *pxUnblockedTCB;
\r
1497 portBASE_TYPE xReturn;
\r
1499 /* THIS FUNCTION MUST BE CALLED WITH INTERRUPTS DISABLED OR THE
\r
1500 SCHEDULER SUSPENDED. It can also be called from within an ISR. */
\r
1502 /* The event list is sorted in priority order, so we can remove the
\r
1503 first in the list, remove the TCB from the delayed list, and add
\r
1504 it to the ready list.
\r
1506 If an event is for a queue that is locked then this function will never
\r
1507 get called - the lock count on the queue will get modified instead. This
\r
1508 means we can always expect exclusive access to the event list here. */
\r
1509 pxUnblockedTCB = ( tskTCB * ) listGET_OWNER_OF_HEAD_ENTRY( pxEventList );
\r
1510 vListRemove( &( pxUnblockedTCB->xEventListItem ) );
\r
1512 if( uxSchedulerSuspended == ( unsigned portBASE_TYPE ) pdFALSE )
\r
1514 vListRemove( &( pxUnblockedTCB->xGenericListItem ) );
\r
1515 prvAddTaskToReadyQueue( pxUnblockedTCB );
\r
1519 /* We cannot access the delayed or ready lists, so will hold this
\r
1520 task pending until the scheduler is resumed. */
\r
1521 vListInsertEnd( ( xList * ) &( xPendingReadyList ), &( pxUnblockedTCB->xEventListItem ) );
\r
1524 if( pxUnblockedTCB->uxPriority >= pxCurrentTCB->uxPriority )
\r
1526 /* Return true if the task removed from the event list has
\r
1527 a higher priority than the calling task. This allows
\r
1528 the calling task to know if it should force a context
\r
1534 xReturn = pdFALSE;
\r
1539 /*-----------------------------------------------------------*/
\r
1541 void vTaskSetTimeOutState( xTimeOutType *pxTimeOut )
\r
1543 pxTimeOut->xOverflowCount = xNumOfOverflows;
\r
1544 pxTimeOut->xTimeOnEntering = xTickCount;
\r
1546 /*-----------------------------------------------------------*/
\r
1548 portBASE_TYPE xTaskCheckForTimeOut( xTimeOutType *pxTimeOut, portTickType *pxTicksToWait )
\r
1550 portBASE_TYPE xReturn;
\r
1552 if( ( xNumOfOverflows != pxTimeOut->xOverflowCount ) && ( xTickCount >= pxTimeOut->xTimeOnEntering ) )
\r
1554 /* The tick count is greater than the time at which vTaskSetTimeout()
\r
1555 was called, but has also overflowed since vTaskSetTimeOut() was called.
\r
1556 It must have wrapped all the way around and gone past us again. This
\r
1557 passed since vTaskSetTimeout() was called. */
\r
1560 else if( ( xTickCount - pxTimeOut->xTimeOnEntering ) < *pxTicksToWait )
\r
1562 /* Not a genuine timeout. Adjust parameters for time remaining. */
\r
1563 *pxTicksToWait -= ( xTickCount - pxTimeOut->xTimeOnEntering );
\r
1564 vTaskSetTimeOutState( pxTimeOut );
\r
1565 xReturn = pdFALSE;
\r
1574 /*-----------------------------------------------------------*/
\r
1576 void vTaskMissedYield( void )
\r
1578 xMissedYield = pdTRUE;
\r
1582 * -----------------------------------------------------------
\r
1584 * ----------------------------------------------------------
\r
1586 * The portTASK_FUNCTION() macro is used to allow port/compiler specific
\r
1587 * language extensions. The equivalent prototype for this function is:
\r
1589 * void prvIdleTask( void *pvParameters );
\r
1592 static portTASK_FUNCTION( prvIdleTask, pvParameters )
\r
1594 /* Stop warnings. */
\r
1595 ( void ) pvParameters;
\r
1599 /* See if any tasks have been deleted. */
\r
1600 prvCheckTasksWaitingTermination();
\r
1602 #if ( configUSE_PREEMPTION == 0 )
\r
1604 /* If we are not using preemption we keep forcing a task switch to
\r
1605 see if any other task has become available. If we are using
\r
1606 preemption we don't need to do this as any task becoming available
\r
1607 will automatically get the processor anyway. */
\r
1612 #if ( ( configUSE_PREEMPTION == 1 ) && ( configIDLE_SHOULD_YIELD == 1 ) )
\r
1614 /* When using preemption tasks of equal priority will be
\r
1615 timesliced. If a task that is sharing the idle priority is ready
\r
1616 to run then the idle task should yield before the end of the
\r
1619 A critical region is not required here as we are just reading from
\r
1620 the list, and an occasional incorrect value will not matter. If
\r
1621 the ready list at the idle priority contains more than one task
\r
1622 then a task other than the idle task is ready to execute. */
\r
1623 if( listCURRENT_LIST_LENGTH( &( pxReadyTasksLists[ tskIDLE_PRIORITY ] ) ) > ( unsigned portBASE_TYPE ) 1 )
\r
1630 #if ( configUSE_IDLE_HOOK == 1 )
\r
1632 extern void vApplicationIdleHook( void );
\r
1634 /* Call the user defined function from within the idle task. This
\r
1635 allows the application designer to add background functionality
\r
1636 without the overhead of a separate task.
\r
1637 NOTE: vApplicationIdleHook() MUST NOT, UNDER ANY CIRCUMSTANCES,
\r
1638 CALL A FUNCTION THAT MIGHT BLOCK. */
\r
1639 vApplicationIdleHook();
\r
1643 } /*lint !e715 pvParameters is not accessed but all task functions require the same prototype. */
\r
1651 /*-----------------------------------------------------------
\r
1652 * File private functions documented at the top of the file.
\r
1653 *----------------------------------------------------------*/
\r
1657 static void prvInitialiseTCBVariables( tskTCB *pxTCB, unsigned portSHORT usStackDepth, const signed portCHAR * const pcName, unsigned portBASE_TYPE uxPriority )
\r
1659 pxTCB->usStackDepth = usStackDepth;
\r
1661 /* Store the function name in the TCB. */
\r
1662 strncpy( ( char * ) pxTCB->pcTaskName, ( const char * ) pcName, ( unsigned portSHORT ) configMAX_TASK_NAME_LEN );
\r
1663 pxTCB->pcTaskName[ ( unsigned portSHORT ) configMAX_TASK_NAME_LEN - ( unsigned portSHORT ) 1 ] = '\0';
\r
1665 /* This is used as an array index so must ensure it's not too large. */
\r
1666 if( uxPriority >= configMAX_PRIORITIES )
\r
1668 uxPriority = configMAX_PRIORITIES - 1;
\r
1671 pxTCB->uxPriority = uxPriority;
\r
1673 vListInitialiseItem( &( pxTCB->xGenericListItem ) );
\r
1674 vListInitialiseItem( &( pxTCB->xEventListItem ) );
\r
1676 /* Set the pxTCB as a link back from the xListItem. This is so we can get
\r
1677 back to the containing TCB from a generic item in a list. */
\r
1678 listSET_LIST_ITEM_OWNER( &( pxTCB->xGenericListItem ), pxTCB );
\r
1680 /* Event lists are always in priority order. */
\r
1681 listSET_LIST_ITEM_VALUE( &( pxTCB->xEventListItem ), configMAX_PRIORITIES - ( portTickType ) uxPriority );
\r
1682 listSET_LIST_ITEM_OWNER( &( pxTCB->xEventListItem ), pxTCB );
\r
1684 /*-----------------------------------------------------------*/
\r
1686 static void prvInitialiseTaskLists( void )
\r
1688 unsigned portBASE_TYPE uxPriority;
\r
1690 for( uxPriority = 0; uxPriority < configMAX_PRIORITIES; uxPriority++ )
\r
1692 vListInitialise( ( xList * ) &( pxReadyTasksLists[ uxPriority ] ) );
\r
1695 vListInitialise( ( xList * ) &xDelayedTaskList1 );
\r
1696 vListInitialise( ( xList * ) &xDelayedTaskList2 );
\r
1697 vListInitialise( ( xList * ) &xPendingReadyList );
\r
1699 #if ( INCLUDE_vTaskDelete == 1 )
\r
1701 vListInitialise( ( xList * ) &xTasksWaitingTermination );
\r
1705 #if ( INCLUDE_vTaskSuspend == 1 )
\r
1707 vListInitialise( ( xList * ) &xSuspendedTaskList );
\r
1711 /* Start with pxDelayedTaskList using list1 and the pxOverflowDelayedTaskList
\r
1713 pxDelayedTaskList = &xDelayedTaskList1;
\r
1714 pxOverflowDelayedTaskList = &xDelayedTaskList2;
\r
1716 /*-----------------------------------------------------------*/
\r
1718 static void prvCheckTasksWaitingTermination( void )
\r
1720 #if ( INCLUDE_vTaskDelete == 1 )
\r
1722 portBASE_TYPE xListIsEmpty;
\r
1724 /* ucTasksDeleted is used to prevent vTaskSuspendAll() being called
\r
1725 too often in the idle task. */
\r
1726 if( uxTasksDeleted > ( unsigned portBASE_TYPE ) 0 )
\r
1728 vTaskSuspendAll();
\r
1729 xListIsEmpty = listLIST_IS_EMPTY( &xTasksWaitingTermination );
\r
1732 if( !xListIsEmpty )
\r
1736 portENTER_CRITICAL();
\r
1738 pxTCB = ( tskTCB * ) listGET_OWNER_OF_HEAD_ENTRY( ( ( xList * ) &xTasksWaitingTermination ) );
\r
1739 vListRemove( &( pxTCB->xGenericListItem ) );
\r
1740 --uxCurrentNumberOfTasks;
\r
1743 portEXIT_CRITICAL();
\r
1745 prvDeleteTCB( pxTCB );
\r
1751 /*-----------------------------------------------------------*/
\r
1753 static tskTCB *prvAllocateTCBAndStack( unsigned portSHORT usStackDepth )
\r
1757 /* Allocate space for the TCB. Where the memory comes from depends on
\r
1758 the implementation of the port malloc function. */
\r
1759 pxNewTCB = ( tskTCB * ) pvPortMalloc( sizeof( tskTCB ) );
\r
1761 if( pxNewTCB != NULL )
\r
1763 /* Allocate space for the stack used by the task being created.
\r
1764 The base of the stack memory stored in the TCB so the task can
\r
1765 be deleted later if required. */
\r
1766 pxNewTCB->pxStack = ( portSTACK_TYPE * ) pvPortMalloc( ( ( size_t )usStackDepth ) * sizeof( portSTACK_TYPE ) );
\r
1768 if( pxNewTCB->pxStack == NULL )
\r
1770 /* Could not allocate the stack. Delete the allocated TCB. */
\r
1771 vPortFree( pxNewTCB );
\r
1776 /* Just to help debugging. */
\r
1777 memset( pxNewTCB->pxStack, tskSTACK_FILL_BYTE, usStackDepth * sizeof( portSTACK_TYPE ) );
\r
1783 /*-----------------------------------------------------------*/
\r
1785 #if ( configUSE_TRACE_FACILITY == 1 )
\r
1787 static void prvListTaskWithinSingleList( signed portCHAR *pcWriteBuffer, xList *pxList, signed portCHAR cStatus )
\r
1789 volatile tskTCB *pxNextTCB, *pxFirstTCB;
\r
1790 static portCHAR pcStatusString[ 50 ];
\r
1791 unsigned portSHORT usStackRemaining;
\r
1793 /* Write the details of all the TCB's in pxList into the buffer. */
\r
1794 listGET_OWNER_OF_NEXT_ENTRY( pxFirstTCB, pxList );
\r
1797 listGET_OWNER_OF_NEXT_ENTRY( pxNextTCB, pxList );
\r
1798 usStackRemaining = usTaskCheckFreeStackSpace( ( unsigned portCHAR * ) pxNextTCB->pxStack );
\r
1799 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
1800 strcat( ( portCHAR * ) pcWriteBuffer, ( portCHAR * ) pcStatusString );
\r
1802 } while( pxNextTCB != pxFirstTCB );
\r
1806 /*-----------------------------------------------------------*/
\r
1808 #if ( configUSE_TRACE_FACILITY == 1 )
\r
1809 unsigned portSHORT usTaskCheckFreeStackSpace( const unsigned portCHAR *pucStackByte )
\r
1811 register unsigned portSHORT usCount = 0;
\r
1813 while( *pucStackByte == tskSTACK_FILL_BYTE )
\r
1815 pucStackByte -= portSTACK_GROWTH;
\r
1819 usCount /= sizeof( portSTACK_TYPE );
\r
1824 /*-----------------------------------------------------------*/
\r
1828 #if ( ( INCLUDE_vTaskDelete == 1 ) || ( INCLUDE_vTaskCleanUpResources == 1 ) )
\r
1830 static void prvDeleteTCB( tskTCB *pxTCB )
\r
1832 /* Free up the memory allocated by the scheduler for the task. It is up to
\r
1833 the task to free any memory allocated at the application level. */
\r
1834 vPortFree( pxTCB->pxStack );
\r
1835 vPortFree( pxTCB );
\r
1841 /*-----------------------------------------------------------*/
\r
1843 #if ( INCLUDE_xTaskGetCurrentTaskHandle == 1 )
\r
1845 xTaskHandle xTaskGetCurrentTaskHandle( void )
\r
1847 xTaskHandle xReturn;
\r
1849 portENTER_CRITICAL();
\r
1851 xReturn = ( xTaskHandle ) pxCurrentTCB;
\r
1853 portEXIT_CRITICAL();
\r