2 FreeRTOS.org V4.2.0 - 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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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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178 + Implement xTaskResumeFromISR().
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180 Changes from V4.0.5
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182 + Added utility functions and xOverflowCount variable to facilitate the
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185 Changes from V4.1.2
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187 + Tasks that block on events with a timeout of portMAX_DELAY are now
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188 blocked indefinitely if configINCLUDE_vTaskSuspend is defined.
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189 Previously portMAX_DELAY was just the longest block time possible.
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191 Changes from V4.1.3
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193 + Very small change made to xTaskCheckForTimeout() as a result of the
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194 SafeRTOS testing. This corrects the case where the function can return an
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195 invalid value - but only in an extremely unlikely scenario.
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199 #include <stdlib.h>
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200 #include <string.h>
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202 #include "FreeRTOS.h"
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206 * Macro to define the amount of stack available to the idle task.
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208 #define tskIDLE_STACK_SIZE configMINIMAL_STACK_SIZE
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212 * Default a definitions for backwards compatibility with old
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213 * portmacro.h files.
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215 #ifndef configMAX_TASK_NAME_LEN
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216 #define configMAX_TASK_NAME_LEN 16
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219 #ifndef INCLUDE_xTaskGetCurrentTaskHandle
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220 #define INCLUDE_xTaskGetCurrentTaskHandle 0
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223 #ifndef configIDLE_SHOULD_YIELD
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224 #define configIDLE_SHOULD_YIELD 1
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227 #if configMAX_TASK_NAME_LEN < 1
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228 #undef configMAX_TASK_NAME_LEN
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229 #define configMAX_TASK_NAME_LEN 1
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232 #ifndef INCLUDE_xTaskResumeFromISR
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233 #define INCLUDE_xTaskResumeFromISR 1
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237 * Task control block. A task control block (TCB) is allocated to each task,
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238 * and stores the context of the task.
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240 typedef struct tskTaskControlBlock
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242 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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243 xListItem xGenericListItem; /*< List item used to place the TCB in ready and blocked queues. */
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244 xListItem xEventListItem; /*< List item used to place the TCB in event lists. */
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245 unsigned portBASE_TYPE uxPriority; /*< The priority of the task where 0 is the lowest priority. */
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246 portSTACK_TYPE *pxStack; /*< Points to the start of the stack. */
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247 unsigned portBASE_TYPE uxTCBNumber; /*< This is used for tracing the scheduler and making debugging easier only. */
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248 signed portCHAR pcTaskName[ configMAX_TASK_NAME_LEN ];/*< Descriptive name given to the task when created. Facilitates debugging only. */
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249 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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254 tskTCB * volatile pxCurrentTCB = NULL;
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256 /* Lists for ready and blocked tasks. --------------------*/
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258 static xList pxReadyTasksLists[ configMAX_PRIORITIES ]; /*< Prioritised ready tasks. */
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259 static xList xDelayedTaskList1; /*< Delayed tasks. */
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260 static xList xDelayedTaskList2; /*< Delayed tasks (two lists are used - one for delays that have overflowed the current tick count. */
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261 static xList * volatile pxDelayedTaskList; /*< Points to the delayed task list currently being used. */
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262 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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263 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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265 #if ( INCLUDE_vTaskDelete == 1 )
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267 static volatile xList xTasksWaitingTermination; /*< Tasks that have been deleted - but the their memory not yet freed. */
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268 static volatile unsigned portBASE_TYPE uxTasksDeleted = ( unsigned portBASE_TYPE ) 0;
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272 #if ( INCLUDE_vTaskSuspend == 1 )
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274 static xList xSuspendedTaskList; /*< Tasks that are currently suspended. */
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278 /* File private variables. --------------------------------*/
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279 static volatile unsigned portBASE_TYPE uxCurrentNumberOfTasks = ( unsigned portBASE_TYPE ) 0;
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280 static volatile portTickType xTickCount = ( portTickType ) 0;
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281 static unsigned portBASE_TYPE uxTopUsedPriority = tskIDLE_PRIORITY;
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282 static volatile unsigned portBASE_TYPE uxTopReadyPriority = tskIDLE_PRIORITY;
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283 static volatile signed portBASE_TYPE xSchedulerRunning = pdFALSE;
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284 static volatile unsigned portBASE_TYPE uxSchedulerSuspended = ( unsigned portBASE_TYPE ) pdFALSE;
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285 static volatile unsigned portBASE_TYPE uxMissedTicks = ( unsigned portBASE_TYPE ) 0;
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286 static volatile portBASE_TYPE xMissedYield = ( portBASE_TYPE ) pdFALSE;
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287 static volatile portBASE_TYPE xNumOfOverflows = ( portBASE_TYPE ) 0;
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288 /* Debugging and trace facilities private variables and macros. ------------*/
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291 * The value used to fill the stack of a task when the task is created. This
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292 * is used purely for checking the high water mark for tasks.
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294 #define tskSTACK_FILL_BYTE ( 0xa5 )
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297 * Macros used by vListTask to indicate which state a task is in.
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299 #define tskBLOCKED_CHAR ( ( signed portCHAR ) 'B' )
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300 #define tskREADY_CHAR ( ( signed portCHAR ) 'R' )
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301 #define tskDELETED_CHAR ( ( signed portCHAR ) 'D' )
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302 #define tskSUSPENDED_CHAR ( ( signed portCHAR ) 'S' )
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305 * Macros and private variables used by the trace facility.
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307 #if ( configUSE_TRACE_FACILITY == 1 )
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309 #define tskSIZE_OF_EACH_TRACE_LINE ( ( unsigned portLONG ) ( sizeof( unsigned portLONG ) + sizeof( unsigned portLONG ) ) )
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310 static volatile signed portCHAR * volatile pcTraceBuffer;
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311 static signed portCHAR *pcTraceBufferStart;
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312 static signed portCHAR *pcTraceBufferEnd;
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313 static signed portBASE_TYPE xTracing = pdFALSE;
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318 * Macro that writes a trace of scheduler activity to a buffer. This trace
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319 * shows which task is running when and is very useful as a debugging tool.
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320 * As this macro is called each context switch it is a good idea to undefine
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321 * it if not using the facility.
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323 #if ( configUSE_TRACE_FACILITY == 1 )
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325 #define vWriteTraceToBuffer() \
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329 static unsigned portBASE_TYPE uxPreviousTask = 255; \
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331 if( uxPreviousTask != pxCurrentTCB->uxTCBNumber ) \
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333 if( ( pcTraceBuffer + tskSIZE_OF_EACH_TRACE_LINE ) < pcTraceBufferEnd ) \
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335 uxPreviousTask = pxCurrentTCB->uxTCBNumber; \
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336 *( unsigned portLONG * ) pcTraceBuffer = ( unsigned portLONG ) xTickCount; \
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337 pcTraceBuffer += sizeof( unsigned portLONG ); \
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338 *( unsigned portLONG * ) pcTraceBuffer = ( unsigned portLONG ) uxPreviousTask; \
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339 pcTraceBuffer += sizeof( unsigned portLONG ); \
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343 xTracing = pdFALSE; \
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351 #define vWriteTraceToBuffer()
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357 * Place the task represented by pxTCB into the appropriate ready queue for
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358 * the task. It is inserted at the end of the list. One quirk of this is
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359 * that if the task being inserted is at the same priority as the currently
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360 * executing task, then it will only be rescheduled after the currently
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361 * executing task has been rescheduled.
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363 #define prvAddTaskToReadyQueue( pxTCB ) \
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365 if( pxTCB->uxPriority > uxTopReadyPriority ) \
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367 uxTopReadyPriority = pxTCB->uxPriority; \
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369 vListInsertEnd( ( xList * ) &( pxReadyTasksLists[ pxTCB->uxPriority ] ), &( pxTCB->xGenericListItem ) ); \
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373 * Macro that looks at the list of tasks that are currently delayed to see if
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374 * any require waking.
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376 * Tasks are stored in the queue in the order of their wake time - meaning
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377 * once one tasks has been found whose timer has not expired we need not look
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378 * any further down the list.
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380 #define prvCheckDelayedTasks() \
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382 register tskTCB *pxTCB; \
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384 while( ( pxTCB = ( tskTCB * ) listGET_OWNER_OF_HEAD_ENTRY( pxDelayedTaskList ) ) != NULL ) \
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386 if( xTickCount < listGET_LIST_ITEM_VALUE( &( pxTCB->xGenericListItem ) ) ) \
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390 vListRemove( &( pxTCB->xGenericListItem ) ); \
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391 /* Is the task waiting on an event also? */ \
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392 if( pxTCB->xEventListItem.pvContainer ) \
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394 vListRemove( &( pxTCB->xEventListItem ) ); \
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396 prvAddTaskToReadyQueue( pxTCB ); \
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401 * Several functions take an xTaskHandle parameter that can optionally be NULL,
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402 * where NULL is used to indicate that the handle of the currently executing
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403 * task should be used in place of the parameter. This macro simply checks to
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404 * see if the parameter is NULL and returns a pointer to the appropriate TCB.
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406 #define prvGetTCBFromHandle( pxHandle ) ( ( pxHandle == NULL ) ? ( tskTCB * ) pxCurrentTCB : ( tskTCB * ) pxHandle )
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409 /* File private functions. --------------------------------*/
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412 * Utility to ready a TCB for a given task. Mainly just copies the parameters
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413 * into the TCB structure.
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415 static void prvInitialiseTCBVariables( tskTCB *pxTCB, unsigned portSHORT usStackDepth, const signed portCHAR * const pcName, unsigned portBASE_TYPE uxPriority );
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418 * Utility to ready all the lists used by the scheduler. This is called
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419 * automatically upon the creation of the first task.
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421 static void prvInitialiseTaskLists( void );
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424 * The idle task, which as all tasks is implemented as a never ending loop.
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425 * The idle task is automatically created and added to the ready lists upon
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426 * creation of the first user task.
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428 * The portTASK_FUNCTION_PROTO() macro is used to allow port/compiler specific
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429 * language extensions. The equivalent prototype for this function is:
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431 * void prvIdleTask( void *pvParameters );
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434 static portTASK_FUNCTION_PROTO( prvIdleTask, pvParameters );
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437 * Utility to free all memory allocated by the scheduler to hold a TCB,
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438 * including the stack pointed to by the TCB.
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440 * This does not free memory allocated by the task itself (i.e. memory
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441 * allocated by calls to pvPortMalloc from within the tasks application code).
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443 #if ( ( INCLUDE_vTaskDelete == 1 ) || ( INCLUDE_vTaskCleanUpResources == 1 ) )
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444 static void prvDeleteTCB( tskTCB *pxTCB );
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448 * Used only by the idle task. This checks to see if anything has been placed
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449 * in the list of tasks waiting to be deleted. If so the task is cleaned up
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450 * and its TCB deleted.
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452 static void prvCheckTasksWaitingTermination( void );
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455 * Allocates memory from the heap for a TCB and associated stack. Checks the
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456 * allocation was successful.
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458 static tskTCB *prvAllocateTCBAndStack( unsigned portSHORT usStackDepth );
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461 * Called from vTaskList. vListTasks details all the tasks currently under
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462 * control of the scheduler. The tasks may be in one of a number of lists.
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463 * prvListTaskWithinSingleList accepts a list and details the tasks from
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464 * within just that list.
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466 * THIS FUNCTION IS INTENDED FOR DEBUGGING ONLY, AND SHOULD NOT BE CALLED FROM
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467 * NORMAL APPLICATION CODE.
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469 #if ( configUSE_TRACE_FACILITY == 1 )
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471 static void prvListTaskWithinSingleList( signed portCHAR *pcWriteBuffer, xList *pxList, signed portCHAR cStatus );
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476 * When a task is created, the stack of the task is filled with a known value.
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477 * This function determines the 'high water mark' of the task stack by
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478 * determining how much of the stack remains at the original preset value.
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480 #if ( configUSE_TRACE_FACILITY == 1 )
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482 unsigned portSHORT usTaskCheckFreeStackSpace( const unsigned portCHAR *pucStackByte );
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492 /*-----------------------------------------------------------
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493 * TASK CREATION API documented in task.h
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494 *----------------------------------------------------------*/
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496 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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498 signed portBASE_TYPE xReturn;
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500 static unsigned portBASE_TYPE uxTaskNumber = 0; /*lint !e956 Static is deliberate - this is guarded before use. */
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502 /* Allocate the memory required by the TCB and stack for the new task.
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503 checking that the allocation was successful. */
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504 pxNewTCB = prvAllocateTCBAndStack( usStackDepth );
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506 if( pxNewTCB != NULL )
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508 portSTACK_TYPE *pxTopOfStack;
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510 /* Setup the newly allocated TCB with the initial state of the task. */
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511 prvInitialiseTCBVariables( pxNewTCB, usStackDepth, pcName, uxPriority );
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513 /* Calculate the top of stack address. This depends on whether the
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514 stack grows from high memory to low (as per the 80x86) or visa versa.
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515 portSTACK_GROWTH is used to make the result positive or negative as
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516 required by the port. */
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517 #if portSTACK_GROWTH < 0
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519 pxTopOfStack = pxNewTCB->pxStack + ( pxNewTCB->usStackDepth - 1 );
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523 pxTopOfStack = pxNewTCB->pxStack;
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527 /* Initialize the TCB stack to look as if the task was already running,
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528 but had been interrupted by the scheduler. The return address is set
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529 to the start of the task function. Once the stack has been initialised
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530 the top of stack variable is updated. */
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531 pxNewTCB->pxTopOfStack = pxPortInitialiseStack( pxTopOfStack, pvTaskCode, pvParameters );
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533 /* We are going to manipulate the task queues to add this task to a
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534 ready list, so must make sure no interrupts occur. */
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535 portENTER_CRITICAL();
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537 uxCurrentNumberOfTasks++;
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538 if( uxCurrentNumberOfTasks == ( unsigned portBASE_TYPE ) 1 )
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540 /* As this is the first task it must also be the current task. */
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541 pxCurrentTCB = pxNewTCB;
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543 /* This is the first task to be created so do the preliminary
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544 initialisation required. We will not recover if this call
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545 fails, but we will report the failure. */
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546 prvInitialiseTaskLists();
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550 /* If the scheduler is not already running, make this task the
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551 current task if it is the highest priority task to be created
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553 if( xSchedulerRunning == pdFALSE )
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555 if( pxCurrentTCB->uxPriority <= uxPriority )
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557 pxCurrentTCB = pxNewTCB;
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562 /* Remember the top priority to make context switching faster. Use
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563 the priority in pxNewTCB as this has been capped to a valid value. */
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564 if( pxNewTCB->uxPriority > uxTopUsedPriority )
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566 uxTopUsedPriority = pxNewTCB->uxPriority;
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569 /* Add a counter into the TCB for tracing only. */
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570 pxNewTCB->uxTCBNumber = uxTaskNumber;
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573 prvAddTaskToReadyQueue( pxNewTCB );
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577 portEXIT_CRITICAL();
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581 xReturn = errCOULD_NOT_ALLOCATE_REQUIRED_MEMORY;
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584 if( xReturn == pdPASS )
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586 if( ( void * ) pxCreatedTask != NULL )
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588 /* Pass the TCB out - in an anonymous way. The calling function/
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589 task can use this as a handle to delete the task later if
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591 *pxCreatedTask = ( xTaskHandle ) pxNewTCB;
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594 if( xSchedulerRunning != pdFALSE )
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596 /* If the created task is of a higher priority than the current task
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597 then it should run now. */
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598 if( pxCurrentTCB->uxPriority < uxPriority )
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607 /*-----------------------------------------------------------*/
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609 #if ( INCLUDE_vTaskDelete == 1 )
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611 void vTaskDelete( xTaskHandle pxTaskToDelete )
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615 taskENTER_CRITICAL();
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617 /* Ensure a yield is performed if the current task is being
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619 if( pxTaskToDelete == pxCurrentTCB )
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621 pxTaskToDelete = NULL;
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624 /* If null is passed in here then we are deleting ourselves. */
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625 pxTCB = prvGetTCBFromHandle( pxTaskToDelete );
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627 /* Remove task from the ready list and place in the termination list.
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628 This will stop the task from be scheduled. The idle task will check
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629 the termination list and free up any memory allocated by the
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630 scheduler for the TCB and stack. */
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631 vListRemove( &( pxTCB->xGenericListItem ) );
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633 /* Is the task waiting on an event also? */
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634 if( pxTCB->xEventListItem.pvContainer )
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636 vListRemove( &( pxTCB->xEventListItem ) );
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639 vListInsertEnd( ( xList * ) &xTasksWaitingTermination, &( pxTCB->xGenericListItem ) );
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641 /* Increment the ucTasksDeleted variable so the idle task knows
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642 there is a task that has been deleted and that it should therefore
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643 check the xTasksWaitingTermination list. */
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646 taskEXIT_CRITICAL();
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648 /* Force a reschedule if we have just deleted the current task. */
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649 if( xSchedulerRunning != pdFALSE )
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651 if( ( void * ) pxTaskToDelete == NULL )
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665 /*-----------------------------------------------------------
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666 * TASK CONTROL API documented in task.h
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667 *----------------------------------------------------------*/
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669 #if ( INCLUDE_vTaskDelayUntil == 1 )
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671 void vTaskDelayUntil( portTickType *pxPreviousWakeTime, portTickType xTimeIncrement )
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673 portTickType xTimeToWake;
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674 portBASE_TYPE xAlreadyYielded, xShouldDelay = pdFALSE;
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678 /* Generate the tick time at which the task wants to wake. */
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679 xTimeToWake = *pxPreviousWakeTime + xTimeIncrement;
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681 if( xTickCount < *pxPreviousWakeTime )
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683 /* The tick count has overflowed since this function was
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684 lasted called. In this case the only time we should ever
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685 actually delay is if the wake time has also overflowed,
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686 and the wake time is greater than the tick time. When this
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687 is the case it is as if neither time had overflowed. */
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688 if( ( xTimeToWake < *pxPreviousWakeTime ) && ( xTimeToWake > xTickCount ) )
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690 xShouldDelay = pdTRUE;
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695 /* The tick time has not overflowed. In this case we will
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696 delay if either the wake time has overflowed, and/or the
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697 tick time is less than the wake time. */
\r
698 if( ( xTimeToWake < *pxPreviousWakeTime ) || ( xTimeToWake > xTickCount ) )
\r
700 xShouldDelay = pdTRUE;
\r
704 /* Update the wake time ready for the next call. */
\r
705 *pxPreviousWakeTime = xTimeToWake;
\r
709 /* We must remove ourselves from the ready list before adding
\r
710 ourselves to the blocked list as the same list item is used for
\r
712 vListRemove( ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
\r
714 /* The list item will be inserted in wake time order. */
\r
715 listSET_LIST_ITEM_VALUE( &( pxCurrentTCB->xGenericListItem ), xTimeToWake );
\r
717 if( xTimeToWake < xTickCount )
\r
719 /* Wake time has overflowed. Place this item in the
\r
721 vListInsert( ( xList * ) pxOverflowDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
\r
725 /* The wake time has not overflowed, so we can use the
\r
726 current block list. */
\r
727 vListInsert( ( xList * ) pxDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
\r
731 xAlreadyYielded = xTaskResumeAll();
\r
733 /* Force a reschedule if xTaskResumeAll has not already done so, we may
\r
734 have put ourselves to sleep. */
\r
735 if( !xAlreadyYielded )
\r
742 /*-----------------------------------------------------------*/
\r
744 #if ( INCLUDE_vTaskDelay == 1 )
\r
746 void vTaskDelay( portTickType xTicksToDelay )
\r
748 portTickType xTimeToWake;
\r
749 signed portBASE_TYPE xAlreadyYielded = pdFALSE;
\r
751 /* A delay time of zero just forces a reschedule. */
\r
752 if( xTicksToDelay > ( portTickType ) 0 )
\r
756 /* A task that is removed from the event list while the
\r
757 scheduler is suspended will not get placed in the ready
\r
758 list or removed from the blocked list until the scheduler
\r
761 This task cannot be in an event list as it is the currently
\r
764 /* Calculate the time to wake - this may overflow but this is
\r
766 xTimeToWake = xTickCount + xTicksToDelay;
\r
768 /* We must remove ourselves from the ready list before adding
\r
769 ourselves to the blocked list as the same list item is used for
\r
771 vListRemove( ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
\r
773 /* The list item will be inserted in wake time order. */
\r
774 listSET_LIST_ITEM_VALUE( &( pxCurrentTCB->xGenericListItem ), xTimeToWake );
\r
776 if( xTimeToWake < xTickCount )
\r
778 /* Wake time has overflowed. Place this item in the
\r
780 vListInsert( ( xList * ) pxOverflowDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
\r
784 /* The wake time has not overflowed, so we can use the
\r
785 current block list. */
\r
786 vListInsert( ( xList * ) pxDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
\r
789 xAlreadyYielded = xTaskResumeAll();
\r
792 /* Force a reschedule if xTaskResumeAll has not already done so, we may
\r
793 have put ourselves to sleep. */
\r
794 if( !xAlreadyYielded )
\r
801 /*-----------------------------------------------------------*/
\r
803 #if ( INCLUDE_uxTaskPriorityGet == 1 )
\r
805 unsigned portBASE_TYPE uxTaskPriorityGet( xTaskHandle pxTask )
\r
808 unsigned portBASE_TYPE uxReturn;
\r
810 taskENTER_CRITICAL();
\r
812 /* If null is passed in here then we are changing the
\r
813 priority of the calling function. */
\r
814 pxTCB = prvGetTCBFromHandle( pxTask );
\r
815 uxReturn = pxTCB->uxPriority;
\r
817 taskEXIT_CRITICAL();
\r
823 /*-----------------------------------------------------------*/
\r
825 #if ( INCLUDE_vTaskPrioritySet == 1 )
\r
827 void vTaskPrioritySet( xTaskHandle pxTask, unsigned portBASE_TYPE uxNewPriority )
\r
830 unsigned portBASE_TYPE uxCurrentPriority, xYieldRequired = pdFALSE;
\r
832 /* Ensure the new priority is valid. */
\r
833 if( uxNewPriority >= configMAX_PRIORITIES )
\r
835 uxNewPriority = configMAX_PRIORITIES - 1;
\r
838 taskENTER_CRITICAL();
\r
840 /* If null is passed in here then we are changing the
\r
841 priority of the calling function. */
\r
842 pxTCB = prvGetTCBFromHandle( pxTask );
\r
843 uxCurrentPriority = pxTCB->uxPriority;
\r
845 if( uxCurrentPriority != uxNewPriority )
\r
847 /* The priority change may have readied a task of higher
\r
848 priority than the calling task. */
\r
849 if( uxNewPriority > pxCurrentTCB->uxPriority )
\r
851 if( pxTask != NULL )
\r
853 /* The priority of another task is being raised. If we
\r
854 were raising the priority of the currently running task
\r
855 there would be no need to switch as it must have already
\r
856 been the highest priority task. */
\r
857 xYieldRequired = pdTRUE;
\r
860 else if( pxTask == NULL )
\r
862 /* Setting our own priority down means there may now be another
\r
863 task of higher priority that is ready to execute. */
\r
864 xYieldRequired = pdTRUE;
\r
867 pxTCB->uxPriority = uxNewPriority;
\r
868 listSET_LIST_ITEM_VALUE( &( pxTCB->xEventListItem ), configMAX_PRIORITIES - ( portTickType ) uxNewPriority );
\r
870 /* If the task is in the blocked or suspended list we need do
\r
871 nothing more than change it's priority variable. However, if
\r
872 the task is in a ready list it needs to be removed and placed
\r
873 in the queue appropriate to its new priority. */
\r
874 if( listIS_CONTAINED_WITHIN( &( pxReadyTasksLists[ uxCurrentPriority ] ), &( pxTCB->xGenericListItem ) ) )
\r
876 /* The task is currently in its ready list - remove before adding
\r
877 it to it's new ready list. As we are in a critical section we
\r
878 can do this even if the scheduler is suspended. */
\r
879 vListRemove( &( pxTCB->xGenericListItem ) );
\r
880 prvAddTaskToReadyQueue( pxTCB );
\r
883 if( xYieldRequired == pdTRUE )
\r
889 taskEXIT_CRITICAL();
\r
893 /*-----------------------------------------------------------*/
\r
895 #if ( INCLUDE_vTaskSuspend == 1 )
\r
897 void vTaskSuspend( xTaskHandle pxTaskToSuspend )
\r
901 taskENTER_CRITICAL();
\r
903 /* Ensure a yield is performed if the current task is being
\r
905 if( pxTaskToSuspend == pxCurrentTCB )
\r
907 pxTaskToSuspend = NULL;
\r
910 /* If null is passed in here then we are suspending ourselves. */
\r
911 pxTCB = prvGetTCBFromHandle( pxTaskToSuspend );
\r
913 /* Remove task from the ready/delayed list and place in the suspended list. */
\r
914 vListRemove( &( pxTCB->xGenericListItem ) );
\r
916 /* Is the task waiting on an event also? */
\r
917 if( pxTCB->xEventListItem.pvContainer )
\r
919 vListRemove( &( pxTCB->xEventListItem ) );
\r
922 vListInsertEnd( ( xList * ) &xSuspendedTaskList, &( pxTCB->xGenericListItem ) );
\r
924 taskEXIT_CRITICAL();
\r
926 /* We may have just suspended the current task. */
\r
927 if( ( void * ) pxTaskToSuspend == NULL )
\r
934 /*-----------------------------------------------------------*/
\r
936 #if ( INCLUDE_vTaskSuspend == 1 )
\r
938 void vTaskResume( xTaskHandle pxTaskToResume )
\r
942 /* Remove the task from whichever list it is currently in, and place
\r
943 it in the ready list. */
\r
944 pxTCB = ( tskTCB * ) pxTaskToResume;
\r
946 /* The parameter cannot be NULL as it is impossible to resume the
\r
947 currently executing task. */
\r
948 if( pxTCB != NULL )
\r
950 taskENTER_CRITICAL();
\r
952 /* Is the task we are attempting to resume actually suspended? */
\r
953 if( listIS_CONTAINED_WITHIN( &xSuspendedTaskList, &( pxTCB->xGenericListItem ) ) != pdFALSE )
\r
955 /* Has the task already been resumed from within an ISR? */
\r
956 if( listIS_CONTAINED_WITHIN( &xPendingReadyList, &( pxTCB->xEventListItem ) ) != pdTRUE )
\r
958 /* As we are in a critical section we can access the ready
\r
959 lists even if the scheduler is suspended. */
\r
960 vListRemove( &( pxTCB->xGenericListItem ) );
\r
961 prvAddTaskToReadyQueue( pxTCB );
\r
963 /* We may have just resumed a higher priority task. */
\r
964 if( pxTCB->uxPriority >= pxCurrentTCB->uxPriority )
\r
966 /* This yield may not cause the task just resumed to run, but
\r
967 will leave the lists in the correct state for the next yield. */
\r
973 taskEXIT_CRITICAL();
\r
979 /*-----------------------------------------------------------*/
\r
981 #if ( ( INCLUDE_xTaskResumeFromISR == 1 ) && ( INCLUDE_vTaskSuspend == 1 ) )
\r
983 portBASE_TYPE xTaskResumeFromISR( xTaskHandle pxTaskToResume )
\r
985 portBASE_TYPE xYieldRequired = pdFALSE;
\r
988 pxTCB = ( tskTCB * ) pxTaskToResume;
\r
990 /* Is the task we are attempting to resume actually suspended? */
\r
991 if( listIS_CONTAINED_WITHIN( &xSuspendedTaskList, &( pxTCB->xGenericListItem ) ) != pdFALSE )
\r
993 /* Has the task already been resumed from within an ISR? */
\r
994 if( listIS_CONTAINED_WITHIN( &xPendingReadyList, &( pxTCB->xEventListItem ) ) != pdTRUE )
\r
996 if( uxSchedulerSuspended == ( unsigned portBASE_TYPE ) pdFALSE )
\r
998 xYieldRequired = ( pxTCB->uxPriority >= pxCurrentTCB->uxPriority );
\r
999 vListRemove( &( pxTCB->xGenericListItem ) );
\r
1000 prvAddTaskToReadyQueue( pxTCB );
\r
1004 /* We cannot access the delayed or ready lists, so will hold this
\r
1005 task pending until the scheduler is resumed, at which point a
\r
1006 yield will be preformed if necessary. */
\r
1007 vListInsertEnd( ( xList * ) &( xPendingReadyList ), &( pxTCB->xEventListItem ) );
\r
1012 return xYieldRequired;
\r
1020 /*-----------------------------------------------------------
\r
1021 * PUBLIC SCHEDULER CONTROL documented in task.h
\r
1022 *----------------------------------------------------------*/
\r
1025 void vTaskStartScheduler( void )
\r
1027 portBASE_TYPE xReturn;
\r
1029 /* Add the idle task at the lowest priority. */
\r
1030 xReturn = xTaskCreate( prvIdleTask, ( signed portCHAR * ) "IDLE", tskIDLE_STACK_SIZE, ( void * ) NULL, tskIDLE_PRIORITY, ( xTaskHandle * ) NULL );
\r
1032 if( xReturn == pdPASS )
\r
1034 /* Interrupts are turned off here, to ensure a tick does not occur
\r
1035 before or during the call to xPortStartScheduler(). The stacks of
\r
1036 the created tasks contain a status word with interrupts switched on
\r
1037 so interrupts will automatically get re-enabled when the first task
\r
1040 STEPPING THROUGH HERE USING A DEBUGGER CAN CAUSE BIG PROBLEMS IF THE
\r
1041 DEBUGGER ALLOWS INTERRUPTS TO BE PROCESSED. */
\r
1042 portDISABLE_INTERRUPTS();
\r
1044 xSchedulerRunning = pdTRUE;
\r
1045 xTickCount = ( portTickType ) 0;
\r
1047 /* Setting up the timer tick is hardware specific and thus in the
\r
1048 portable interface. */
\r
1049 if( xPortStartScheduler() )
\r
1051 /* Should not reach here as if the scheduler is running the
\r
1052 function will not return. */
\r
1056 /* Should only reach here if a task calls xTaskEndScheduler(). */
\r
1060 /*-----------------------------------------------------------*/
\r
1062 void vTaskEndScheduler( void )
\r
1064 /* Stop the scheduler interrupts and call the portable scheduler end
\r
1065 routine so the original ISRs can be restored if necessary. The port
\r
1066 layer must ensure interrupts enable bit is left in the correct state. */
\r
1067 portDISABLE_INTERRUPTS();
\r
1068 xSchedulerRunning = pdFALSE;
\r
1069 vPortEndScheduler();
\r
1071 /*----------------------------------------------------------*/
\r
1073 void vTaskSuspendAll( void )
\r
1075 portENTER_CRITICAL();
\r
1076 ++uxSchedulerSuspended;
\r
1077 portEXIT_CRITICAL();
\r
1079 /*----------------------------------------------------------*/
\r
1081 signed portBASE_TYPE xTaskResumeAll( void )
\r
1083 register tskTCB *pxTCB;
\r
1084 signed portBASE_TYPE xAlreadyYielded = pdFALSE;
\r
1086 /* It is possible that an ISR caused a task to be removed from an event
\r
1087 list while the scheduler was suspended. If this was the case then the
\r
1088 removed task will have been added to the xPendingReadyList. Once the
\r
1089 scheduler has been resumed it is safe to move all the pending ready
\r
1090 tasks from this list into their appropriate ready list. */
\r
1091 portENTER_CRITICAL();
\r
1093 --uxSchedulerSuspended;
\r
1095 if( uxSchedulerSuspended == ( unsigned portBASE_TYPE ) pdFALSE )
\r
1097 if( uxCurrentNumberOfTasks > ( unsigned portBASE_TYPE ) 0 )
\r
1099 portBASE_TYPE xYieldRequired = pdFALSE;
\r
1101 /* Move any readied tasks from the pending list into the
\r
1102 appropriate ready list. */
\r
1103 while( ( pxTCB = ( tskTCB * ) listGET_OWNER_OF_HEAD_ENTRY( ( ( xList * ) &xPendingReadyList ) ) ) != NULL )
\r
1105 vListRemove( &( pxTCB->xEventListItem ) );
\r
1106 vListRemove( &( pxTCB->xGenericListItem ) );
\r
1107 prvAddTaskToReadyQueue( pxTCB );
\r
1109 /* If we have moved a task that has a priority higher than
\r
1110 the current task then we should yield. */
\r
1111 if( pxTCB->uxPriority >= pxCurrentTCB->uxPriority )
\r
1113 xYieldRequired = pdTRUE;
\r
1117 /* If any ticks occurred while the scheduler was suspended then
\r
1118 they should be processed now. This ensures the tick count does not
\r
1119 slip, and that any delayed tasks are resumed at the correct time. */
\r
1120 if( uxMissedTicks > ( unsigned portBASE_TYPE ) 0 )
\r
1122 while( uxMissedTicks > ( unsigned portBASE_TYPE ) 0 )
\r
1124 vTaskIncrementTick();
\r
1128 /* As we have processed some ticks it is appropriate to yield
\r
1129 to ensure the highest priority task that is ready to run is
\r
1130 the task actually running. */
\r
1131 xYieldRequired = pdTRUE;
\r
1134 if( ( xYieldRequired == pdTRUE ) || ( xMissedYield == pdTRUE ) )
\r
1136 xAlreadyYielded = pdTRUE;
\r
1137 xMissedYield = pdFALSE;
\r
1143 portEXIT_CRITICAL();
\r
1145 return xAlreadyYielded;
\r
1153 /*-----------------------------------------------------------
\r
1154 * PUBLIC TASK UTILITIES documented in task.h
\r
1155 *----------------------------------------------------------*/
\r
1159 portTickType xTaskGetTickCount( void )
\r
1161 portTickType xTicks;
\r
1163 /* Critical section required if running on a 16 bit processor. */
\r
1164 taskENTER_CRITICAL();
\r
1166 xTicks = xTickCount;
\r
1168 taskEXIT_CRITICAL();
\r
1172 /*-----------------------------------------------------------*/
\r
1174 unsigned portBASE_TYPE uxTaskGetNumberOfTasks( void )
\r
1176 unsigned portBASE_TYPE uxNumberOfTasks;
\r
1178 taskENTER_CRITICAL();
\r
1179 uxNumberOfTasks = uxCurrentNumberOfTasks;
\r
1180 taskEXIT_CRITICAL();
\r
1182 return uxNumberOfTasks;
\r
1184 /*-----------------------------------------------------------*/
\r
1186 #if ( ( configUSE_TRACE_FACILITY == 1 ) && ( INCLUDE_vTaskDelete == 1 ) && ( INCLUDE_vTaskSuspend == 1 ) )
\r
1188 void vTaskList( signed portCHAR *pcWriteBuffer )
\r
1190 unsigned portBASE_TYPE uxQueue;
\r
1192 /* This is a VERY costly function that should be used for debug only.
\r
1193 It leaves interrupts disabled for a LONG time. */
\r
1195 vTaskSuspendAll();
\r
1197 /* Run through all the lists that could potentially contain a TCB and
\r
1198 report the task name, state and stack high water mark. */
\r
1200 pcWriteBuffer[ 0 ] = ( signed portCHAR ) 0x00;
\r
1201 strcat( ( portCHAR * ) pcWriteBuffer, ( const portCHAR * ) "\r\n" );
\r
1203 uxQueue = uxTopUsedPriority + 1;
\r
1209 if( !listLIST_IS_EMPTY( &( pxReadyTasksLists[ uxQueue ] ) ) )
\r
1211 prvListTaskWithinSingleList( pcWriteBuffer, ( xList * ) &( pxReadyTasksLists[ uxQueue ] ), tskREADY_CHAR );
\r
1213 }while( uxQueue > ( unsigned portSHORT ) tskIDLE_PRIORITY );
\r
1215 if( !listLIST_IS_EMPTY( pxDelayedTaskList ) )
\r
1217 prvListTaskWithinSingleList( pcWriteBuffer, ( xList * ) pxDelayedTaskList, tskBLOCKED_CHAR );
\r
1220 if( !listLIST_IS_EMPTY( pxOverflowDelayedTaskList ) )
\r
1222 prvListTaskWithinSingleList( pcWriteBuffer, ( xList * ) pxOverflowDelayedTaskList, tskBLOCKED_CHAR );
\r
1225 if( !listLIST_IS_EMPTY( &xTasksWaitingTermination ) )
\r
1227 prvListTaskWithinSingleList( pcWriteBuffer, ( xList * ) &xTasksWaitingTermination, tskDELETED_CHAR );
\r
1230 if( !listLIST_IS_EMPTY( &xSuspendedTaskList ) )
\r
1232 prvListTaskWithinSingleList( pcWriteBuffer, ( xList * ) &xSuspendedTaskList, tskSUSPENDED_CHAR );
\r
1239 /*----------------------------------------------------------*/
\r
1241 #if ( configUSE_TRACE_FACILITY == 1 )
\r
1243 void vTaskStartTrace( signed portCHAR * pcBuffer, unsigned portLONG ulBufferSize )
\r
1245 portENTER_CRITICAL();
\r
1247 pcTraceBuffer = ( volatile signed portCHAR * volatile )pcBuffer;
\r
1248 pcTraceBufferStart = pcBuffer;
\r
1249 pcTraceBufferEnd = pcBuffer + ( ulBufferSize - tskSIZE_OF_EACH_TRACE_LINE );
\r
1250 xTracing = pdTRUE;
\r
1252 portEXIT_CRITICAL();
\r
1256 /*----------------------------------------------------------*/
\r
1258 #if ( configUSE_TRACE_FACILITY == 1 )
\r
1260 unsigned portLONG ulTaskEndTrace( void )
\r
1262 unsigned portLONG ulBufferLength;
\r
1264 portENTER_CRITICAL();
\r
1265 xTracing = pdFALSE;
\r
1266 portEXIT_CRITICAL();
\r
1268 ulBufferLength = ( unsigned portLONG ) ( pcTraceBuffer - pcTraceBufferStart );
\r
1270 return ulBufferLength;
\r
1277 /*-----------------------------------------------------------
\r
1278 * SCHEDULER INTERNALS AVAILABLE FOR PORTING PURPOSES
\r
1279 * documented in task.h
\r
1280 *----------------------------------------------------------*/
\r
1283 inline void vTaskIncrementTick( void )
\r
1285 /* Called by the portable layer each time a tick interrupt occurs.
\r
1286 Increments the tick then checks to see if the new tick value will cause any
\r
1287 tasks to be unblocked. */
\r
1288 if( uxSchedulerSuspended == ( unsigned portBASE_TYPE ) pdFALSE )
\r
1291 if( xTickCount == ( portTickType ) 0 )
\r
1295 /* Tick count has overflowed so we need to swap the delay lists.
\r
1296 If there are any items in pxDelayedTaskList here then there is
\r
1298 pxTemp = pxDelayedTaskList;
\r
1299 pxDelayedTaskList = pxOverflowDelayedTaskList;
\r
1300 pxOverflowDelayedTaskList = pxTemp;
\r
1301 xNumOfOverflows++;
\r
1304 /* See if this tick has made a timeout expire. */
\r
1305 prvCheckDelayedTasks();
\r
1311 /* The tick hook gets called at regular intervals, even if the
\r
1312 scheduler is locked. */
\r
1313 #if ( configUSE_TICK_HOOK == 1 )
\r
1315 extern void vApplicationTickHook( void );
\r
1317 vApplicationTickHook();
\r
1322 #if ( configUSE_TICK_HOOK == 1 )
\r
1324 extern void vApplicationTickHook( void );
\r
1326 /* Guard against the tick hook being called when the missed tick
\r
1327 count is being unwound (when the scheduler is being unlocked. */
\r
1328 if( uxMissedTicks == 0 )
\r
1330 vApplicationTickHook();
\r
1335 /*-----------------------------------------------------------*/
\r
1337 #if ( ( INCLUDE_vTaskCleanUpResources == 1 ) && ( INCLUDE_vTaskSuspend == 1 ) )
\r
1339 void vTaskCleanUpResources( void )
\r
1341 unsigned portSHORT usQueue;
\r
1342 volatile tskTCB *pxTCB;
\r
1344 usQueue = ( unsigned portSHORT ) uxTopUsedPriority + ( unsigned portSHORT ) 1;
\r
1346 /* Remove any TCB's from the ready queues. */
\r
1351 while( !listLIST_IS_EMPTY( &( pxReadyTasksLists[ usQueue ] ) ) )
\r
1353 listGET_OWNER_OF_NEXT_ENTRY( pxTCB, &( pxReadyTasksLists[ usQueue ] ) );
\r
1354 vListRemove( ( xListItem * ) &( pxTCB->xGenericListItem ) );
\r
1356 prvDeleteTCB( ( tskTCB * ) pxTCB );
\r
1358 }while( usQueue > ( unsigned portSHORT ) tskIDLE_PRIORITY );
\r
1360 /* Remove any TCB's from the delayed queue. */
\r
1361 while( !listLIST_IS_EMPTY( &xDelayedTaskList1 ) )
\r
1363 listGET_OWNER_OF_NEXT_ENTRY( pxTCB, &xDelayedTaskList1 );
\r
1364 vListRemove( ( xListItem * ) &( pxTCB->xGenericListItem ) );
\r
1366 prvDeleteTCB( ( tskTCB * ) pxTCB );
\r
1369 /* Remove any TCB's from the overflow delayed queue. */
\r
1370 while( !listLIST_IS_EMPTY( &xDelayedTaskList2 ) )
\r
1372 listGET_OWNER_OF_NEXT_ENTRY( pxTCB, &xDelayedTaskList2 );
\r
1373 vListRemove( ( xListItem * ) &( pxTCB->xGenericListItem ) );
\r
1375 prvDeleteTCB( ( tskTCB * ) pxTCB );
\r
1378 while( !listLIST_IS_EMPTY( &xSuspendedTaskList ) )
\r
1380 listGET_OWNER_OF_NEXT_ENTRY( pxTCB, &xSuspendedTaskList );
\r
1381 vListRemove( ( xListItem * ) &( pxTCB->xGenericListItem ) );
\r
1383 prvDeleteTCB( ( tskTCB * ) pxTCB );
\r
1386 while( !listLIST_IS_EMPTY( &xPendingReadyList ) )
\r
1388 listGET_OWNER_OF_NEXT_ENTRY( pxTCB, &xPendingReadyList );
\r
1389 vListRemove( ( xListItem * ) &( pxTCB->xGenericListItem ) );
\r
1391 prvDeleteTCB( ( tskTCB * ) pxTCB );
\r
1396 /*-----------------------------------------------------------*/
\r
1398 void vTaskSwitchContext( void )
\r
1400 if( uxSchedulerSuspended != ( unsigned portBASE_TYPE ) pdFALSE )
\r
1402 /* The scheduler is currently suspended - do not allow a context
\r
1404 xMissedYield = pdTRUE;
\r
1408 /* Find the highest priority queue that contains ready tasks. */
\r
1409 while( listLIST_IS_EMPTY( &( pxReadyTasksLists[ uxTopReadyPriority ] ) ) )
\r
1411 --uxTopReadyPriority;
\r
1414 /* listGET_OWNER_OF_NEXT_ENTRY walks through the list, so the tasks of the
\r
1415 same priority get an equal share of the processor time. */
\r
1416 listGET_OWNER_OF_NEXT_ENTRY( pxCurrentTCB, &( pxReadyTasksLists[ uxTopReadyPriority ] ) );
\r
1417 vWriteTraceToBuffer();
\r
1419 /*-----------------------------------------------------------*/
\r
1421 void vTaskPlaceOnEventList( xList *pxEventList, portTickType xTicksToWait )
\r
1423 portTickType xTimeToWake;
\r
1425 /* THIS FUNCTION MUST BE CALLED WITH INTERRUPTS DISABLED OR THE
\r
1426 SCHEDULER SUSPENDED. */
\r
1428 /* Place the event list item of the TCB in the appropriate event list.
\r
1429 This is placed in the list in priority order so the highest priority task
\r
1430 is the first to be woken by the event. */
\r
1431 vListInsert( ( xList * ) pxEventList, ( xListItem * ) &( pxCurrentTCB->xEventListItem ) );
\r
1433 /* We must remove ourselves from the ready list before adding ourselves
\r
1434 to the blocked list as the same list item is used for both lists. We have
\r
1435 exclusive access to the ready lists as the scheduler is locked. */
\r
1436 vListRemove( ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
\r
1439 #if ( INCLUDE_vTaskSuspend == 1 )
\r
1441 if( xTicksToWait == portMAX_DELAY )
\r
1443 /* Add ourselves to the suspended task list instead of a delayed task
\r
1444 list to ensure we are not woken by a timing event. We will block
\r
1446 vListInsertEnd( ( xList * ) &xSuspendedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
\r
1450 /* Calculate the time at which the task should be woken if the event does
\r
1451 not occur. This may overflow but this doesn't matter. */
\r
1452 xTimeToWake = xTickCount + xTicksToWait;
\r
1454 listSET_LIST_ITEM_VALUE( &( pxCurrentTCB->xGenericListItem ), xTimeToWake );
\r
1456 if( xTimeToWake < xTickCount )
\r
1458 /* Wake time has overflowed. Place this item in the overflow list. */
\r
1459 vListInsert( ( xList * ) pxOverflowDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
\r
1463 /* The wake time has not overflowed, so we can use the current block list. */
\r
1464 vListInsert( ( xList * ) pxDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
\r
1470 /* Calculate the time at which the task should be woken if the event does
\r
1471 not occur. This may overflow but this doesn't matter. */
\r
1472 xTimeToWake = xTickCount + xTicksToWait;
\r
1474 listSET_LIST_ITEM_VALUE( &( pxCurrentTCB->xGenericListItem ), xTimeToWake );
\r
1476 if( xTimeToWake < xTickCount )
\r
1478 /* Wake time has overflowed. Place this item in the overflow list. */
\r
1479 vListInsert( ( xList * ) pxOverflowDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
\r
1483 /* The wake time has not overflowed, so we can use the current block list. */
\r
1484 vListInsert( ( xList * ) pxDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
\r
1489 /*-----------------------------------------------------------*/
\r
1491 signed portBASE_TYPE xTaskRemoveFromEventList( const xList *pxEventList )
\r
1493 tskTCB *pxUnblockedTCB;
\r
1494 portBASE_TYPE xReturn;
\r
1496 /* THIS FUNCTION MUST BE CALLED WITH INTERRUPTS DISABLED OR THE
\r
1497 SCHEDULER SUSPENDED. It can also be called from within an ISR. */
\r
1499 /* The event list is sorted in priority order, so we can remove the
\r
1500 first in the list, remove the TCB from the delayed list, and add
\r
1501 it to the ready list.
\r
1503 If an event is for a queue that is locked then this function will never
\r
1504 get called - the lock count on the queue will get modified instead. This
\r
1505 means we can always expect exclusive access to the event list here. */
\r
1506 pxUnblockedTCB = ( tskTCB * ) listGET_OWNER_OF_HEAD_ENTRY( pxEventList );
\r
1507 vListRemove( &( pxUnblockedTCB->xEventListItem ) );
\r
1509 if( uxSchedulerSuspended == ( unsigned portBASE_TYPE ) pdFALSE )
\r
1511 vListRemove( &( pxUnblockedTCB->xGenericListItem ) );
\r
1512 prvAddTaskToReadyQueue( pxUnblockedTCB );
\r
1516 /* We cannot access the delayed or ready lists, so will hold this
\r
1517 task pending until the scheduler is resumed. */
\r
1518 vListInsertEnd( ( xList * ) &( xPendingReadyList ), &( pxUnblockedTCB->xEventListItem ) );
\r
1521 if( pxUnblockedTCB->uxPriority >= pxCurrentTCB->uxPriority )
\r
1523 /* Return true if the task removed from the event list has
\r
1524 a higher priority than the calling task. This allows
\r
1525 the calling task to know if it should force a context
\r
1531 xReturn = pdFALSE;
\r
1536 /*-----------------------------------------------------------*/
\r
1538 void vTaskSetTimeOutState( xTimeOutType *pxTimeOut )
\r
1540 pxTimeOut->xOverflowCount = xNumOfOverflows;
\r
1541 pxTimeOut->xTimeOnEntering = xTickCount;
\r
1543 /*-----------------------------------------------------------*/
\r
1545 portBASE_TYPE xTaskCheckForTimeOut( xTimeOutType *pxTimeOut, portTickType *pxTicksToWait )
\r
1547 portBASE_TYPE xReturn;
\r
1549 if( ( xNumOfOverflows != pxTimeOut->xOverflowCount ) && ( xTickCount >= pxTimeOut->xTimeOnEntering ) )
\r
1551 /* The tick count is greater than the time at which vTaskSetTimeout()
\r
1552 was called, but has also overflowed since vTaskSetTimeOut() was called.
\r
1553 It must have wrapped all the way around and gone past us again. This
\r
1554 passed since vTaskSetTimeout() was called. */
\r
1557 else if( ( xTickCount - pxTimeOut->xTimeOnEntering ) < *pxTicksToWait )
\r
1559 /* Not a genuine timeout. Adjust parameters for time remaining. */
\r
1560 *pxTicksToWait -= ( xTickCount - pxTimeOut->xTimeOnEntering );
\r
1561 vTaskSetTimeOutState( pxTimeOut );
\r
1562 xReturn = pdFALSE;
\r
1571 /*-----------------------------------------------------------*/
\r
1573 void vTaskMissedYield( void )
\r
1575 xMissedYield = pdTRUE;
\r
1579 * -----------------------------------------------------------
\r
1581 * ----------------------------------------------------------
\r
1583 * The portTASK_FUNCTION() macro is used to allow port/compiler specific
\r
1584 * language extensions. The equivalent prototype for this function is:
\r
1586 * void prvIdleTask( void *pvParameters );
\r
1589 static portTASK_FUNCTION( prvIdleTask, pvParameters )
\r
1591 /* Stop warnings. */
\r
1592 ( void ) pvParameters;
\r
1596 /* See if any tasks have been deleted. */
\r
1597 prvCheckTasksWaitingTermination();
\r
1599 #if ( configUSE_PREEMPTION == 0 )
\r
1601 /* If we are not using preemption we keep forcing a task switch to
\r
1602 see if any other task has become available. If we are using
\r
1603 preemption we don't need to do this as any task becoming available
\r
1604 will automatically get the processor anyway. */
\r
1609 #if ( ( configUSE_PREEMPTION == 1 ) && ( configIDLE_SHOULD_YIELD == 1 ) )
\r
1611 /* When using preemption tasks of equal priority will be
\r
1612 timesliced. If a task that is sharing the idle priority is ready
\r
1613 to run then the idle task should yield before the end of the
\r
1616 A critical region is not required here as we are just reading from
\r
1617 the list, and an occasional incorrect value will not matter. If
\r
1618 the ready list at the idle priority contains more than one task
\r
1619 then a task other than the idle task is ready to execute. */
\r
1620 if( listCURRENT_LIST_LENGTH( &( pxReadyTasksLists[ tskIDLE_PRIORITY ] ) ) > ( unsigned portBASE_TYPE ) 1 )
\r
1627 #if ( configUSE_IDLE_HOOK == 1 )
\r
1629 extern void vApplicationIdleHook( void );
\r
1631 /* Call the user defined function from within the idle task. This
\r
1632 allows the application designer to add background functionality
\r
1633 without the overhead of a separate task.
\r
1634 NOTE: vApplicationIdleHook() MUST NOT, UNDER ANY CIRCUMSTANCES,
\r
1635 CALL A FUNCTION THAT MIGHT BLOCK. */
\r
1636 vApplicationIdleHook();
\r
1640 } /*lint !e715 pvParameters is not accessed but all task functions require the same prototype. */
\r
1648 /*-----------------------------------------------------------
\r
1649 * File private functions documented at the top of the file.
\r
1650 *----------------------------------------------------------*/
\r
1654 static void prvInitialiseTCBVariables( tskTCB *pxTCB, unsigned portSHORT usStackDepth, const signed portCHAR * const pcName, unsigned portBASE_TYPE uxPriority )
\r
1656 pxTCB->usStackDepth = usStackDepth;
\r
1658 /* Store the function name in the TCB. */
\r
1659 strncpy( ( char * ) pxTCB->pcTaskName, ( const char * ) pcName, ( unsigned portSHORT ) configMAX_TASK_NAME_LEN );
\r
1660 pxTCB->pcTaskName[ ( unsigned portSHORT ) configMAX_TASK_NAME_LEN - ( unsigned portSHORT ) 1 ] = '\0';
\r
1662 /* This is used as an array index so must ensure it's not too large. */
\r
1663 if( uxPriority >= configMAX_PRIORITIES )
\r
1665 uxPriority = configMAX_PRIORITIES - 1;
\r
1668 pxTCB->uxPriority = uxPriority;
\r
1670 vListInitialiseItem( &( pxTCB->xGenericListItem ) );
\r
1671 vListInitialiseItem( &( pxTCB->xEventListItem ) );
\r
1673 /* Set the pxTCB as a link back from the xListItem. This is so we can get
\r
1674 back to the containing TCB from a generic item in a list. */
\r
1675 listSET_LIST_ITEM_OWNER( &( pxTCB->xGenericListItem ), pxTCB );
\r
1677 /* Event lists are always in priority order. */
\r
1678 listSET_LIST_ITEM_VALUE( &( pxTCB->xEventListItem ), configMAX_PRIORITIES - ( portTickType ) uxPriority );
\r
1679 listSET_LIST_ITEM_OWNER( &( pxTCB->xEventListItem ), pxTCB );
\r
1681 /*-----------------------------------------------------------*/
\r
1683 static void prvInitialiseTaskLists( void )
\r
1685 unsigned portBASE_TYPE uxPriority;
\r
1687 for( uxPriority = 0; uxPriority < configMAX_PRIORITIES; uxPriority++ )
\r
1689 vListInitialise( ( xList * ) &( pxReadyTasksLists[ uxPriority ] ) );
\r
1692 vListInitialise( ( xList * ) &xDelayedTaskList1 );
\r
1693 vListInitialise( ( xList * ) &xDelayedTaskList2 );
\r
1694 vListInitialise( ( xList * ) &xPendingReadyList );
\r
1696 #if ( INCLUDE_vTaskDelete == 1 )
\r
1698 vListInitialise( ( xList * ) &xTasksWaitingTermination );
\r
1702 #if ( INCLUDE_vTaskSuspend == 1 )
\r
1704 vListInitialise( ( xList * ) &xSuspendedTaskList );
\r
1708 /* Start with pxDelayedTaskList using list1 and the pxOverflowDelayedTaskList
\r
1710 pxDelayedTaskList = &xDelayedTaskList1;
\r
1711 pxOverflowDelayedTaskList = &xDelayedTaskList2;
\r
1713 /*-----------------------------------------------------------*/
\r
1715 static void prvCheckTasksWaitingTermination( void )
\r
1717 #if ( INCLUDE_vTaskDelete == 1 )
\r
1719 portBASE_TYPE xListIsEmpty;
\r
1721 /* ucTasksDeleted is used to prevent vTaskSuspendAll() being called
\r
1722 too often in the idle task. */
\r
1723 if( uxTasksDeleted > ( unsigned portBASE_TYPE ) 0 )
\r
1725 vTaskSuspendAll();
\r
1726 xListIsEmpty = listLIST_IS_EMPTY( &xTasksWaitingTermination );
\r
1729 if( !xListIsEmpty )
\r
1733 portENTER_CRITICAL();
\r
1735 pxTCB = ( tskTCB * ) listGET_OWNER_OF_HEAD_ENTRY( ( ( xList * ) &xTasksWaitingTermination ) );
\r
1736 vListRemove( &( pxTCB->xGenericListItem ) );
\r
1737 --uxCurrentNumberOfTasks;
\r
1740 portEXIT_CRITICAL();
\r
1742 prvDeleteTCB( pxTCB );
\r
1748 /*-----------------------------------------------------------*/
\r
1750 static tskTCB *prvAllocateTCBAndStack( unsigned portSHORT usStackDepth )
\r
1754 /* Allocate space for the TCB. Where the memory comes from depends on
\r
1755 the implementation of the port malloc function. */
\r
1756 pxNewTCB = ( tskTCB * ) pvPortMalloc( sizeof( tskTCB ) );
\r
1758 if( pxNewTCB != NULL )
\r
1760 /* Allocate space for the stack used by the task being created.
\r
1761 The base of the stack memory stored in the TCB so the task can
\r
1762 be deleted later if required. */
\r
1763 pxNewTCB->pxStack = ( portSTACK_TYPE * ) pvPortMalloc( ( ( size_t )usStackDepth ) * sizeof( portSTACK_TYPE ) );
\r
1765 if( pxNewTCB->pxStack == NULL )
\r
1767 /* Could not allocate the stack. Delete the allocated TCB. */
\r
1768 vPortFree( pxNewTCB );
\r
1773 /* Just to help debugging. */
\r
1774 memset( pxNewTCB->pxStack, tskSTACK_FILL_BYTE, usStackDepth * sizeof( portSTACK_TYPE ) );
\r
1780 /*-----------------------------------------------------------*/
\r
1782 #if ( configUSE_TRACE_FACILITY == 1 )
\r
1784 static void prvListTaskWithinSingleList( signed portCHAR *pcWriteBuffer, xList *pxList, signed portCHAR cStatus )
\r
1786 volatile tskTCB *pxNextTCB, *pxFirstTCB;
\r
1787 static portCHAR pcStatusString[ 50 ];
\r
1788 unsigned portSHORT usStackRemaining;
\r
1790 /* Write the details of all the TCB's in pxList into the buffer. */
\r
1791 listGET_OWNER_OF_NEXT_ENTRY( pxFirstTCB, pxList );
\r
1794 listGET_OWNER_OF_NEXT_ENTRY( pxNextTCB, pxList );
\r
1795 usStackRemaining = usTaskCheckFreeStackSpace( ( unsigned portCHAR * ) pxNextTCB->pxStack );
\r
1796 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
1797 strcat( ( portCHAR * ) pcWriteBuffer, ( portCHAR * ) pcStatusString );
\r
1799 } while( pxNextTCB != pxFirstTCB );
\r
1803 /*-----------------------------------------------------------*/
\r
1805 #if ( configUSE_TRACE_FACILITY == 1 )
\r
1806 unsigned portSHORT usTaskCheckFreeStackSpace( const unsigned portCHAR *pucStackByte )
\r
1808 register unsigned portSHORT usCount = 0;
\r
1810 while( *pucStackByte == tskSTACK_FILL_BYTE )
\r
1812 pucStackByte -= portSTACK_GROWTH;
\r
1816 usCount /= sizeof( portSTACK_TYPE );
\r
1821 /*-----------------------------------------------------------*/
\r
1825 #if ( ( INCLUDE_vTaskDelete == 1 ) || ( INCLUDE_vTaskCleanUpResources == 1 ) )
\r
1827 static void prvDeleteTCB( tskTCB *pxTCB )
\r
1829 /* Free up the memory allocated by the scheduler for the task. It is up to
\r
1830 the task to free any memory allocated at the application level. */
\r
1831 vPortFree( pxTCB->pxStack );
\r
1832 vPortFree( pxTCB );
\r
1838 /*-----------------------------------------------------------*/
\r
1840 #if ( INCLUDE_xTaskGetCurrentTaskHandle == 1 )
\r
1842 xTaskHandle xTaskGetCurrentTaskHandle( void )
\r
1844 xTaskHandle xReturn;
\r
1846 portENTER_CRITICAL();
\r
1848 xReturn = ( xTaskHandle ) pxCurrentTCB;
\r
1850 portEXIT_CRITICAL();
\r