2 FreeRTOS.org V4.4.0 - 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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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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200 Changes since V4.3.1:
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202 + Added xTaskGetSchedulerState() function.
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203 + Added prvIsTaskSuspended() to take into account the Occurrence of
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204 vTaskResume() or vTaskResumeFromISR() being called passing in the
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205 handle of a task that appears in the Suspended list only because it
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206 is blocked on an event without a timeout being specified.
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207 + Updated xTaskCheckForTimeout() to take into account that tasks blocked
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208 using the Suspended list should never time out.
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212 #include <stdlib.h>
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213 #include <string.h>
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215 #include "FreeRTOS.h"
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219 * Macro to define the amount of stack available to the idle task.
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221 #define tskIDLE_STACK_SIZE configMINIMAL_STACK_SIZE
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225 * Default a definitions for backwards compatibility with old
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226 * portmacro.h files.
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228 #ifndef configMAX_TASK_NAME_LEN
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229 #define configMAX_TASK_NAME_LEN 16
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232 #ifndef INCLUDE_xTaskGetCurrentTaskHandle
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233 #define INCLUDE_xTaskGetCurrentTaskHandle 0
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236 #ifndef configIDLE_SHOULD_YIELD
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237 #define configIDLE_SHOULD_YIELD 1
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240 #if configMAX_TASK_NAME_LEN < 1
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241 #undef configMAX_TASK_NAME_LEN
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242 #define configMAX_TASK_NAME_LEN 1
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245 #ifndef INCLUDE_xTaskResumeFromISR
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246 #define INCLUDE_xTaskResumeFromISR 1
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249 #ifndef INCLUDE_xTaskGetSchedulerState
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250 #define INCLUDE_xTaskGetSchedulerState 0
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254 * Task control block. A task control block (TCB) is allocated to each task,
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255 * and stores the context of the task.
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257 typedef struct tskTaskControlBlock
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259 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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260 xListItem xGenericListItem; /*< List item used to place the TCB in ready and blocked queues. */
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261 xListItem xEventListItem; /*< List item used to place the TCB in event lists. */
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262 unsigned portBASE_TYPE uxPriority; /*< The priority of the task where 0 is the lowest priority. */
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263 portSTACK_TYPE *pxStack; /*< Points to the start of the stack. */
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264 unsigned portBASE_TYPE uxTCBNumber; /*< This is used for tracing the scheduler and making debugging easier only. */
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265 signed portCHAR pcTaskName[ configMAX_TASK_NAME_LEN ];/*< Descriptive name given to the task when created. Facilitates debugging only. */
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266 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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271 tskTCB * volatile pxCurrentTCB = NULL;
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273 /* Lists for ready and blocked tasks. --------------------*/
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275 static xList pxReadyTasksLists[ configMAX_PRIORITIES ]; /*< Prioritised ready tasks. */
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276 static xList xDelayedTaskList1; /*< Delayed tasks. */
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277 static xList xDelayedTaskList2; /*< Delayed tasks (two lists are used - one for delays that have overflowed the current tick count. */
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278 static xList * volatile pxDelayedTaskList; /*< Points to the delayed task list currently being used. */
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279 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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280 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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282 #if ( INCLUDE_vTaskDelete == 1 )
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284 static volatile xList xTasksWaitingTermination; /*< Tasks that have been deleted - but the their memory not yet freed. */
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285 static volatile unsigned portBASE_TYPE uxTasksDeleted = ( unsigned portBASE_TYPE ) 0;
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289 #if ( INCLUDE_vTaskSuspend == 1 )
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291 static xList xSuspendedTaskList; /*< Tasks that are currently suspended. */
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295 /* File private variables. --------------------------------*/
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296 static volatile unsigned portBASE_TYPE uxCurrentNumberOfTasks = ( unsigned portBASE_TYPE ) 0;
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297 static volatile portTickType xTickCount = ( portTickType ) 0;
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298 static unsigned portBASE_TYPE uxTopUsedPriority = tskIDLE_PRIORITY;
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299 static volatile unsigned portBASE_TYPE uxTopReadyPriority = tskIDLE_PRIORITY;
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300 static volatile signed portBASE_TYPE xSchedulerRunning = pdFALSE;
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301 static volatile unsigned portBASE_TYPE uxSchedulerSuspended = ( unsigned portBASE_TYPE ) pdFALSE;
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302 static volatile unsigned portBASE_TYPE uxMissedTicks = ( unsigned portBASE_TYPE ) 0;
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303 static volatile portBASE_TYPE xMissedYield = ( portBASE_TYPE ) pdFALSE;
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304 static volatile portBASE_TYPE xNumOfOverflows = ( portBASE_TYPE ) 0;
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305 /* Debugging and trace facilities private variables and macros. ------------*/
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308 * The value used to fill the stack of a task when the task is created. This
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309 * is used purely for checking the high water mark for tasks.
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311 #define tskSTACK_FILL_BYTE ( 0xa5 )
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314 * Macros used by vListTask to indicate which state a task is in.
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316 #define tskBLOCKED_CHAR ( ( signed portCHAR ) 'B' )
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317 #define tskREADY_CHAR ( ( signed portCHAR ) 'R' )
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318 #define tskDELETED_CHAR ( ( signed portCHAR ) 'D' )
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319 #define tskSUSPENDED_CHAR ( ( signed portCHAR ) 'S' )
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322 * Macros and private variables used by the trace facility.
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324 #if ( configUSE_TRACE_FACILITY == 1 )
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326 #define tskSIZE_OF_EACH_TRACE_LINE ( ( unsigned portLONG ) ( sizeof( unsigned portLONG ) + sizeof( unsigned portLONG ) ) )
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327 static volatile signed portCHAR * volatile pcTraceBuffer;
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328 static signed portCHAR *pcTraceBufferStart;
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329 static signed portCHAR *pcTraceBufferEnd;
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330 static signed portBASE_TYPE xTracing = pdFALSE;
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335 * Macro that writes a trace of scheduler activity to a buffer. This trace
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336 * shows which task is running when and is very useful as a debugging tool.
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337 * As this macro is called each context switch it is a good idea to undefine
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338 * it if not using the facility.
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340 #if ( configUSE_TRACE_FACILITY == 1 )
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342 #define vWriteTraceToBuffer() \
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346 static unsigned portBASE_TYPE uxPreviousTask = 255; \
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348 if( uxPreviousTask != pxCurrentTCB->uxTCBNumber ) \
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350 if( ( pcTraceBuffer + tskSIZE_OF_EACH_TRACE_LINE ) < pcTraceBufferEnd ) \
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352 uxPreviousTask = pxCurrentTCB->uxTCBNumber; \
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353 *( unsigned portLONG * ) pcTraceBuffer = ( unsigned portLONG ) xTickCount; \
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354 pcTraceBuffer += sizeof( unsigned portLONG ); \
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355 *( unsigned portLONG * ) pcTraceBuffer = ( unsigned portLONG ) uxPreviousTask; \
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356 pcTraceBuffer += sizeof( unsigned portLONG ); \
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360 xTracing = pdFALSE; \
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368 #define vWriteTraceToBuffer()
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374 * Place the task represented by pxTCB into the appropriate ready queue for
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375 * the task. It is inserted at the end of the list. One quirk of this is
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376 * that if the task being inserted is at the same priority as the currently
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377 * executing task, then it will only be rescheduled after the currently
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378 * executing task has been rescheduled.
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380 #define prvAddTaskToReadyQueue( pxTCB ) \
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382 if( pxTCB->uxPriority > uxTopReadyPriority ) \
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384 uxTopReadyPriority = pxTCB->uxPriority; \
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386 vListInsertEnd( ( xList * ) &( pxReadyTasksLists[ pxTCB->uxPriority ] ), &( pxTCB->xGenericListItem ) ); \
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390 * Macro that looks at the list of tasks that are currently delayed to see if
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391 * any require waking.
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393 * Tasks are stored in the queue in the order of their wake time - meaning
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394 * once one tasks has been found whose timer has not expired we need not look
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395 * any further down the list.
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397 #define prvCheckDelayedTasks() \
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399 register tskTCB *pxTCB; \
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401 while( ( pxTCB = ( tskTCB * ) listGET_OWNER_OF_HEAD_ENTRY( pxDelayedTaskList ) ) != NULL ) \
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403 if( xTickCount < listGET_LIST_ITEM_VALUE( &( pxTCB->xGenericListItem ) ) ) \
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407 vListRemove( &( pxTCB->xGenericListItem ) ); \
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408 /* Is the task waiting on an event also? */ \
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409 if( pxTCB->xEventListItem.pvContainer ) \
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411 vListRemove( &( pxTCB->xEventListItem ) ); \
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413 prvAddTaskToReadyQueue( pxTCB ); \
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418 * Several functions take an xTaskHandle parameter that can optionally be NULL,
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419 * where NULL is used to indicate that the handle of the currently executing
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420 * task should be used in place of the parameter. This macro simply checks to
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421 * see if the parameter is NULL and returns a pointer to the appropriate TCB.
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423 #define prvGetTCBFromHandle( pxHandle ) ( ( pxHandle == NULL ) ? ( tskTCB * ) pxCurrentTCB : ( tskTCB * ) pxHandle )
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426 /* File private functions. --------------------------------*/
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429 * Utility to ready a TCB for a given task. Mainly just copies the parameters
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430 * into the TCB structure.
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432 static void prvInitialiseTCBVariables( tskTCB *pxTCB, unsigned portSHORT usStackDepth, const signed portCHAR * const pcName, unsigned portBASE_TYPE uxPriority );
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435 * Utility to ready all the lists used by the scheduler. This is called
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436 * automatically upon the creation of the first task.
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438 static void prvInitialiseTaskLists( void );
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441 * The idle task, which as all tasks is implemented as a never ending loop.
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442 * The idle task is automatically created and added to the ready lists upon
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443 * creation of the first user task.
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445 * The portTASK_FUNCTION_PROTO() macro is used to allow port/compiler specific
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446 * language extensions. The equivalent prototype for this function is:
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448 * void prvIdleTask( void *pvParameters );
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451 static portTASK_FUNCTION_PROTO( prvIdleTask, pvParameters );
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454 * Utility to free all memory allocated by the scheduler to hold a TCB,
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455 * including the stack pointed to by the TCB.
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457 * This does not free memory allocated by the task itself (i.e. memory
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458 * allocated by calls to pvPortMalloc from within the tasks application code).
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460 #if ( ( INCLUDE_vTaskDelete == 1 ) || ( INCLUDE_vTaskCleanUpResources == 1 ) )
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461 static void prvDeleteTCB( tskTCB *pxTCB );
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465 * Used only by the idle task. This checks to see if anything has been placed
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466 * in the list of tasks waiting to be deleted. If so the task is cleaned up
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467 * and its TCB deleted.
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469 static void prvCheckTasksWaitingTermination( void );
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472 * Allocates memory from the heap for a TCB and associated stack. Checks the
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473 * allocation was successful.
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475 static tskTCB *prvAllocateTCBAndStack( unsigned portSHORT usStackDepth );
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478 * Called from vTaskList. vListTasks details all the tasks currently under
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479 * control of the scheduler. The tasks may be in one of a number of lists.
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480 * prvListTaskWithinSingleList accepts a list and details the tasks from
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481 * within just that list.
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483 * THIS FUNCTION IS INTENDED FOR DEBUGGING ONLY, AND SHOULD NOT BE CALLED FROM
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484 * NORMAL APPLICATION CODE.
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486 #if ( configUSE_TRACE_FACILITY == 1 )
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488 static void prvListTaskWithinSingleList( signed portCHAR *pcWriteBuffer, xList *pxList, signed portCHAR cStatus );
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493 * When a task is created, the stack of the task is filled with a known value.
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494 * This function determines the 'high water mark' of the task stack by
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495 * determining how much of the stack remains at the original preset value.
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497 #if ( configUSE_TRACE_FACILITY == 1 )
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499 unsigned portSHORT usTaskCheckFreeStackSpace( const unsigned portCHAR *pucStackByte );
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504 * Checks that a task being resumed (unsuspended) is actually in the Suspended
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507 #if ( INCLUDE_vTaskSuspend == 1 )
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509 static portBASE_TYPE prvIsTaskSuspended( const tskTCB * const pxTCB );
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519 /*-----------------------------------------------------------
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520 * TASK CREATION API documented in task.h
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521 *----------------------------------------------------------*/
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523 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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525 signed portBASE_TYPE xReturn;
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527 static unsigned portBASE_TYPE uxTaskNumber = 0; /*lint !e956 Static is deliberate - this is guarded before use. */
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529 /* Allocate the memory required by the TCB and stack for the new task.
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530 checking that the allocation was successful. */
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531 pxNewTCB = prvAllocateTCBAndStack( usStackDepth );
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533 if( pxNewTCB != NULL )
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535 portSTACK_TYPE *pxTopOfStack;
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537 /* Setup the newly allocated TCB with the initial state of the task. */
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538 prvInitialiseTCBVariables( pxNewTCB, usStackDepth, pcName, uxPriority );
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540 /* Calculate the top of stack address. This depends on whether the
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541 stack grows from high memory to low (as per the 80x86) or visa versa.
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542 portSTACK_GROWTH is used to make the result positive or negative as
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543 required by the port. */
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544 #if portSTACK_GROWTH < 0
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546 pxTopOfStack = pxNewTCB->pxStack + ( pxNewTCB->usStackDepth - 1 );
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550 pxTopOfStack = pxNewTCB->pxStack;
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554 /* Initialize the TCB stack to look as if the task was already running,
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555 but had been interrupted by the scheduler. The return address is set
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556 to the start of the task function. Once the stack has been initialised
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557 the top of stack variable is updated. */
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558 pxNewTCB->pxTopOfStack = pxPortInitialiseStack( pxTopOfStack, pvTaskCode, pvParameters );
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560 /* We are going to manipulate the task queues to add this task to a
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561 ready list, so must make sure no interrupts occur. */
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562 portENTER_CRITICAL();
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564 uxCurrentNumberOfTasks++;
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565 if( uxCurrentNumberOfTasks == ( unsigned portBASE_TYPE ) 1 )
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567 /* As this is the first task it must also be the current task. */
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568 pxCurrentTCB = pxNewTCB;
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570 /* This is the first task to be created so do the preliminary
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571 initialisation required. We will not recover if this call
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572 fails, but we will report the failure. */
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573 prvInitialiseTaskLists();
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577 /* If the scheduler is not already running, make this task the
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578 current task if it is the highest priority task to be created
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580 if( xSchedulerRunning == pdFALSE )
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582 if( pxCurrentTCB->uxPriority <= uxPriority )
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584 pxCurrentTCB = pxNewTCB;
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589 /* Remember the top priority to make context switching faster. Use
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590 the priority in pxNewTCB as this has been capped to a valid value. */
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591 if( pxNewTCB->uxPriority > uxTopUsedPriority )
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593 uxTopUsedPriority = pxNewTCB->uxPriority;
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596 /* Add a counter into the TCB for tracing only. */
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597 pxNewTCB->uxTCBNumber = uxTaskNumber;
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600 prvAddTaskToReadyQueue( pxNewTCB );
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604 portEXIT_CRITICAL();
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608 xReturn = errCOULD_NOT_ALLOCATE_REQUIRED_MEMORY;
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611 if( xReturn == pdPASS )
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613 if( ( void * ) pxCreatedTask != NULL )
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615 /* Pass the TCB out - in an anonymous way. The calling function/
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616 task can use this as a handle to delete the task later if
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618 *pxCreatedTask = ( xTaskHandle ) pxNewTCB;
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621 if( xSchedulerRunning != pdFALSE )
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623 /* If the created task is of a higher priority than the current task
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624 then it should run now. */
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625 if( pxCurrentTCB->uxPriority < uxPriority )
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634 /*-----------------------------------------------------------*/
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636 #if ( INCLUDE_vTaskDelete == 1 )
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638 void vTaskDelete( xTaskHandle pxTaskToDelete )
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642 taskENTER_CRITICAL();
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644 /* Ensure a yield is performed if the current task is being
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646 if( pxTaskToDelete == pxCurrentTCB )
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648 pxTaskToDelete = NULL;
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651 /* If null is passed in here then we are deleting ourselves. */
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652 pxTCB = prvGetTCBFromHandle( pxTaskToDelete );
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654 /* Remove task from the ready list and place in the termination list.
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655 This will stop the task from be scheduled. The idle task will check
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656 the termination list and free up any memory allocated by the
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657 scheduler for the TCB and stack. */
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658 vListRemove( &( pxTCB->xGenericListItem ) );
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660 /* Is the task waiting on an event also? */
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661 if( pxTCB->xEventListItem.pvContainer )
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663 vListRemove( &( pxTCB->xEventListItem ) );
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666 vListInsertEnd( ( xList * ) &xTasksWaitingTermination, &( pxTCB->xGenericListItem ) );
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668 /* Increment the ucTasksDeleted variable so the idle task knows
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669 there is a task that has been deleted and that it should therefore
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670 check the xTasksWaitingTermination list. */
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673 taskEXIT_CRITICAL();
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675 /* Force a reschedule if we have just deleted the current task. */
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676 if( xSchedulerRunning != pdFALSE )
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678 if( ( void * ) pxTaskToDelete == NULL )
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692 /*-----------------------------------------------------------
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693 * TASK CONTROL API documented in task.h
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694 *----------------------------------------------------------*/
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696 #if ( INCLUDE_vTaskDelayUntil == 1 )
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698 void vTaskDelayUntil( portTickType *pxPreviousWakeTime, portTickType xTimeIncrement )
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700 portTickType xTimeToWake;
\r
701 portBASE_TYPE xAlreadyYielded, xShouldDelay = pdFALSE;
\r
705 /* Generate the tick time at which the task wants to wake. */
\r
706 xTimeToWake = *pxPreviousWakeTime + xTimeIncrement;
\r
708 if( xTickCount < *pxPreviousWakeTime )
\r
710 /* The tick count has overflowed since this function was
\r
711 lasted called. In this case the only time we should ever
\r
712 actually delay is if the wake time has also overflowed,
\r
713 and the wake time is greater than the tick time. When this
\r
714 is the case it is as if neither time had overflowed. */
\r
715 if( ( xTimeToWake < *pxPreviousWakeTime ) && ( xTimeToWake > xTickCount ) )
\r
717 xShouldDelay = pdTRUE;
\r
722 /* The tick time has not overflowed. In this case we will
\r
723 delay if either the wake time has overflowed, and/or the
\r
724 tick time is less than the wake time. */
\r
725 if( ( xTimeToWake < *pxPreviousWakeTime ) || ( xTimeToWake > xTickCount ) )
\r
727 xShouldDelay = pdTRUE;
\r
731 /* Update the wake time ready for the next call. */
\r
732 *pxPreviousWakeTime = xTimeToWake;
\r
736 /* We must remove ourselves from the ready list before adding
\r
737 ourselves to the blocked list as the same list item is used for
\r
739 vListRemove( ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
\r
741 /* The list item will be inserted in wake time order. */
\r
742 listSET_LIST_ITEM_VALUE( &( pxCurrentTCB->xGenericListItem ), xTimeToWake );
\r
744 if( xTimeToWake < xTickCount )
\r
746 /* Wake time has overflowed. Place this item in the
\r
748 vListInsert( ( xList * ) pxOverflowDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
\r
752 /* The wake time has not overflowed, so we can use the
\r
753 current block list. */
\r
754 vListInsert( ( xList * ) pxDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
\r
758 xAlreadyYielded = xTaskResumeAll();
\r
760 /* Force a reschedule if xTaskResumeAll has not already done so, we may
\r
761 have put ourselves to sleep. */
\r
762 if( !xAlreadyYielded )
\r
769 /*-----------------------------------------------------------*/
\r
771 #if ( INCLUDE_vTaskDelay == 1 )
\r
773 void vTaskDelay( portTickType xTicksToDelay )
\r
775 portTickType xTimeToWake;
\r
776 signed portBASE_TYPE xAlreadyYielded = pdFALSE;
\r
778 /* A delay time of zero just forces a reschedule. */
\r
779 if( xTicksToDelay > ( portTickType ) 0 )
\r
783 /* A task that is removed from the event list while the
\r
784 scheduler is suspended will not get placed in the ready
\r
785 list or removed from the blocked list until the scheduler
\r
788 This task cannot be in an event list as it is the currently
\r
791 /* Calculate the time to wake - this may overflow but this is
\r
793 xTimeToWake = xTickCount + xTicksToDelay;
\r
795 /* We must remove ourselves from the ready list before adding
\r
796 ourselves to the blocked list as the same list item is used for
\r
798 vListRemove( ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
\r
800 /* The list item will be inserted in wake time order. */
\r
801 listSET_LIST_ITEM_VALUE( &( pxCurrentTCB->xGenericListItem ), xTimeToWake );
\r
803 if( xTimeToWake < xTickCount )
\r
805 /* Wake time has overflowed. Place this item in the
\r
807 vListInsert( ( xList * ) pxOverflowDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
\r
811 /* The wake time has not overflowed, so we can use the
\r
812 current block list. */
\r
813 vListInsert( ( xList * ) pxDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
\r
816 xAlreadyYielded = xTaskResumeAll();
\r
819 /* Force a reschedule if xTaskResumeAll has not already done so, we may
\r
820 have put ourselves to sleep. */
\r
821 if( !xAlreadyYielded )
\r
828 /*-----------------------------------------------------------*/
\r
830 #if ( INCLUDE_uxTaskPriorityGet == 1 )
\r
832 unsigned portBASE_TYPE uxTaskPriorityGet( xTaskHandle pxTask )
\r
835 unsigned portBASE_TYPE uxReturn;
\r
837 taskENTER_CRITICAL();
\r
839 /* If null is passed in here then we are changing the
\r
840 priority of the calling function. */
\r
841 pxTCB = prvGetTCBFromHandle( pxTask );
\r
842 uxReturn = pxTCB->uxPriority;
\r
844 taskEXIT_CRITICAL();
\r
850 /*-----------------------------------------------------------*/
\r
852 #if ( INCLUDE_vTaskPrioritySet == 1 )
\r
854 void vTaskPrioritySet( xTaskHandle pxTask, unsigned portBASE_TYPE uxNewPriority )
\r
857 unsigned portBASE_TYPE uxCurrentPriority, xYieldRequired = pdFALSE;
\r
859 /* Ensure the new priority is valid. */
\r
860 if( uxNewPriority >= configMAX_PRIORITIES )
\r
862 uxNewPriority = configMAX_PRIORITIES - 1;
\r
865 taskENTER_CRITICAL();
\r
867 /* If null is passed in here then we are changing the
\r
868 priority of the calling function. */
\r
869 pxTCB = prvGetTCBFromHandle( pxTask );
\r
870 uxCurrentPriority = pxTCB->uxPriority;
\r
872 if( uxCurrentPriority != uxNewPriority )
\r
874 /* The priority change may have readied a task of higher
\r
875 priority than the calling task. */
\r
876 if( uxNewPriority > pxCurrentTCB->uxPriority )
\r
878 if( pxTask != NULL )
\r
880 /* The priority of another task is being raised. If we
\r
881 were raising the priority of the currently running task
\r
882 there would be no need to switch as it must have already
\r
883 been the highest priority task. */
\r
884 xYieldRequired = pdTRUE;
\r
887 else if( pxTask == NULL )
\r
889 /* Setting our own priority down means there may now be another
\r
890 task of higher priority that is ready to execute. */
\r
891 xYieldRequired = pdTRUE;
\r
894 pxTCB->uxPriority = uxNewPriority;
\r
895 listSET_LIST_ITEM_VALUE( &( pxTCB->xEventListItem ), configMAX_PRIORITIES - ( portTickType ) uxNewPriority );
\r
897 /* If the task is in the blocked or suspended list we need do
\r
898 nothing more than change it's priority variable. However, if
\r
899 the task is in a ready list it needs to be removed and placed
\r
900 in the queue appropriate to its new priority. */
\r
901 if( listIS_CONTAINED_WITHIN( &( pxReadyTasksLists[ uxCurrentPriority ] ), &( pxTCB->xGenericListItem ) ) )
\r
903 /* The task is currently in its ready list - remove before adding
\r
904 it to it's new ready list. As we are in a critical section we
\r
905 can do this even if the scheduler is suspended. */
\r
906 vListRemove( &( pxTCB->xGenericListItem ) );
\r
907 prvAddTaskToReadyQueue( pxTCB );
\r
910 if( xYieldRequired == pdTRUE )
\r
916 taskEXIT_CRITICAL();
\r
920 /*-----------------------------------------------------------*/
\r
922 #if ( INCLUDE_vTaskSuspend == 1 )
\r
924 void vTaskSuspend( xTaskHandle pxTaskToSuspend )
\r
928 taskENTER_CRITICAL();
\r
930 /* Ensure a yield is performed if the current task is being
\r
932 if( pxTaskToSuspend == pxCurrentTCB )
\r
934 pxTaskToSuspend = NULL;
\r
937 /* If null is passed in here then we are suspending ourselves. */
\r
938 pxTCB = prvGetTCBFromHandle( pxTaskToSuspend );
\r
940 /* Remove task from the ready/delayed list and place in the suspended list. */
\r
941 vListRemove( &( pxTCB->xGenericListItem ) );
\r
943 /* Is the task waiting on an event also? */
\r
944 if( pxTCB->xEventListItem.pvContainer )
\r
946 vListRemove( &( pxTCB->xEventListItem ) );
\r
949 vListInsertEnd( ( xList * ) &xSuspendedTaskList, &( pxTCB->xGenericListItem ) );
\r
951 taskEXIT_CRITICAL();
\r
953 /* We may have just suspended the current task. */
\r
954 if( ( void * ) pxTaskToSuspend == NULL )
\r
961 /*-----------------------------------------------------------*/
\r
963 #if ( INCLUDE_vTaskSuspend == 1 )
\r
965 static portBASE_TYPE prvIsTaskSuspended( const tskTCB * const pxTCB )
\r
967 portBASE_TYPE xReturn = pdFALSE;
\r
969 /* Is the task we are attempting to resume actually in the
\r
971 if( listIS_CONTAINED_WITHIN( &xSuspendedTaskList, &( pxTCB->xGenericListItem ) ) != pdFALSE )
\r
973 /* Has the task already been resumed from within an ISR? */
\r
974 if( listIS_CONTAINED_WITHIN( &xPendingReadyList, &( pxTCB->xEventListItem ) ) != pdTRUE )
\r
976 /* Is it in the suspended list because it is in the
\r
977 Suspended state? It is possible to be in the suspended
\r
978 list because it is blocked on a task with no timeout
\r
980 if( listIS_CONTAINED_WITHIN( NULL, &( pxTCB->xEventListItem ) ) == pdTRUE )
\r
991 /*-----------------------------------------------------------*/
\r
993 #if ( INCLUDE_vTaskSuspend == 1 )
\r
995 void vTaskResume( xTaskHandle pxTaskToResume )
\r
999 /* Remove the task from whichever list it is currently in, and place
\r
1000 it in the ready list. */
\r
1001 pxTCB = ( tskTCB * ) pxTaskToResume;
\r
1003 /* The parameter cannot be NULL as it is impossible to resume the
\r
1004 currently executing task. */
\r
1005 if( pxTCB != NULL )
\r
1007 taskENTER_CRITICAL();
\r
1009 if( prvIsTaskSuspended( pxTCB ) == pdTRUE )
\r
1011 /* As we are in a critical section we can access the ready
\r
1012 lists even if the scheduler is suspended. */
\r
1013 vListRemove( &( pxTCB->xGenericListItem ) );
\r
1014 prvAddTaskToReadyQueue( pxTCB );
\r
1016 /* We may have just resumed a higher priority task. */
\r
1017 if( pxTCB->uxPriority >= pxCurrentTCB->uxPriority )
\r
1019 /* This yield may not cause the task just resumed to run, but
\r
1020 will leave the lists in the correct state for the next yield. */
\r
1025 taskEXIT_CRITICAL();
\r
1031 /*-----------------------------------------------------------*/
\r
1033 #if ( ( INCLUDE_xTaskResumeFromISR == 1 ) && ( INCLUDE_vTaskSuspend == 1 ) )
\r
1035 portBASE_TYPE xTaskResumeFromISR( xTaskHandle pxTaskToResume )
\r
1037 portBASE_TYPE xYieldRequired = pdFALSE;
\r
1040 pxTCB = ( tskTCB * ) pxTaskToResume;
\r
1042 if( prvIsTaskSuspended( pxTCB ) == pdTRUE )
\r
1044 if( uxSchedulerSuspended == ( unsigned portBASE_TYPE ) pdFALSE )
\r
1046 xYieldRequired = ( pxTCB->uxPriority >= pxCurrentTCB->uxPriority );
\r
1047 vListRemove( &( pxTCB->xGenericListItem ) );
\r
1048 prvAddTaskToReadyQueue( pxTCB );
\r
1052 /* We cannot access the delayed or ready lists, so will hold this
\r
1053 task pending until the scheduler is resumed, at which point a
\r
1054 yield will be preformed if necessary. */
\r
1055 vListInsertEnd( ( xList * ) &( xPendingReadyList ), &( pxTCB->xEventListItem ) );
\r
1059 return xYieldRequired;
\r
1067 /*-----------------------------------------------------------
\r
1068 * PUBLIC SCHEDULER CONTROL documented in task.h
\r
1069 *----------------------------------------------------------*/
\r
1072 void vTaskStartScheduler( void )
\r
1074 portBASE_TYPE xReturn;
\r
1076 /* Add the idle task at the lowest priority. */
\r
1077 xReturn = xTaskCreate( prvIdleTask, ( signed portCHAR * ) "IDLE", tskIDLE_STACK_SIZE, ( void * ) NULL, tskIDLE_PRIORITY, ( xTaskHandle * ) NULL );
\r
1079 if( xReturn == pdPASS )
\r
1081 /* Interrupts are turned off here, to ensure a tick does not occur
\r
1082 before or during the call to xPortStartScheduler(). The stacks of
\r
1083 the created tasks contain a status word with interrupts switched on
\r
1084 so interrupts will automatically get re-enabled when the first task
\r
1087 STEPPING THROUGH HERE USING A DEBUGGER CAN CAUSE BIG PROBLEMS IF THE
\r
1088 DEBUGGER ALLOWS INTERRUPTS TO BE PROCESSED. */
\r
1089 portDISABLE_INTERRUPTS();
\r
1091 xSchedulerRunning = pdTRUE;
\r
1092 xTickCount = ( portTickType ) 0;
\r
1094 /* Setting up the timer tick is hardware specific and thus in the
\r
1095 portable interface. */
\r
1096 if( xPortStartScheduler() )
\r
1098 /* Should not reach here as if the scheduler is running the
\r
1099 function will not return. */
\r
1103 /* Should only reach here if a task calls xTaskEndScheduler(). */
\r
1107 /*-----------------------------------------------------------*/
\r
1109 void vTaskEndScheduler( void )
\r
1111 /* Stop the scheduler interrupts and call the portable scheduler end
\r
1112 routine so the original ISRs can be restored if necessary. The port
\r
1113 layer must ensure interrupts enable bit is left in the correct state. */
\r
1114 portDISABLE_INTERRUPTS();
\r
1115 xSchedulerRunning = pdFALSE;
\r
1116 vPortEndScheduler();
\r
1118 /*----------------------------------------------------------*/
\r
1120 void vTaskSuspendAll( void )
\r
1122 portENTER_CRITICAL();
\r
1123 ++uxSchedulerSuspended;
\r
1124 portEXIT_CRITICAL();
\r
1126 /*----------------------------------------------------------*/
\r
1128 signed portBASE_TYPE xTaskResumeAll( void )
\r
1130 register tskTCB *pxTCB;
\r
1131 signed portBASE_TYPE xAlreadyYielded = pdFALSE;
\r
1133 /* It is possible that an ISR caused a task to be removed from an event
\r
1134 list while the scheduler was suspended. If this was the case then the
\r
1135 removed task will have been added to the xPendingReadyList. Once the
\r
1136 scheduler has been resumed it is safe to move all the pending ready
\r
1137 tasks from this list into their appropriate ready list. */
\r
1138 portENTER_CRITICAL();
\r
1140 --uxSchedulerSuspended;
\r
1142 if( uxSchedulerSuspended == ( unsigned portBASE_TYPE ) pdFALSE )
\r
1144 if( uxCurrentNumberOfTasks > ( unsigned portBASE_TYPE ) 0 )
\r
1146 portBASE_TYPE xYieldRequired = pdFALSE;
\r
1148 /* Move any readied tasks from the pending list into the
\r
1149 appropriate ready list. */
\r
1150 while( ( pxTCB = ( tskTCB * ) listGET_OWNER_OF_HEAD_ENTRY( ( ( xList * ) &xPendingReadyList ) ) ) != NULL )
\r
1152 vListRemove( &( pxTCB->xEventListItem ) );
\r
1153 vListRemove( &( pxTCB->xGenericListItem ) );
\r
1154 prvAddTaskToReadyQueue( pxTCB );
\r
1156 /* If we have moved a task that has a priority higher than
\r
1157 the current task then we should yield. */
\r
1158 if( pxTCB->uxPriority >= pxCurrentTCB->uxPriority )
\r
1160 xYieldRequired = pdTRUE;
\r
1164 /* If any ticks occurred while the scheduler was suspended then
\r
1165 they should be processed now. This ensures the tick count does not
\r
1166 slip, and that any delayed tasks are resumed at the correct time. */
\r
1167 if( uxMissedTicks > ( unsigned portBASE_TYPE ) 0 )
\r
1169 while( uxMissedTicks > ( unsigned portBASE_TYPE ) 0 )
\r
1171 vTaskIncrementTick();
\r
1175 /* As we have processed some ticks it is appropriate to yield
\r
1176 to ensure the highest priority task that is ready to run is
\r
1177 the task actually running. */
\r
1178 xYieldRequired = pdTRUE;
\r
1181 if( ( xYieldRequired == pdTRUE ) || ( xMissedYield == pdTRUE ) )
\r
1183 xAlreadyYielded = pdTRUE;
\r
1184 xMissedYield = pdFALSE;
\r
1190 portEXIT_CRITICAL();
\r
1192 return xAlreadyYielded;
\r
1200 /*-----------------------------------------------------------
\r
1201 * PUBLIC TASK UTILITIES documented in task.h
\r
1202 *----------------------------------------------------------*/
\r
1206 portTickType xTaskGetTickCount( void )
\r
1208 portTickType xTicks;
\r
1210 /* Critical section required if running on a 16 bit processor. */
\r
1211 taskENTER_CRITICAL();
\r
1213 xTicks = xTickCount;
\r
1215 taskEXIT_CRITICAL();
\r
1219 /*-----------------------------------------------------------*/
\r
1221 unsigned portBASE_TYPE uxTaskGetNumberOfTasks( void )
\r
1223 unsigned portBASE_TYPE uxNumberOfTasks;
\r
1225 taskENTER_CRITICAL();
\r
1226 uxNumberOfTasks = uxCurrentNumberOfTasks;
\r
1227 taskEXIT_CRITICAL();
\r
1229 return uxNumberOfTasks;
\r
1231 /*-----------------------------------------------------------*/
\r
1233 #if ( ( configUSE_TRACE_FACILITY == 1 ) && ( INCLUDE_vTaskDelete == 1 ) && ( INCLUDE_vTaskSuspend == 1 ) )
\r
1235 void vTaskList( signed portCHAR *pcWriteBuffer )
\r
1237 unsigned portBASE_TYPE uxQueue;
\r
1239 /* This is a VERY costly function that should be used for debug only.
\r
1240 It leaves interrupts disabled for a LONG time. */
\r
1242 vTaskSuspendAll();
\r
1244 /* Run through all the lists that could potentially contain a TCB and
\r
1245 report the task name, state and stack high water mark. */
\r
1247 pcWriteBuffer[ 0 ] = ( signed portCHAR ) 0x00;
\r
1248 strcat( ( portCHAR * ) pcWriteBuffer, ( const portCHAR * ) "\r\n" );
\r
1250 uxQueue = uxTopUsedPriority + 1;
\r
1256 if( !listLIST_IS_EMPTY( &( pxReadyTasksLists[ uxQueue ] ) ) )
\r
1258 prvListTaskWithinSingleList( pcWriteBuffer, ( xList * ) &( pxReadyTasksLists[ uxQueue ] ), tskREADY_CHAR );
\r
1260 }while( uxQueue > ( unsigned portSHORT ) tskIDLE_PRIORITY );
\r
1262 if( !listLIST_IS_EMPTY( pxDelayedTaskList ) )
\r
1264 prvListTaskWithinSingleList( pcWriteBuffer, ( xList * ) pxDelayedTaskList, tskBLOCKED_CHAR );
\r
1267 if( !listLIST_IS_EMPTY( pxOverflowDelayedTaskList ) )
\r
1269 prvListTaskWithinSingleList( pcWriteBuffer, ( xList * ) pxOverflowDelayedTaskList, tskBLOCKED_CHAR );
\r
1272 if( !listLIST_IS_EMPTY( &xTasksWaitingTermination ) )
\r
1274 prvListTaskWithinSingleList( pcWriteBuffer, ( xList * ) &xTasksWaitingTermination, tskDELETED_CHAR );
\r
1277 if( !listLIST_IS_EMPTY( &xSuspendedTaskList ) )
\r
1279 prvListTaskWithinSingleList( pcWriteBuffer, ( xList * ) &xSuspendedTaskList, tskSUSPENDED_CHAR );
\r
1286 /*----------------------------------------------------------*/
\r
1288 #if ( configUSE_TRACE_FACILITY == 1 )
\r
1290 void vTaskStartTrace( signed portCHAR * pcBuffer, unsigned portLONG ulBufferSize )
\r
1292 portENTER_CRITICAL();
\r
1294 pcTraceBuffer = ( volatile signed portCHAR * volatile )pcBuffer;
\r
1295 pcTraceBufferStart = pcBuffer;
\r
1296 pcTraceBufferEnd = pcBuffer + ( ulBufferSize - tskSIZE_OF_EACH_TRACE_LINE );
\r
1297 xTracing = pdTRUE;
\r
1299 portEXIT_CRITICAL();
\r
1303 /*----------------------------------------------------------*/
\r
1305 #if ( configUSE_TRACE_FACILITY == 1 )
\r
1307 unsigned portLONG ulTaskEndTrace( void )
\r
1309 unsigned portLONG ulBufferLength;
\r
1311 portENTER_CRITICAL();
\r
1312 xTracing = pdFALSE;
\r
1313 portEXIT_CRITICAL();
\r
1315 ulBufferLength = ( unsigned portLONG ) ( pcTraceBuffer - pcTraceBufferStart );
\r
1317 return ulBufferLength;
\r
1324 /*-----------------------------------------------------------
\r
1325 * SCHEDULER INTERNALS AVAILABLE FOR PORTING PURPOSES
\r
1326 * documented in task.h
\r
1327 *----------------------------------------------------------*/
\r
1330 inline void vTaskIncrementTick( void )
\r
1332 /* Called by the portable layer each time a tick interrupt occurs.
\r
1333 Increments the tick then checks to see if the new tick value will cause any
\r
1334 tasks to be unblocked. */
\r
1335 if( uxSchedulerSuspended == ( unsigned portBASE_TYPE ) pdFALSE )
\r
1338 if( xTickCount == ( portTickType ) 0 )
\r
1342 /* Tick count has overflowed so we need to swap the delay lists.
\r
1343 If there are any items in pxDelayedTaskList here then there is
\r
1345 pxTemp = pxDelayedTaskList;
\r
1346 pxDelayedTaskList = pxOverflowDelayedTaskList;
\r
1347 pxOverflowDelayedTaskList = pxTemp;
\r
1348 xNumOfOverflows++;
\r
1351 /* See if this tick has made a timeout expire. */
\r
1352 prvCheckDelayedTasks();
\r
1358 /* The tick hook gets called at regular intervals, even if the
\r
1359 scheduler is locked. */
\r
1360 #if ( configUSE_TICK_HOOK == 1 )
\r
1362 extern void vApplicationTickHook( void );
\r
1364 vApplicationTickHook();
\r
1369 #if ( configUSE_TICK_HOOK == 1 )
\r
1371 extern void vApplicationTickHook( void );
\r
1373 /* Guard against the tick hook being called when the missed tick
\r
1374 count is being unwound (when the scheduler is being unlocked. */
\r
1375 if( uxMissedTicks == 0 )
\r
1377 vApplicationTickHook();
\r
1382 /*-----------------------------------------------------------*/
\r
1384 #if ( ( INCLUDE_vTaskCleanUpResources == 1 ) && ( INCLUDE_vTaskSuspend == 1 ) )
\r
1386 void vTaskCleanUpResources( void )
\r
1388 unsigned portSHORT usQueue;
\r
1389 volatile tskTCB *pxTCB;
\r
1391 usQueue = ( unsigned portSHORT ) uxTopUsedPriority + ( unsigned portSHORT ) 1;
\r
1393 /* Remove any TCB's from the ready queues. */
\r
1398 while( !listLIST_IS_EMPTY( &( pxReadyTasksLists[ usQueue ] ) ) )
\r
1400 listGET_OWNER_OF_NEXT_ENTRY( pxTCB, &( pxReadyTasksLists[ usQueue ] ) );
\r
1401 vListRemove( ( xListItem * ) &( pxTCB->xGenericListItem ) );
\r
1403 prvDeleteTCB( ( tskTCB * ) pxTCB );
\r
1405 }while( usQueue > ( unsigned portSHORT ) tskIDLE_PRIORITY );
\r
1407 /* Remove any TCB's from the delayed queue. */
\r
1408 while( !listLIST_IS_EMPTY( &xDelayedTaskList1 ) )
\r
1410 listGET_OWNER_OF_NEXT_ENTRY( pxTCB, &xDelayedTaskList1 );
\r
1411 vListRemove( ( xListItem * ) &( pxTCB->xGenericListItem ) );
\r
1413 prvDeleteTCB( ( tskTCB * ) pxTCB );
\r
1416 /* Remove any TCB's from the overflow delayed queue. */
\r
1417 while( !listLIST_IS_EMPTY( &xDelayedTaskList2 ) )
\r
1419 listGET_OWNER_OF_NEXT_ENTRY( pxTCB, &xDelayedTaskList2 );
\r
1420 vListRemove( ( xListItem * ) &( pxTCB->xGenericListItem ) );
\r
1422 prvDeleteTCB( ( tskTCB * ) pxTCB );
\r
1425 while( !listLIST_IS_EMPTY( &xSuspendedTaskList ) )
\r
1427 listGET_OWNER_OF_NEXT_ENTRY( pxTCB, &xSuspendedTaskList );
\r
1428 vListRemove( ( xListItem * ) &( pxTCB->xGenericListItem ) );
\r
1430 prvDeleteTCB( ( tskTCB * ) pxTCB );
\r
1435 /*-----------------------------------------------------------*/
\r
1437 void vTaskSwitchContext( void )
\r
1439 if( uxSchedulerSuspended != ( unsigned portBASE_TYPE ) pdFALSE )
\r
1441 /* The scheduler is currently suspended - do not allow a context
\r
1443 xMissedYield = pdTRUE;
\r
1447 /* Find the highest priority queue that contains ready tasks. */
\r
1448 while( listLIST_IS_EMPTY( &( pxReadyTasksLists[ uxTopReadyPriority ] ) ) )
\r
1450 --uxTopReadyPriority;
\r
1453 /* listGET_OWNER_OF_NEXT_ENTRY walks through the list, so the tasks of the
\r
1454 same priority get an equal share of the processor time. */
\r
1455 listGET_OWNER_OF_NEXT_ENTRY( pxCurrentTCB, &( pxReadyTasksLists[ uxTopReadyPriority ] ) );
\r
1456 vWriteTraceToBuffer();
\r
1458 /*-----------------------------------------------------------*/
\r
1460 void vTaskPlaceOnEventList( xList *pxEventList, portTickType xTicksToWait )
\r
1462 portTickType xTimeToWake;
\r
1464 /* THIS FUNCTION MUST BE CALLED WITH INTERRUPTS DISABLED OR THE
\r
1465 SCHEDULER SUSPENDED. */
\r
1467 /* Place the event list item of the TCB in the appropriate event list.
\r
1468 This is placed in the list in priority order so the highest priority task
\r
1469 is the first to be woken by the event. */
\r
1470 vListInsert( ( xList * ) pxEventList, ( xListItem * ) &( pxCurrentTCB->xEventListItem ) );
\r
1472 /* We must remove ourselves from the ready list before adding ourselves
\r
1473 to the blocked list as the same list item is used for both lists. We have
\r
1474 exclusive access to the ready lists as the scheduler is locked. */
\r
1475 vListRemove( ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
\r
1478 #if ( INCLUDE_vTaskSuspend == 1 )
\r
1480 if( xTicksToWait == portMAX_DELAY )
\r
1482 /* Add ourselves to the suspended task list instead of a delayed task
\r
1483 list to ensure we are not woken by a timing event. We will block
\r
1485 vListInsertEnd( ( xList * ) &xSuspendedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
\r
1489 /* Calculate the time at which the task should be woken if the event does
\r
1490 not occur. This may overflow but this doesn't matter. */
\r
1491 xTimeToWake = xTickCount + xTicksToWait;
\r
1493 listSET_LIST_ITEM_VALUE( &( pxCurrentTCB->xGenericListItem ), xTimeToWake );
\r
1495 if( xTimeToWake < xTickCount )
\r
1497 /* Wake time has overflowed. Place this item in the overflow list. */
\r
1498 vListInsert( ( xList * ) pxOverflowDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
\r
1502 /* The wake time has not overflowed, so we can use the current block list. */
\r
1503 vListInsert( ( xList * ) pxDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
\r
1509 /* Calculate the time at which the task should be woken if the event does
\r
1510 not occur. This may overflow but this doesn't matter. */
\r
1511 xTimeToWake = xTickCount + xTicksToWait;
\r
1513 listSET_LIST_ITEM_VALUE( &( pxCurrentTCB->xGenericListItem ), xTimeToWake );
\r
1515 if( xTimeToWake < xTickCount )
\r
1517 /* Wake time has overflowed. Place this item in the overflow list. */
\r
1518 vListInsert( ( xList * ) pxOverflowDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
\r
1522 /* The wake time has not overflowed, so we can use the current block list. */
\r
1523 vListInsert( ( xList * ) pxDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
\r
1528 /*-----------------------------------------------------------*/
\r
1530 signed portBASE_TYPE xTaskRemoveFromEventList( const xList *pxEventList )
\r
1532 tskTCB *pxUnblockedTCB;
\r
1533 portBASE_TYPE xReturn;
\r
1535 /* THIS FUNCTION MUST BE CALLED WITH INTERRUPTS DISABLED OR THE
\r
1536 SCHEDULER SUSPENDED. It can also be called from within an ISR. */
\r
1538 /* The event list is sorted in priority order, so we can remove the
\r
1539 first in the list, remove the TCB from the delayed list, and add
\r
1540 it to the ready list.
\r
1542 If an event is for a queue that is locked then this function will never
\r
1543 get called - the lock count on the queue will get modified instead. This
\r
1544 means we can always expect exclusive access to the event list here. */
\r
1545 pxUnblockedTCB = ( tskTCB * ) listGET_OWNER_OF_HEAD_ENTRY( pxEventList );
\r
1546 vListRemove( &( pxUnblockedTCB->xEventListItem ) );
\r
1548 if( uxSchedulerSuspended == ( unsigned portBASE_TYPE ) pdFALSE )
\r
1550 vListRemove( &( pxUnblockedTCB->xGenericListItem ) );
\r
1551 prvAddTaskToReadyQueue( pxUnblockedTCB );
\r
1555 /* We cannot access the delayed or ready lists, so will hold this
\r
1556 task pending until the scheduler is resumed. */
\r
1557 vListInsertEnd( ( xList * ) &( xPendingReadyList ), &( pxUnblockedTCB->xEventListItem ) );
\r
1560 if( pxUnblockedTCB->uxPriority >= pxCurrentTCB->uxPriority )
\r
1562 /* Return true if the task removed from the event list has
\r
1563 a higher priority than the calling task. This allows
\r
1564 the calling task to know if it should force a context
\r
1570 xReturn = pdFALSE;
\r
1575 /*-----------------------------------------------------------*/
\r
1577 void vTaskSetTimeOutState( xTimeOutType *pxTimeOut )
\r
1579 pxTimeOut->xOverflowCount = xNumOfOverflows;
\r
1580 pxTimeOut->xTimeOnEntering = xTickCount;
\r
1582 /*-----------------------------------------------------------*/
\r
1584 portBASE_TYPE xTaskCheckForTimeOut( xTimeOutType *pxTimeOut, portTickType * const pxTicksToWait )
\r
1586 portBASE_TYPE xReturn;
\r
1588 #if ( INCLUDE_vTaskSuspend == 1 )
\r
1589 /* If INCLUDE_vTaskSuspend is set to 1 and the block time specified is
\r
1590 the maximum block time then the task should block indefinitely, and
\r
1591 therefore never time out. */
\r
1592 if( *pxTicksToWait == portMAX_DELAY )
\r
1594 xReturn = pdFALSE;
\r
1596 else /* We are not blocking indefinitely, perform the checks below. */
\r
1599 if( ( xNumOfOverflows != pxTimeOut->xOverflowCount ) && ( xTickCount >= pxTimeOut->xTimeOnEntering ) )
\r
1601 /* The tick count is greater than the time at which vTaskSetTimeout()
\r
1602 was called, but has also overflowed since vTaskSetTimeOut() was called.
\r
1603 It must have wrapped all the way around and gone past us again. This
\r
1604 passed since vTaskSetTimeout() was called. */
\r
1607 else if( ( xTickCount - pxTimeOut->xTimeOnEntering ) < *pxTicksToWait )
\r
1609 /* Not a genuine timeout. Adjust parameters for time remaining. */
\r
1610 *pxTicksToWait -= ( xTickCount - pxTimeOut->xTimeOnEntering );
\r
1611 vTaskSetTimeOutState( pxTimeOut );
\r
1612 xReturn = pdFALSE;
\r
1621 /*-----------------------------------------------------------*/
\r
1623 void vTaskMissedYield( void )
\r
1625 xMissedYield = pdTRUE;
\r
1629 * -----------------------------------------------------------
\r
1631 * ----------------------------------------------------------
\r
1633 * The portTASK_FUNCTION() macro is used to allow port/compiler specific
\r
1634 * language extensions. The equivalent prototype for this function is:
\r
1636 * void prvIdleTask( void *pvParameters );
\r
1639 static portTASK_FUNCTION( prvIdleTask, pvParameters )
\r
1641 /* Stop warnings. */
\r
1642 ( void ) pvParameters;
\r
1646 /* See if any tasks have been deleted. */
\r
1647 prvCheckTasksWaitingTermination();
\r
1649 #if ( configUSE_PREEMPTION == 0 )
\r
1651 /* If we are not using preemption we keep forcing a task switch to
\r
1652 see if any other task has become available. If we are using
\r
1653 preemption we don't need to do this as any task becoming available
\r
1654 will automatically get the processor anyway. */
\r
1659 #if ( ( configUSE_PREEMPTION == 1 ) && ( configIDLE_SHOULD_YIELD == 1 ) )
\r
1661 /* When using preemption tasks of equal priority will be
\r
1662 timesliced. If a task that is sharing the idle priority is ready
\r
1663 to run then the idle task should yield before the end of the
\r
1666 A critical region is not required here as we are just reading from
\r
1667 the list, and an occasional incorrect value will not matter. If
\r
1668 the ready list at the idle priority contains more than one task
\r
1669 then a task other than the idle task is ready to execute. */
\r
1670 if( listCURRENT_LIST_LENGTH( &( pxReadyTasksLists[ tskIDLE_PRIORITY ] ) ) > ( unsigned portBASE_TYPE ) 1 )
\r
1677 #if ( configUSE_IDLE_HOOK == 1 )
\r
1679 extern void vApplicationIdleHook( void );
\r
1681 /* Call the user defined function from within the idle task. This
\r
1682 allows the application designer to add background functionality
\r
1683 without the overhead of a separate task.
\r
1684 NOTE: vApplicationIdleHook() MUST NOT, UNDER ANY CIRCUMSTANCES,
\r
1685 CALL A FUNCTION THAT MIGHT BLOCK. */
\r
1686 vApplicationIdleHook();
\r
1690 } /*lint !e715 pvParameters is not accessed but all task functions require the same prototype. */
\r
1698 /*-----------------------------------------------------------
\r
1699 * File private functions documented at the top of the file.
\r
1700 *----------------------------------------------------------*/
\r
1704 static void prvInitialiseTCBVariables( tskTCB *pxTCB, unsigned portSHORT usStackDepth, const signed portCHAR * const pcName, unsigned portBASE_TYPE uxPriority )
\r
1706 pxTCB->usStackDepth = usStackDepth;
\r
1708 /* Store the function name in the TCB. */
\r
1709 strncpy( ( char * ) pxTCB->pcTaskName, ( const char * ) pcName, ( unsigned portSHORT ) configMAX_TASK_NAME_LEN );
\r
1710 pxTCB->pcTaskName[ ( unsigned portSHORT ) configMAX_TASK_NAME_LEN - ( unsigned portSHORT ) 1 ] = '\0';
\r
1712 /* This is used as an array index so must ensure it's not too large. */
\r
1713 if( uxPriority >= configMAX_PRIORITIES )
\r
1715 uxPriority = configMAX_PRIORITIES - 1;
\r
1718 pxTCB->uxPriority = uxPriority;
\r
1720 vListInitialiseItem( &( pxTCB->xGenericListItem ) );
\r
1721 vListInitialiseItem( &( pxTCB->xEventListItem ) );
\r
1723 /* Set the pxTCB as a link back from the xListItem. This is so we can get
\r
1724 back to the containing TCB from a generic item in a list. */
\r
1725 listSET_LIST_ITEM_OWNER( &( pxTCB->xGenericListItem ), pxTCB );
\r
1727 /* Event lists are always in priority order. */
\r
1728 listSET_LIST_ITEM_VALUE( &( pxTCB->xEventListItem ), configMAX_PRIORITIES - ( portTickType ) uxPriority );
\r
1729 listSET_LIST_ITEM_OWNER( &( pxTCB->xEventListItem ), pxTCB );
\r
1731 /*-----------------------------------------------------------*/
\r
1733 static void prvInitialiseTaskLists( void )
\r
1735 unsigned portBASE_TYPE uxPriority;
\r
1737 for( uxPriority = 0; uxPriority < configMAX_PRIORITIES; uxPriority++ )
\r
1739 vListInitialise( ( xList * ) &( pxReadyTasksLists[ uxPriority ] ) );
\r
1742 vListInitialise( ( xList * ) &xDelayedTaskList1 );
\r
1743 vListInitialise( ( xList * ) &xDelayedTaskList2 );
\r
1744 vListInitialise( ( xList * ) &xPendingReadyList );
\r
1746 #if ( INCLUDE_vTaskDelete == 1 )
\r
1748 vListInitialise( ( xList * ) &xTasksWaitingTermination );
\r
1752 #if ( INCLUDE_vTaskSuspend == 1 )
\r
1754 vListInitialise( ( xList * ) &xSuspendedTaskList );
\r
1758 /* Start with pxDelayedTaskList using list1 and the pxOverflowDelayedTaskList
\r
1760 pxDelayedTaskList = &xDelayedTaskList1;
\r
1761 pxOverflowDelayedTaskList = &xDelayedTaskList2;
\r
1763 /*-----------------------------------------------------------*/
\r
1765 static void prvCheckTasksWaitingTermination( void )
\r
1767 #if ( INCLUDE_vTaskDelete == 1 )
\r
1769 portBASE_TYPE xListIsEmpty;
\r
1771 /* ucTasksDeleted is used to prevent vTaskSuspendAll() being called
\r
1772 too often in the idle task. */
\r
1773 if( uxTasksDeleted > ( unsigned portBASE_TYPE ) 0 )
\r
1775 vTaskSuspendAll();
\r
1776 xListIsEmpty = listLIST_IS_EMPTY( &xTasksWaitingTermination );
\r
1779 if( !xListIsEmpty )
\r
1783 portENTER_CRITICAL();
\r
1785 pxTCB = ( tskTCB * ) listGET_OWNER_OF_HEAD_ENTRY( ( ( xList * ) &xTasksWaitingTermination ) );
\r
1786 vListRemove( &( pxTCB->xGenericListItem ) );
\r
1787 --uxCurrentNumberOfTasks;
\r
1790 portEXIT_CRITICAL();
\r
1792 prvDeleteTCB( pxTCB );
\r
1798 /*-----------------------------------------------------------*/
\r
1800 static tskTCB *prvAllocateTCBAndStack( unsigned portSHORT usStackDepth )
\r
1804 /* Allocate space for the TCB. Where the memory comes from depends on
\r
1805 the implementation of the port malloc function. */
\r
1806 pxNewTCB = ( tskTCB * ) pvPortMalloc( sizeof( tskTCB ) );
\r
1808 if( pxNewTCB != NULL )
\r
1810 /* Allocate space for the stack used by the task being created.
\r
1811 The base of the stack memory stored in the TCB so the task can
\r
1812 be deleted later if required. */
\r
1813 pxNewTCB->pxStack = ( portSTACK_TYPE * ) pvPortMalloc( ( ( size_t )usStackDepth ) * sizeof( portSTACK_TYPE ) );
\r
1815 if( pxNewTCB->pxStack == NULL )
\r
1817 /* Could not allocate the stack. Delete the allocated TCB. */
\r
1818 vPortFree( pxNewTCB );
\r
1823 /* Just to help debugging. */
\r
1824 memset( pxNewTCB->pxStack, tskSTACK_FILL_BYTE, usStackDepth * sizeof( portSTACK_TYPE ) );
\r
1830 /*-----------------------------------------------------------*/
\r
1832 #if ( configUSE_TRACE_FACILITY == 1 )
\r
1834 static void prvListTaskWithinSingleList( signed portCHAR *pcWriteBuffer, xList *pxList, signed portCHAR cStatus )
\r
1836 volatile tskTCB *pxNextTCB, *pxFirstTCB;
\r
1837 static portCHAR pcStatusString[ 50 ];
\r
1838 unsigned portSHORT usStackRemaining;
\r
1840 /* Write the details of all the TCB's in pxList into the buffer. */
\r
1841 listGET_OWNER_OF_NEXT_ENTRY( pxFirstTCB, pxList );
\r
1844 listGET_OWNER_OF_NEXT_ENTRY( pxNextTCB, pxList );
\r
1845 usStackRemaining = usTaskCheckFreeStackSpace( ( unsigned portCHAR * ) pxNextTCB->pxStack );
\r
1846 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
1847 strcat( ( portCHAR * ) pcWriteBuffer, ( portCHAR * ) pcStatusString );
\r
1849 } while( pxNextTCB != pxFirstTCB );
\r
1853 /*-----------------------------------------------------------*/
\r
1855 #if ( configUSE_TRACE_FACILITY == 1 )
\r
1856 unsigned portSHORT usTaskCheckFreeStackSpace( const unsigned portCHAR *pucStackByte )
\r
1858 register unsigned portSHORT usCount = 0;
\r
1860 while( *pucStackByte == tskSTACK_FILL_BYTE )
\r
1862 pucStackByte -= portSTACK_GROWTH;
\r
1866 usCount /= sizeof( portSTACK_TYPE );
\r
1871 /*-----------------------------------------------------------*/
\r
1875 #if ( ( INCLUDE_vTaskDelete == 1 ) || ( INCLUDE_vTaskCleanUpResources == 1 ) )
\r
1877 static void prvDeleteTCB( tskTCB *pxTCB )
\r
1879 /* Free up the memory allocated by the scheduler for the task. It is up to
\r
1880 the task to free any memory allocated at the application level. */
\r
1881 vPortFree( pxTCB->pxStack );
\r
1882 vPortFree( pxTCB );
\r
1888 /*-----------------------------------------------------------*/
\r
1890 #if ( INCLUDE_xTaskGetCurrentTaskHandle == 1 )
\r
1892 xTaskHandle xTaskGetCurrentTaskHandle( void )
\r
1894 xTaskHandle xReturn;
\r
1896 portENTER_CRITICAL();
\r
1898 xReturn = ( xTaskHandle ) pxCurrentTCB;
\r
1900 portEXIT_CRITICAL();
\r
1907 /*-----------------------------------------------------------*/
\r
1909 #if ( INCLUDE_xTaskGetSchedulerState == 1 )
\r
1911 portBASE_TYPE xTaskGetSchedulerState( void )
\r
1913 portBASE_TYPE xReturn;
\r
1915 if( xSchedulerRunning == pdFALSE )
\r
1917 xReturn = taskSCHEDULER_NOT_STARTED;
\r
1921 if( uxSchedulerSuspended == ( unsigned portBASE_TYPE ) pdFALSE )
\r
1923 xReturn = taskSCHEDULER_RUNNING;
\r
1927 xReturn = taskSCHEDULER_SUSPENDED;
\r