2 FreeRTOS.org V4.1.3 - Copyright (C) 2003-2006 Richard Barry.
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4 This file is part of the FreeRTOS.org distribution.
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6 FreeRTOS.org is free software; you can redistribute it and/or modify
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7 it under the terms of the GNU General Public License as published by
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8 the Free Software Foundation; either version 2 of the License, or
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9 (at your option) any later version.
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11 FreeRTOS.org is distributed in the hope that it will be useful,
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12 but WITHOUT ANY WARRANTY; without even the implied warranty of
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13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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14 GNU General Public License for more details.
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16 You should have received a copy of the GNU General Public License
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17 along with FreeRTOS.org; if not, write to the Free Software
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18 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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20 A special exception to the GPL can be applied should you wish to distribute
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21 a combined work that includes FreeRTOS.org, without being obliged to provide
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22 the source code for any proprietary components. See the licensing section
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23 of http://www.FreeRTOS.org for full details of how and when the exception
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26 ***************************************************************************
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27 See http://www.FreeRTOS.org for documentation, latest information, license
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28 and contact details. Please ensure to read the configuration and relevant
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29 port sections of the online documentation.
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30 ***************************************************************************
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36 + Call to portRESTORE_CONTEXT has been removed. The first context
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37 switch is now performed within sPortStartScheduler().
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41 + More use of 8bit data types.
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42 + Function name prefixes changed where the data type returned has changed.
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43 + configUSE_TRACE_FACILITY is no longer defined by default.
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47 + Introduced ucTopReadyPriority. This tracks the highest priority ready
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48 queue that contains a valid TCB and thus makes the context switch
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51 + prvAddTaskToReadyQueue() has been made a macro.
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55 + Added conditional compilation directives.
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57 + Rearranged function order.
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58 + Creating a task now causes a context switch if the task being created
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59 has a higher priority than the calling task - assuming the kernel is
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61 + vTaskDelete() now only causes a context switch if the calling task is
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62 the task being deleted.
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66 + Allow the type of the tick count to be 16 or 32 bits.
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67 + Introduce xPendingReadyList feature to allow the time interrupts have to
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68 be disabled to be minimised.
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69 + Remove the #if( INCLUDE_vTaskSuspendAll ) statements. vTaskSuspendAll()
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70 is now always included as it is used by the scheduler itself.
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74 + Bug fix - pxCurrentTCB is now initialised before the call to
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75 prvInitializeTaskLists(). Previously pxCurrentTCB could be accessed
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80 + Change to where lStackSize is declared within sTaskCreate() to prevent
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81 compiler warnings with 8051 port.
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85 + Explicit use of 'signed' qualifier on portCHAR types added.
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86 + Changed odd calculation of initial pxTopOfStack value when
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87 portSTACK_GROWTH < 0.
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88 + Removed pcVersionNumber definition.
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92 + cTaskResumeAll() modified to ensure it can be called prior to the task
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93 lists being initialised.
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97 + Added API function vTaskDelayUntil().
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98 + Added INCLUDE_vTaskDelay conditional compilation.
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100 Changes from V2.6.0
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102 + Updated the vWriteTraceToBuffer macro to always be 4 byte aligned so it
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103 can be used on ARM architectures.
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104 + tskMAX_TASK_NAME_LEN definition replaced with the port specific
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105 configMAX_TASK_NAME_LEN definition.
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106 + Removed the call to strcpy when copying across the task name into the
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108 + Added ucTasksDeleted variable to prevent vTaskSuspendAll() being called
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109 too often in the idle task.
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111 Changes between V3.0.0 and V2.6.1
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113 + When resuming the scheduler a yield is performed if either a tick has
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114 been missed, or a task is moved from the pending ready list into a ready
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115 list. Previously a yield was not performed on this second condition.
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116 + Introduced the type portBASE_TYPE. This necessitates several API
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118 + Removed the sUsingPreemption variable. The constant defined in
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119 portmacro.h is now used directly.
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120 + The idle task can now include an optional hook function - and no longer
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121 completes its time slice if other tasks with equal priority to it are
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123 + See the FreeRTOS.org documentation for more information on V2.x.x to
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124 V3.x.x modifications.
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126 Changes from V3.1.1
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128 + Modified vTaskPrioritySet() and vTaskResume() to allow these functions to
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129 be called while the scheduler is suspended.
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130 + Corrected the task ordering within event lists.
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132 Changes from V3.2.0
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134 + Added function xTaskGetCurrentTaskHandle().
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136 Changes from V3.2.4
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138 + Changed the volatile declarations on some variables to reflect the
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139 changes to the list definitions.
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140 + Changed the order of the TCB definition so there is commonality between
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141 the task control block and a co-routine control block.
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142 + Allow the scheduler to be started even if no tasks other than the idle
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143 task has been created. This allows co-routines to run even when no tasks
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145 + The need for a context switch is now signalled if a task woken by an
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146 event has a priority greater or equal to the currently running task.
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147 Previously this was only greater than.
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149 Changes from V4.0.0
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151 + Added the xMissedYield handling.
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153 Changes from V4.0.1
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155 + The function vTaskList() now suspends the scheduler rather than disabling
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156 interrupts during the creation of the task list.
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157 + Allow a task to delete itself by passing in its own handle. Previously
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158 this could only be done by passing in NULL.
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159 + The tick hook function is now called only within a tick isr. Previously
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160 it was also called when the tick function was called during the scheduler
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163 Changes from V4.0.3
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165 + Extra checks have been placed in vTaskPrioritySet() to avoid unnecessary
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168 Changed from V4.0.4
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170 + Bug fix: The 'value' of the event list item is updated when the priority
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171 of a task is changed. Previously only the priority of the TCB itself was
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173 + When resuming a task a check is first made to see if the task is actually
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175 + vTaskPrioritySet() and vTaskResume() no longer use the event list item.
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176 This has not been necessary since V4.0.1 when the xMissedYield handling
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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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193 #include <stdlib.h>
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194 #include <string.h>
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196 #include "FreeRTOS.h"
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200 * Macro to define the amount of stack available to the idle task.
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202 #define tskIDLE_STACK_SIZE configMINIMAL_STACK_SIZE
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206 * Default a definitions for backwards compatibility with old
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207 * portmacro.h files.
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209 #ifndef configMAX_TASK_NAME_LEN
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210 #define configMAX_TASK_NAME_LEN 16
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213 #ifndef INCLUDE_xTaskGetCurrentTaskHandle
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214 #define INCLUDE_xTaskGetCurrentTaskHandle 0
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217 #ifndef configIDLE_SHOULD_YIELD
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218 #define configIDLE_SHOULD_YIELD 1
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221 #if configMAX_TASK_NAME_LEN < 1
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222 #undef configMAX_TASK_NAME_LEN
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223 #define configMAX_TASK_NAME_LEN 1
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226 #ifndef INCLUDE_xTaskResumeFromISR
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227 #define INCLUDE_xTaskResumeFromISR 1
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231 * Task control block. A task control block (TCB) is allocated to each task,
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232 * and stores the context of the task.
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234 typedef struct tskTaskControlBlock
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236 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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237 xListItem xGenericListItem; /*< List item used to place the TCB in ready and blocked queues. */
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238 xListItem xEventListItem; /*< List item used to place the TCB in event lists. */
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239 unsigned portBASE_TYPE uxPriority; /*< The priority of the task where 0 is the lowest priority. */
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240 portSTACK_TYPE *pxStack; /*< Points to the start of the stack. */
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241 unsigned portBASE_TYPE uxTCBNumber; /*< This is used for tracing the scheduler and making debugging easier only. */
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242 signed portCHAR pcTaskName[ configMAX_TASK_NAME_LEN ];/*< Descriptive name given to the task when created. Facilitates debugging only. */
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243 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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248 tskTCB * volatile pxCurrentTCB = NULL;
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250 /* Lists for ready and blocked tasks. --------------------*/
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252 static xList pxReadyTasksLists[ configMAX_PRIORITIES ]; /*< Prioritised ready tasks. */
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253 static xList xDelayedTaskList1; /*< Delayed tasks. */
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254 static xList xDelayedTaskList2; /*< Delayed tasks (two lists are used - one for delays that have overflowed the current tick count. */
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255 static xList * volatile pxDelayedTaskList; /*< Points to the delayed task list currently being used. */
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256 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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257 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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259 #if ( INCLUDE_vTaskDelete == 1 )
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261 static volatile xList xTasksWaitingTermination; /*< Tasks that have been deleted - but the their memory not yet freed. */
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262 static volatile unsigned portBASE_TYPE uxTasksDeleted = ( unsigned portBASE_TYPE ) 0;
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266 #if ( INCLUDE_vTaskSuspend == 1 )
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268 static xList xSuspendedTaskList; /*< Tasks that are currently suspended. */
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272 /* File private variables. --------------------------------*/
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273 static volatile unsigned portBASE_TYPE uxCurrentNumberOfTasks = ( unsigned portBASE_TYPE ) 0;
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274 static volatile portTickType xTickCount = ( portTickType ) 0;
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275 static unsigned portBASE_TYPE uxTopUsedPriority = tskIDLE_PRIORITY;
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276 static volatile unsigned portBASE_TYPE uxTopReadyPriority = tskIDLE_PRIORITY;
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277 static volatile signed portBASE_TYPE xSchedulerRunning = pdFALSE;
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278 static volatile unsigned portBASE_TYPE uxSchedulerSuspended = ( unsigned portBASE_TYPE ) pdFALSE;
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279 static volatile unsigned portBASE_TYPE uxMissedTicks = ( unsigned portBASE_TYPE ) 0;
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280 static volatile portBASE_TYPE xMissedYield = ( portBASE_TYPE ) pdFALSE;
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281 static volatile portBASE_TYPE xNumOfOverflows = ( portBASE_TYPE ) 0;
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282 /* Debugging and trace facilities private variables and macros. ------------*/
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285 * The value used to fill the stack of a task when the task is created. This
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286 * is used purely for checking the high water mark for tasks.
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288 #define tskSTACK_FILL_BYTE ( 0xa5 )
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291 * Macros used by vListTask to indicate which state a task is in.
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293 #define tskBLOCKED_CHAR ( ( signed portCHAR ) 'B' )
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294 #define tskREADY_CHAR ( ( signed portCHAR ) 'R' )
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295 #define tskDELETED_CHAR ( ( signed portCHAR ) 'D' )
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296 #define tskSUSPENDED_CHAR ( ( signed portCHAR ) 'S' )
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299 * Macros and private variables used by the trace facility.
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301 #if ( configUSE_TRACE_FACILITY == 1 )
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303 #define tskSIZE_OF_EACH_TRACE_LINE ( ( unsigned portLONG ) ( sizeof( unsigned portLONG ) + sizeof( unsigned portLONG ) ) )
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304 static volatile signed portCHAR * volatile pcTraceBuffer;
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305 static signed portCHAR *pcTraceBufferStart;
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306 static signed portCHAR *pcTraceBufferEnd;
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307 static signed portBASE_TYPE xTracing = pdFALSE;
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312 * Macro that writes a trace of scheduler activity to a buffer. This trace
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313 * shows which task is running when and is very useful as a debugging tool.
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314 * As this macro is called each context switch it is a good idea to undefine
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315 * it if not using the facility.
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317 #if ( configUSE_TRACE_FACILITY == 1 )
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319 #define vWriteTraceToBuffer() \
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323 static unsigned portBASE_TYPE uxPreviousTask = 255; \
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325 if( uxPreviousTask != pxCurrentTCB->uxTCBNumber ) \
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327 if( ( pcTraceBuffer + tskSIZE_OF_EACH_TRACE_LINE ) < pcTraceBufferEnd ) \
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329 uxPreviousTask = pxCurrentTCB->uxTCBNumber; \
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330 *( unsigned portLONG * ) pcTraceBuffer = ( unsigned portLONG ) xTickCount; \
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331 pcTraceBuffer += sizeof( unsigned portLONG ); \
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332 *( unsigned portLONG * ) pcTraceBuffer = ( unsigned portLONG ) uxPreviousTask; \
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333 pcTraceBuffer += sizeof( unsigned portLONG ); \
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337 xTracing = pdFALSE; \
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345 #define vWriteTraceToBuffer()
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351 * Place the task represented by pxTCB into the appropriate ready queue for
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352 * the task. It is inserted at the end of the list. One quirk of this is
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353 * that if the task being inserted is at the same priority as the currently
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354 * executing task, then it will only be rescheduled after the currently
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355 * executing task has been rescheduled.
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357 #define prvAddTaskToReadyQueue( pxTCB ) \
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359 if( pxTCB->uxPriority > uxTopReadyPriority ) \
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361 uxTopReadyPriority = pxTCB->uxPriority; \
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363 vListInsertEnd( ( xList * ) &( pxReadyTasksLists[ pxTCB->uxPriority ] ), &( pxTCB->xGenericListItem ) ); \
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367 * Macro that looks at the list of tasks that are currently delayed to see if
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368 * any require waking.
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370 * Tasks are stored in the queue in the order of their wake time - meaning
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371 * once one tasks has been found whose timer has not expired we need not look
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372 * any further down the list.
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374 #define prvCheckDelayedTasks() \
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376 register tskTCB *pxTCB; \
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378 while( ( pxTCB = ( tskTCB * ) listGET_OWNER_OF_HEAD_ENTRY( pxDelayedTaskList ) ) != NULL ) \
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380 if( xTickCount < listGET_LIST_ITEM_VALUE( &( pxTCB->xGenericListItem ) ) ) \
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384 vListRemove( &( pxTCB->xGenericListItem ) ); \
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385 /* Is the task waiting on an event also? */ \
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386 if( pxTCB->xEventListItem.pvContainer ) \
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388 vListRemove( &( pxTCB->xEventListItem ) ); \
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390 prvAddTaskToReadyQueue( pxTCB ); \
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395 * Several functions take an xTaskHandle parameter that can optionally be NULL,
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396 * where NULL is used to indicate that the handle of the currently executing
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397 * task should be used in place of the parameter. This macro simply checks to
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398 * see if the parameter is NULL and returns a pointer to the appropriate TCB.
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400 #define prvGetTCBFromHandle( pxHandle ) ( ( pxHandle == NULL ) ? ( tskTCB * ) pxCurrentTCB : ( tskTCB * ) pxHandle )
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403 /* File private functions. --------------------------------*/
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406 * Utility to ready a TCB for a given task. Mainly just copies the parameters
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407 * into the TCB structure.
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409 static void prvInitialiseTCBVariables( tskTCB *pxTCB, unsigned portSHORT usStackDepth, const signed portCHAR * const pcName, unsigned portBASE_TYPE uxPriority );
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412 * Utility to ready all the lists used by the scheduler. This is called
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413 * automatically upon the creation of the first task.
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415 static void prvInitialiseTaskLists( void );
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418 * The idle task, which as all tasks is implemented as a never ending loop.
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419 * The idle task is automatically created and added to the ready lists upon
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420 * creation of the first user task.
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422 * The portTASK_FUNCTION_PROTO() macro is used to allow port/compiler specific
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423 * language extensions. The equivalent prototype for this function is:
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425 * void prvIdleTask( void *pvParameters );
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428 static portTASK_FUNCTION_PROTO( prvIdleTask, pvParameters );
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431 * Utility to free all memory allocated by the scheduler to hold a TCB,
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432 * including the stack pointed to by the TCB.
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434 * This does not free memory allocated by the task itself (i.e. memory
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435 * allocated by calls to pvPortMalloc from within the tasks application code).
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437 #if ( ( INCLUDE_vTaskDelete == 1 ) || ( INCLUDE_vTaskCleanUpResources == 1 ) )
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438 static void prvDeleteTCB( tskTCB *pxTCB );
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442 * Used only by the idle task. This checks to see if anything has been placed
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443 * in the list of tasks waiting to be deleted. If so the task is cleaned up
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444 * and its TCB deleted.
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446 static void prvCheckTasksWaitingTermination( void );
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449 * Allocates memory from the heap for a TCB and associated stack. Checks the
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450 * allocation was successful.
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452 static tskTCB *prvAllocateTCBAndStack( unsigned portSHORT usStackDepth );
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455 * Called from vTaskList. vListTasks details all the tasks currently under
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456 * control of the scheduler. The tasks may be in one of a number of lists.
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457 * prvListTaskWithinSingleList accepts a list and details the tasks from
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458 * within just that list.
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460 * THIS FUNCTION IS INTENDED FOR DEBUGGING ONLY, AND SHOULD NOT BE CALLED FROM
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461 * NORMAL APPLICATION CODE.
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463 #if ( configUSE_TRACE_FACILITY == 1 )
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465 static void prvListTaskWithinSingleList( signed portCHAR *pcWriteBuffer, xList *pxList, signed portCHAR cStatus );
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470 * When a task is created, the stack of the task is filled with a known value.
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471 * This function determines the 'high water mark' of the task stack by
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472 * determining how much of the stack remains at the original preset value.
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474 #if ( configUSE_TRACE_FACILITY == 1 )
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476 unsigned portSHORT usTaskCheckFreeStackSpace( const unsigned portCHAR *pucStackByte );
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486 /*-----------------------------------------------------------
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487 * TASK CREATION API documented in task.h
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488 *----------------------------------------------------------*/
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490 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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492 signed portBASE_TYPE xReturn;
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494 static unsigned portBASE_TYPE uxTaskNumber = 0; /*lint !e956 Static is deliberate - this is guarded before use. */
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496 /* Allocate the memory required by the TCB and stack for the new task.
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497 checking that the allocation was successful. */
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498 pxNewTCB = prvAllocateTCBAndStack( usStackDepth );
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500 if( pxNewTCB != NULL )
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502 portSTACK_TYPE *pxTopOfStack;
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504 /* Setup the newly allocated TCB with the initial state of the task. */
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505 prvInitialiseTCBVariables( pxNewTCB, usStackDepth, pcName, uxPriority );
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507 /* Calculate the top of stack address. This depends on whether the
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508 stack grows from high memory to low (as per the 80x86) or visa versa.
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509 portSTACK_GROWTH is used to make the result positive or negative as
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510 required by the port. */
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511 #if portSTACK_GROWTH < 0
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513 pxTopOfStack = pxNewTCB->pxStack + ( pxNewTCB->usStackDepth - 1 );
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517 pxTopOfStack = pxNewTCB->pxStack;
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521 /* Initialize the TCB stack to look as if the task was already running,
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522 but had been interrupted by the scheduler. The return address is set
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523 to the start of the task function. Once the stack has been initialised
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524 the top of stack variable is updated. */
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525 pxNewTCB->pxTopOfStack = pxPortInitialiseStack( pxTopOfStack, pvTaskCode, pvParameters );
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527 /* We are going to manipulate the task queues to add this task to a
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528 ready list, so must make sure no interrupts occur. */
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529 portENTER_CRITICAL();
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531 uxCurrentNumberOfTasks++;
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532 if( uxCurrentNumberOfTasks == ( unsigned portBASE_TYPE ) 1 )
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534 /* As this is the first task it must also be the current task. */
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535 pxCurrentTCB = pxNewTCB;
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537 /* This is the first task to be created so do the preliminary
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538 initialisation required. We will not recover if this call
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539 fails, but we will report the failure. */
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540 prvInitialiseTaskLists();
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544 /* If the scheduler is not already running, make this task the
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545 current task if it is the highest priority task to be created
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547 if( xSchedulerRunning == pdFALSE )
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549 if( pxCurrentTCB->uxPriority <= uxPriority )
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551 pxCurrentTCB = pxNewTCB;
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556 /* Remember the top priority to make context switching faster. Use
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557 the priority in pxNewTCB as this has been capped to a valid value. */
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558 if( pxNewTCB->uxPriority > uxTopUsedPriority )
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560 uxTopUsedPriority = pxNewTCB->uxPriority;
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563 /* Add a counter into the TCB for tracing only. */
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564 pxNewTCB->uxTCBNumber = uxTaskNumber;
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567 prvAddTaskToReadyQueue( pxNewTCB );
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571 portEXIT_CRITICAL();
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575 xReturn = errCOULD_NOT_ALLOCATE_REQUIRED_MEMORY;
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578 if( xReturn == pdPASS )
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580 if( ( void * ) pxCreatedTask != NULL )
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582 /* Pass the TCB out - in an anonymous way. The calling function/
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583 task can use this as a handle to delete the task later if
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585 *pxCreatedTask = ( xTaskHandle ) pxNewTCB;
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588 if( xSchedulerRunning != pdFALSE )
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590 /* If the created task is of a higher priority than the current task
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591 then it should run now. */
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592 if( pxCurrentTCB->uxPriority < uxPriority )
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601 /*-----------------------------------------------------------*/
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603 #if ( INCLUDE_vTaskDelete == 1 )
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605 void vTaskDelete( xTaskHandle pxTaskToDelete )
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609 taskENTER_CRITICAL();
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611 /* Ensure a yield is performed if the current task is being
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613 if( pxTaskToDelete == pxCurrentTCB )
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615 pxTaskToDelete = NULL;
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618 /* If null is passed in here then we are deleting ourselves. */
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619 pxTCB = prvGetTCBFromHandle( pxTaskToDelete );
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621 /* Remove task from the ready list and place in the termination list.
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622 This will stop the task from be scheduled. The idle task will check
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623 the termination list and free up any memory allocated by the
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624 scheduler for the TCB and stack. */
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625 vListRemove( &( pxTCB->xGenericListItem ) );
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627 /* Is the task waiting on an event also? */
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628 if( pxTCB->xEventListItem.pvContainer )
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630 vListRemove( &( pxTCB->xEventListItem ) );
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633 vListInsertEnd( ( xList * ) &xTasksWaitingTermination, &( pxTCB->xGenericListItem ) );
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635 /* Increment the ucTasksDeleted variable so the idle task knows
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636 there is a task that has been deleted and that it should therefore
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637 check the xTasksWaitingTermination list. */
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640 taskEXIT_CRITICAL();
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642 /* Force a reschedule if we have just deleted the current task. */
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643 if( xSchedulerRunning != pdFALSE )
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645 if( ( void * ) pxTaskToDelete == NULL )
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659 /*-----------------------------------------------------------
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660 * TASK CONTROL API documented in task.h
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661 *----------------------------------------------------------*/
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663 #if ( INCLUDE_vTaskDelayUntil == 1 )
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665 void vTaskDelayUntil( portTickType *pxPreviousWakeTime, portTickType xTimeIncrement )
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667 portTickType xTimeToWake;
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668 portBASE_TYPE xAlreadyYielded, xShouldDelay = pdFALSE;
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672 /* Generate the tick time at which the task wants to wake. */
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673 xTimeToWake = *pxPreviousWakeTime + xTimeIncrement;
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675 if( xTickCount < *pxPreviousWakeTime )
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677 /* The tick count has overflowed since this function was
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678 lasted called. In this case the only time we should ever
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679 actually delay is if the wake time has also overflowed,
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680 and the wake time is greater than the tick time. When this
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681 is the case it is as if neither time had overflowed. */
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682 if( ( xTimeToWake < *pxPreviousWakeTime ) && ( xTimeToWake > xTickCount ) )
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684 xShouldDelay = pdTRUE;
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689 /* The tick time has not overflowed. In this case we will
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690 delay if either the wake time has overflowed, and/or the
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691 tick time is less than the wake time. */
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692 if( ( xTimeToWake < *pxPreviousWakeTime ) || ( xTimeToWake > xTickCount ) )
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694 xShouldDelay = pdTRUE;
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698 /* Update the wake time ready for the next call. */
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699 *pxPreviousWakeTime = xTimeToWake;
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703 /* We must remove ourselves from the ready list before adding
\r
704 ourselves to the blocked list as the same list item is used for
\r
706 vListRemove( ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
\r
708 /* The list item will be inserted in wake time order. */
\r
709 listSET_LIST_ITEM_VALUE( &( pxCurrentTCB->xGenericListItem ), xTimeToWake );
\r
711 if( xTimeToWake < xTickCount )
\r
713 /* Wake time has overflowed. Place this item in the
\r
715 vListInsert( ( xList * ) pxOverflowDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
\r
719 /* The wake time has not overflowed, so we can use the
\r
720 current block list. */
\r
721 vListInsert( ( xList * ) pxDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
\r
725 xAlreadyYielded = xTaskResumeAll();
\r
727 /* Force a reschedule if xTaskResumeAll has not already done so, we may
\r
728 have put ourselves to sleep. */
\r
729 if( !xAlreadyYielded )
\r
736 /*-----------------------------------------------------------*/
\r
738 #if ( INCLUDE_vTaskDelay == 1 )
\r
740 void vTaskDelay( portTickType xTicksToDelay )
\r
742 portTickType xTimeToWake;
\r
743 signed portBASE_TYPE xAlreadyYielded = pdFALSE;
\r
745 /* A delay time of zero just forces a reschedule. */
\r
746 if( xTicksToDelay > ( portTickType ) 0 )
\r
750 /* A task that is removed from the event list while the
\r
751 scheduler is suspended will not get placed in the ready
\r
752 list or removed from the blocked list until the scheduler
\r
755 This task cannot be in an event list as it is the currently
\r
758 /* Calculate the time to wake - this may overflow but this is
\r
760 xTimeToWake = xTickCount + xTicksToDelay;
\r
762 /* We must remove ourselves from the ready list before adding
\r
763 ourselves to the blocked list as the same list item is used for
\r
765 vListRemove( ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
\r
767 /* The list item will be inserted in wake time order. */
\r
768 listSET_LIST_ITEM_VALUE( &( pxCurrentTCB->xGenericListItem ), xTimeToWake );
\r
770 if( xTimeToWake < xTickCount )
\r
772 /* Wake time has overflowed. Place this item in the
\r
774 vListInsert( ( xList * ) pxOverflowDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
\r
778 /* The wake time has not overflowed, so we can use the
\r
779 current block list. */
\r
780 vListInsert( ( xList * ) pxDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
\r
783 xAlreadyYielded = xTaskResumeAll();
\r
786 /* Force a reschedule if xTaskResumeAll has not already done so, we may
\r
787 have put ourselves to sleep. */
\r
788 if( !xAlreadyYielded )
\r
795 /*-----------------------------------------------------------*/
\r
797 #if ( INCLUDE_uxTaskPriorityGet == 1 )
\r
799 unsigned portBASE_TYPE uxTaskPriorityGet( xTaskHandle pxTask )
\r
802 unsigned portBASE_TYPE uxReturn;
\r
804 taskENTER_CRITICAL();
\r
806 /* If null is passed in here then we are changing the
\r
807 priority of the calling function. */
\r
808 pxTCB = prvGetTCBFromHandle( pxTask );
\r
809 uxReturn = pxTCB->uxPriority;
\r
811 taskEXIT_CRITICAL();
\r
817 /*-----------------------------------------------------------*/
\r
819 #if ( INCLUDE_vTaskPrioritySet == 1 )
\r
821 void vTaskPrioritySet( xTaskHandle pxTask, unsigned portBASE_TYPE uxNewPriority )
\r
824 unsigned portBASE_TYPE uxCurrentPriority, xYieldRequired = pdFALSE;
\r
826 /* Ensure the new priority is valid. */
\r
827 if( uxNewPriority >= configMAX_PRIORITIES )
\r
829 uxNewPriority = configMAX_PRIORITIES - 1;
\r
832 taskENTER_CRITICAL();
\r
834 /* If null is passed in here then we are changing the
\r
835 priority of the calling function. */
\r
836 pxTCB = prvGetTCBFromHandle( pxTask );
\r
837 uxCurrentPriority = pxTCB->uxPriority;
\r
839 if( uxCurrentPriority != uxNewPriority )
\r
841 /* The priority change may have readied a task of higher
\r
842 priority than the calling task. */
\r
843 if( uxNewPriority > pxCurrentTCB->uxPriority )
\r
845 if( pxTask != NULL )
\r
847 /* The priority of another task is being raised. If we
\r
848 were raising the priority of the currently running task
\r
849 there would be no need to switch as it must have already
\r
850 been the highest priority task. */
\r
851 xYieldRequired = pdTRUE;
\r
854 else if( pxTask == NULL )
\r
856 /* Setting our own priority down means there may now be another
\r
857 task of higher priority that is ready to execute. */
\r
858 xYieldRequired = pdTRUE;
\r
861 pxTCB->uxPriority = uxNewPriority;
\r
862 listSET_LIST_ITEM_VALUE( &( pxTCB->xEventListItem ), configMAX_PRIORITIES - ( portTickType ) uxNewPriority );
\r
864 /* If the task is in the blocked or suspended list we need do
\r
865 nothing more than change it's priority variable. However, if
\r
866 the task is in a ready list it needs to be removed and placed
\r
867 in the queue appropriate to its new priority. */
\r
868 if( listIS_CONTAINED_WITHIN( &( pxReadyTasksLists[ uxCurrentPriority ] ), &( pxTCB->xGenericListItem ) ) )
\r
870 /* The task is currently in its ready list - remove before adding
\r
871 it to it's new ready list. As we are in a critical section we
\r
872 can do this even if the scheduler is suspended. */
\r
873 vListRemove( &( pxTCB->xGenericListItem ) );
\r
874 prvAddTaskToReadyQueue( pxTCB );
\r
877 if( xYieldRequired == pdTRUE )
\r
883 taskEXIT_CRITICAL();
\r
887 /*-----------------------------------------------------------*/
\r
889 #if ( INCLUDE_vTaskSuspend == 1 )
\r
891 void vTaskSuspend( xTaskHandle pxTaskToSuspend )
\r
895 taskENTER_CRITICAL();
\r
897 /* Ensure a yield is performed if the current task is being
\r
899 if( pxTaskToSuspend == pxCurrentTCB )
\r
901 pxTaskToSuspend = NULL;
\r
904 /* If null is passed in here then we are suspending ourselves. */
\r
905 pxTCB = prvGetTCBFromHandle( pxTaskToSuspend );
\r
907 /* Remove task from the ready/delayed list and place in the suspended list. */
\r
908 vListRemove( &( pxTCB->xGenericListItem ) );
\r
910 /* Is the task waiting on an event also? */
\r
911 if( pxTCB->xEventListItem.pvContainer )
\r
913 vListRemove( &( pxTCB->xEventListItem ) );
\r
916 vListInsertEnd( ( xList * ) &xSuspendedTaskList, &( pxTCB->xGenericListItem ) );
\r
918 taskEXIT_CRITICAL();
\r
920 /* We may have just suspended the current task. */
\r
921 if( ( void * ) pxTaskToSuspend == NULL )
\r
928 /*-----------------------------------------------------------*/
\r
930 #if ( INCLUDE_vTaskSuspend == 1 )
\r
932 void vTaskResume( xTaskHandle pxTaskToResume )
\r
936 /* Remove the task from whichever list it is currently in, and place
\r
937 it in the ready list. */
\r
938 pxTCB = ( tskTCB * ) pxTaskToResume;
\r
940 /* The parameter cannot be NULL as it is impossible to resume the
\r
941 currently executing task. */
\r
942 if( pxTCB != NULL )
\r
944 taskENTER_CRITICAL();
\r
946 /* Is the task we are attempting to resume actually suspended? */
\r
947 if( listIS_CONTAINED_WITHIN( &xSuspendedTaskList, &( pxTCB->xGenericListItem ) ) != pdFALSE )
\r
949 /* Has the task already been resumed from within an ISR? */
\r
950 if( listIS_CONTAINED_WITHIN( &xPendingReadyList, &( pxTCB->xEventListItem ) ) != pdTRUE )
\r
952 /* As we are in a critical section we can access the ready
\r
953 lists even if the scheduler is suspended. */
\r
954 vListRemove( &( pxTCB->xGenericListItem ) );
\r
955 prvAddTaskToReadyQueue( pxTCB );
\r
957 /* We may have just resumed a higher priority task. */
\r
958 if( pxTCB->uxPriority >= pxCurrentTCB->uxPriority )
\r
960 /* This yield may not cause the task just resumed to run, but
\r
961 will leave the lists in the correct state for the next yield. */
\r
967 taskEXIT_CRITICAL();
\r
973 /*-----------------------------------------------------------*/
\r
975 #if ( ( INCLUDE_xTaskResumeFromISR == 1 ) && ( INCLUDE_vTaskSuspend == 1 ) )
\r
977 portBASE_TYPE xTaskResumeFromISR( xTaskHandle pxTaskToResume )
\r
979 portBASE_TYPE xYieldRequired = pdFALSE;
\r
982 pxTCB = ( tskTCB * ) pxTaskToResume;
\r
984 /* Is the task we are attempting to resume actually suspended? */
\r
985 if( listIS_CONTAINED_WITHIN( &xSuspendedTaskList, &( pxTCB->xGenericListItem ) ) != pdFALSE )
\r
987 /* Has the task already been resumed from within an ISR? */
\r
988 if( listIS_CONTAINED_WITHIN( &xPendingReadyList, &( pxTCB->xEventListItem ) ) != pdTRUE )
\r
990 if( uxSchedulerSuspended == ( unsigned portBASE_TYPE ) pdFALSE )
\r
992 xYieldRequired = ( pxTCB->uxPriority >= pxCurrentTCB->uxPriority );
\r
993 vListRemove( &( pxTCB->xGenericListItem ) );
\r
994 prvAddTaskToReadyQueue( pxTCB );
\r
998 /* We cannot access the delayed or ready lists, so will hold this
\r
999 task pending until the scheduler is resumed, at which point a
\r
1000 yield will be preformed if necessary. */
\r
1001 vListInsertEnd( ( xList * ) &( xPendingReadyList ), &( pxTCB->xEventListItem ) );
\r
1006 return xYieldRequired;
\r
1014 /*-----------------------------------------------------------
\r
1015 * PUBLIC SCHEDULER CONTROL documented in task.h
\r
1016 *----------------------------------------------------------*/
\r
1019 void vTaskStartScheduler( void )
\r
1021 portBASE_TYPE xReturn;
\r
1023 /* Add the idle task at the lowest priority. */
\r
1024 xReturn = xTaskCreate( prvIdleTask, ( signed portCHAR * ) "IDLE", tskIDLE_STACK_SIZE, ( void * ) NULL, tskIDLE_PRIORITY, ( xTaskHandle * ) NULL );
\r
1026 if( xReturn == pdPASS )
\r
1028 /* Interrupts are turned off here, to ensure a tick does not occur
\r
1029 before or during the call to xPortStartScheduler(). The stacks of
\r
1030 the created tasks contain a status word with interrupts switched on
\r
1031 so interrupts will automatically get re-enabled when the first task
\r
1034 STEPPING THROUGH HERE USING A DEBUGGER CAN CAUSE BIG PROBLEMS IF THE
\r
1035 DEBUGGER ALLOWS INTERRUPTS TO BE PROCESSED. */
\r
1036 portDISABLE_INTERRUPTS();
\r
1038 xSchedulerRunning = pdTRUE;
\r
1039 xTickCount = ( portTickType ) 0;
\r
1041 /* Setting up the timer tick is hardware specific and thus in the
\r
1042 portable interface. */
\r
1043 if( xPortStartScheduler() )
\r
1045 /* Should not reach here as if the scheduler is running the
\r
1046 function will not return. */
\r
1050 /* Should only reach here if a task calls xTaskEndScheduler(). */
\r
1054 /*-----------------------------------------------------------*/
\r
1056 void vTaskEndScheduler( void )
\r
1058 /* Stop the scheduler interrupts and call the portable scheduler end
\r
1059 routine so the original ISRs can be restored if necessary. The port
\r
1060 layer must ensure interrupts enable bit is left in the correct state. */
\r
1061 portDISABLE_INTERRUPTS();
\r
1062 xSchedulerRunning = pdFALSE;
\r
1063 vPortEndScheduler();
\r
1065 /*----------------------------------------------------------*/
\r
1067 void vTaskSuspendAll( void )
\r
1069 portENTER_CRITICAL();
\r
1070 ++uxSchedulerSuspended;
\r
1071 portEXIT_CRITICAL();
\r
1073 /*----------------------------------------------------------*/
\r
1075 signed portBASE_TYPE xTaskResumeAll( void )
\r
1077 register tskTCB *pxTCB;
\r
1078 signed portBASE_TYPE xAlreadyYielded = pdFALSE;
\r
1080 /* It is possible that an ISR caused a task to be removed from an event
\r
1081 list while the scheduler was suspended. If this was the case then the
\r
1082 removed task will have been added to the xPendingReadyList. Once the
\r
1083 scheduler has been resumed it is safe to move all the pending ready
\r
1084 tasks from this list into their appropriate ready list. */
\r
1085 portENTER_CRITICAL();
\r
1087 --uxSchedulerSuspended;
\r
1089 if( uxSchedulerSuspended == ( unsigned portBASE_TYPE ) pdFALSE )
\r
1091 if( uxCurrentNumberOfTasks > ( unsigned portBASE_TYPE ) 0 )
\r
1093 portBASE_TYPE xYieldRequired = pdFALSE;
\r
1095 /* Move any readied tasks from the pending list into the
\r
1096 appropriate ready list. */
\r
1097 while( ( pxTCB = ( tskTCB * ) listGET_OWNER_OF_HEAD_ENTRY( ( ( xList * ) &xPendingReadyList ) ) ) != NULL )
\r
1099 vListRemove( &( pxTCB->xEventListItem ) );
\r
1100 vListRemove( &( pxTCB->xGenericListItem ) );
\r
1101 prvAddTaskToReadyQueue( pxTCB );
\r
1103 /* If we have moved a task that has a priority higher than
\r
1104 the current task then we should yield. */
\r
1105 if( pxTCB->uxPriority >= pxCurrentTCB->uxPriority )
\r
1107 xYieldRequired = pdTRUE;
\r
1111 /* If any ticks occurred while the scheduler was suspended then
\r
1112 they should be processed now. This ensures the tick count does not
\r
1113 slip, and that any delayed tasks are resumed at the correct time. */
\r
1114 if( uxMissedTicks > ( unsigned portBASE_TYPE ) 0 )
\r
1116 while( uxMissedTicks > ( unsigned portBASE_TYPE ) 0 )
\r
1118 vTaskIncrementTick();
\r
1122 /* As we have processed some ticks it is appropriate to yield
\r
1123 to ensure the highest priority task that is ready to run is
\r
1124 the task actually running. */
\r
1125 xYieldRequired = pdTRUE;
\r
1128 if( ( xYieldRequired == pdTRUE ) || ( xMissedYield == pdTRUE ) )
\r
1130 xAlreadyYielded = pdTRUE;
\r
1131 xMissedYield = pdFALSE;
\r
1137 portEXIT_CRITICAL();
\r
1139 return xAlreadyYielded;
\r
1147 /*-----------------------------------------------------------
\r
1148 * PUBLIC TASK UTILITIES documented in task.h
\r
1149 *----------------------------------------------------------*/
\r
1153 portTickType xTaskGetTickCount( void )
\r
1155 portTickType xTicks;
\r
1157 /* Critical section required if running on a 16 bit processor. */
\r
1158 taskENTER_CRITICAL();
\r
1160 xTicks = xTickCount;
\r
1162 taskEXIT_CRITICAL();
\r
1166 /*-----------------------------------------------------------*/
\r
1168 unsigned portBASE_TYPE uxTaskGetNumberOfTasks( void )
\r
1170 unsigned portBASE_TYPE uxNumberOfTasks;
\r
1172 taskENTER_CRITICAL();
\r
1173 uxNumberOfTasks = uxCurrentNumberOfTasks;
\r
1174 taskEXIT_CRITICAL();
\r
1176 return uxNumberOfTasks;
\r
1178 /*-----------------------------------------------------------*/
\r
1180 #if ( ( configUSE_TRACE_FACILITY == 1 ) && ( INCLUDE_vTaskDelete == 1 ) && ( INCLUDE_vTaskSuspend == 1 ) )
\r
1182 void vTaskList( signed portCHAR *pcWriteBuffer )
\r
1184 unsigned portBASE_TYPE uxQueue;
\r
1186 /* This is a VERY costly function that should be used for debug only.
\r
1187 It leaves interrupts disabled for a LONG time. */
\r
1189 vTaskSuspendAll();
\r
1191 /* Run through all the lists that could potentially contain a TCB and
\r
1192 report the task name, state and stack high water mark. */
\r
1194 pcWriteBuffer[ 0 ] = ( signed portCHAR ) 0x00;
\r
1195 strcat( ( portCHAR * ) pcWriteBuffer, ( const portCHAR * ) "\r\n" );
\r
1197 uxQueue = uxTopUsedPriority + 1;
\r
1203 if( !listLIST_IS_EMPTY( &( pxReadyTasksLists[ uxQueue ] ) ) )
\r
1205 prvListTaskWithinSingleList( pcWriteBuffer, ( xList * ) &( pxReadyTasksLists[ uxQueue ] ), tskREADY_CHAR );
\r
1207 }while( uxQueue > ( unsigned portSHORT ) tskIDLE_PRIORITY );
\r
1209 if( !listLIST_IS_EMPTY( pxDelayedTaskList ) )
\r
1211 prvListTaskWithinSingleList( pcWriteBuffer, ( xList * ) pxDelayedTaskList, tskBLOCKED_CHAR );
\r
1214 if( !listLIST_IS_EMPTY( pxOverflowDelayedTaskList ) )
\r
1216 prvListTaskWithinSingleList( pcWriteBuffer, ( xList * ) pxOverflowDelayedTaskList, tskBLOCKED_CHAR );
\r
1219 if( !listLIST_IS_EMPTY( &xTasksWaitingTermination ) )
\r
1221 prvListTaskWithinSingleList( pcWriteBuffer, ( xList * ) &xTasksWaitingTermination, tskDELETED_CHAR );
\r
1224 if( !listLIST_IS_EMPTY( &xSuspendedTaskList ) )
\r
1226 prvListTaskWithinSingleList( pcWriteBuffer, ( xList * ) &xSuspendedTaskList, tskSUSPENDED_CHAR );
\r
1233 /*----------------------------------------------------------*/
\r
1235 #if ( configUSE_TRACE_FACILITY == 1 )
\r
1237 void vTaskStartTrace( signed portCHAR * pcBuffer, unsigned portLONG ulBufferSize )
\r
1239 portENTER_CRITICAL();
\r
1241 pcTraceBuffer = ( volatile signed portCHAR * volatile )pcBuffer;
\r
1242 pcTraceBufferStart = pcBuffer;
\r
1243 pcTraceBufferEnd = pcBuffer + ( ulBufferSize - tskSIZE_OF_EACH_TRACE_LINE );
\r
1244 xTracing = pdTRUE;
\r
1246 portEXIT_CRITICAL();
\r
1250 /*----------------------------------------------------------*/
\r
1252 #if ( configUSE_TRACE_FACILITY == 1 )
\r
1254 unsigned portLONG ulTaskEndTrace( void )
\r
1256 unsigned portLONG ulBufferLength;
\r
1258 portENTER_CRITICAL();
\r
1259 xTracing = pdFALSE;
\r
1260 portEXIT_CRITICAL();
\r
1262 ulBufferLength = ( unsigned portLONG ) ( pcTraceBuffer - pcTraceBufferStart );
\r
1264 return ulBufferLength;
\r
1271 /*-----------------------------------------------------------
\r
1272 * SCHEDULER INTERNALS AVAILABLE FOR PORTING PURPOSES
\r
1273 * documented in task.h
\r
1274 *----------------------------------------------------------*/
\r
1277 inline void vTaskIncrementTick( void )
\r
1279 /* Called by the portable layer each time a tick interrupt occurs.
\r
1280 Increments the tick then checks to see if the new tick value will cause any
\r
1281 tasks to be unblocked. */
\r
1282 if( uxSchedulerSuspended == ( unsigned portBASE_TYPE ) pdFALSE )
\r
1285 if( xTickCount == ( portTickType ) 0 )
\r
1289 /* Tick count has overflowed so we need to swap the delay lists.
\r
1290 If there are any items in pxDelayedTaskList here then there is
\r
1292 pxTemp = pxDelayedTaskList;
\r
1293 pxDelayedTaskList = pxOverflowDelayedTaskList;
\r
1294 pxOverflowDelayedTaskList = pxTemp;
\r
1295 xNumOfOverflows++;
\r
1298 /* See if this tick has made a timeout expire. */
\r
1299 prvCheckDelayedTasks();
\r
1305 /* The tick hook gets called at regular intervals, even if the
\r
1306 scheduler is locked. */
\r
1307 #if ( configUSE_TICK_HOOK == 1 )
\r
1309 extern void vApplicationTickHook( void );
\r
1311 vApplicationTickHook();
\r
1316 #if ( configUSE_TICK_HOOK == 1 )
\r
1318 extern void vApplicationTickHook( void );
\r
1320 /* Guard against the tick hook being called when the missed tick
\r
1321 count is being unwound (when the scheduler is being unlocked. */
\r
1322 if( uxMissedTicks == 0 )
\r
1324 vApplicationTickHook();
\r
1329 /*-----------------------------------------------------------*/
\r
1331 #if ( ( INCLUDE_vTaskCleanUpResources == 1 ) && ( INCLUDE_vTaskSuspend == 1 ) )
\r
1333 void vTaskCleanUpResources( void )
\r
1335 unsigned portSHORT usQueue;
\r
1336 volatile tskTCB *pxTCB;
\r
1338 usQueue = ( unsigned portSHORT ) uxTopUsedPriority + ( unsigned portSHORT ) 1;
\r
1340 /* Remove any TCB's from the ready queues. */
\r
1345 while( !listLIST_IS_EMPTY( &( pxReadyTasksLists[ usQueue ] ) ) )
\r
1347 listGET_OWNER_OF_NEXT_ENTRY( pxTCB, &( pxReadyTasksLists[ usQueue ] ) );
\r
1348 vListRemove( ( xListItem * ) &( pxTCB->xGenericListItem ) );
\r
1350 prvDeleteTCB( ( tskTCB * ) pxTCB );
\r
1352 }while( usQueue > ( unsigned portSHORT ) tskIDLE_PRIORITY );
\r
1354 /* Remove any TCB's from the delayed queue. */
\r
1355 while( !listLIST_IS_EMPTY( &xDelayedTaskList1 ) )
\r
1357 listGET_OWNER_OF_NEXT_ENTRY( pxTCB, &xDelayedTaskList1 );
\r
1358 vListRemove( ( xListItem * ) &( pxTCB->xGenericListItem ) );
\r
1360 prvDeleteTCB( ( tskTCB * ) pxTCB );
\r
1363 /* Remove any TCB's from the overflow delayed queue. */
\r
1364 while( !listLIST_IS_EMPTY( &xDelayedTaskList2 ) )
\r
1366 listGET_OWNER_OF_NEXT_ENTRY( pxTCB, &xDelayedTaskList2 );
\r
1367 vListRemove( ( xListItem * ) &( pxTCB->xGenericListItem ) );
\r
1369 prvDeleteTCB( ( tskTCB * ) pxTCB );
\r
1372 while( !listLIST_IS_EMPTY( &xSuspendedTaskList ) )
\r
1374 listGET_OWNER_OF_NEXT_ENTRY( pxTCB, &xSuspendedTaskList );
\r
1375 vListRemove( ( xListItem * ) &( pxTCB->xGenericListItem ) );
\r
1377 prvDeleteTCB( ( tskTCB * ) pxTCB );
\r
1380 while( !listLIST_IS_EMPTY( &xPendingReadyList ) )
\r
1382 listGET_OWNER_OF_NEXT_ENTRY( pxTCB, &xPendingReadyList );
\r
1383 vListRemove( ( xListItem * ) &( pxTCB->xGenericListItem ) );
\r
1385 prvDeleteTCB( ( tskTCB * ) pxTCB );
\r
1390 /*-----------------------------------------------------------*/
\r
1392 void vTaskSwitchContext( void )
\r
1394 if( uxSchedulerSuspended != ( unsigned portBASE_TYPE ) pdFALSE )
\r
1396 /* The scheduler is currently suspended - do not allow a context
\r
1398 xMissedYield = pdTRUE;
\r
1402 /* Find the highest priority queue that contains ready tasks. */
\r
1403 while( listLIST_IS_EMPTY( &( pxReadyTasksLists[ uxTopReadyPriority ] ) ) )
\r
1405 --uxTopReadyPriority;
\r
1408 /* listGET_OWNER_OF_NEXT_ENTRY walks through the list, so the tasks of the
\r
1409 same priority get an equal share of the processor time. */
\r
1410 listGET_OWNER_OF_NEXT_ENTRY( pxCurrentTCB, &( pxReadyTasksLists[ uxTopReadyPriority ] ) );
\r
1411 vWriteTraceToBuffer();
\r
1413 /*-----------------------------------------------------------*/
\r
1415 void vTaskPlaceOnEventList( xList *pxEventList, portTickType xTicksToWait )
\r
1417 portTickType xTimeToWake;
\r
1419 /* THIS FUNCTION MUST BE CALLED WITH INTERRUPTS DISABLED OR THE
\r
1420 SCHEDULER SUSPENDED. */
\r
1422 /* Place the event list item of the TCB in the appropriate event list.
\r
1423 This is placed in the list in priority order so the highest priority task
\r
1424 is the first to be woken by the event. */
\r
1425 vListInsert( ( xList * ) pxEventList, ( xListItem * ) &( pxCurrentTCB->xEventListItem ) );
\r
1427 /* We must remove ourselves from the ready list before adding ourselves
\r
1428 to the blocked list as the same list item is used for both lists. We have
\r
1429 exclusive access to the ready lists as the scheduler is locked. */
\r
1430 vListRemove( ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
\r
1433 #if ( INCLUDE_vTaskSuspend == 1 )
\r
1435 if( xTicksToWait == portMAX_DELAY )
\r
1437 /* Add ourselves to the suspended task list instead of a delayed task
\r
1438 list to ensure we are not woken by a timing event. We will block
\r
1440 vListInsertEnd( ( xList * ) &xSuspendedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
\r
1444 /* Calculate the time at which the task should be woken if the event does
\r
1445 not occur. This may overflow but this doesn't matter. */
\r
1446 xTimeToWake = xTickCount + xTicksToWait;
\r
1448 listSET_LIST_ITEM_VALUE( &( pxCurrentTCB->xGenericListItem ), xTimeToWake );
\r
1450 if( xTimeToWake < xTickCount )
\r
1452 /* Wake time has overflowed. Place this item in the overflow list. */
\r
1453 vListInsert( ( xList * ) pxOverflowDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
\r
1457 /* The wake time has not overflowed, so we can use the current block list. */
\r
1458 vListInsert( ( xList * ) pxDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
\r
1464 /* Calculate the time at which the task should be woken if the event does
\r
1465 not occur. This may overflow but this doesn't matter. */
\r
1466 xTimeToWake = xTickCount + xTicksToWait;
\r
1468 listSET_LIST_ITEM_VALUE( &( pxCurrentTCB->xGenericListItem ), xTimeToWake );
\r
1470 if( xTimeToWake < xTickCount )
\r
1472 /* Wake time has overflowed. Place this item in the overflow list. */
\r
1473 vListInsert( ( xList * ) pxOverflowDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
\r
1477 /* The wake time has not overflowed, so we can use the current block list. */
\r
1478 vListInsert( ( xList * ) pxDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
\r
1483 /*-----------------------------------------------------------*/
\r
1485 signed portBASE_TYPE xTaskRemoveFromEventList( const xList *pxEventList )
\r
1487 tskTCB *pxUnblockedTCB;
\r
1488 portBASE_TYPE xReturn;
\r
1490 /* THIS FUNCTION MUST BE CALLED WITH INTERRUPTS DISABLED OR THE
\r
1491 SCHEDULER SUSPENDED. It can also be called from within an ISR. */
\r
1493 /* The event list is sorted in priority order, so we can remove the
\r
1494 first in the list, remove the TCB from the delayed list, and add
\r
1495 it to the ready list.
\r
1497 If an event is for a queue that is locked then this function will never
\r
1498 get called - the lock count on the queue will get modified instead. This
\r
1499 means we can always expect exclusive access to the event list here. */
\r
1500 pxUnblockedTCB = ( tskTCB * ) listGET_OWNER_OF_HEAD_ENTRY( pxEventList );
\r
1501 vListRemove( &( pxUnblockedTCB->xEventListItem ) );
\r
1503 if( uxSchedulerSuspended == ( unsigned portBASE_TYPE ) pdFALSE )
\r
1505 vListRemove( &( pxUnblockedTCB->xGenericListItem ) );
\r
1506 prvAddTaskToReadyQueue( pxUnblockedTCB );
\r
1510 /* We cannot access the delayed or ready lists, so will hold this
\r
1511 task pending until the scheduler is resumed. */
\r
1512 vListInsertEnd( ( xList * ) &( xPendingReadyList ), &( pxUnblockedTCB->xEventListItem ) );
\r
1515 if( pxUnblockedTCB->uxPriority >= pxCurrentTCB->uxPriority )
\r
1517 /* Return true if the task removed from the event list has
\r
1518 a higher priority than the calling task. This allows
\r
1519 the calling task to know if it should force a context
\r
1525 xReturn = pdFALSE;
\r
1530 /*-----------------------------------------------------------*/
\r
1532 void vTaskSetTimeOutState( xTimeOutType *pxTimeOut )
\r
1534 pxTimeOut->xOverflowCount = xNumOfOverflows;
\r
1535 pxTimeOut->xTimeOnEntering = xTickCount;
\r
1537 /*-----------------------------------------------------------*/
\r
1539 portBASE_TYPE xTaskCheckForTimeOut( xTimeOutType *pxTimeOut, portTickType *pxTicksToWait )
\r
1541 portBASE_TYPE xReturn;
\r
1543 if( ( xNumOfOverflows != pxTimeOut->xOverflowCount ) && ( xTickCount > pxTimeOut->xTimeOnEntering ) )
\r
1545 /* The tick count is greater than the time at which vTaskSetTimeout()
\r
1546 was called, but has also overflowed since vTaskSetTimeOut() was called.
\r
1547 It must have wrapped all the way around and gone past us again. This
\r
1548 passed since vTaskSetTimeout() was called. */
\r
1551 else if( ( xTickCount - pxTimeOut->xTimeOnEntering ) < *pxTicksToWait )
\r
1553 /* Not a genuine timeout. Adjust parameters for time remaining. */
\r
1554 *pxTicksToWait -= ( xTickCount - pxTimeOut->xTimeOnEntering );
\r
1555 vTaskSetTimeOutState( pxTimeOut );
\r
1556 xReturn = pdFALSE;
\r
1565 /*-----------------------------------------------------------*/
\r
1567 void vTaskMissedYield( void )
\r
1569 xMissedYield = pdTRUE;
\r
1573 * -----------------------------------------------------------
\r
1575 * ----------------------------------------------------------
\r
1577 * The portTASK_FUNCTION() macro is used to allow port/compiler specific
\r
1578 * language extensions. The equivalent prototype for this function is:
\r
1580 * void prvIdleTask( void *pvParameters );
\r
1583 static portTASK_FUNCTION( prvIdleTask, pvParameters )
\r
1585 /* Stop warnings. */
\r
1586 ( void ) pvParameters;
\r
1590 /* See if any tasks have been deleted. */
\r
1591 prvCheckTasksWaitingTermination();
\r
1593 #if ( configUSE_PREEMPTION == 0 )
\r
1595 /* If we are not using preemption we keep forcing a task switch to
\r
1596 see if any other task has become available. If we are using
\r
1597 preemption we don't need to do this as any task becoming available
\r
1598 will automatically get the processor anyway. */
\r
1603 #if ( ( configUSE_PREEMPTION == 1 ) && ( configIDLE_SHOULD_YIELD == 1 ) )
\r
1605 /* When using preemption tasks of equal priority will be
\r
1606 timesliced. If a task that is sharing the idle priority is ready
\r
1607 to run then the idle task should yield before the end of the
\r
1610 A critical region is not required here as we are just reading from
\r
1611 the list, and an occasional incorrect value will not matter. If
\r
1612 the ready list at the idle priority contains more than one task
\r
1613 then a task other than the idle task is ready to execute. */
\r
1614 if( listCURRENT_LIST_LENGTH( &( pxReadyTasksLists[ tskIDLE_PRIORITY ] ) ) > ( unsigned portBASE_TYPE ) 1 )
\r
1621 #if ( configUSE_IDLE_HOOK == 1 )
\r
1623 extern void vApplicationIdleHook( void );
\r
1625 /* Call the user defined function from within the idle task. This
\r
1626 allows the application designer to add background functionality
\r
1627 without the overhead of a separate task.
\r
1628 NOTE: vApplicationIdleHook() MUST NOT, UNDER ANY CIRCUMSTANCES,
\r
1629 CALL A FUNCTION THAT MIGHT BLOCK. */
\r
1630 vApplicationIdleHook();
\r
1634 } /*lint !e715 pvParameters is not accessed but all task functions require the same prototype. */
\r
1642 /*-----------------------------------------------------------
\r
1643 * File private functions documented at the top of the file.
\r
1644 *----------------------------------------------------------*/
\r
1648 static void prvInitialiseTCBVariables( tskTCB *pxTCB, unsigned portSHORT usStackDepth, const signed portCHAR * const pcName, unsigned portBASE_TYPE uxPriority )
\r
1650 pxTCB->usStackDepth = usStackDepth;
\r
1652 /* Store the function name in the TCB. */
\r
1653 strncpy( ( char * ) pxTCB->pcTaskName, ( const char * ) pcName, ( unsigned portSHORT ) configMAX_TASK_NAME_LEN );
\r
1654 pxTCB->pcTaskName[ ( unsigned portSHORT ) configMAX_TASK_NAME_LEN - ( unsigned portSHORT ) 1 ] = '\0';
\r
1656 /* This is used as an array index so must ensure it's not too large. */
\r
1657 if( uxPriority >= configMAX_PRIORITIES )
\r
1659 uxPriority = configMAX_PRIORITIES - 1;
\r
1662 pxTCB->uxPriority = uxPriority;
\r
1664 vListInitialiseItem( &( pxTCB->xGenericListItem ) );
\r
1665 vListInitialiseItem( &( pxTCB->xEventListItem ) );
\r
1667 /* Set the pxTCB as a link back from the xListItem. This is so we can get
\r
1668 back to the containing TCB from a generic item in a list. */
\r
1669 listSET_LIST_ITEM_OWNER( &( pxTCB->xGenericListItem ), pxTCB );
\r
1671 /* Event lists are always in priority order. */
\r
1672 listSET_LIST_ITEM_VALUE( &( pxTCB->xEventListItem ), configMAX_PRIORITIES - ( portTickType ) uxPriority );
\r
1673 listSET_LIST_ITEM_OWNER( &( pxTCB->xEventListItem ), pxTCB );
\r
1675 /*-----------------------------------------------------------*/
\r
1677 static void prvInitialiseTaskLists( void )
\r
1679 unsigned portBASE_TYPE uxPriority;
\r
1681 for( uxPriority = 0; uxPriority < configMAX_PRIORITIES; uxPriority++ )
\r
1683 vListInitialise( ( xList * ) &( pxReadyTasksLists[ uxPriority ] ) );
\r
1686 vListInitialise( ( xList * ) &xDelayedTaskList1 );
\r
1687 vListInitialise( ( xList * ) &xDelayedTaskList2 );
\r
1688 vListInitialise( ( xList * ) &xPendingReadyList );
\r
1690 #if ( INCLUDE_vTaskDelete == 1 )
\r
1692 vListInitialise( ( xList * ) &xTasksWaitingTermination );
\r
1696 #if ( INCLUDE_vTaskSuspend == 1 )
\r
1698 vListInitialise( ( xList * ) &xSuspendedTaskList );
\r
1702 /* Start with pxDelayedTaskList using list1 and the pxOverflowDelayedTaskList
\r
1704 pxDelayedTaskList = &xDelayedTaskList1;
\r
1705 pxOverflowDelayedTaskList = &xDelayedTaskList2;
\r
1707 /*-----------------------------------------------------------*/
\r
1709 static void prvCheckTasksWaitingTermination( void )
\r
1711 #if ( INCLUDE_vTaskDelete == 1 )
\r
1713 portBASE_TYPE xListIsEmpty;
\r
1715 /* ucTasksDeleted is used to prevent vTaskSuspendAll() being called
\r
1716 too often in the idle task. */
\r
1717 if( uxTasksDeleted > ( unsigned portBASE_TYPE ) 0 )
\r
1719 vTaskSuspendAll();
\r
1720 xListIsEmpty = listLIST_IS_EMPTY( &xTasksWaitingTermination );
\r
1723 if( !xListIsEmpty )
\r
1727 portENTER_CRITICAL();
\r
1729 pxTCB = ( tskTCB * ) listGET_OWNER_OF_HEAD_ENTRY( ( ( xList * ) &xTasksWaitingTermination ) );
\r
1730 vListRemove( &( pxTCB->xGenericListItem ) );
\r
1731 --uxCurrentNumberOfTasks;
\r
1734 portEXIT_CRITICAL();
\r
1736 prvDeleteTCB( pxTCB );
\r
1742 /*-----------------------------------------------------------*/
\r
1744 static tskTCB *prvAllocateTCBAndStack( unsigned portSHORT usStackDepth )
\r
1748 /* Allocate space for the TCB. Where the memory comes from depends on
\r
1749 the implementation of the port malloc function. */
\r
1750 pxNewTCB = ( tskTCB * ) pvPortMalloc( sizeof( tskTCB ) );
\r
1752 if( pxNewTCB != NULL )
\r
1754 /* Allocate space for the stack used by the task being created.
\r
1755 The base of the stack memory stored in the TCB so the task can
\r
1756 be deleted later if required. */
\r
1757 pxNewTCB->pxStack = ( portSTACK_TYPE * ) pvPortMalloc( ( ( size_t )usStackDepth ) * sizeof( portSTACK_TYPE ) );
\r
1759 if( pxNewTCB->pxStack == NULL )
\r
1761 /* Could not allocate the stack. Delete the allocated TCB. */
\r
1762 vPortFree( pxNewTCB );
\r
1767 /* Just to help debugging. */
\r
1768 memset( pxNewTCB->pxStack, tskSTACK_FILL_BYTE, usStackDepth * sizeof( portSTACK_TYPE ) );
\r
1774 /*-----------------------------------------------------------*/
\r
1776 #if ( configUSE_TRACE_FACILITY == 1 )
\r
1778 static void prvListTaskWithinSingleList( signed portCHAR *pcWriteBuffer, xList *pxList, signed portCHAR cStatus )
\r
1780 volatile tskTCB *pxNextTCB, *pxFirstTCB;
\r
1781 static portCHAR pcStatusString[ 50 ];
\r
1782 unsigned portSHORT usStackRemaining;
\r
1784 /* Write the details of all the TCB's in pxList into the buffer. */
\r
1785 listGET_OWNER_OF_NEXT_ENTRY( pxFirstTCB, pxList );
\r
1788 listGET_OWNER_OF_NEXT_ENTRY( pxNextTCB, pxList );
\r
1789 usStackRemaining = usTaskCheckFreeStackSpace( ( unsigned portCHAR * ) pxNextTCB->pxStack );
\r
1790 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
1791 strcat( ( portCHAR * ) pcWriteBuffer, ( portCHAR * ) pcStatusString );
\r
1793 } while( pxNextTCB != pxFirstTCB );
\r
1797 /*-----------------------------------------------------------*/
\r
1799 #if ( configUSE_TRACE_FACILITY == 1 )
\r
1800 unsigned portSHORT usTaskCheckFreeStackSpace( const unsigned portCHAR *pucStackByte )
\r
1802 register unsigned portSHORT usCount = 0;
\r
1804 while( *pucStackByte == tskSTACK_FILL_BYTE )
\r
1806 pucStackByte -= portSTACK_GROWTH;
\r
1810 usCount /= sizeof( portSTACK_TYPE );
\r
1815 /*-----------------------------------------------------------*/
\r
1819 #if ( ( INCLUDE_vTaskDelete == 1 ) || ( INCLUDE_vTaskCleanUpResources == 1 ) )
\r
1821 static void prvDeleteTCB( tskTCB *pxTCB )
\r
1823 /* Free up the memory allocated by the scheduler for the task. It is up to
\r
1824 the task to free any memory allocated at the application level. */
\r
1825 vPortFree( pxTCB->pxStack );
\r
1826 vPortFree( pxTCB );
\r
1832 /*-----------------------------------------------------------*/
\r
1834 #if ( INCLUDE_xTaskGetCurrentTaskHandle == 1 )
\r
1836 xTaskHandle xTaskGetCurrentTaskHandle( void )
\r
1838 xTaskHandle xReturn;
\r
1840 portENTER_CRITICAL();
\r
1842 xReturn = ( xTaskHandle ) pxCurrentTCB;
\r
1844 portEXIT_CRITICAL();
\r