2 FreeRTOS.org V4.0.5 - 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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182 #include <stdlib.h>
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183 #include <string.h>
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185 #include "FreeRTOS.h"
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189 * Macro to define the amount of stack available to the idle task.
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191 #define tskIDLE_STACK_SIZE configMINIMAL_STACK_SIZE
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195 * Default a definitions for backwards compatibility with old
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196 * portmacro.h files.
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198 #ifndef configMAX_TASK_NAME_LEN
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199 #define configMAX_TASK_NAME_LEN 16
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202 #ifndef INCLUDE_xTaskGetCurrentTaskHandle
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203 #define INCLUDE_xTaskGetCurrentTaskHandle 0
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206 #ifndef configIDLE_SHOULD_YIELD
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207 #define configIDLE_SHOULD_YIELD 1
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210 #if configMAX_TASK_NAME_LEN < 1
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211 #undef configMAX_TASK_NAME_LEN
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212 #define configMAX_TASK_NAME_LEN 1
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215 #ifndef INCLUDE_xTaskResumeFromISR
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216 #define INCLUDE_xTaskResumeFromISR 1
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220 * Task control block. A task control block (TCB) is allocated to each task,
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221 * and stores the context of the task.
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223 typedef struct tskTaskControlBlock
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225 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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226 xListItem xGenericListItem; /*< List item used to place the TCB in ready and blocked queues. */
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227 xListItem xEventListItem; /*< List item used to place the TCB in event lists. */
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228 unsigned portBASE_TYPE uxPriority; /*< The priority of the task where 0 is the lowest priority. */
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229 portSTACK_TYPE *pxStack; /*< Points to the start of the stack. */
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230 unsigned portBASE_TYPE uxTCBNumber; /*< This is used for tracing the scheduler and making debugging easier only. */
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231 signed portCHAR pcTaskName[ configMAX_TASK_NAME_LEN ];/*< Descriptive name given to the task when created. Facilitates debugging only. */
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232 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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237 tskTCB * volatile pxCurrentTCB = NULL;
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239 /* Lists for ready and blocked tasks. --------------------*/
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241 static xList pxReadyTasksLists[ configMAX_PRIORITIES ]; /*< Prioritised ready tasks. */
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242 static xList xDelayedTaskList1; /*< Delayed tasks. */
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243 static xList xDelayedTaskList2; /*< Delayed tasks (two lists are used - one for delays that have overflowed the current tick count. */
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244 static xList * volatile pxDelayedTaskList; /*< Points to the delayed task list currently being used. */
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245 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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246 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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248 #if ( INCLUDE_vTaskDelete == 1 )
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250 static volatile xList xTasksWaitingTermination; /*< Tasks that have been deleted - but the their memory not yet freed. */
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251 static volatile unsigned portBASE_TYPE uxTasksDeleted = ( unsigned portBASE_TYPE ) 0;
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255 #if ( INCLUDE_vTaskSuspend == 1 )
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257 static xList xSuspendedTaskList; /*< Tasks that are currently suspended. */
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261 /* File private variables. --------------------------------*/
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262 static volatile unsigned portBASE_TYPE uxCurrentNumberOfTasks = ( unsigned portBASE_TYPE ) 0;
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263 static volatile portTickType xTickCount = ( portTickType ) 0;
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264 static unsigned portBASE_TYPE uxTopUsedPriority = tskIDLE_PRIORITY;
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265 static volatile unsigned portBASE_TYPE uxTopReadyPriority = tskIDLE_PRIORITY;
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266 static volatile signed portBASE_TYPE xSchedulerRunning = pdFALSE;
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267 static volatile unsigned portBASE_TYPE uxSchedulerSuspended = ( unsigned portBASE_TYPE ) pdFALSE;
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268 static volatile unsigned portBASE_TYPE uxMissedTicks = ( unsigned portBASE_TYPE ) 0;
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269 static volatile portBASE_TYPE xMissedYield = ( portBASE_TYPE ) pdFALSE;
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271 /* Debugging and trace facilities private variables and macros. ------------*/
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274 * The value used to fill the stack of a task when the task is created. This
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275 * is used purely for checking the high water mark for tasks.
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277 #define tskSTACK_FILL_BYTE ( 0xa5 )
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280 * Macros used by vListTask to indicate which state a task is in.
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282 #define tskBLOCKED_CHAR ( ( signed portCHAR ) 'B' )
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283 #define tskREADY_CHAR ( ( signed portCHAR ) 'R' )
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284 #define tskDELETED_CHAR ( ( signed portCHAR ) 'D' )
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285 #define tskSUSPENDED_CHAR ( ( signed portCHAR ) 'S' )
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288 * Macros and private variables used by the trace facility.
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290 #if ( configUSE_TRACE_FACILITY == 1 )
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292 #define tskSIZE_OF_EACH_TRACE_LINE ( ( unsigned portLONG ) ( sizeof( unsigned portLONG ) + sizeof( unsigned portLONG ) ) )
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293 static volatile signed portCHAR * volatile pcTraceBuffer;
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294 static signed portCHAR *pcTraceBufferStart;
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295 static signed portCHAR *pcTraceBufferEnd;
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296 static signed portBASE_TYPE xTracing = pdFALSE;
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301 * Macro that writes a trace of scheduler activity to a buffer. This trace
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302 * shows which task is running when and is very useful as a debugging tool.
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303 * As this macro is called each context switch it is a good idea to undefine
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304 * it if not using the facility.
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306 #if ( configUSE_TRACE_FACILITY == 1 )
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308 #define vWriteTraceToBuffer() \
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312 static unsigned portBASE_TYPE uxPreviousTask = 255; \
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314 if( uxPreviousTask != pxCurrentTCB->uxTCBNumber ) \
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316 if( ( pcTraceBuffer + tskSIZE_OF_EACH_TRACE_LINE ) < pcTraceBufferEnd ) \
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318 uxPreviousTask = pxCurrentTCB->uxTCBNumber; \
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319 *( unsigned portLONG * ) pcTraceBuffer = ( unsigned portLONG ) xTickCount; \
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320 pcTraceBuffer += sizeof( unsigned portLONG ); \
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321 *( unsigned portLONG * ) pcTraceBuffer = ( unsigned portLONG ) uxPreviousTask; \
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322 pcTraceBuffer += sizeof( unsigned portLONG ); \
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326 xTracing = pdFALSE; \
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334 #define vWriteTraceToBuffer()
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340 * Place the task represented by pxTCB into the appropriate ready queue for
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341 * the task. It is inserted at the end of the list. One quirk of this is
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342 * that if the task being inserted is at the same priority as the currently
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343 * executing task, then it will only be rescheduled after the currently
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344 * executing task has been rescheduled.
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346 #define prvAddTaskToReadyQueue( pxTCB ) \
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348 if( pxTCB->uxPriority > uxTopReadyPriority ) \
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350 uxTopReadyPriority = pxTCB->uxPriority; \
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352 vListInsertEnd( ( xList * ) &( pxReadyTasksLists[ pxTCB->uxPriority ] ), &( pxTCB->xGenericListItem ) ); \
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356 * Macro that looks at the list of tasks that are currently delayed to see if
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357 * any require waking.
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359 * Tasks are stored in the queue in the order of their wake time - meaning
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360 * once one tasks has been found whose timer has not expired we need not look
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361 * any further down the list.
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363 #define prvCheckDelayedTasks() \
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365 register tskTCB *pxTCB; \
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367 while( ( pxTCB = ( tskTCB * ) listGET_OWNER_OF_HEAD_ENTRY( pxDelayedTaskList ) ) != NULL ) \
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369 if( xTickCount < listGET_LIST_ITEM_VALUE( &( pxTCB->xGenericListItem ) ) ) \
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373 vListRemove( &( pxTCB->xGenericListItem ) ); \
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374 /* Is the task waiting on an event also? */ \
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375 if( pxTCB->xEventListItem.pvContainer ) \
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377 vListRemove( &( pxTCB->xEventListItem ) ); \
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379 prvAddTaskToReadyQueue( pxTCB ); \
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384 * Several functions take an xTaskHandle parameter that can optionally be NULL,
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385 * where NULL is used to indicate that the handle of the currently executing
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386 * task should be used in place of the parameter. This macro simply checks to
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387 * see if the parameter is NULL and returns a pointer to the appropriate TCB.
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389 #define prvGetTCBFromHandle( pxHandle ) ( ( pxHandle == NULL ) ? ( tskTCB * ) pxCurrentTCB : ( tskTCB * ) pxHandle )
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392 /* File private functions. --------------------------------*/
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395 * Utility to ready a TCB for a given task. Mainly just copies the parameters
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396 * into the TCB structure.
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398 static void prvInitialiseTCBVariables( tskTCB *pxTCB, unsigned portSHORT usStackDepth, const signed portCHAR * const pcName, unsigned portBASE_TYPE uxPriority );
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401 * Utility to ready all the lists used by the scheduler. This is called
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402 * automatically upon the creation of the first task.
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404 static void prvInitialiseTaskLists( void );
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407 * The idle task, which as all tasks is implemented as a never ending loop.
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408 * The idle task is automatically created and added to the ready lists upon
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409 * creation of the first user task.
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411 * The portTASK_FUNCTION_PROTO() macro is used to allow port/compiler specific
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412 * language extensions. The equivalent prototype for this function is:
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414 * void prvIdleTask( void *pvParameters );
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417 static portTASK_FUNCTION_PROTO( prvIdleTask, pvParameters );
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420 * Utility to free all memory allocated by the scheduler to hold a TCB,
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421 * including the stack pointed to by the TCB.
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423 * This does not free memory allocated by the task itself (i.e. memory
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424 * allocated by calls to pvPortMalloc from within the tasks application code).
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426 #if ( ( INCLUDE_vTaskDelete == 1 ) || ( INCLUDE_vTaskCleanUpResources == 1 ) )
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427 static void prvDeleteTCB( tskTCB *pxTCB );
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431 * Used only by the idle task. This checks to see if anything has been placed
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432 * in the list of tasks waiting to be deleted. If so the task is cleaned up
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433 * and its TCB deleted.
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435 static void prvCheckTasksWaitingTermination( void );
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438 * Allocates memory from the heap for a TCB and associated stack. Checks the
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439 * allocation was successful.
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441 static tskTCB *prvAllocateTCBAndStack( unsigned portSHORT usStackDepth );
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444 * Called from vTaskList. vListTasks details all the tasks currently under
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445 * control of the scheduler. The tasks may be in one of a number of lists.
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446 * prvListTaskWithinSingleList accepts a list and details the tasks from
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447 * within just that list.
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449 * THIS FUNCTION IS INTENDED FOR DEBUGGING ONLY, AND SHOULD NOT BE CALLED FROM
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450 * NORMAL APPLICATION CODE.
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452 #if ( configUSE_TRACE_FACILITY == 1 )
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454 static void prvListTaskWithinSingleList( signed portCHAR *pcWriteBuffer, xList *pxList, signed portCHAR cStatus );
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459 * When a task is created, the stack of the task is filled with a known value.
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460 * This function determines the 'high water mark' of the task stack by
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461 * determining how much of the stack remains at the original preset value.
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463 #if ( configUSE_TRACE_FACILITY == 1 )
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465 unsigned portSHORT usTaskCheckFreeStackSpace( const unsigned portCHAR *pucStackByte );
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475 /*-----------------------------------------------------------
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476 * TASK CREATION API documented in task.h
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477 *----------------------------------------------------------*/
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479 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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481 signed portBASE_TYPE xReturn;
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483 static unsigned portBASE_TYPE uxTaskNumber = 0; /*lint !e956 Static is deliberate - this is guarded before use. */
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485 /* Allocate the memory required by the TCB and stack for the new task.
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486 checking that the allocation was successful. */
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487 pxNewTCB = prvAllocateTCBAndStack( usStackDepth );
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489 if( pxNewTCB != NULL )
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491 portSTACK_TYPE *pxTopOfStack;
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493 /* Setup the newly allocated TCB with the initial state of the task. */
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494 prvInitialiseTCBVariables( pxNewTCB, usStackDepth, pcName, uxPriority );
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496 /* Calculate the top of stack address. This depends on whether the
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497 stack grows from high memory to low (as per the 80x86) or visa versa.
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498 portSTACK_GROWTH is used to make the result positive or negative as
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499 required by the port. */
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500 #if portSTACK_GROWTH < 0
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502 pxTopOfStack = pxNewTCB->pxStack + ( pxNewTCB->usStackDepth - 1 );
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506 pxTopOfStack = pxNewTCB->pxStack;
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510 /* Initialize the TCB stack to look as if the task was already running,
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511 but had been interrupted by the scheduler. The return address is set
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512 to the start of the task function. Once the stack has been initialised
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513 the top of stack variable is updated. */
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514 pxNewTCB->pxTopOfStack = pxPortInitialiseStack( pxTopOfStack, pvTaskCode, pvParameters );
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516 /* We are going to manipulate the task queues to add this task to a
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517 ready list, so must make sure no interrupts occur. */
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518 portENTER_CRITICAL();
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520 uxCurrentNumberOfTasks++;
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521 if( uxCurrentNumberOfTasks == ( unsigned portBASE_TYPE ) 1 )
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523 /* As this is the first task it must also be the current task. */
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524 pxCurrentTCB = pxNewTCB;
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526 /* This is the first task to be created so do the preliminary
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527 initialisation required. We will not recover if this call
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528 fails, but we will report the failure. */
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529 prvInitialiseTaskLists();
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533 /* If the scheduler is not already running, make this task the
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534 current task if it is the highest priority task to be created
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536 if( xSchedulerRunning == pdFALSE )
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538 if( pxCurrentTCB->uxPriority <= uxPriority )
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540 pxCurrentTCB = pxNewTCB;
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545 /* Remember the top priority to make context switching faster. Use
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546 the priority in pxNewTCB as this has been capped to a valid value. */
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547 if( pxNewTCB->uxPriority > uxTopUsedPriority )
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549 uxTopUsedPriority = pxNewTCB->uxPriority;
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552 /* Add a counter into the TCB for tracing only. */
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553 pxNewTCB->uxTCBNumber = uxTaskNumber;
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556 prvAddTaskToReadyQueue( pxNewTCB );
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560 portEXIT_CRITICAL();
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564 xReturn = errCOULD_NOT_ALLOCATE_REQUIRED_MEMORY;
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567 if( xReturn == pdPASS )
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569 if( ( void * ) pxCreatedTask != NULL )
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571 /* Pass the TCB out - in an anonymous way. The calling function/
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572 task can use this as a handle to delete the task later if
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574 *pxCreatedTask = ( xTaskHandle ) pxNewTCB;
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577 if( xSchedulerRunning != pdFALSE )
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579 /* If the created task is of a higher priority than the current task
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580 then it should run now. */
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581 if( pxCurrentTCB->uxPriority < uxPriority )
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590 /*-----------------------------------------------------------*/
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592 #if ( INCLUDE_vTaskDelete == 1 )
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594 void vTaskDelete( xTaskHandle pxTaskToDelete )
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598 taskENTER_CRITICAL();
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600 /* Ensure a yield is performed if the current task is being
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602 if( pxTaskToDelete == pxCurrentTCB )
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604 pxTaskToDelete = NULL;
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607 /* If null is passed in here then we are deleting ourselves. */
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608 pxTCB = prvGetTCBFromHandle( pxTaskToDelete );
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610 /* Remove task from the ready list and place in the termination list.
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611 This will stop the task from be scheduled. The idle task will check
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612 the termination list and free up any memory allocated by the
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613 scheduler for the TCB and stack. */
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614 vListRemove( &( pxTCB->xGenericListItem ) );
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616 /* Is the task waiting on an event also? */
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617 if( pxTCB->xEventListItem.pvContainer )
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619 vListRemove( &( pxTCB->xEventListItem ) );
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622 vListInsertEnd( ( xList * ) &xTasksWaitingTermination, &( pxTCB->xGenericListItem ) );
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624 /* Increment the ucTasksDeleted variable so the idle task knows
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625 there is a task that has been deleted and that it should therefore
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626 check the xTasksWaitingTermination list. */
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629 taskEXIT_CRITICAL();
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631 /* Force a reschedule if we have just deleted the current task. */
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632 if( xSchedulerRunning != pdFALSE )
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634 if( ( void * ) pxTaskToDelete == NULL )
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648 /*-----------------------------------------------------------
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649 * TASK CONTROL API documented in task.h
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650 *----------------------------------------------------------*/
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652 #if ( INCLUDE_vTaskDelayUntil == 1 )
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654 void vTaskDelayUntil( portTickType *pxPreviousWakeTime, portTickType xTimeIncrement )
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656 portTickType xTimeToWake;
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657 portBASE_TYPE xAlreadyYielded, xShouldDelay = pdFALSE;
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661 /* Generate the tick time at which the task wants to wake. */
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662 xTimeToWake = *pxPreviousWakeTime + xTimeIncrement;
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664 if( xTickCount < *pxPreviousWakeTime )
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666 /* The tick count has overflowed since this function was
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667 lasted called. In this case the only time we should ever
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668 actually delay is if the wake time has also overflowed,
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669 and the wake time is greater than the tick time. When this
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670 is the case it is as if neither time had overflowed. */
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671 if( ( xTimeToWake < *pxPreviousWakeTime ) && ( xTimeToWake > xTickCount ) )
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673 xShouldDelay = pdTRUE;
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678 /* The tick time has not overflowed. In this case we will
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679 delay if either the wake time has overflowed, and/or the
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680 tick time is less than the wake time. */
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681 if( ( xTimeToWake < *pxPreviousWakeTime ) || ( xTimeToWake > xTickCount ) )
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683 xShouldDelay = pdTRUE;
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687 /* Update the wake time ready for the next call. */
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688 *pxPreviousWakeTime = xTimeToWake;
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692 /* We must remove ourselves from the ready list before adding
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693 ourselves to the blocked list as the same list item is used for
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695 vListRemove( ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
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697 /* The list item will be inserted in wake time order. */
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698 listSET_LIST_ITEM_VALUE( &( pxCurrentTCB->xGenericListItem ), xTimeToWake );
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700 if( xTimeToWake < xTickCount )
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702 /* Wake time has overflowed. Place this item in the
\r
704 vListInsert( ( xList * ) pxOverflowDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
\r
708 /* The wake time has not overflowed, so we can use the
\r
709 current block list. */
\r
710 vListInsert( ( xList * ) pxDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
\r
714 xAlreadyYielded = xTaskResumeAll();
\r
716 /* Force a reschedule if xTaskResumeAll has not already done so, we may
\r
717 have put ourselves to sleep. */
\r
718 if( !xAlreadyYielded )
\r
725 /*-----------------------------------------------------------*/
\r
727 #if ( INCLUDE_vTaskDelay == 1 )
\r
729 void vTaskDelay( portTickType xTicksToDelay )
\r
731 portTickType xTimeToWake;
\r
732 signed portBASE_TYPE xAlreadyYielded = pdFALSE;
\r
734 /* A delay time of zero just forces a reschedule. */
\r
735 if( xTicksToDelay > ( portTickType ) 0 )
\r
739 /* A task that is removed from the event list while the
\r
740 scheduler is suspended will not get placed in the ready
\r
741 list or removed from the blocked list until the scheduler
\r
744 This task cannot be in an event list as it is the currently
\r
747 /* Calculate the time to wake - this may overflow but this is
\r
749 xTimeToWake = xTickCount + xTicksToDelay;
\r
751 /* We must remove ourselves from the ready list before adding
\r
752 ourselves to the blocked list as the same list item is used for
\r
754 vListRemove( ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
\r
756 /* The list item will be inserted in wake time order. */
\r
757 listSET_LIST_ITEM_VALUE( &( pxCurrentTCB->xGenericListItem ), xTimeToWake );
\r
759 if( xTimeToWake < xTickCount )
\r
761 /* Wake time has overflowed. Place this item in the
\r
763 vListInsert( ( xList * ) pxOverflowDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
\r
767 /* The wake time has not overflowed, so we can use the
\r
768 current block list. */
\r
769 vListInsert( ( xList * ) pxDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
\r
772 xAlreadyYielded = xTaskResumeAll();
\r
775 /* Force a reschedule if xTaskResumeAll has not already done so, we may
\r
776 have put ourselves to sleep. */
\r
777 if( !xAlreadyYielded )
\r
784 /*-----------------------------------------------------------*/
\r
786 #if ( INCLUDE_uxTaskPriorityGet == 1 )
\r
788 unsigned portBASE_TYPE uxTaskPriorityGet( xTaskHandle pxTask )
\r
791 unsigned portBASE_TYPE uxReturn;
\r
793 taskENTER_CRITICAL();
\r
795 /* If null is passed in here then we are changing the
\r
796 priority of the calling function. */
\r
797 pxTCB = prvGetTCBFromHandle( pxTask );
\r
798 uxReturn = pxTCB->uxPriority;
\r
800 taskEXIT_CRITICAL();
\r
806 /*-----------------------------------------------------------*/
\r
808 #if ( INCLUDE_vTaskPrioritySet == 1 )
\r
810 void vTaskPrioritySet( xTaskHandle pxTask, unsigned portBASE_TYPE uxNewPriority )
\r
813 unsigned portBASE_TYPE uxCurrentPriority, xYieldRequired = pdFALSE;
\r
815 /* Ensure the new priority is valid. */
\r
816 if( uxNewPriority >= configMAX_PRIORITIES )
\r
818 uxNewPriority = configMAX_PRIORITIES - 1;
\r
821 taskENTER_CRITICAL();
\r
823 /* If null is passed in here then we are changing the
\r
824 priority of the calling function. */
\r
825 pxTCB = prvGetTCBFromHandle( pxTask );
\r
826 uxCurrentPriority = pxTCB->uxPriority;
\r
828 if( uxCurrentPriority != uxNewPriority )
\r
830 /* The priority change may have readied a task of higher
\r
831 priority than the calling task. */
\r
832 if( uxNewPriority > pxCurrentTCB->uxPriority )
\r
834 if( pxTask != NULL )
\r
836 /* The priority of another task is being raised. If we
\r
837 were raising the priority of the currently running task
\r
838 there would be no need to switch as it must have already
\r
839 been the highest priority task. */
\r
840 xYieldRequired = pdTRUE;
\r
843 else if( pxTask == NULL )
\r
845 /* Setting our own priority down means there may now be another
\r
846 task of higher priority that is ready to execute. */
\r
847 xYieldRequired = pdTRUE;
\r
850 pxTCB->uxPriority = uxNewPriority;
\r
851 listSET_LIST_ITEM_VALUE( &( pxTCB->xEventListItem ), configMAX_PRIORITIES - ( portTickType ) uxNewPriority );
\r
853 /* If the task is in the blocked or suspended list we need do
\r
854 nothing more than change it's priority variable. However, if
\r
855 the task is in a ready list it needs to be removed and placed
\r
856 in the queue appropriate to its new priority. */
\r
857 if( listIS_CONTAINED_WITHIN( &( pxReadyTasksLists[ uxCurrentPriority ] ), &( pxTCB->xGenericListItem ) ) )
\r
859 /* The task is currently in its ready list - remove before adding
\r
860 it to it's new ready list. As we are in a critical section we
\r
861 can do this even if the scheduler is suspended. */
\r
862 vListRemove( &( pxTCB->xGenericListItem ) );
\r
863 prvAddTaskToReadyQueue( pxTCB );
\r
866 if( xYieldRequired == pdTRUE )
\r
872 taskEXIT_CRITICAL();
\r
876 /*-----------------------------------------------------------*/
\r
878 #if ( INCLUDE_vTaskSuspend == 1 )
\r
880 void vTaskSuspend( xTaskHandle pxTaskToSuspend )
\r
884 taskENTER_CRITICAL();
\r
886 /* Ensure a yield is performed if the current task is being
\r
888 if( pxTaskToSuspend == pxCurrentTCB )
\r
890 pxTaskToSuspend = NULL;
\r
893 /* If null is passed in here then we are suspending ourselves. */
\r
894 pxTCB = prvGetTCBFromHandle( pxTaskToSuspend );
\r
896 /* Remove task from the ready/delayed list and place in the suspended list. */
\r
897 vListRemove( &( pxTCB->xGenericListItem ) );
\r
899 /* Is the task waiting on an event also? */
\r
900 if( pxTCB->xEventListItem.pvContainer )
\r
902 vListRemove( &( pxTCB->xEventListItem ) );
\r
905 vListInsertEnd( ( xList * ) &xSuspendedTaskList, &( pxTCB->xGenericListItem ) );
\r
907 taskEXIT_CRITICAL();
\r
909 /* We may have just suspended the current task. */
\r
910 if( ( void * ) pxTaskToSuspend == NULL )
\r
917 /*-----------------------------------------------------------*/
\r
919 #if ( INCLUDE_vTaskSuspend == 1 )
\r
921 void vTaskResume( xTaskHandle pxTaskToResume )
\r
925 /* Remove the task from whichever list it is currently in, and place
\r
926 it in the ready list. */
\r
927 pxTCB = ( tskTCB * ) pxTaskToResume;
\r
929 /* The parameter cannot be NULL as it is impossible to resume the
\r
930 currently executing task. */
\r
931 if( pxTCB != NULL )
\r
933 taskENTER_CRITICAL();
\r
935 /* Is the task we are attempting to resume actually suspended? */
\r
936 if( listIS_CONTAINED_WITHIN( &xSuspendedTaskList, &( pxTCB->xGenericListItem ) ) != pdFALSE )
\r
938 /* Has the task already been resumed from within an ISR? */
\r
939 if( listIS_CONTAINED_WITHIN( &xPendingReadyList, &( pxTCB->xEventListItem ) ) != pdTRUE )
\r
941 /* As we are in a critical section we can access the ready
\r
942 lists even if the scheduler is suspended. */
\r
943 vListRemove( &( pxTCB->xGenericListItem ) );
\r
944 prvAddTaskToReadyQueue( pxTCB );
\r
946 /* We may have just resumed a higher priority task. */
\r
947 if( pxTCB->uxPriority >= pxCurrentTCB->uxPriority )
\r
949 /* This yield may not cause the task just resumed to run, but
\r
950 will leave the lists in the correct state for the next yield. */
\r
956 taskEXIT_CRITICAL();
\r
962 /*-----------------------------------------------------------*/
\r
964 #if ( ( INCLUDE_xTaskResumeFromISR == 1 ) && ( INCLUDE_vTaskSuspend == 1 ) )
\r
966 portBASE_TYPE xTaskResumeFromISR( xTaskHandle pxTaskToResume )
\r
968 portBASE_TYPE xYieldRequired = pdFALSE;
\r
971 pxTCB = ( tskTCB * ) pxTaskToResume;
\r
973 /* Is the task we are attempting to resume actually suspended? */
\r
974 if( listIS_CONTAINED_WITHIN( &xSuspendedTaskList, &( pxTCB->xGenericListItem ) ) != pdFALSE )
\r
976 /* Has the task already been resumed from within an ISR? */
\r
977 if( listIS_CONTAINED_WITHIN( &xPendingReadyList, &( pxTCB->xEventListItem ) ) != pdTRUE )
\r
979 if( uxSchedulerSuspended == ( unsigned portBASE_TYPE ) pdFALSE )
\r
981 xYieldRequired = ( pxTCB->uxPriority >= pxCurrentTCB->uxPriority );
\r
982 vListRemove( &( pxTCB->xGenericListItem ) );
\r
983 prvAddTaskToReadyQueue( pxTCB );
\r
987 /* We cannot access the delayed or ready lists, so will hold this
\r
988 task pending until the scheduler is resumed, at which point a
\r
989 yield will be preformed if necessary. */
\r
990 vListInsertEnd( ( xList * ) &( xPendingReadyList ), &( pxTCB->xEventListItem ) );
\r
995 return xYieldRequired;
\r
1003 /*-----------------------------------------------------------
\r
1004 * PUBLIC SCHEDULER CONTROL documented in task.h
\r
1005 *----------------------------------------------------------*/
\r
1008 void vTaskStartScheduler( void )
\r
1010 portBASE_TYPE xReturn;
\r
1012 /* Add the idle task at the lowest priority. */
\r
1013 xReturn = xTaskCreate( prvIdleTask, ( signed portCHAR * ) "IDLE", tskIDLE_STACK_SIZE, ( void * ) NULL, tskIDLE_PRIORITY, ( xTaskHandle * ) NULL );
\r
1015 if( xReturn == pdPASS )
\r
1017 /* Interrupts are turned off here, to ensure a tick does not occur
\r
1018 before or during the call to xPortStartScheduler(). The stacks of
\r
1019 the created tasks contain a status word with interrupts switched on
\r
1020 so interrupts will automatically get re-enabled when the first task
\r
1023 STEPPING THROUGH HERE USING A DEBUGGER CAN CAUSE BIG PROBLEMS IF THE
\r
1024 DEBUGGER ALLOWS INTERRUPTS TO BE PROCESSED. */
\r
1025 portDISABLE_INTERRUPTS();
\r
1027 xSchedulerRunning = pdTRUE;
\r
1028 xTickCount = ( portTickType ) 0;
\r
1030 /* Setting up the timer tick is hardware specific and thus in the
\r
1031 portable interface. */
\r
1032 if( xPortStartScheduler() )
\r
1034 /* Should not reach here as if the scheduler is running the
\r
1035 function will not return. */
\r
1039 /* Should only reach here if a task calls xTaskEndScheduler(). */
\r
1043 /*-----------------------------------------------------------*/
\r
1045 void vTaskEndScheduler( void )
\r
1047 /* Stop the scheduler interrupts and call the portable scheduler end
\r
1048 routine so the original ISRs can be restored if necessary. The port
\r
1049 layer must ensure interrupts enable bit is left in the correct state. */
\r
1050 portDISABLE_INTERRUPTS();
\r
1051 xSchedulerRunning = pdFALSE;
\r
1052 vPortEndScheduler();
\r
1054 /*----------------------------------------------------------*/
\r
1056 void vTaskSuspendAll( void )
\r
1058 portENTER_CRITICAL();
\r
1059 ++uxSchedulerSuspended;
\r
1060 portEXIT_CRITICAL();
\r
1062 /*----------------------------------------------------------*/
\r
1064 signed portBASE_TYPE xTaskResumeAll( void )
\r
1066 register tskTCB *pxTCB;
\r
1067 signed portBASE_TYPE xAlreadyYielded = pdFALSE;
\r
1069 /* It is possible that an ISR caused a task to be removed from an event
\r
1070 list while the scheduler was suspended. If this was the case then the
\r
1071 removed task will have been added to the xPendingReadyList. Once the
\r
1072 scheduler has been resumed it is safe to move all the pending ready
\r
1073 tasks from this list into their appropriate ready list. */
\r
1074 portENTER_CRITICAL();
\r
1076 --uxSchedulerSuspended;
\r
1078 if( uxSchedulerSuspended == ( unsigned portBASE_TYPE ) pdFALSE )
\r
1080 if( uxCurrentNumberOfTasks > ( unsigned portBASE_TYPE ) 0 )
\r
1082 portBASE_TYPE xYieldRequired = pdFALSE;
\r
1084 /* Move any readied tasks from the pending list into the
\r
1085 appropriate ready list. */
\r
1086 while( ( pxTCB = ( tskTCB * ) listGET_OWNER_OF_HEAD_ENTRY( ( ( xList * ) &xPendingReadyList ) ) ) != NULL )
\r
1088 vListRemove( &( pxTCB->xEventListItem ) );
\r
1089 vListRemove( &( pxTCB->xGenericListItem ) );
\r
1090 prvAddTaskToReadyQueue( pxTCB );
\r
1092 /* If we have moved a task that has a priority higher than
\r
1093 the current task then we should yield. */
\r
1094 if( pxTCB->uxPriority >= pxCurrentTCB->uxPriority )
\r
1096 xYieldRequired = pdTRUE;
\r
1100 /* If any ticks occurred while the scheduler was suspended then
\r
1101 they should be processed now. This ensures the tick count does not
\r
1102 slip, and that any delayed tasks are resumed at the correct time. */
\r
1103 if( uxMissedTicks > ( unsigned portBASE_TYPE ) 0 )
\r
1105 while( uxMissedTicks > ( unsigned portBASE_TYPE ) 0 )
\r
1107 vTaskIncrementTick();
\r
1111 /* As we have processed some ticks it is appropriate to yield
\r
1112 to ensure the highest priority task that is ready to run is
\r
1113 the task actually running. */
\r
1114 xYieldRequired = pdTRUE;
\r
1117 if( ( xYieldRequired == pdTRUE ) || ( xMissedYield == pdTRUE ) )
\r
1119 xAlreadyYielded = pdTRUE;
\r
1120 xMissedYield = pdFALSE;
\r
1126 portEXIT_CRITICAL();
\r
1128 return xAlreadyYielded;
\r
1136 /*-----------------------------------------------------------
\r
1137 * PUBLIC TASK UTILITIES documented in task.h
\r
1138 *----------------------------------------------------------*/
\r
1142 portTickType xTaskGetTickCount( void )
\r
1144 portTickType xTicks;
\r
1146 /* Critical section required if running on a 16 bit processor. */
\r
1147 taskENTER_CRITICAL();
\r
1149 xTicks = xTickCount;
\r
1151 taskEXIT_CRITICAL();
\r
1155 /*-----------------------------------------------------------*/
\r
1157 unsigned portBASE_TYPE uxTaskGetNumberOfTasks( void )
\r
1159 unsigned portBASE_TYPE uxNumberOfTasks;
\r
1161 taskENTER_CRITICAL();
\r
1162 uxNumberOfTasks = uxCurrentNumberOfTasks;
\r
1163 taskEXIT_CRITICAL();
\r
1165 return uxNumberOfTasks;
\r
1167 /*-----------------------------------------------------------*/
\r
1169 #if ( ( configUSE_TRACE_FACILITY == 1 ) && ( INCLUDE_vTaskDelete == 1 ) && ( INCLUDE_vTaskSuspend == 1 ) )
\r
1171 void vTaskList( signed portCHAR *pcWriteBuffer )
\r
1173 unsigned portBASE_TYPE uxQueue;
\r
1175 /* This is a VERY costly function that should be used for debug only.
\r
1176 It leaves interrupts disabled for a LONG time. */
\r
1178 vTaskSuspendAll();
\r
1180 /* Run through all the lists that could potentially contain a TCB and
\r
1181 report the task name, state and stack high water mark. */
\r
1183 pcWriteBuffer[ 0 ] = ( signed portCHAR ) 0x00;
\r
1184 strcat( ( portCHAR * ) pcWriteBuffer, ( const portCHAR * ) "\r\n" );
\r
1186 uxQueue = uxTopUsedPriority + 1;
\r
1192 if( !listLIST_IS_EMPTY( &( pxReadyTasksLists[ uxQueue ] ) ) )
\r
1194 prvListTaskWithinSingleList( pcWriteBuffer, ( xList * ) &( pxReadyTasksLists[ uxQueue ] ), tskREADY_CHAR );
\r
1196 }while( uxQueue > ( unsigned portSHORT ) tskIDLE_PRIORITY );
\r
1198 if( !listLIST_IS_EMPTY( pxDelayedTaskList ) )
\r
1200 prvListTaskWithinSingleList( pcWriteBuffer, ( xList * ) pxDelayedTaskList, tskBLOCKED_CHAR );
\r
1203 if( !listLIST_IS_EMPTY( pxOverflowDelayedTaskList ) )
\r
1205 prvListTaskWithinSingleList( pcWriteBuffer, ( xList * ) pxOverflowDelayedTaskList, tskBLOCKED_CHAR );
\r
1208 if( !listLIST_IS_EMPTY( &xTasksWaitingTermination ) )
\r
1210 prvListTaskWithinSingleList( pcWriteBuffer, ( xList * ) &xTasksWaitingTermination, tskDELETED_CHAR );
\r
1213 if( !listLIST_IS_EMPTY( &xSuspendedTaskList ) )
\r
1215 prvListTaskWithinSingleList( pcWriteBuffer, ( xList * ) &xSuspendedTaskList, tskSUSPENDED_CHAR );
\r
1222 /*----------------------------------------------------------*/
\r
1224 #if ( configUSE_TRACE_FACILITY == 1 )
\r
1226 void vTaskStartTrace( signed portCHAR * pcBuffer, unsigned portLONG ulBufferSize )
\r
1228 portENTER_CRITICAL();
\r
1230 pcTraceBuffer = ( volatile signed portCHAR * volatile )pcBuffer;
\r
1231 pcTraceBufferStart = pcBuffer;
\r
1232 pcTraceBufferEnd = pcBuffer + ( ulBufferSize - tskSIZE_OF_EACH_TRACE_LINE );
\r
1233 xTracing = pdTRUE;
\r
1235 portEXIT_CRITICAL();
\r
1239 /*----------------------------------------------------------*/
\r
1241 #if ( configUSE_TRACE_FACILITY == 1 )
\r
1243 unsigned portLONG ulTaskEndTrace( void )
\r
1245 unsigned portLONG ulBufferLength;
\r
1247 portENTER_CRITICAL();
\r
1248 xTracing = pdFALSE;
\r
1249 portEXIT_CRITICAL();
\r
1251 ulBufferLength = ( unsigned portLONG ) ( pcTraceBuffer - pcTraceBufferStart );
\r
1253 return ulBufferLength;
\r
1260 /*-----------------------------------------------------------
\r
1261 * SCHEDULER INTERNALS AVAILABLE FOR PORTING PURPOSES
\r
1262 * documented in task.h
\r
1263 *----------------------------------------------------------*/
\r
1266 inline void vTaskIncrementTick( void )
\r
1268 /* Called by the portable layer each time a tick interrupt occurs.
\r
1269 Increments the tick then checks to see if the new tick value will cause any
\r
1270 tasks to be unblocked. */
\r
1271 if( uxSchedulerSuspended == ( unsigned portBASE_TYPE ) pdFALSE )
\r
1274 if( xTickCount == ( portTickType ) 0 )
\r
1278 /* Tick count has overflowed so we need to swap the delay lists.
\r
1279 If there are any items in pxDelayedTaskList here then there is
\r
1281 pxTemp = pxDelayedTaskList;
\r
1282 pxDelayedTaskList = pxOverflowDelayedTaskList;
\r
1283 pxOverflowDelayedTaskList = pxTemp;
\r
1286 /* See if this tick has made a timeout expire. */
\r
1287 prvCheckDelayedTasks();
\r
1293 /* The tick hook gets called at regular intervals, even if the
\r
1294 scheduler is locked. */
\r
1295 #if ( configUSE_TICK_HOOK == 1 )
\r
1297 extern void vApplicationTickHook( void );
\r
1299 vApplicationTickHook();
\r
1304 #if ( configUSE_TICK_HOOK == 1 )
\r
1306 extern void vApplicationTickHook( void );
\r
1308 /* Guard against the tick hook being called when the missed tick
\r
1309 count is being unwound (when the scheduler is being unlocked. */
\r
1310 if( uxMissedTicks == 0 )
\r
1312 vApplicationTickHook();
\r
1317 /*-----------------------------------------------------------*/
\r
1319 #if ( ( INCLUDE_vTaskCleanUpResources == 1 ) && ( INCLUDE_vTaskSuspend == 1 ) )
\r
1321 void vTaskCleanUpResources( void )
\r
1323 unsigned portSHORT usQueue;
\r
1324 volatile tskTCB *pxTCB;
\r
1326 usQueue = ( unsigned portSHORT ) uxTopUsedPriority + ( unsigned portSHORT ) 1;
\r
1328 /* Remove any TCB's from the ready queues. */
\r
1333 while( !listLIST_IS_EMPTY( &( pxReadyTasksLists[ usQueue ] ) ) )
\r
1335 listGET_OWNER_OF_NEXT_ENTRY( pxTCB, &( pxReadyTasksLists[ usQueue ] ) );
\r
1336 vListRemove( ( xListItem * ) &( pxTCB->xGenericListItem ) );
\r
1338 prvDeleteTCB( ( tskTCB * ) pxTCB );
\r
1340 }while( usQueue > ( unsigned portSHORT ) tskIDLE_PRIORITY );
\r
1342 /* Remove any TCB's from the delayed queue. */
\r
1343 while( !listLIST_IS_EMPTY( &xDelayedTaskList1 ) )
\r
1345 listGET_OWNER_OF_NEXT_ENTRY( pxTCB, &xDelayedTaskList1 );
\r
1346 vListRemove( ( xListItem * ) &( pxTCB->xGenericListItem ) );
\r
1348 prvDeleteTCB( ( tskTCB * ) pxTCB );
\r
1351 /* Remove any TCB's from the overflow delayed queue. */
\r
1352 while( !listLIST_IS_EMPTY( &xDelayedTaskList2 ) )
\r
1354 listGET_OWNER_OF_NEXT_ENTRY( pxTCB, &xDelayedTaskList2 );
\r
1355 vListRemove( ( xListItem * ) &( pxTCB->xGenericListItem ) );
\r
1357 prvDeleteTCB( ( tskTCB * ) pxTCB );
\r
1360 while( !listLIST_IS_EMPTY( &xSuspendedTaskList ) )
\r
1362 listGET_OWNER_OF_NEXT_ENTRY( pxTCB, &xSuspendedTaskList );
\r
1363 vListRemove( ( xListItem * ) &( pxTCB->xGenericListItem ) );
\r
1365 prvDeleteTCB( ( tskTCB * ) pxTCB );
\r
1368 while( !listLIST_IS_EMPTY( &xPendingReadyList ) )
\r
1370 listGET_OWNER_OF_NEXT_ENTRY( pxTCB, &xPendingReadyList );
\r
1371 vListRemove( ( xListItem * ) &( pxTCB->xGenericListItem ) );
\r
1373 prvDeleteTCB( ( tskTCB * ) pxTCB );
\r
1378 /*-----------------------------------------------------------*/
\r
1380 void vTaskSwitchContext( void )
\r
1382 if( uxSchedulerSuspended != ( unsigned portBASE_TYPE ) pdFALSE )
\r
1384 /* The scheduler is currently suspended - do not allow a context
\r
1386 xMissedYield = pdTRUE;
\r
1390 /* Find the highest priority queue that contains ready tasks. */
\r
1391 while( listLIST_IS_EMPTY( &( pxReadyTasksLists[ uxTopReadyPriority ] ) ) )
\r
1393 --uxTopReadyPriority;
\r
1396 /* listGET_OWNER_OF_NEXT_ENTRY walks through the list, so the tasks of the
\r
1397 same priority get an equal share of the processor time. */
\r
1398 listGET_OWNER_OF_NEXT_ENTRY( pxCurrentTCB, &( pxReadyTasksLists[ uxTopReadyPriority ] ) );
\r
1399 vWriteTraceToBuffer();
\r
1401 /*-----------------------------------------------------------*/
\r
1403 void vTaskPlaceOnEventList( xList *pxEventList, portTickType xTicksToWait )
\r
1405 portTickType xTimeToWake;
\r
1407 /* THIS FUNCTION MUST BE CALLED WITH INTERRUPTS DISABLED OR THE
\r
1408 SCHEDULER SUSPENDED. */
\r
1410 /* Place the event list item of the TCB in the appropriate event list.
\r
1411 This is placed in the list in priority order so the highest priority task
\r
1412 is the first to be woken by the event. */
\r
1413 vListInsert( ( xList * ) pxEventList, ( xListItem * ) &( pxCurrentTCB->xEventListItem ) );
\r
1415 /* Calculate the time at which the task should be woken if the event does
\r
1416 not occur. This may overflow but this doesn't matter. */
\r
1417 xTimeToWake = xTickCount + xTicksToWait;
\r
1419 /* We must remove ourselves from the ready list before adding ourselves
\r
1420 to the blocked list as the same list item is used for both lists. We have
\r
1421 exclusive access to the ready lists as the scheduler is locked. */
\r
1422 vListRemove( ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
\r
1424 listSET_LIST_ITEM_VALUE( &( pxCurrentTCB->xGenericListItem ), xTimeToWake );
\r
1426 if( xTimeToWake < xTickCount )
\r
1428 /* Wake time has overflowed. Place this item in the overflow list. */
\r
1429 vListInsert( ( xList * ) pxOverflowDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
\r
1433 /* The wake time has not overflowed, so we can use the current block list. */
\r
1434 vListInsert( ( xList * ) pxDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
\r
1437 /*-----------------------------------------------------------*/
\r
1439 signed portBASE_TYPE xTaskRemoveFromEventList( const xList *pxEventList )
\r
1441 tskTCB *pxUnblockedTCB;
\r
1442 portBASE_TYPE xReturn;
\r
1444 /* THIS FUNCTION MUST BE CALLED WITH INTERRUPTS DISABLED OR THE
\r
1445 SCHEDULER SUSPENDED. It can also be called from within an ISR. */
\r
1447 /* The event list is sorted in priority order, so we can remove the
\r
1448 first in the list, remove the TCB from the delayed list, and add
\r
1449 it to the ready list.
\r
1451 If an event is for a queue that is locked then this function will never
\r
1452 get called - the lock count on the queue will get modified instead. This
\r
1453 means we can always expect exclusive access to the event list here. */
\r
1454 pxUnblockedTCB = ( tskTCB * ) listGET_OWNER_OF_HEAD_ENTRY( pxEventList );
\r
1455 vListRemove( &( pxUnblockedTCB->xEventListItem ) );
\r
1457 if( uxSchedulerSuspended == ( unsigned portBASE_TYPE ) pdFALSE )
\r
1459 vListRemove( &( pxUnblockedTCB->xGenericListItem ) );
\r
1460 prvAddTaskToReadyQueue( pxUnblockedTCB );
\r
1464 /* We cannot access the delayed or ready lists, so will hold this
\r
1465 task pending until the scheduler is resumed. */
\r
1466 vListInsertEnd( ( xList * ) &( xPendingReadyList ), &( pxUnblockedTCB->xEventListItem ) );
\r
1469 if( pxUnblockedTCB->uxPriority >= pxCurrentTCB->uxPriority )
\r
1471 /* Return true if the task removed from the event list has
\r
1472 a higher priority than the calling task. This allows
\r
1473 the calling task to know if it should force a context
\r
1479 xReturn = pdFALSE;
\r
1490 * -----------------------------------------------------------
\r
1492 * ----------------------------------------------------------
\r
1494 * The portTASK_FUNCTION() macro is used to allow port/compiler specific
\r
1495 * language extensions. The equivalent prototype for this function is:
\r
1497 * void prvIdleTask( void *pvParameters );
\r
1500 static portTASK_FUNCTION( prvIdleTask, pvParameters )
\r
1502 /* Stop warnings. */
\r
1503 ( void ) pvParameters;
\r
1507 /* See if any tasks have been deleted. */
\r
1508 prvCheckTasksWaitingTermination();
\r
1510 #if ( configUSE_PREEMPTION == 0 )
\r
1512 /* If we are not using preemption we keep forcing a task switch to
\r
1513 see if any other task has become available. If we are using
\r
1514 preemption we don't need to do this as any task becoming available
\r
1515 will automatically get the processor anyway. */
\r
1520 #if ( ( configUSE_PREEMPTION == 1 ) && ( configIDLE_SHOULD_YIELD == 1 ) )
\r
1522 /* When using preemption tasks of equal priority will be
\r
1523 timesliced. If a task that is sharing the idle priority is ready
\r
1524 to run then the idle task should yield before the end of the
\r
1527 A critical region is not required here as we are just reading from
\r
1528 the list, and an occasional incorrect value will not matter. If
\r
1529 the ready list at the idle priority contains more than one task
\r
1530 then a task other than the idle task is ready to execute. */
\r
1531 if( listCURRENT_LIST_LENGTH( &( pxReadyTasksLists[ tskIDLE_PRIORITY ] ) ) > ( unsigned portBASE_TYPE ) 1 )
\r
1538 #if ( configUSE_IDLE_HOOK == 1 )
\r
1540 extern void vApplicationIdleHook( void );
\r
1542 /* Call the user defined function from within the idle task. This
\r
1543 allows the application designer to add background functionality
\r
1544 without the overhead of a separate task.
\r
1545 NOTE: vApplicationIdleHook() MUST NOT, UNDER ANY CIRCUMSTANCES,
\r
1546 CALL A FUNCTION THAT MIGHT BLOCK. */
\r
1547 vApplicationIdleHook();
\r
1551 } /*lint !e715 pvParameters is not accessed but all task functions require the same prototype. */
\r
1559 /*-----------------------------------------------------------
\r
1560 * File private functions documented at the top of the file.
\r
1561 *----------------------------------------------------------*/
\r
1565 static void prvInitialiseTCBVariables( tskTCB *pxTCB, unsigned portSHORT usStackDepth, const signed portCHAR * const pcName, unsigned portBASE_TYPE uxPriority )
\r
1567 pxTCB->usStackDepth = usStackDepth;
\r
1569 /* Store the function name in the TCB. */
\r
1570 strncpy( ( char * ) pxTCB->pcTaskName, ( const char * ) pcName, ( unsigned portSHORT ) configMAX_TASK_NAME_LEN );
\r
1571 pxTCB->pcTaskName[ ( unsigned portSHORT ) configMAX_TASK_NAME_LEN - ( unsigned portSHORT ) 1 ] = '\0';
\r
1573 /* This is used as an array index so must ensure it's not too large. */
\r
1574 if( uxPriority >= configMAX_PRIORITIES )
\r
1576 uxPriority = configMAX_PRIORITIES - 1;
\r
1579 pxTCB->uxPriority = uxPriority;
\r
1581 vListInitialiseItem( &( pxTCB->xGenericListItem ) );
\r
1582 vListInitialiseItem( &( pxTCB->xEventListItem ) );
\r
1584 /* Set the pxTCB as a link back from the xListItem. This is so we can get
\r
1585 back to the containing TCB from a generic item in a list. */
\r
1586 listSET_LIST_ITEM_OWNER( &( pxTCB->xGenericListItem ), pxTCB );
\r
1588 /* Event lists are always in priority order. */
\r
1589 listSET_LIST_ITEM_VALUE( &( pxTCB->xEventListItem ), configMAX_PRIORITIES - ( portTickType ) uxPriority );
\r
1590 listSET_LIST_ITEM_OWNER( &( pxTCB->xEventListItem ), pxTCB );
\r
1592 /*-----------------------------------------------------------*/
\r
1594 static void prvInitialiseTaskLists( void )
\r
1596 unsigned portBASE_TYPE uxPriority;
\r
1598 for( uxPriority = 0; uxPriority < configMAX_PRIORITIES; uxPriority++ )
\r
1600 vListInitialise( ( xList * ) &( pxReadyTasksLists[ uxPriority ] ) );
\r
1603 vListInitialise( ( xList * ) &xDelayedTaskList1 );
\r
1604 vListInitialise( ( xList * ) &xDelayedTaskList2 );
\r
1605 vListInitialise( ( xList * ) &xPendingReadyList );
\r
1607 #if ( INCLUDE_vTaskDelete == 1 )
\r
1609 vListInitialise( ( xList * ) &xTasksWaitingTermination );
\r
1613 #if ( INCLUDE_vTaskSuspend == 1 )
\r
1615 vListInitialise( ( xList * ) &xSuspendedTaskList );
\r
1619 /* Start with pxDelayedTaskList using list1 and the pxOverflowDelayedTaskList
\r
1621 pxDelayedTaskList = &xDelayedTaskList1;
\r
1622 pxOverflowDelayedTaskList = &xDelayedTaskList2;
\r
1624 /*-----------------------------------------------------------*/
\r
1626 static void prvCheckTasksWaitingTermination( void )
\r
1628 #if ( INCLUDE_vTaskDelete == 1 )
\r
1630 portBASE_TYPE xListIsEmpty;
\r
1632 /* ucTasksDeleted is used to prevent vTaskSuspendAll() being called
\r
1633 too often in the idle task. */
\r
1634 if( uxTasksDeleted > ( unsigned portBASE_TYPE ) 0 )
\r
1636 vTaskSuspendAll();
\r
1637 xListIsEmpty = listLIST_IS_EMPTY( &xTasksWaitingTermination );
\r
1640 if( !xListIsEmpty )
\r
1644 portENTER_CRITICAL();
\r
1646 pxTCB = ( tskTCB * ) listGET_OWNER_OF_HEAD_ENTRY( ( ( xList * ) &xTasksWaitingTermination ) );
\r
1647 vListRemove( &( pxTCB->xGenericListItem ) );
\r
1648 --uxCurrentNumberOfTasks;
\r
1651 portEXIT_CRITICAL();
\r
1653 prvDeleteTCB( pxTCB );
\r
1659 /*-----------------------------------------------------------*/
\r
1661 static tskTCB *prvAllocateTCBAndStack( unsigned portSHORT usStackDepth )
\r
1665 /* Allocate space for the TCB. Where the memory comes from depends on
\r
1666 the implementation of the port malloc function. */
\r
1667 pxNewTCB = ( tskTCB * ) pvPortMalloc( sizeof( tskTCB ) );
\r
1669 if( pxNewTCB != NULL )
\r
1671 /* Allocate space for the stack used by the task being created.
\r
1672 The base of the stack memory stored in the TCB so the task can
\r
1673 be deleted later if required. */
\r
1674 pxNewTCB->pxStack = ( portSTACK_TYPE * ) pvPortMalloc( ( ( size_t )usStackDepth ) * sizeof( portSTACK_TYPE ) );
\r
1676 if( pxNewTCB->pxStack == NULL )
\r
1678 /* Could not allocate the stack. Delete the allocated TCB. */
\r
1679 vPortFree( pxNewTCB );
\r
1684 /* Just to help debugging. */
\r
1685 memset( pxNewTCB->pxStack, tskSTACK_FILL_BYTE, usStackDepth * sizeof( portSTACK_TYPE ) );
\r
1691 /*-----------------------------------------------------------*/
\r
1693 #if ( configUSE_TRACE_FACILITY == 1 )
\r
1695 static void prvListTaskWithinSingleList( signed portCHAR *pcWriteBuffer, xList *pxList, signed portCHAR cStatus )
\r
1697 volatile tskTCB *pxNextTCB, *pxFirstTCB;
\r
1698 static portCHAR pcStatusString[ 50 ];
\r
1699 unsigned portSHORT usStackRemaining;
\r
1701 /* Write the details of all the TCB's in pxList into the buffer. */
\r
1702 listGET_OWNER_OF_NEXT_ENTRY( pxFirstTCB, pxList );
\r
1705 listGET_OWNER_OF_NEXT_ENTRY( pxNextTCB, pxList );
\r
1706 usStackRemaining = usTaskCheckFreeStackSpace( ( unsigned portCHAR * ) pxNextTCB->pxStack );
\r
1707 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
1708 strcat( ( portCHAR * ) pcWriteBuffer, ( portCHAR * ) pcStatusString );
\r
1710 } while( pxNextTCB != pxFirstTCB );
\r
1714 /*-----------------------------------------------------------*/
\r
1716 #if ( configUSE_TRACE_FACILITY == 1 )
\r
1717 unsigned portSHORT usTaskCheckFreeStackSpace( const unsigned portCHAR *pucStackByte )
\r
1719 register unsigned portSHORT usCount = 0;
\r
1721 while( *pucStackByte == tskSTACK_FILL_BYTE )
\r
1723 pucStackByte -= portSTACK_GROWTH;
\r
1727 usCount /= sizeof( portSTACK_TYPE );
\r
1732 /*-----------------------------------------------------------*/
\r
1736 #if ( ( INCLUDE_vTaskDelete == 1 ) || ( INCLUDE_vTaskCleanUpResources == 1 ) )
\r
1738 static void prvDeleteTCB( tskTCB *pxTCB )
\r
1740 /* Free up the memory allocated by the scheduler for the task. It is up to
\r
1741 the task to free any memory allocated at the application level. */
\r
1742 vPortFree( pxTCB->pxStack );
\r
1743 vPortFree( pxTCB );
\r
1749 /*-----------------------------------------------------------*/
\r
1751 #if ( INCLUDE_xTaskGetCurrentTaskHandle == 1 )
\r
1753 xTaskHandle xTaskGetCurrentTaskHandle( void )
\r
1755 xTaskHandle xReturn;
\r
1757 portENTER_CRITICAL();
\r
1759 xReturn = ( xTaskHandle ) pxCurrentTCB;
\r
1761 portEXIT_CRITICAL();
\r