2 FreeRTOS.org V4.0.3 - 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 interrups 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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165 #include <stdlib.h>
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166 #include <string.h>
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168 #include "FreeRTOS.h"
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172 * Macro to define the amount of stack available to the idle task.
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174 #define tskIDLE_STACK_SIZE configMINIMAL_STACK_SIZE
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178 * Default a definitions for backwards compatibility with old
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179 * portmacro.h files.
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181 #ifndef configMAX_TASK_NAME_LEN
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182 #define configMAX_TASK_NAME_LEN 16
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185 #ifndef INCLUDE_xTaskGetCurrentTaskHandle
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186 #define INCLUDE_xTaskGetCurrentTaskHandle 0
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189 #ifndef configIDLE_SHOULD_YIELD
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190 #define configIDLE_SHOULD_YIELD 1
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193 #if configMAX_TASK_NAME_LEN < 1
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194 #undef configMAX_TASK_NAME_LEN
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195 #define configMAX_TASK_NAME_LEN 1
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200 * Task control block. A task control block (TCB) is allocated to each task,
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201 * and stores the context of the task.
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203 typedef struct tskTaskControlBlock
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205 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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206 xListItem xGenericListItem; /*< List item used to place the TCB in ready and blocked queues. */
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207 xListItem xEventListItem; /*< List item used to place the TCB in event lists. */
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208 unsigned portBASE_TYPE uxPriority; /*< The priority of the task where 0 is the lowest priority. */
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209 portSTACK_TYPE *pxStack; /*< Points to the start of the stack. */
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210 unsigned portBASE_TYPE uxTCBNumber; /*< This is used for tracing the scheduler and making debugging easier only. */
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211 signed portCHAR pcTaskName[ configMAX_TASK_NAME_LEN ];/*< Descriptive name given to the task when created. Facilitates debugging only. */
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212 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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217 tskTCB * volatile pxCurrentTCB = NULL;
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219 /* Lists for ready and blocked tasks. --------------------*/
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221 static xList pxReadyTasksLists[ configMAX_PRIORITIES ]; /*< Prioritised ready tasks. */
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222 static xList xDelayedTaskList1; /*< Delayed tasks. */
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223 static xList xDelayedTaskList2; /*< Delayed tasks (two lists are used - one for delays that have overflowed the current tick count. */
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224 static xList * volatile pxDelayedTaskList; /*< Points to the delayed task list currently being used. */
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225 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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226 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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228 #if ( INCLUDE_vTaskDelete == 1 )
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230 static volatile xList xTasksWaitingTermination; /*< Tasks that have been deleted - but the their memory not yet freed. */
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231 static volatile unsigned portBASE_TYPE uxTasksDeleted = ( unsigned portBASE_TYPE ) 0;
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235 #if ( INCLUDE_vTaskSuspend == 1 )
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237 static xList xSuspendedTaskList; /*< Tasks that are currently suspended. */
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241 /* File private variables. --------------------------------*/
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242 static volatile unsigned portBASE_TYPE uxCurrentNumberOfTasks = ( unsigned portBASE_TYPE ) 0;
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243 static volatile portTickType xTickCount = ( portTickType ) 0;
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244 static unsigned portBASE_TYPE uxTopUsedPriority = tskIDLE_PRIORITY;
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245 static volatile unsigned portBASE_TYPE uxTopReadyPriority = tskIDLE_PRIORITY;
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246 static volatile signed portBASE_TYPE xSchedulerRunning = pdFALSE;
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247 static volatile unsigned portBASE_TYPE uxSchedulerSuspended = ( unsigned portBASE_TYPE ) pdFALSE;
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248 static volatile unsigned portBASE_TYPE uxMissedTicks = ( unsigned portBASE_TYPE ) 0;
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249 static volatile portBASE_TYPE xMissedYield = ( portBASE_TYPE ) pdFALSE;
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251 /* Debugging and trace facilities private variables and macros. ------------*/
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254 * The value used to fill the stack of a task when the task is created. This
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255 * is used purely for checking the high water mark for tasks.
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257 #define tskSTACK_FILL_BYTE ( 0xa5 )
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260 * Macros used by vListTask to indicate which state a task is in.
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262 #define tskBLOCKED_CHAR ( ( signed portCHAR ) 'B' )
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263 #define tskREADY_CHAR ( ( signed portCHAR ) 'R' )
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264 #define tskDELETED_CHAR ( ( signed portCHAR ) 'D' )
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265 #define tskSUSPENDED_CHAR ( ( signed portCHAR ) 'S' )
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268 * Macros and private variables used by the trace facility.
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270 #if ( configUSE_TRACE_FACILITY == 1 )
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272 #define tskSIZE_OF_EACH_TRACE_LINE ( ( unsigned portLONG ) ( sizeof( unsigned portLONG ) + sizeof( unsigned portLONG ) ) )
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273 static volatile signed portCHAR * volatile pcTraceBuffer;
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274 static signed portCHAR *pcTraceBufferStart;
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275 static signed portCHAR *pcTraceBufferEnd;
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276 static signed portBASE_TYPE xTracing = pdFALSE;
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281 * Macro that writes a trace of scheduler activity to a buffer. This trace
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282 * shows which task is running when and is very useful as a debugging tool.
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283 * As this macro is called each context switch it is a good idea to undefine
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284 * it if not using the facility.
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286 #if ( configUSE_TRACE_FACILITY == 1 )
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288 #define vWriteTraceToBuffer() \
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292 static unsigned portBASE_TYPE uxPreviousTask = 255; \
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294 if( uxPreviousTask != pxCurrentTCB->uxTCBNumber ) \
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296 if( ( pcTraceBuffer + tskSIZE_OF_EACH_TRACE_LINE ) < pcTraceBufferEnd ) \
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298 uxPreviousTask = pxCurrentTCB->uxTCBNumber; \
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299 *( unsigned portLONG * ) pcTraceBuffer = ( unsigned portLONG ) xTickCount; \
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300 pcTraceBuffer += sizeof( unsigned portLONG ); \
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301 *( unsigned portLONG * ) pcTraceBuffer = ( unsigned portLONG ) uxPreviousTask; \
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302 pcTraceBuffer += sizeof( unsigned portLONG ); \
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306 xTracing = pdFALSE; \
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314 #define vWriteTraceToBuffer()
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320 * Place the task represented by pxTCB into the appropriate ready queue for
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321 * the task. It is inserted at the end of the list. One quirk of this is
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322 * that if the task being inserted is at the same priority as the currently
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323 * executing task, then it will only be rescheduled after the currently
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324 * executing task has been rescheduled.
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326 #define prvAddTaskToReadyQueue( pxTCB ) \
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328 if( pxTCB->uxPriority > uxTopReadyPriority ) \
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330 uxTopReadyPriority = pxTCB->uxPriority; \
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332 vListInsertEnd( ( xList * ) &( pxReadyTasksLists[ pxTCB->uxPriority ] ), &( pxTCB->xGenericListItem ) ); \
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337 * Macro that looks at the list of tasks that are currently delayed to see if
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338 * any require waking.
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340 * Tasks are stored in the queue in the order of their wake time - meaning
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341 * once one tasks has been found whose timer has not expired we need not look
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342 * any further down the list.
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344 #define prvCheckDelayedTasks() \
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346 register tskTCB *pxTCB; \
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348 while( ( pxTCB = ( tskTCB * ) listGET_OWNER_OF_HEAD_ENTRY( pxDelayedTaskList ) ) != NULL ) \
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350 if( xTickCount < listGET_LIST_ITEM_VALUE( &( pxTCB->xGenericListItem ) ) ) \
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354 vListRemove( &( pxTCB->xGenericListItem ) ); \
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355 /* Is the task waiting on an event also? */ \
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356 if( pxTCB->xEventListItem.pvContainer ) \
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358 vListRemove( &( pxTCB->xEventListItem ) ); \
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360 prvAddTaskToReadyQueue( pxTCB ); \
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365 * Several functions take an xTaskHandle parameter that can optionally be NULL,
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366 * where NULL is used to indicate that the handle of the currently executing
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367 * task should be used in place of the parameter. This macro simply checks to
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368 * see if the parameter is NULL and returns a pointer to the appropriate TCB.
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370 #define prvGetTCBFromHandle( pxHandle ) ( ( pxHandle == NULL ) ? ( tskTCB * ) pxCurrentTCB : ( tskTCB * ) pxHandle )
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373 /* File private functions. --------------------------------*/
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376 * Utility to ready a TCB for a given task. Mainly just copies the parameters
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377 * into the TCB structure.
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379 static void prvInitialiseTCBVariables( tskTCB *pxTCB, unsigned portSHORT usStackDepth, const signed portCHAR * const pcName, unsigned portBASE_TYPE uxPriority );
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382 * Utility to ready all the lists used by the scheduler. This is called
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383 * automatically upon the creation of the first task.
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385 static void prvInitialiseTaskLists( void );
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388 * The idle task, which as all tasks is implemented as a never ending loop.
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389 * The idle task is automatically created and added to the ready lists upon
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390 * creation of the first user task.
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392 * The portTASK_FUNCTION_PROTO() macro is used to allow port/compiler specific
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393 * language extensions. The equivalent prototype for this function is:
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395 * void prvIdleTask( void *pvParameters );
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398 static portTASK_FUNCTION_PROTO( prvIdleTask, pvParameters );
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401 * Utility to free all memory allocated by the scheduler to hold a TCB,
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402 * including the stack pointed to by the TCB.
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404 * This does not free memory allocated by the task itself (i.e. memory
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405 * allocated by calls to pvPortMalloc from within the tasks application code).
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407 #if ( ( INCLUDE_vTaskDelete == 1 ) || ( INCLUDE_vTaskCleanUpResources == 1 ) )
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408 static void prvDeleteTCB( tskTCB *pxTCB );
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412 * Used only by the idle task. This checks to see if anything has been placed
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413 * in the list of tasks waiting to be deleted. If so the task is cleaned up
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414 * and its TCB deleted.
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416 static void prvCheckTasksWaitingTermination( void );
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419 * Allocates memory from the heap for a TCB and associated stack. Checks the
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420 * allocation was successful.
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422 static tskTCB *prvAllocateTCBAndStack( unsigned portSHORT usStackDepth );
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425 * Called from vTaskList. vListTasks details all the tasks currently under
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426 * control of the scheduler. The tasks may be in one of a number of lists.
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427 * prvListTaskWithinSingleList accepts a list and details the tasks from
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428 * within just that list.
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430 * THIS FUNCTION IS INTENDED FOR DEBUGGING ONLY, AND SHOULD NOT BE CALLED FROM
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431 * NORMAL APPLICATION CODE.
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433 #if ( configUSE_TRACE_FACILITY == 1 )
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435 static void prvListTaskWithinSingleList( signed portCHAR *pcWriteBuffer, xList *pxList, signed portCHAR cStatus );
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440 * When a task is created, the stack of the task is filled with a known value.
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441 * This function determines the 'high water mark' of the task stack by
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442 * determining how much of the stack remains at the original preset value.
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444 #if ( configUSE_TRACE_FACILITY == 1 )
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446 unsigned portSHORT usTaskCheckFreeStackSpace( const unsigned portCHAR *pucStackByte );
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456 /*-----------------------------------------------------------
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457 * TASK CREATION API documented in task.h
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458 *----------------------------------------------------------*/
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460 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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462 signed portBASE_TYPE xReturn;
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464 static unsigned portBASE_TYPE uxTaskNumber = 0; /*lint !e956 Static is deliberate - this is guarded before use. */
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466 /* Allocate the memory required by the TCB and stack for the new task.
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467 checking that the allocation was successful. */
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468 pxNewTCB = prvAllocateTCBAndStack( usStackDepth );
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470 if( pxNewTCB != NULL )
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472 portSTACK_TYPE *pxTopOfStack;
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474 /* Setup the newly allocated TCB with the initial state of the task. */
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475 prvInitialiseTCBVariables( pxNewTCB, usStackDepth, pcName, uxPriority );
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477 /* Calculate the top of stack address. This depends on whether the
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478 stack grows from high memory to low (as per the 80x86) or visa versa.
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479 portSTACK_GROWTH is used to make the result positive or negative as
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480 required by the port. */
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481 #if portSTACK_GROWTH < 0
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483 pxTopOfStack = pxNewTCB->pxStack + ( pxNewTCB->usStackDepth - 1 );
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487 pxTopOfStack = pxNewTCB->pxStack;
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491 /* Initialize the TCB stack to look as if the task was already running,
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492 but had been interrupted by the scheduler. The return address is set
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493 to the start of the task function. Once the stack has been initialised
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494 the top of stack variable is updated. */
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495 pxNewTCB->pxTopOfStack = pxPortInitialiseStack( pxTopOfStack, pvTaskCode, pvParameters );
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497 /* We are going to manipulate the task queues to add this task to a
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498 ready list, so must make sure no interrupts occur. */
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499 portENTER_CRITICAL();
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501 uxCurrentNumberOfTasks++;
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502 if( uxCurrentNumberOfTasks == ( unsigned portBASE_TYPE ) 1 )
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504 /* As this is the first task it must also be the current task. */
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505 pxCurrentTCB = pxNewTCB;
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507 /* This is the first task to be created so do the preliminary
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508 initialisation required. We will not recover if this call
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509 fails, but we will report the failure. */
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510 prvInitialiseTaskLists();
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514 /* If the scheduler is not already running, make this task the
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515 current task if it is the highest priority task to be created
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517 if( xSchedulerRunning == pdFALSE )
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519 if( pxCurrentTCB->uxPriority <= uxPriority )
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521 pxCurrentTCB = pxNewTCB;
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526 /* Remember the top priority to make context switching faster. Use
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527 the priority in pxNewTCB as this has been capped to a valid value. */
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528 if( pxNewTCB->uxPriority > uxTopUsedPriority )
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530 uxTopUsedPriority = pxNewTCB->uxPriority;
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533 /* Add a counter into the TCB for tracing only. */
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534 pxNewTCB->uxTCBNumber = uxTaskNumber;
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537 prvAddTaskToReadyQueue( pxNewTCB );
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541 portEXIT_CRITICAL();
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545 xReturn = errCOULD_NOT_ALLOCATE_REQUIRED_MEMORY;
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548 if( xReturn == pdPASS )
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550 if( ( void * ) pxCreatedTask != NULL )
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552 /* Pass the TCB out - in an anonymous way. The calling function/
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553 task can use this as a handle to delete the task later if
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555 *pxCreatedTask = ( xTaskHandle ) pxNewTCB;
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558 if( xSchedulerRunning != pdFALSE )
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560 /* If the created task is of a higher priority than the current task
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561 then it should run now. */
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562 if( pxCurrentTCB->uxPriority < uxPriority )
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571 /*-----------------------------------------------------------*/
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573 #if ( INCLUDE_vTaskDelete == 1 )
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575 void vTaskDelete( xTaskHandle pxTaskToDelete )
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579 taskENTER_CRITICAL();
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581 /* Ensure a yield is performed if the current task is being
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583 if( pxTaskToDelete == pxCurrentTCB )
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585 pxTaskToDelete = NULL;
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588 /* If null is passed in here then we are deleting ourselves. */
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589 pxTCB = prvGetTCBFromHandle( pxTaskToDelete );
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591 /* Remove task from the ready list and place in the termination list.
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592 This will stop the task from be scheduled. The idle task will check
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593 the termination list and free up any memory allocated by the
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594 scheduler for the TCB and stack. */
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595 vListRemove( &( pxTCB->xGenericListItem ) );
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597 /* Is the task waiting on an event also? */
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598 if( pxTCB->xEventListItem.pvContainer )
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600 vListRemove( &( pxTCB->xEventListItem ) );
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603 vListInsertEnd( ( xList * ) &xTasksWaitingTermination, &( pxTCB->xGenericListItem ) );
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605 /* Increment the ucTasksDeleted variable so the idle task knows
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606 there is a task that has been deleted and that it should therefore
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607 check the xTasksWaitingTermination list. */
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610 taskEXIT_CRITICAL();
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612 /* Force a reschedule if we have just deleted the current task. */
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613 if( ( void * ) pxTaskToDelete == NULL )
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626 /*-----------------------------------------------------------
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627 * TASK CONTROL API documented in task.h
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628 *----------------------------------------------------------*/
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630 #if ( INCLUDE_vTaskDelayUntil == 1 )
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632 void vTaskDelayUntil( portTickType *pxPreviousWakeTime, portTickType xTimeIncrement )
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634 portTickType xTimeToWake;
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635 portBASE_TYPE xAlreadyYielded, xShouldDelay = pdFALSE;
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639 /* Generate the tick time at which the task wants to wake. */
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640 xTimeToWake = *pxPreviousWakeTime + xTimeIncrement;
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642 if( xTickCount < *pxPreviousWakeTime )
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644 /* The tick count has overflowed since this function was
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645 lasted called. In this case the only time we should ever
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646 actually delay is if the wake time has also overflowed,
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647 and the wake time is greater than the tick time. When this
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648 is the case it is as if neither time had overflowed. */
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649 if( ( xTimeToWake < *pxPreviousWakeTime ) && ( xTimeToWake > xTickCount ) )
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651 xShouldDelay = pdTRUE;
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656 /* The tick time has not overflowed. In this case we will
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657 delay if either the wake time has overflowed, and/or the
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658 tick time is less than the wake time. */
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659 if( ( xTimeToWake < *pxPreviousWakeTime ) || ( xTimeToWake > xTickCount ) )
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661 xShouldDelay = pdTRUE;
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665 /* Update the wake time ready for the next call. */
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666 *pxPreviousWakeTime = xTimeToWake;
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670 /* We must remove ourselves from the ready list before adding
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671 ourselves to the blocked list as the same list item is used for
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673 vListRemove( ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
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675 /* The list item will be inserted in wake time order. */
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676 listSET_LIST_ITEM_VALUE( &( pxCurrentTCB->xGenericListItem ), xTimeToWake );
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678 if( xTimeToWake < xTickCount )
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680 /* Wake time has overflowed. Place this item in the
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682 vListInsert( ( xList * ) pxOverflowDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
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686 /* The wake time has not overflowed, so we can use the
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687 current block list. */
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688 vListInsert( ( xList * ) pxDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
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692 xAlreadyYielded = xTaskResumeAll();
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694 /* Force a reschedule if xTaskResumeAll has not already done so, we may
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695 have put ourselves to sleep. */
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696 if( !xAlreadyYielded )
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703 /*-----------------------------------------------------------*/
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705 #if ( INCLUDE_vTaskDelay == 1 )
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707 void vTaskDelay( portTickType xTicksToDelay )
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709 portTickType xTimeToWake;
\r
710 signed portBASE_TYPE xAlreadyYielded = pdFALSE;
\r
712 /* A delay time of zero just forces a reschedule. */
\r
713 if( xTicksToDelay > ( portTickType ) 0 )
\r
717 /* A task that is removed from the event list while the
\r
718 scheduler is suspended will not get placed in the ready
\r
719 list or removed from the blocked list until the scheduler
\r
722 This task cannot be in an event list as it is the currently
\r
725 /* Calculate the time to wake - this may overflow but this is
\r
727 xTimeToWake = xTickCount + xTicksToDelay;
\r
729 /* We must remove ourselves from the ready list before adding
\r
730 ourselves to the blocked list as the same list item is used for
\r
732 vListRemove( ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
\r
734 /* The list item will be inserted in wake time order. */
\r
735 listSET_LIST_ITEM_VALUE( &( pxCurrentTCB->xGenericListItem ), xTimeToWake );
\r
737 if( xTimeToWake < xTickCount )
\r
739 /* Wake time has overflowed. Place this item in the
\r
741 vListInsert( ( xList * ) pxOverflowDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
\r
745 /* The wake time has not overflowed, so we can use the
\r
746 current block list. */
\r
747 vListInsert( ( xList * ) pxDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
\r
750 xAlreadyYielded = xTaskResumeAll();
\r
753 /* Force a reschedule if xTaskResumeAll has not already done so, we may
\r
754 have put ourselves to sleep. */
\r
755 if( !xAlreadyYielded )
\r
762 /*-----------------------------------------------------------*/
\r
764 #if ( INCLUDE_uxTaskPriorityGet == 1 )
\r
766 unsigned portBASE_TYPE uxTaskPriorityGet( xTaskHandle pxTask )
\r
769 unsigned portBASE_TYPE uxReturn;
\r
771 taskENTER_CRITICAL();
\r
773 /* If null is passed in here then we are changing the
\r
774 priority of the calling function. */
\r
775 pxTCB = prvGetTCBFromHandle( pxTask );
\r
776 uxReturn = pxTCB->uxPriority;
\r
778 taskEXIT_CRITICAL();
\r
784 /*-----------------------------------------------------------*/
\r
786 #if ( INCLUDE_vTaskPrioritySet == 1 )
\r
788 void vTaskPrioritySet( xTaskHandle pxTask, unsigned portBASE_TYPE uxNewPriority )
\r
791 unsigned portBASE_TYPE uxCurrentPriority;
\r
793 /* Ensure the new priority is valid. */
\r
794 if( uxNewPriority >= configMAX_PRIORITIES )
\r
796 uxNewPriority = configMAX_PRIORITIES - 1;
\r
799 taskENTER_CRITICAL();
\r
801 /* If null is passed in here then we are changing the
\r
802 priority of the calling function. */
\r
803 pxTCB = prvGetTCBFromHandle( pxTask );
\r
804 uxCurrentPriority = pxTCB->uxPriority;
\r
806 if( uxCurrentPriority != uxNewPriority )
\r
808 pxTCB->uxPriority = uxNewPriority;
\r
810 /* If the task is in the blocked or suspended list we need do
\r
811 nothing more than change it's priority variable. However, if
\r
812 the task is in a ready list it needs to be removed and placed
\r
813 in the queue appropriate to its new priority. */
\r
814 if( listIS_CONTAINED_WITHIN( &( pxReadyTasksLists[ uxCurrentPriority ] ), &( pxTCB->xGenericListItem ) ) )
\r
816 if( uxSchedulerSuspended == ( unsigned portBASE_TYPE ) pdFALSE )
\r
818 /* The task is currently in its ready list - remove before adding
\r
819 it to it's new ready list. */
\r
820 vListRemove( &( pxTCB->xGenericListItem ) );
\r
821 prvAddTaskToReadyQueue( pxTCB );
\r
825 /* We cannot access the delayed or ready lists, so will hold this
\r
826 task pending until the scheduler is resumed. */
\r
827 vListInsertEnd( ( xList * ) &( xPendingReadyList ), &( pxTCB->xEventListItem ) );
\r
832 taskEXIT_CRITICAL();
\r
834 /* The priority change may have readied a task of higher
\r
835 priority than the calling task. */
\r
840 /*-----------------------------------------------------------*/
\r
842 #if ( INCLUDE_vTaskSuspend == 1 )
\r
844 void vTaskSuspend( xTaskHandle pxTaskToSuspend )
\r
848 taskENTER_CRITICAL();
\r
850 /* Ensure a yield is performed if the current task is being
\r
852 if( pxTaskToSuspend == pxCurrentTCB )
\r
854 pxTaskToSuspend = NULL;
\r
857 /* If null is passed in here then we are suspending ourselves. */
\r
858 pxTCB = prvGetTCBFromHandle( pxTaskToSuspend );
\r
860 /* Remove task from the ready/delayed list and place in the suspended list. */
\r
861 vListRemove( &( pxTCB->xGenericListItem ) );
\r
863 /* Is the task waiting on an event also? */
\r
864 if( pxTCB->xEventListItem.pvContainer )
\r
866 vListRemove( &( pxTCB->xEventListItem ) );
\r
869 vListInsertEnd( ( xList * ) &xSuspendedTaskList, &( pxTCB->xGenericListItem ) );
\r
871 taskEXIT_CRITICAL();
\r
873 /* We may have just suspended the current task. */
\r
874 if( ( void * ) pxTaskToSuspend == NULL )
\r
881 /*-----------------------------------------------------------*/
\r
883 #if ( INCLUDE_vTaskSuspend == 1 )
\r
885 void vTaskResume( xTaskHandle pxTaskToResume )
\r
888 portBASE_TYPE xYieldRequired;
\r
890 /* Remove the task from whichever list it is currently in, and place
\r
891 it in the ready list. */
\r
892 pxTCB = ( tskTCB * ) pxTaskToResume;
\r
894 /* The parameter cannot be NULL as it is impossible to resume the
\r
895 currently executing task. */
\r
896 if( pxTCB != NULL )
\r
898 taskENTER_CRITICAL();
\r
900 if( uxSchedulerSuspended == ( unsigned portBASE_TYPE ) pdFALSE )
\r
902 xYieldRequired = ( pxTCB->uxPriority >= pxCurrentTCB->uxPriority );
\r
903 vListRemove( &( pxTCB->xGenericListItem ) );
\r
904 prvAddTaskToReadyQueue( pxTCB );
\r
908 /* We cannot access the delayed or ready lists, so will hold this
\r
909 task pending until the scheduler is resumed. */
\r
910 xYieldRequired = pdFALSE;
\r
911 vListInsertEnd( ( xList * ) &( xPendingReadyList ), &( pxTCB->xEventListItem ) );
\r
914 taskEXIT_CRITICAL();
\r
916 /* We may have just resumed a higher priority task. */
\r
917 if( xYieldRequired )
\r
919 /* This yield may not cause the task just resumed to run, but
\r
920 will leave the lists in the correct state for the next yield. */
\r
932 /*-----------------------------------------------------------
\r
933 * PUBLIC SCHEDULER CONTROL documented in task.h
\r
934 *----------------------------------------------------------*/
\r
937 void vTaskStartScheduler( void )
\r
939 portBASE_TYPE xReturn;
\r
941 /* Add the idle task at the lowest priority. */
\r
942 xReturn = xTaskCreate( prvIdleTask, ( signed portCHAR * ) "IDLE", tskIDLE_STACK_SIZE, ( void * ) NULL, tskIDLE_PRIORITY, ( xTaskHandle * ) NULL );
\r
944 if( xReturn == pdPASS )
\r
946 /* Interrupts are turned off here, to ensure a tick does not occur
\r
947 before or during the call to xPortStartScheduler(). The stacks of
\r
948 the created tasks contain a status word with interrupts switched on
\r
949 so interrupts will automatically get re-enabled when the first task
\r
952 STEPPING THROUGH HERE USING A DEBUGGER CAN CAUSE BIG PROBLEMS IF THE
\r
953 DEBUGGER ALLOWS INTERRUPTS TO BE PROCESSED. */
\r
954 portDISABLE_INTERRUPTS();
\r
956 xSchedulerRunning = pdTRUE;
\r
957 xTickCount = ( portTickType ) 0;
\r
959 /* Setting up the timer tick is hardware specific and thus in the
\r
960 portable interface. */
\r
961 if( xPortStartScheduler() )
\r
963 /* Should not reach here as if the scheduler is running the
\r
964 function will not return. */
\r
968 /* Should only reach here if a task calls xTaskEndScheduler(). */
\r
972 /*-----------------------------------------------------------*/
\r
974 void vTaskEndScheduler( void )
\r
976 /* Stop the scheduler interrupts and call the portable scheduler end
\r
977 routine so the original ISRs can be restored if necessary. The port
\r
978 layer must ensure interrupts enable bit is left in the correct state. */
\r
979 portDISABLE_INTERRUPTS();
\r
980 xSchedulerRunning = pdFALSE;
\r
981 vPortEndScheduler();
\r
983 /*----------------------------------------------------------*/
\r
985 void vTaskSuspendAll( void )
\r
987 portENTER_CRITICAL();
\r
988 ++uxSchedulerSuspended;
\r
989 portEXIT_CRITICAL();
\r
991 /*----------------------------------------------------------*/
\r
993 signed portBASE_TYPE xTaskResumeAll( void )
\r
995 register tskTCB *pxTCB;
\r
996 signed portBASE_TYPE xAlreadyYielded = pdFALSE;
\r
998 /* It is possible that an ISR caused a task to be removed from an event
\r
999 list while the scheduler was suspended. If this was the case then the
\r
1000 removed task will have been added to the xPendingReadyList. Once the
\r
1001 scheduler has been resumed it is safe to move all the pending ready
\r
1002 tasks from this list into their appropriate ready list. */
\r
1003 portENTER_CRITICAL();
\r
1005 --uxSchedulerSuspended;
\r
1007 if( uxSchedulerSuspended == ( unsigned portBASE_TYPE ) pdFALSE )
\r
1009 if( uxCurrentNumberOfTasks > ( unsigned portBASE_TYPE ) 0 )
\r
1011 portBASE_TYPE xYieldRequired = pdFALSE;
\r
1013 /* Move any readied tasks from the pending list into the
\r
1014 appropriate ready list. */
\r
1015 while( ( pxTCB = ( tskTCB * ) listGET_OWNER_OF_HEAD_ENTRY( ( ( xList * ) &xPendingReadyList ) ) ) != NULL )
\r
1017 vListRemove( &( pxTCB->xEventListItem ) );
\r
1018 vListRemove( &( pxTCB->xGenericListItem ) );
\r
1019 prvAddTaskToReadyQueue( pxTCB );
\r
1021 /* If we have moved a task that has a priority higher than
\r
1022 the current task then we should yield. */
\r
1023 if( pxTCB->uxPriority >= pxCurrentTCB->uxPriority )
\r
1025 xYieldRequired = pdTRUE;
\r
1029 /* If any ticks occurred while the scheduler was suspended then
\r
1030 they should be processed now. This ensures the tick count does not
\r
1031 slip, and that any delayed tasks are resumed at the correct time. */
\r
1032 if( uxMissedTicks > ( unsigned portBASE_TYPE ) 0 )
\r
1034 while( uxMissedTicks > ( unsigned portBASE_TYPE ) 0 )
\r
1036 vTaskIncrementTick();
\r
1040 /* As we have processed some ticks it is appropriate to yield
\r
1041 to ensure the highest priority task that is ready to run is
\r
1042 the task actually running. */
\r
1043 xYieldRequired = pdTRUE;
\r
1046 if( ( xYieldRequired == pdTRUE ) || ( xMissedYield == pdTRUE ) )
\r
1048 xAlreadyYielded = pdTRUE;
\r
1049 xMissedYield = pdFALSE;
\r
1055 portEXIT_CRITICAL();
\r
1057 return xAlreadyYielded;
\r
1065 /*-----------------------------------------------------------
\r
1066 * PUBLIC TASK UTILITIES documented in task.h
\r
1067 *----------------------------------------------------------*/
\r
1071 portTickType xTaskGetTickCount( void )
\r
1073 portTickType xTicks;
\r
1075 /* Critical section required if running on a 16 bit processor. */
\r
1076 taskENTER_CRITICAL();
\r
1078 xTicks = xTickCount;
\r
1080 taskEXIT_CRITICAL();
\r
1084 /*-----------------------------------------------------------*/
\r
1086 unsigned portBASE_TYPE uxTaskGetNumberOfTasks( void )
\r
1088 unsigned portBASE_TYPE uxNumberOfTasks;
\r
1090 taskENTER_CRITICAL();
\r
1091 uxNumberOfTasks = uxCurrentNumberOfTasks;
\r
1092 taskEXIT_CRITICAL();
\r
1094 return uxNumberOfTasks;
\r
1096 /*-----------------------------------------------------------*/
\r
1098 #if ( ( configUSE_TRACE_FACILITY == 1 ) && ( INCLUDE_vTaskDelete == 1 ) && ( INCLUDE_vTaskSuspend == 1 ) )
\r
1100 void vTaskList( signed portCHAR *pcWriteBuffer )
\r
1102 unsigned portBASE_TYPE uxQueue;
\r
1104 /* This is a VERY costly function that should be used for debug only.
\r
1105 It leaves interrupts disabled for a LONG time. */
\r
1107 vTaskSuspendAll();
\r
1109 /* Run through all the lists that could potentially contain a TCB and
\r
1110 report the task name, state and stack high water mark. */
\r
1112 pcWriteBuffer[ 0 ] = ( signed portCHAR ) 0x00;
\r
1113 strcat( ( portCHAR * ) pcWriteBuffer, ( const portCHAR * ) "\r\n" );
\r
1115 uxQueue = uxTopUsedPriority + 1;
\r
1121 if( !listLIST_IS_EMPTY( &( pxReadyTasksLists[ uxQueue ] ) ) )
\r
1123 prvListTaskWithinSingleList( pcWriteBuffer, ( xList * ) &( pxReadyTasksLists[ uxQueue ] ), tskREADY_CHAR );
\r
1125 }while( uxQueue > ( unsigned portSHORT ) tskIDLE_PRIORITY );
\r
1127 if( !listLIST_IS_EMPTY( pxDelayedTaskList ) )
\r
1129 prvListTaskWithinSingleList( pcWriteBuffer, ( xList * ) pxDelayedTaskList, tskBLOCKED_CHAR );
\r
1132 if( !listLIST_IS_EMPTY( pxOverflowDelayedTaskList ) )
\r
1134 prvListTaskWithinSingleList( pcWriteBuffer, ( xList * ) pxOverflowDelayedTaskList, tskBLOCKED_CHAR );
\r
1137 if( !listLIST_IS_EMPTY( &xTasksWaitingTermination ) )
\r
1139 prvListTaskWithinSingleList( pcWriteBuffer, ( xList * ) &xTasksWaitingTermination, tskDELETED_CHAR );
\r
1142 if( !listLIST_IS_EMPTY( &xSuspendedTaskList ) )
\r
1144 prvListTaskWithinSingleList( pcWriteBuffer, ( xList * ) &xSuspendedTaskList, tskSUSPENDED_CHAR );
\r
1151 /*----------------------------------------------------------*/
\r
1153 #if ( configUSE_TRACE_FACILITY == 1 )
\r
1155 void vTaskStartTrace( signed portCHAR * pcBuffer, unsigned portLONG ulBufferSize )
\r
1157 portENTER_CRITICAL();
\r
1159 pcTraceBuffer = ( volatile signed portCHAR * volatile )pcBuffer;
\r
1160 pcTraceBufferStart = pcBuffer;
\r
1161 pcTraceBufferEnd = pcBuffer + ( ulBufferSize - tskSIZE_OF_EACH_TRACE_LINE );
\r
1162 xTracing = pdTRUE;
\r
1164 portEXIT_CRITICAL();
\r
1168 /*----------------------------------------------------------*/
\r
1170 #if ( configUSE_TRACE_FACILITY == 1 )
\r
1172 unsigned portLONG ulTaskEndTrace( void )
\r
1174 unsigned portLONG ulBufferLength;
\r
1176 portENTER_CRITICAL();
\r
1177 xTracing = pdFALSE;
\r
1178 portEXIT_CRITICAL();
\r
1180 ulBufferLength = ( unsigned portLONG ) ( pcTraceBuffer - pcTraceBufferStart );
\r
1182 return ulBufferLength;
\r
1189 /*-----------------------------------------------------------
\r
1190 * SCHEDULER INTERNALS AVAILABLE FOR PORTING PURPOSES
\r
1191 * documented in task.h
\r
1192 *----------------------------------------------------------*/
\r
1195 inline void vTaskIncrementTick( void )
\r
1197 /* Called by the portable layer each time a tick interrupt occurs.
\r
1198 Increments the tick then checks to see if the new tick value will cause any
\r
1199 tasks to be unblocked. */
\r
1200 if( uxSchedulerSuspended == ( unsigned portBASE_TYPE ) pdFALSE )
\r
1203 if( xTickCount == ( portTickType ) 0 )
\r
1207 /* Tick count has overflowed so we need to swap the delay lists.
\r
1208 If there are any items in pxDelayedTaskList here then there is
\r
1210 pxTemp = pxDelayedTaskList;
\r
1211 pxDelayedTaskList = pxOverflowDelayedTaskList;
\r
1212 pxOverflowDelayedTaskList = pxTemp;
\r
1215 /* See if this tick has made a timeout expire. */
\r
1216 prvCheckDelayedTasks();
\r
1222 /* The tick hook gets called at regular intervals, even if the
\r
1223 scheduler is locked. */
\r
1224 #if ( configUSE_TICK_HOOK == 1 )
\r
1226 extern void vApplicationTickHook( void );
\r
1228 vApplicationTickHook();
\r
1233 #if ( configUSE_TICK_HOOK == 1 )
\r
1235 extern void vApplicationTickHook( void );
\r
1237 /* Guard against the tick hook being called when the missed tick
\r
1238 count is being unwound (when the scheduler is being unlocked. */
\r
1239 if( uxMissedTicks == 0 )
\r
1241 vApplicationTickHook();
\r
1246 /*-----------------------------------------------------------*/
\r
1248 #if ( ( INCLUDE_vTaskCleanUpResources == 1 ) && ( INCLUDE_vTaskSuspend == 1 ) )
\r
1250 void vTaskCleanUpResources( void )
\r
1252 unsigned portSHORT usQueue;
\r
1253 volatile tskTCB *pxTCB;
\r
1255 usQueue = ( unsigned portSHORT ) uxTopUsedPriority + ( unsigned portSHORT ) 1;
\r
1257 /* Remove any TCB's from the ready queues. */
\r
1262 while( !listLIST_IS_EMPTY( &( pxReadyTasksLists[ usQueue ] ) ) )
\r
1264 listGET_OWNER_OF_NEXT_ENTRY( pxTCB, &( pxReadyTasksLists[ usQueue ] ) );
\r
1265 vListRemove( ( xListItem * ) &( pxTCB->xGenericListItem ) );
\r
1267 prvDeleteTCB( ( tskTCB * ) pxTCB );
\r
1269 }while( usQueue > ( unsigned portSHORT ) tskIDLE_PRIORITY );
\r
1271 /* Remove any TCB's from the delayed queue. */
\r
1272 while( !listLIST_IS_EMPTY( &xDelayedTaskList1 ) )
\r
1274 listGET_OWNER_OF_NEXT_ENTRY( pxTCB, &xDelayedTaskList1 );
\r
1275 vListRemove( ( xListItem * ) &( pxTCB->xGenericListItem ) );
\r
1277 prvDeleteTCB( ( tskTCB * ) pxTCB );
\r
1280 /* Remove any TCB's from the overflow delayed queue. */
\r
1281 while( !listLIST_IS_EMPTY( &xDelayedTaskList2 ) )
\r
1283 listGET_OWNER_OF_NEXT_ENTRY( pxTCB, &xDelayedTaskList2 );
\r
1284 vListRemove( ( xListItem * ) &( pxTCB->xGenericListItem ) );
\r
1286 prvDeleteTCB( ( tskTCB * ) pxTCB );
\r
1289 while( !listLIST_IS_EMPTY( &xSuspendedTaskList ) )
\r
1291 listGET_OWNER_OF_NEXT_ENTRY( pxTCB, &xSuspendedTaskList );
\r
1292 vListRemove( ( xListItem * ) &( pxTCB->xGenericListItem ) );
\r
1294 prvDeleteTCB( ( tskTCB * ) pxTCB );
\r
1297 while( !listLIST_IS_EMPTY( &xPendingReadyList ) )
\r
1299 listGET_OWNER_OF_NEXT_ENTRY( pxTCB, &xPendingReadyList );
\r
1300 vListRemove( ( xListItem * ) &( pxTCB->xGenericListItem ) );
\r
1302 prvDeleteTCB( ( tskTCB * ) pxTCB );
\r
1307 /*-----------------------------------------------------------*/
\r
1309 void vTaskSwitchContext( void )
\r
1311 if( uxSchedulerSuspended != ( unsigned portBASE_TYPE ) pdFALSE )
\r
1313 /* The scheduler is currently suspended - do not allow a context
\r
1315 xMissedYield = pdTRUE;
\r
1319 /* Find the highest priority queue that contains ready tasks. */
\r
1320 while( listLIST_IS_EMPTY( &( pxReadyTasksLists[ uxTopReadyPriority ] ) ) )
\r
1322 --uxTopReadyPriority;
\r
1325 /* listGET_OWNER_OF_NEXT_ENTRY walks through the list, so the tasks of the
\r
1326 same priority get an equal share of the processor time. */
\r
1327 listGET_OWNER_OF_NEXT_ENTRY( pxCurrentTCB, &( pxReadyTasksLists[ uxTopReadyPriority ] ) );
\r
1328 vWriteTraceToBuffer();
\r
1330 /*-----------------------------------------------------------*/
\r
1332 void vTaskPlaceOnEventList( xList *pxEventList, portTickType xTicksToWait )
\r
1334 portTickType xTimeToWake;
\r
1336 /* THIS FUNCTION MUST BE CALLED WITH INTERRUPTS DISABLED OR THE
\r
1337 SCHEDULER SUSPENDED. */
\r
1339 /* Place the event list item of the TCB in the appropriate event list.
\r
1340 This is placed in the list in priority order so the highest priority task
\r
1341 is the first to be woken by the event. */
\r
1342 vListInsert( ( xList * ) pxEventList, ( xListItem * ) &( pxCurrentTCB->xEventListItem ) );
\r
1344 /* Calculate the time at which the task should be woken if the event does
\r
1345 not occur. This may overflow but this doesn't matter. */
\r
1346 xTimeToWake = xTickCount + xTicksToWait;
\r
1348 /* We must remove ourselves from the ready list before adding ourselves
\r
1349 to the blocked list as the same list item is used for both lists. We have
\r
1350 exclusive access to the ready lists as the scheduler is locked. */
\r
1351 vListRemove( ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
\r
1353 listSET_LIST_ITEM_VALUE( &( pxCurrentTCB->xGenericListItem ), xTimeToWake );
\r
1355 if( xTimeToWake < xTickCount )
\r
1357 /* Wake time has overflowed. Place this item in the overflow list. */
\r
1358 vListInsert( ( xList * ) pxOverflowDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
\r
1362 /* The wake time has not overflowed, so we can use the current block list. */
\r
1363 vListInsert( ( xList * ) pxDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
\r
1366 /*-----------------------------------------------------------*/
\r
1368 signed portBASE_TYPE xTaskRemoveFromEventList( const xList *pxEventList )
\r
1370 tskTCB *pxUnblockedTCB;
\r
1371 portBASE_TYPE xReturn;
\r
1373 /* THIS FUNCTION MUST BE CALLED WITH INTERRUPTS DISABLED OR THE
\r
1374 SCHEDULER SUSPENDED. It can also be called from within an ISR. */
\r
1376 /* The event list is sorted in priority order, so we can remove the
\r
1377 first in the list, remove the TCB from the delayed list, and add
\r
1378 it to the ready list.
\r
1380 If an event is for a queue that is locked then this function will never
\r
1381 get called - the lock count on the queue will get modified instead. This
\r
1382 means we can always expect exclusive access to the event list here. */
\r
1383 pxUnblockedTCB = ( tskTCB * ) listGET_OWNER_OF_HEAD_ENTRY( pxEventList );
\r
1384 vListRemove( &( pxUnblockedTCB->xEventListItem ) );
\r
1386 if( uxSchedulerSuspended == ( unsigned portBASE_TYPE ) pdFALSE )
\r
1388 vListRemove( &( pxUnblockedTCB->xGenericListItem ) );
\r
1389 prvAddTaskToReadyQueue( pxUnblockedTCB );
\r
1393 /* We cannot access the delayed or ready lists, so will hold this
\r
1394 task pending until the scheduler is resumed. */
\r
1395 vListInsertEnd( ( xList * ) &( xPendingReadyList ), &( pxUnblockedTCB->xEventListItem ) );
\r
1398 if( pxUnblockedTCB->uxPriority >= pxCurrentTCB->uxPriority )
\r
1400 /* Return true if the task removed from the event list has
\r
1401 a higher priority than the calling task. This allows
\r
1402 the calling task to know if it should force a context
\r
1408 xReturn = pdFALSE;
\r
1419 * -----------------------------------------------------------
\r
1421 * ----------------------------------------------------------
\r
1423 * The portTASK_FUNCTION() macro is used to allow port/compiler specific
\r
1424 * language extensions. The equivalent prototype for this function is:
\r
1426 * void prvIdleTask( void *pvParameters );
\r
1429 static portTASK_FUNCTION( prvIdleTask, pvParameters )
\r
1431 /* Stop warnings. */
\r
1432 ( void ) pvParameters;
\r
1436 /* See if any tasks have been deleted. */
\r
1437 prvCheckTasksWaitingTermination();
\r
1439 #if ( configUSE_PREEMPTION == 0 )
\r
1441 /* If we are not using preemption we keep forcing a task switch to
\r
1442 see if any other task has become available. If we are using
\r
1443 preemption we don't need to do this as any task becoming available
\r
1444 will automatically get the processor anyway. */
\r
1449 #if ( ( configUSE_PREEMPTION == 1 ) && ( configIDLE_SHOULD_YIELD == 1 ) )
\r
1451 /* When using preemption tasks of equal priority will be
\r
1452 timesliced. If a task that is sharing the idle priority is ready
\r
1453 to run then the idle task should yield before the end of the
\r
1456 A critical region is not required here as we are just reading from
\r
1457 the list, and an occasional incorrect value will not matter. If
\r
1458 the ready list at the idle priority contains more than one task
\r
1459 then a task other than the idle task is ready to execute. */
\r
1460 if( listCURRENT_LIST_LENGTH( &( pxReadyTasksLists[ tskIDLE_PRIORITY ] ) ) > ( unsigned portBASE_TYPE ) 1 )
\r
1467 #if ( configUSE_IDLE_HOOK == 1 )
\r
1469 extern void vApplicationIdleHook( void );
\r
1471 /* Call the user defined function from within the idle task. This
\r
1472 allows the application designer to add background functionality
\r
1473 without the overhead of a separate task.
\r
1474 NOTE: vApplicationIdleHook() MUST NOT, UNDER ANY CIRCUMSTANCES,
\r
1475 CALL A FUNCTION THAT MIGHT BLOCK. */
\r
1476 vApplicationIdleHook();
\r
1480 } /*lint !e715 pvParameters is not accessed but all task functions require the same prototype. */
\r
1488 /*-----------------------------------------------------------
\r
1489 * File private functions documented at the top of the file.
\r
1490 *----------------------------------------------------------*/
\r
1494 static void prvInitialiseTCBVariables( tskTCB *pxTCB, unsigned portSHORT usStackDepth, const signed portCHAR * const pcName, unsigned portBASE_TYPE uxPriority )
\r
1496 pxTCB->usStackDepth = usStackDepth;
\r
1498 /* Store the function name in the TCB. */
\r
1499 strncpy( ( char * ) pxTCB->pcTaskName, ( const char * ) pcName, ( unsigned portSHORT ) configMAX_TASK_NAME_LEN );
\r
1500 pxTCB->pcTaskName[ ( unsigned portSHORT ) configMAX_TASK_NAME_LEN - ( unsigned portSHORT ) 1 ] = '\0';
\r
1502 /* This is used as an array index so must ensure it's not too large. */
\r
1503 if( uxPriority >= configMAX_PRIORITIES )
\r
1505 uxPriority = configMAX_PRIORITIES - 1;
\r
1508 pxTCB->uxPriority = uxPriority;
\r
1510 vListInitialiseItem( &( pxTCB->xGenericListItem ) );
\r
1511 vListInitialiseItem( &( pxTCB->xEventListItem ) );
\r
1513 /* Set the pxTCB as a link back from the xListItem. This is so we can get
\r
1514 back to the containing TCB from a generic item in a list. */
\r
1515 listSET_LIST_ITEM_OWNER( &( pxTCB->xGenericListItem ), pxTCB );
\r
1517 /* Event lists are always in priority order. */
\r
1518 listSET_LIST_ITEM_VALUE( &( pxTCB->xEventListItem ), configMAX_PRIORITIES - ( portTickType ) uxPriority );
\r
1519 listSET_LIST_ITEM_OWNER( &( pxTCB->xEventListItem ), pxTCB );
\r
1521 /*-----------------------------------------------------------*/
\r
1523 static void prvInitialiseTaskLists( void )
\r
1525 unsigned portBASE_TYPE uxPriority;
\r
1527 for( uxPriority = 0; uxPriority < configMAX_PRIORITIES; uxPriority++ )
\r
1529 vListInitialise( ( xList * ) &( pxReadyTasksLists[ uxPriority ] ) );
\r
1532 vListInitialise( ( xList * ) &xDelayedTaskList1 );
\r
1533 vListInitialise( ( xList * ) &xDelayedTaskList2 );
\r
1534 vListInitialise( ( xList * ) &xPendingReadyList );
\r
1536 #if ( INCLUDE_vTaskDelete == 1 )
\r
1538 vListInitialise( ( xList * ) &xTasksWaitingTermination );
\r
1542 #if ( INCLUDE_vTaskSuspend == 1 )
\r
1544 vListInitialise( ( xList * ) &xSuspendedTaskList );
\r
1548 /* Start with pxDelayedTaskList using list1 and the pxOverflowDelayedTaskList
\r
1550 pxDelayedTaskList = &xDelayedTaskList1;
\r
1551 pxOverflowDelayedTaskList = &xDelayedTaskList2;
\r
1553 /*-----------------------------------------------------------*/
\r
1555 static void prvCheckTasksWaitingTermination( void )
\r
1557 #if ( INCLUDE_vTaskDelete == 1 )
\r
1559 portBASE_TYPE xListIsEmpty;
\r
1561 /* ucTasksDeleted is used to prevent vTaskSuspendAll() being called
\r
1562 too often in the idle task. */
\r
1563 if( uxTasksDeleted > ( unsigned portBASE_TYPE ) 0 )
\r
1565 vTaskSuspendAll();
\r
1566 xListIsEmpty = listLIST_IS_EMPTY( &xTasksWaitingTermination );
\r
1569 if( !xListIsEmpty )
\r
1573 portENTER_CRITICAL();
\r
1575 pxTCB = ( tskTCB * ) listGET_OWNER_OF_HEAD_ENTRY( ( ( xList * ) &xTasksWaitingTermination ) );
\r
1576 vListRemove( &( pxTCB->xGenericListItem ) );
\r
1577 --uxCurrentNumberOfTasks;
\r
1580 portEXIT_CRITICAL();
\r
1582 prvDeleteTCB( pxTCB );
\r
1588 /*-----------------------------------------------------------*/
\r
1590 static tskTCB *prvAllocateTCBAndStack( unsigned portSHORT usStackDepth )
\r
1594 /* Allocate space for the TCB. Where the memory comes from depends on
\r
1595 the implementation of the port malloc function. */
\r
1596 pxNewTCB = ( tskTCB * ) pvPortMalloc( sizeof( tskTCB ) );
\r
1598 if( pxNewTCB != NULL )
\r
1600 /* Allocate space for the stack used by the task being created.
\r
1601 The base of the stack memory stored in the TCB so the task can
\r
1602 be deleted later if required. */
\r
1603 pxNewTCB->pxStack = ( portSTACK_TYPE * ) pvPortMalloc( ( ( size_t )usStackDepth ) * sizeof( portSTACK_TYPE ) );
\r
1605 if( pxNewTCB->pxStack == NULL )
\r
1607 /* Could not allocate the stack. Delete the allocated TCB. */
\r
1608 vPortFree( pxNewTCB );
\r
1613 /* Just to help debugging. */
\r
1614 memset( pxNewTCB->pxStack, tskSTACK_FILL_BYTE, usStackDepth * sizeof( portSTACK_TYPE ) );
\r
1620 /*-----------------------------------------------------------*/
\r
1622 #if ( configUSE_TRACE_FACILITY == 1 )
\r
1624 static void prvListTaskWithinSingleList( signed portCHAR *pcWriteBuffer, xList *pxList, signed portCHAR cStatus )
\r
1626 volatile tskTCB *pxNextTCB, *pxFirstTCB;
\r
1627 static portCHAR pcStatusString[ 50 ];
\r
1628 unsigned portSHORT usStackRemaining;
\r
1630 /* Write the details of all the TCB's in pxList into the buffer. */
\r
1631 listGET_OWNER_OF_NEXT_ENTRY( pxFirstTCB, pxList );
\r
1634 listGET_OWNER_OF_NEXT_ENTRY( pxNextTCB, pxList );
\r
1635 usStackRemaining = usTaskCheckFreeStackSpace( ( unsigned portCHAR * ) pxNextTCB->pxStack );
\r
1636 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
1637 strcat( ( portCHAR * ) pcWriteBuffer, ( portCHAR * ) pcStatusString );
\r
1639 } while( pxNextTCB != pxFirstTCB );
\r
1643 /*-----------------------------------------------------------*/
\r
1645 #if ( configUSE_TRACE_FACILITY == 1 )
\r
1646 unsigned portSHORT usTaskCheckFreeStackSpace( const unsigned portCHAR *pucStackByte )
\r
1648 register unsigned portSHORT usCount = 0;
\r
1650 while( *pucStackByte == tskSTACK_FILL_BYTE )
\r
1652 pucStackByte -= portSTACK_GROWTH;
\r
1656 usCount /= sizeof( portSTACK_TYPE );
\r
1661 /*-----------------------------------------------------------*/
\r
1665 #if ( ( INCLUDE_vTaskDelete == 1 ) || ( INCLUDE_vTaskCleanUpResources == 1 ) )
\r
1667 static void prvDeleteTCB( tskTCB *pxTCB )
\r
1669 /* Free up the memory allocated by the scheduler for the task. It is up to
\r
1670 the task to free any memory allocated at the application level. */
\r
1671 vPortFree( pxTCB->pxStack );
\r
1672 vPortFree( pxTCB );
\r
1678 /*-----------------------------------------------------------*/
\r
1680 #if ( INCLUDE_xTaskGetCurrentTaskHandle == 1 )
\r
1682 xTaskHandle xTaskGetCurrentTaskHandle( void )
\r
1684 xTaskHandle xReturn;
\r
1686 portENTER_CRITICAL();
\r
1688 xReturn = ( xTaskHandle ) pxCurrentTCB;
\r
1690 portEXIT_CRITICAL();
\r