2 FreeRTOS.org V5.2.0 - Copyright (C) 2003-2009 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 it
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7 under the terms of the GNU General Public License (version 2) as published
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8 by the Free Software Foundation and modified by the FreeRTOS exception.
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10 FreeRTOS.org is distributed in the hope that it will be useful, but WITHOUT
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11 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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12 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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15 You should have received a copy of the GNU General Public License along
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16 with FreeRTOS.org; if not, write to the Free Software Foundation, Inc., 59
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17 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
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19 A special exception to the GPL is included to allow you to distribute a
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20 combined work that includes FreeRTOS.org without being obliged to provide
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21 the source code for any proprietary components. See the licensing section
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22 of http://www.FreeRTOS.org for full details.
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25 ***************************************************************************
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27 * Get the FreeRTOS eBook! See http://www.FreeRTOS.org/Documentation *
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29 * This is a concise, step by step, 'hands on' guide that describes both *
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30 * general multitasking concepts and FreeRTOS specifics. It presents and *
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31 * explains numerous examples that are written using the FreeRTOS API. *
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32 * Full source code for all the examples is provided in an accompanying *
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35 ***************************************************************************
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39 Please ensure to read the configuration and relevant port sections of the
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40 online documentation.
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42 http://www.FreeRTOS.org - Documentation, latest information, license and
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45 http://www.SafeRTOS.com - A version that is certified for use in safety
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48 http://www.OpenRTOS.com - Commercial support, development, porting,
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49 licensing and training services.
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57 #include "FreeRTOS.h"
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59 #include "StackMacros.h"
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62 * Macro to define the amount of stack available to the idle task.
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64 #define tskIDLE_STACK_SIZE configMINIMAL_STACK_SIZE
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67 * Task control block. A task control block (TCB) is allocated to each task,
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68 * and stores the context of the task.
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70 typedef struct tskTaskControlBlock
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72 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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73 xListItem xGenericListItem; /*< List item used to place the TCB in ready and blocked queues. */
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74 xListItem xEventListItem; /*< List item used to place the TCB in event lists. */
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75 unsigned portBASE_TYPE uxPriority; /*< The priority of the task where 0 is the lowest priority. */
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76 portSTACK_TYPE *pxStack; /*< Points to the start of the stack. */
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77 signed portCHAR pcTaskName[ configMAX_TASK_NAME_LEN ];/*< Descriptive name given to the task when created. Facilitates debugging only. */
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79 #if ( portSTACK_GROWTH > 0 )
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80 portSTACK_TYPE *pxEndOfStack; /*< Used for stack overflow checking on architectures where the stack grows up from low memory. */
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83 #if ( portCRITICAL_NESTING_IN_TCB == 1 )
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84 unsigned portBASE_TYPE uxCriticalNesting;
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87 #if ( configUSE_TRACE_FACILITY == 1 )
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88 unsigned portBASE_TYPE uxTCBNumber; /*< This is used for tracing the scheduler and making debugging easier only. */
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91 #if ( configUSE_MUTEXES == 1 )
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92 unsigned portBASE_TYPE uxBasePriority;
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95 #if ( configUSE_APPLICATION_TASK_TAG == 1 )
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96 pdTASK_HOOK_CODE pxTaskTag;
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102 * Some kernel aware debuggers require data to be viewed to be global, rather
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105 #ifdef portREMOVE_STATIC_QUALIFIER
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111 tskTCB * volatile pxCurrentTCB = NULL;
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113 /* Lists for ready and blocked tasks. --------------------*/
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115 static xList pxReadyTasksLists[ configMAX_PRIORITIES ]; /*< Prioritised ready tasks. */
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116 static xList xDelayedTaskList1; /*< Delayed tasks. */
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117 static xList xDelayedTaskList2; /*< Delayed tasks (two lists are used - one for delays that have overflowed the current tick count. */
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118 static xList * volatile pxDelayedTaskList; /*< Points to the delayed task list currently being used. */
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119 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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120 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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122 #if ( INCLUDE_vTaskDelete == 1 )
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124 static volatile xList xTasksWaitingTermination; /*< Tasks that have been deleted - but the their memory not yet freed. */
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125 static volatile unsigned portBASE_TYPE uxTasksDeleted = ( unsigned portBASE_TYPE ) 0;
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129 #if ( INCLUDE_vTaskSuspend == 1 )
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131 static xList xSuspendedTaskList; /*< Tasks that are currently suspended. */
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135 /* File private variables. --------------------------------*/
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136 static volatile unsigned portBASE_TYPE uxCurrentNumberOfTasks = ( unsigned portBASE_TYPE ) 0;
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137 static volatile portTickType xTickCount = ( portTickType ) 0;
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138 static unsigned portBASE_TYPE uxTopUsedPriority = tskIDLE_PRIORITY;
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139 static volatile unsigned portBASE_TYPE uxTopReadyPriority = tskIDLE_PRIORITY;
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140 static volatile signed portBASE_TYPE xSchedulerRunning = pdFALSE;
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141 static volatile unsigned portBASE_TYPE uxSchedulerSuspended = ( unsigned portBASE_TYPE ) pdFALSE;
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142 static volatile unsigned portBASE_TYPE uxMissedTicks = ( unsigned portBASE_TYPE ) 0;
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143 static volatile portBASE_TYPE xMissedYield = ( portBASE_TYPE ) pdFALSE;
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144 static volatile portBASE_TYPE xNumOfOverflows = ( portBASE_TYPE ) 0;
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145 static unsigned portBASE_TYPE uxTaskNumber = ( unsigned portBASE_TYPE ) 0;
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147 /* Debugging and trace facilities private variables and macros. ------------*/
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150 * The value used to fill the stack of a task when the task is created. This
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151 * is used purely for checking the high water mark for tasks.
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153 #define tskSTACK_FILL_BYTE ( 0xa5 )
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156 * Macros used by vListTask to indicate which state a task is in.
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158 #define tskBLOCKED_CHAR ( ( signed portCHAR ) 'B' )
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159 #define tskREADY_CHAR ( ( signed portCHAR ) 'R' )
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160 #define tskDELETED_CHAR ( ( signed portCHAR ) 'D' )
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161 #define tskSUSPENDED_CHAR ( ( signed portCHAR ) 'S' )
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164 * Macros and private variables used by the trace facility.
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166 #if ( configUSE_TRACE_FACILITY == 1 )
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168 #define tskSIZE_OF_EACH_TRACE_LINE ( ( unsigned portLONG ) ( sizeof( unsigned portLONG ) + sizeof( unsigned portLONG ) ) )
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169 static volatile signed portCHAR * volatile pcTraceBuffer;
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170 static signed portCHAR *pcTraceBufferStart;
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171 static signed portCHAR *pcTraceBufferEnd;
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172 static signed portBASE_TYPE xTracing = pdFALSE;
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173 static unsigned portBASE_TYPE uxPreviousTask = 255;
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174 static portCHAR pcStatusString[ 50 ];
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177 /*-----------------------------------------------------------*/
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180 * Macro that writes a trace of scheduler activity to a buffer. This trace
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181 * shows which task is running when and is very useful as a debugging tool.
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182 * As this macro is called each context switch it is a good idea to undefine
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183 * it if not using the facility.
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185 #if ( configUSE_TRACE_FACILITY == 1 )
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187 #define vWriteTraceToBuffer() \
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191 if( uxPreviousTask != pxCurrentTCB->uxTCBNumber ) \
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193 if( ( pcTraceBuffer + tskSIZE_OF_EACH_TRACE_LINE ) < pcTraceBufferEnd ) \
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195 uxPreviousTask = pxCurrentTCB->uxTCBNumber; \
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196 *( unsigned portLONG * ) pcTraceBuffer = ( unsigned portLONG ) xTickCount; \
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197 pcTraceBuffer += sizeof( unsigned portLONG ); \
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198 *( unsigned portLONG * ) pcTraceBuffer = ( unsigned portLONG ) uxPreviousTask; \
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199 pcTraceBuffer += sizeof( unsigned portLONG ); \
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203 xTracing = pdFALSE; \
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211 #define vWriteTraceToBuffer()
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214 /*-----------------------------------------------------------*/
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217 * Place the task represented by pxTCB into the appropriate ready queue for
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218 * the task. It is inserted at the end of the list. One quirk of this is
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219 * that if the task being inserted is at the same priority as the currently
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220 * executing task, then it will only be rescheduled after the currently
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221 * executing task has been rescheduled.
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223 #define prvAddTaskToReadyQueue( pxTCB ) \
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225 if( pxTCB->uxPriority > uxTopReadyPriority ) \
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227 uxTopReadyPriority = pxTCB->uxPriority; \
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229 vListInsertEnd( ( xList * ) &( pxReadyTasksLists[ pxTCB->uxPriority ] ), &( pxTCB->xGenericListItem ) ); \
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231 /*-----------------------------------------------------------*/
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234 * Macro that looks at the list of tasks that are currently delayed to see if
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235 * any require waking.
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237 * Tasks are stored in the queue in the order of their wake time - meaning
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238 * once one tasks has been found whose timer has not expired we need not look
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239 * any further down the list.
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241 #define prvCheckDelayedTasks() \
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243 register tskTCB *pxTCB; \
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245 while( ( pxTCB = ( tskTCB * ) listGET_OWNER_OF_HEAD_ENTRY( pxDelayedTaskList ) ) != NULL ) \
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247 if( xTickCount < listGET_LIST_ITEM_VALUE( &( pxTCB->xGenericListItem ) ) ) \
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251 vListRemove( &( pxTCB->xGenericListItem ) ); \
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252 /* Is the task waiting on an event also? */ \
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253 if( pxTCB->xEventListItem.pvContainer ) \
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255 vListRemove( &( pxTCB->xEventListItem ) ); \
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257 prvAddTaskToReadyQueue( pxTCB ); \
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260 /*-----------------------------------------------------------*/
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263 * Several functions take an xTaskHandle parameter that can optionally be NULL,
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264 * where NULL is used to indicate that the handle of the currently executing
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265 * task should be used in place of the parameter. This macro simply checks to
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266 * see if the parameter is NULL and returns a pointer to the appropriate TCB.
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268 #define prvGetTCBFromHandle( pxHandle ) ( ( pxHandle == NULL ) ? ( tskTCB * ) pxCurrentTCB : ( tskTCB * ) pxHandle )
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271 /* File private functions. --------------------------------*/
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274 * Utility to ready a TCB for a given task. Mainly just copies the parameters
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275 * into the TCB structure.
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277 static void prvInitialiseTCBVariables( tskTCB *pxTCB, const signed portCHAR * const pcName, unsigned portBASE_TYPE uxPriority );
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280 * Utility to ready all the lists used by the scheduler. This is called
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281 * automatically upon the creation of the first task.
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283 static void prvInitialiseTaskLists( void );
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286 * The idle task, which as all tasks is implemented as a never ending loop.
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287 * The idle task is automatically created and added to the ready lists upon
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288 * creation of the first user task.
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290 * The portTASK_FUNCTION_PROTO() macro is used to allow port/compiler specific
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291 * language extensions. The equivalent prototype for this function is:
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293 * void prvIdleTask( void *pvParameters );
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296 static portTASK_FUNCTION_PROTO( prvIdleTask, pvParameters );
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299 * Utility to free all memory allocated by the scheduler to hold a TCB,
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300 * including the stack pointed to by the TCB.
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302 * This does not free memory allocated by the task itself (i.e. memory
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303 * allocated by calls to pvPortMalloc from within the tasks application code).
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305 #if ( ( INCLUDE_vTaskDelete == 1 ) || ( INCLUDE_vTaskCleanUpResources == 1 ) )
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306 static void prvDeleteTCB( tskTCB *pxTCB );
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310 * Used only by the idle task. This checks to see if anything has been placed
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311 * in the list of tasks waiting to be deleted. If so the task is cleaned up
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312 * and its TCB deleted.
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314 static void prvCheckTasksWaitingTermination( void );
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317 * Allocates memory from the heap for a TCB and associated stack. Checks the
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318 * allocation was successful.
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320 static tskTCB *prvAllocateTCBAndStack( unsigned portSHORT usStackDepth );
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323 * Called from vTaskList. vListTasks details all the tasks currently under
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324 * control of the scheduler. The tasks may be in one of a number of lists.
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325 * prvListTaskWithinSingleList accepts a list and details the tasks from
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326 * within just that list.
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328 * THIS FUNCTION IS INTENDED FOR DEBUGGING ONLY, AND SHOULD NOT BE CALLED FROM
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329 * NORMAL APPLICATION CODE.
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331 #if ( configUSE_TRACE_FACILITY == 1 )
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333 static void prvListTaskWithinSingleList( const signed portCHAR *pcWriteBuffer, xList *pxList, signed portCHAR cStatus );
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338 * When a task is created, the stack of the task is filled with a known value.
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339 * This function determines the 'high water mark' of the task stack by
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340 * determining how much of the stack remains at the original preset value.
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342 #if ( ( configUSE_TRACE_FACILITY == 1 ) || ( INCLUDE_uxTaskGetStackHighWaterMark == 1 ) )
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344 unsigned portSHORT usTaskCheckFreeStackSpace( const unsigned portCHAR * pucStackByte );
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353 /*-----------------------------------------------------------
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354 * TASK CREATION API documented in task.h
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355 *----------------------------------------------------------*/
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357 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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359 signed portBASE_TYPE xReturn;
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362 /* Allocate the memory required by the TCB and stack for the new task.
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363 checking that the allocation was successful. */
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364 pxNewTCB = prvAllocateTCBAndStack( usStackDepth );
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366 if( pxNewTCB != NULL )
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368 portSTACK_TYPE *pxTopOfStack;
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370 /* Setup the newly allocated TCB with the initial state of the task. */
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371 prvInitialiseTCBVariables( pxNewTCB, pcName, uxPriority );
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373 /* Calculate the top of stack address. This depends on whether the
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374 stack grows from high memory to low (as per the 80x86) or visa versa.
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375 portSTACK_GROWTH is used to make the result positive or negative as
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376 required by the port. */
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377 #if portSTACK_GROWTH < 0
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379 pxTopOfStack = pxNewTCB->pxStack + ( usStackDepth - 1 );
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383 pxTopOfStack = pxNewTCB->pxStack;
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385 /* If we want to use stack checking on architectures that use
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386 a positive stack growth direction then we also need to store the
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387 other extreme of the stack space. */
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388 pxNewTCB->pxEndOfStack = pxNewTCB->pxStack + ( usStackDepth - 1 );
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392 /* Initialize the TCB stack to look as if the task was already running,
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393 but had been interrupted by the scheduler. The return address is set
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394 to the start of the task function. Once the stack has been initialised
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395 the top of stack variable is updated. */
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396 pxNewTCB->pxTopOfStack = pxPortInitialiseStack( pxTopOfStack, pvTaskCode, pvParameters );
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398 /* We are going to manipulate the task queues to add this task to a
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399 ready list, so must make sure no interrupts occur. */
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400 portENTER_CRITICAL();
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402 uxCurrentNumberOfTasks++;
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403 if( uxCurrentNumberOfTasks == ( unsigned portBASE_TYPE ) 1 )
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405 /* As this is the first task it must also be the current task. */
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406 pxCurrentTCB = pxNewTCB;
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408 /* This is the first task to be created so do the preliminary
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409 initialisation required. We will not recover if this call
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410 fails, but we will report the failure. */
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411 prvInitialiseTaskLists();
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415 /* If the scheduler is not already running, make this task the
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416 current task if it is the highest priority task to be created
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418 if( xSchedulerRunning == pdFALSE )
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420 if( pxCurrentTCB->uxPriority <= uxPriority )
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422 pxCurrentTCB = pxNewTCB;
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427 /* Remember the top priority to make context switching faster. Use
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428 the priority in pxNewTCB as this has been capped to a valid value. */
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429 if( pxNewTCB->uxPriority > uxTopUsedPriority )
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431 uxTopUsedPriority = pxNewTCB->uxPriority;
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434 #if ( configUSE_TRACE_FACILITY == 1 )
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436 /* Add a counter into the TCB for tracing only. */
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437 pxNewTCB->uxTCBNumber = uxTaskNumber;
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442 prvAddTaskToReadyQueue( pxNewTCB );
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445 traceTASK_CREATE( pxNewTCB );
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447 portEXIT_CRITICAL();
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451 xReturn = errCOULD_NOT_ALLOCATE_REQUIRED_MEMORY;
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452 traceTASK_CREATE_FAILED( pxNewTCB );
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455 if( xReturn == pdPASS )
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457 if( ( void * ) pxCreatedTask != NULL )
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459 /* Pass the TCB out - in an anonymous way. The calling function/
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460 task can use this as a handle to delete the task later if
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462 *pxCreatedTask = ( xTaskHandle ) pxNewTCB;
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465 if( xSchedulerRunning != pdFALSE )
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467 /* If the created task is of a higher priority than the current task
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468 then it should run now. */
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469 if( pxCurrentTCB->uxPriority < uxPriority )
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478 /*-----------------------------------------------------------*/
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480 #if ( INCLUDE_vTaskDelete == 1 )
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482 void vTaskDelete( xTaskHandle pxTaskToDelete )
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486 taskENTER_CRITICAL();
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488 /* Ensure a yield is performed if the current task is being
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490 if( pxTaskToDelete == pxCurrentTCB )
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492 pxTaskToDelete = NULL;
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495 /* If null is passed in here then we are deleting ourselves. */
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496 pxTCB = prvGetTCBFromHandle( pxTaskToDelete );
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498 traceTASK_DELETE( pxTCB );
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500 /* Remove task from the ready list and place in the termination list.
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501 This will stop the task from be scheduled. The idle task will check
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502 the termination list and free up any memory allocated by the
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503 scheduler for the TCB and stack. */
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504 vListRemove( &( pxTCB->xGenericListItem ) );
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506 /* Is the task waiting on an event also? */
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507 if( pxTCB->xEventListItem.pvContainer )
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509 vListRemove( &( pxTCB->xEventListItem ) );
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512 vListInsertEnd( ( xList * ) &xTasksWaitingTermination, &( pxTCB->xGenericListItem ) );
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514 /* Increment the ucTasksDeleted variable so the idle task knows
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515 there is a task that has been deleted and that it should therefore
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516 check the xTasksWaitingTermination list. */
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519 /* Increment the uxTaskNumberVariable also so kernel aware debuggers
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520 can detect that the task lists need re-generating. */
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523 taskEXIT_CRITICAL();
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525 /* Force a reschedule if we have just deleted the current task. */
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526 if( xSchedulerRunning != pdFALSE )
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528 if( ( void * ) pxTaskToDelete == NULL )
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542 /*-----------------------------------------------------------
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543 * TASK CONTROL API documented in task.h
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544 *----------------------------------------------------------*/
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546 #if ( INCLUDE_vTaskDelayUntil == 1 )
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548 void vTaskDelayUntil( portTickType * const pxPreviousWakeTime, portTickType xTimeIncrement )
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550 portTickType xTimeToWake;
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551 portBASE_TYPE xAlreadyYielded, xShouldDelay = pdFALSE;
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555 /* Generate the tick time at which the task wants to wake. */
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556 xTimeToWake = *pxPreviousWakeTime + xTimeIncrement;
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558 if( xTickCount < *pxPreviousWakeTime )
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560 /* The tick count has overflowed since this function was
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561 lasted called. In this case the only time we should ever
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562 actually delay is if the wake time has also overflowed,
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563 and the wake time is greater than the tick time. When this
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564 is the case it is as if neither time had overflowed. */
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565 if( ( xTimeToWake < *pxPreviousWakeTime ) && ( xTimeToWake > xTickCount ) )
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567 xShouldDelay = pdTRUE;
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572 /* The tick time has not overflowed. In this case we will
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573 delay if either the wake time has overflowed, and/or the
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574 tick time is less than the wake time. */
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575 if( ( xTimeToWake < *pxPreviousWakeTime ) || ( xTimeToWake > xTickCount ) )
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577 xShouldDelay = pdTRUE;
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581 /* Update the wake time ready for the next call. */
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582 *pxPreviousWakeTime = xTimeToWake;
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586 traceTASK_DELAY_UNTIL();
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588 /* We must remove ourselves from the ready list before adding
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589 ourselves to the blocked list as the same list item is used for
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591 vListRemove( ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
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593 /* The list item will be inserted in wake time order. */
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594 listSET_LIST_ITEM_VALUE( &( pxCurrentTCB->xGenericListItem ), xTimeToWake );
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596 if( xTimeToWake < xTickCount )
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598 /* Wake time has overflowed. Place this item in the
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600 vListInsert( ( xList * ) pxOverflowDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
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604 /* The wake time has not overflowed, so we can use the
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605 current block list. */
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606 vListInsert( ( xList * ) pxDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
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610 xAlreadyYielded = xTaskResumeAll();
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612 /* Force a reschedule if xTaskResumeAll has not already done so, we may
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613 have put ourselves to sleep. */
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614 if( !xAlreadyYielded )
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621 /*-----------------------------------------------------------*/
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623 #if ( INCLUDE_vTaskDelay == 1 )
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625 void vTaskDelay( portTickType xTicksToDelay )
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627 portTickType xTimeToWake;
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628 signed portBASE_TYPE xAlreadyYielded = pdFALSE;
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630 /* A delay time of zero just forces a reschedule. */
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631 if( xTicksToDelay > ( portTickType ) 0 )
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637 /* A task that is removed from the event list while the
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638 scheduler is suspended will not get placed in the ready
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639 list or removed from the blocked list until the scheduler
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642 This task cannot be in an event list as it is the currently
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645 /* Calculate the time to wake - this may overflow but this is
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647 xTimeToWake = xTickCount + xTicksToDelay;
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649 /* We must remove ourselves from the ready list before adding
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650 ourselves to the blocked list as the same list item is used for
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652 vListRemove( ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
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654 /* The list item will be inserted in wake time order. */
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655 listSET_LIST_ITEM_VALUE( &( pxCurrentTCB->xGenericListItem ), xTimeToWake );
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657 if( xTimeToWake < xTickCount )
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659 /* Wake time has overflowed. Place this item in the
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661 vListInsert( ( xList * ) pxOverflowDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
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665 /* The wake time has not overflowed, so we can use the
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666 current block list. */
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667 vListInsert( ( xList * ) pxDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
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670 xAlreadyYielded = xTaskResumeAll();
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673 /* Force a reschedule if xTaskResumeAll has not already done so, we may
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674 have put ourselves to sleep. */
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675 if( !xAlreadyYielded )
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682 /*-----------------------------------------------------------*/
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684 #if ( INCLUDE_uxTaskPriorityGet == 1 )
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686 unsigned portBASE_TYPE uxTaskPriorityGet( xTaskHandle pxTask )
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689 unsigned portBASE_TYPE uxReturn;
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691 taskENTER_CRITICAL();
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693 /* If null is passed in here then we are changing the
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694 priority of the calling function. */
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695 pxTCB = prvGetTCBFromHandle( pxTask );
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696 uxReturn = pxTCB->uxPriority;
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698 taskEXIT_CRITICAL();
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704 /*-----------------------------------------------------------*/
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706 #if ( INCLUDE_vTaskPrioritySet == 1 )
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708 void vTaskPrioritySet( xTaskHandle pxTask, unsigned portBASE_TYPE uxNewPriority )
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711 unsigned portBASE_TYPE uxCurrentPriority, xYieldRequired = pdFALSE;
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713 /* Ensure the new priority is valid. */
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714 if( uxNewPriority >= configMAX_PRIORITIES )
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716 uxNewPriority = configMAX_PRIORITIES - 1;
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719 taskENTER_CRITICAL();
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721 if( pxTask == pxCurrentTCB )
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726 /* If null is passed in here then we are changing the
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727 priority of the calling function. */
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728 pxTCB = prvGetTCBFromHandle( pxTask );
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730 traceTASK_PRIORITY_SET( pxTask, uxNewPriority );
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732 #if ( configUSE_MUTEXES == 1 )
\r
734 uxCurrentPriority = pxTCB->uxBasePriority;
\r
738 uxCurrentPriority = pxTCB->uxPriority;
\r
742 if( uxCurrentPriority != uxNewPriority )
\r
744 /* The priority change may have readied a task of higher
\r
745 priority than the calling task. */
\r
746 if( uxNewPriority > uxCurrentPriority )
\r
748 if( pxTask != NULL )
\r
750 /* The priority of another task is being raised. If we
\r
751 were raising the priority of the currently running task
\r
752 there would be no need to switch as it must have already
\r
753 been the highest priority task. */
\r
754 xYieldRequired = pdTRUE;
\r
757 else if( pxTask == NULL )
\r
759 /* Setting our own priority down means there may now be another
\r
760 task of higher priority that is ready to execute. */
\r
761 xYieldRequired = pdTRUE;
\r
766 #if ( configUSE_MUTEXES == 1 )
\r
768 /* Only change the priority being used if the task is not
\r
769 currently using an inherited priority. */
\r
770 if( pxTCB->uxBasePriority == pxTCB->uxPriority )
\r
772 pxTCB->uxPriority = uxNewPriority;
\r
775 /* The base priority gets set whatever. */
\r
776 pxTCB->uxBasePriority = uxNewPriority;
\r
780 pxTCB->uxPriority = uxNewPriority;
\r
784 listSET_LIST_ITEM_VALUE( &( pxTCB->xEventListItem ), ( configMAX_PRIORITIES - ( portTickType ) uxNewPriority ) );
\r
786 /* If the task is in the blocked or suspended list we need do
\r
787 nothing more than change it's priority variable. However, if
\r
788 the task is in a ready list it needs to be removed and placed
\r
789 in the queue appropriate to its new priority. */
\r
790 if( listIS_CONTAINED_WITHIN( &( pxReadyTasksLists[ uxCurrentPriority ] ), &( pxTCB->xGenericListItem ) ) )
\r
792 /* The task is currently in its ready list - remove before adding
\r
793 it to it's new ready list. As we are in a critical section we
\r
794 can do this even if the scheduler is suspended. */
\r
795 vListRemove( &( pxTCB->xGenericListItem ) );
\r
796 prvAddTaskToReadyQueue( pxTCB );
\r
799 if( xYieldRequired == pdTRUE )
\r
805 taskEXIT_CRITICAL();
\r
809 /*-----------------------------------------------------------*/
\r
811 #if ( INCLUDE_vTaskSuspend == 1 )
\r
813 void vTaskSuspend( xTaskHandle pxTaskToSuspend )
\r
817 taskENTER_CRITICAL();
\r
819 /* Ensure a yield is performed if the current task is being
\r
821 if( pxTaskToSuspend == pxCurrentTCB )
\r
823 pxTaskToSuspend = NULL;
\r
826 /* If null is passed in here then we are suspending ourselves. */
\r
827 pxTCB = prvGetTCBFromHandle( pxTaskToSuspend );
\r
829 traceTASK_SUSPEND( pxTaskToSuspend );
\r
831 /* Remove task from the ready/delayed list and place in the suspended list. */
\r
832 vListRemove( &( pxTCB->xGenericListItem ) );
\r
834 /* Is the task waiting on an event also? */
\r
835 if( pxTCB->xEventListItem.pvContainer )
\r
837 vListRemove( &( pxTCB->xEventListItem ) );
\r
840 vListInsertEnd( ( xList * ) &xSuspendedTaskList, &( pxTCB->xGenericListItem ) );
\r
842 taskEXIT_CRITICAL();
\r
844 /* We may have just suspended the current task. */
\r
845 if( ( void * ) pxTaskToSuspend == NULL )
\r
852 /*-----------------------------------------------------------*/
\r
854 #if ( INCLUDE_vTaskSuspend == 1 )
\r
856 signed portBASE_TYPE xTaskIsTaskSuspended( xTaskHandle xTask )
\r
858 portBASE_TYPE xReturn = pdFALSE;
\r
859 const tskTCB * const pxTCB = ( tskTCB * ) xTask;
\r
861 /* Is the task we are attempting to resume actually in the
\r
863 if( listIS_CONTAINED_WITHIN( &xSuspendedTaskList, &( pxTCB->xGenericListItem ) ) != pdFALSE )
\r
865 /* Has the task already been resumed from within an ISR? */
\r
866 if( listIS_CONTAINED_WITHIN( &xPendingReadyList, &( pxTCB->xEventListItem ) ) != pdTRUE )
\r
868 /* Is it in the suspended list because it is in the
\r
869 Suspended state? It is possible to be in the suspended
\r
870 list because it is blocked on a task with no timeout
\r
872 if( listIS_CONTAINED_WITHIN( NULL, &( pxTCB->xEventListItem ) ) == pdTRUE )
\r
883 /*-----------------------------------------------------------*/
\r
885 #if ( INCLUDE_vTaskSuspend == 1 )
\r
887 void vTaskResume( xTaskHandle pxTaskToResume )
\r
891 /* Remove the task from whichever list it is currently in, and place
\r
892 it in the ready list. */
\r
893 pxTCB = ( tskTCB * ) pxTaskToResume;
\r
895 /* The parameter cannot be NULL as it is impossible to resume the
\r
896 currently executing task. */
\r
897 if( ( pxTCB != NULL ) && ( pxTCB != pxCurrentTCB ) )
\r
899 taskENTER_CRITICAL();
\r
901 if( xTaskIsTaskSuspended( pxTCB ) == pdTRUE )
\r
903 traceTASK_RESUME( pxTCB );
\r
905 /* As we are in a critical section we can access the ready
\r
906 lists even if the scheduler is suspended. */
\r
907 vListRemove( &( pxTCB->xGenericListItem ) );
\r
908 prvAddTaskToReadyQueue( pxTCB );
\r
910 /* We may have just resumed a higher priority task. */
\r
911 if( pxTCB->uxPriority >= pxCurrentTCB->uxPriority )
\r
913 /* This yield may not cause the task just resumed to run, but
\r
914 will leave the lists in the correct state for the next yield. */
\r
919 taskEXIT_CRITICAL();
\r
925 /*-----------------------------------------------------------*/
\r
927 #if ( ( INCLUDE_xTaskResumeFromISR == 1 ) && ( INCLUDE_vTaskSuspend == 1 ) )
\r
929 portBASE_TYPE xTaskResumeFromISR( xTaskHandle pxTaskToResume )
\r
931 portBASE_TYPE xYieldRequired = pdFALSE;
\r
934 pxTCB = ( tskTCB * ) pxTaskToResume;
\r
936 if( xTaskIsTaskSuspended( pxTCB ) == pdTRUE )
\r
938 traceTASK_RESUME_FROM_ISR( pxTCB );
\r
940 if( uxSchedulerSuspended == ( unsigned portBASE_TYPE ) pdFALSE )
\r
942 xYieldRequired = ( pxTCB->uxPriority >= pxCurrentTCB->uxPriority );
\r
943 vListRemove( &( pxTCB->xGenericListItem ) );
\r
944 prvAddTaskToReadyQueue( pxTCB );
\r
948 /* We cannot access the delayed or ready lists, so will hold this
\r
949 task pending until the scheduler is resumed, at which point a
\r
950 yield will be performed if necessary. */
\r
951 vListInsertEnd( ( xList * ) &( xPendingReadyList ), &( pxTCB->xEventListItem ) );
\r
955 return xYieldRequired;
\r
963 /*-----------------------------------------------------------
\r
964 * PUBLIC SCHEDULER CONTROL documented in task.h
\r
965 *----------------------------------------------------------*/
\r
968 void vTaskStartScheduler( void )
\r
970 portBASE_TYPE xReturn;
\r
972 /* Add the idle task at the lowest priority. */
\r
973 xReturn = xTaskCreate( prvIdleTask, ( signed portCHAR * ) "IDLE", tskIDLE_STACK_SIZE, ( void * ) NULL, tskIDLE_PRIORITY, ( xTaskHandle * ) NULL );
\r
975 if( xReturn == pdPASS )
\r
977 /* Interrupts are turned off here, to ensure a tick does not occur
\r
978 before or during the call to xPortStartScheduler(). The stacks of
\r
979 the created tasks contain a status word with interrupts switched on
\r
980 so interrupts will automatically get re-enabled when the first task
\r
983 STEPPING THROUGH HERE USING A DEBUGGER CAN CAUSE BIG PROBLEMS IF THE
\r
984 DEBUGGER ALLOWS INTERRUPTS TO BE PROCESSED. */
\r
985 portDISABLE_INTERRUPTS();
\r
987 xSchedulerRunning = pdTRUE;
\r
988 xTickCount = ( portTickType ) 0;
\r
990 /* Setting up the timer tick is hardware specific and thus in the
\r
991 portable interface. */
\r
992 if( xPortStartScheduler() )
\r
994 /* Should not reach here as if the scheduler is running the
\r
995 function will not return. */
\r
999 /* Should only reach here if a task calls xTaskEndScheduler(). */
\r
1003 /*-----------------------------------------------------------*/
\r
1005 void vTaskEndScheduler( void )
\r
1007 /* Stop the scheduler interrupts and call the portable scheduler end
\r
1008 routine so the original ISRs can be restored if necessary. The port
\r
1009 layer must ensure interrupts enable bit is left in the correct state. */
\r
1010 portDISABLE_INTERRUPTS();
\r
1011 xSchedulerRunning = pdFALSE;
\r
1012 vPortEndScheduler();
\r
1014 /*----------------------------------------------------------*/
\r
1016 void vTaskSuspendAll( void )
\r
1018 /* A critical section is not required as the variable is of type
\r
1020 ++uxSchedulerSuspended;
\r
1022 /*----------------------------------------------------------*/
\r
1024 signed portBASE_TYPE xTaskResumeAll( void )
\r
1026 register tskTCB *pxTCB;
\r
1027 signed portBASE_TYPE xAlreadyYielded = pdFALSE;
\r
1029 /* It is possible that an ISR caused a task to be removed from an event
\r
1030 list while the scheduler was suspended. If this was the case then the
\r
1031 removed task will have been added to the xPendingReadyList. Once the
\r
1032 scheduler has been resumed it is safe to move all the pending ready
\r
1033 tasks from this list into their appropriate ready list. */
\r
1034 portENTER_CRITICAL();
\r
1036 --uxSchedulerSuspended;
\r
1038 if( uxSchedulerSuspended == ( unsigned portBASE_TYPE ) pdFALSE )
\r
1040 if( uxCurrentNumberOfTasks > ( unsigned portBASE_TYPE ) 0 )
\r
1042 portBASE_TYPE xYieldRequired = pdFALSE;
\r
1044 /* Move any readied tasks from the pending list into the
\r
1045 appropriate ready list. */
\r
1046 while( ( pxTCB = ( tskTCB * ) listGET_OWNER_OF_HEAD_ENTRY( ( ( xList * ) &xPendingReadyList ) ) ) != NULL )
\r
1048 vListRemove( &( pxTCB->xEventListItem ) );
\r
1049 vListRemove( &( pxTCB->xGenericListItem ) );
\r
1050 prvAddTaskToReadyQueue( pxTCB );
\r
1052 /* If we have moved a task that has a priority higher than
\r
1053 the current task then we should yield. */
\r
1054 if( pxTCB->uxPriority >= pxCurrentTCB->uxPriority )
\r
1056 xYieldRequired = pdTRUE;
\r
1060 /* If any ticks occurred while the scheduler was suspended then
\r
1061 they should be processed now. This ensures the tick count does not
\r
1062 slip, and that any delayed tasks are resumed at the correct time. */
\r
1063 if( uxMissedTicks > ( unsigned portBASE_TYPE ) 0 )
\r
1065 while( uxMissedTicks > ( unsigned portBASE_TYPE ) 0 )
\r
1067 vTaskIncrementTick();
\r
1071 /* As we have processed some ticks it is appropriate to yield
\r
1072 to ensure the highest priority task that is ready to run is
\r
1073 the task actually running. */
\r
1074 #if configUSE_PREEMPTION == 1
\r
1076 xYieldRequired = pdTRUE;
\r
1081 if( ( xYieldRequired == pdTRUE ) || ( xMissedYield == pdTRUE ) )
\r
1083 xAlreadyYielded = pdTRUE;
\r
1084 xMissedYield = pdFALSE;
\r
1090 portEXIT_CRITICAL();
\r
1092 return xAlreadyYielded;
\r
1100 /*-----------------------------------------------------------
\r
1101 * PUBLIC TASK UTILITIES documented in task.h
\r
1102 *----------------------------------------------------------*/
\r
1106 portTickType xTaskGetTickCount( void )
\r
1108 portTickType xTicks;
\r
1110 /* Critical section required if running on a 16 bit processor. */
\r
1111 taskENTER_CRITICAL();
\r
1113 xTicks = xTickCount;
\r
1115 taskEXIT_CRITICAL();
\r
1119 /*-----------------------------------------------------------*/
\r
1121 unsigned portBASE_TYPE uxTaskGetNumberOfTasks( void )
\r
1123 /* A critical section is not required because the variables are of type
\r
1125 return uxCurrentNumberOfTasks;
\r
1127 /*-----------------------------------------------------------*/
\r
1129 #if ( ( configUSE_TRACE_FACILITY == 1 ) && ( INCLUDE_vTaskDelete == 1 ) && ( INCLUDE_vTaskSuspend == 1 ) )
\r
1131 void vTaskList( signed portCHAR *pcWriteBuffer )
\r
1133 unsigned portBASE_TYPE uxQueue;
\r
1135 /* This is a VERY costly function that should be used for debug only.
\r
1136 It leaves interrupts disabled for a LONG time. */
\r
1138 vTaskSuspendAll();
\r
1140 /* Run through all the lists that could potentially contain a TCB and
\r
1141 report the task name, state and stack high water mark. */
\r
1143 pcWriteBuffer[ 0 ] = ( signed portCHAR ) 0x00;
\r
1144 strcat( ( portCHAR * ) pcWriteBuffer, ( const portCHAR * ) "\r\n" );
\r
1146 uxQueue = uxTopUsedPriority + 1;
\r
1152 if( !listLIST_IS_EMPTY( &( pxReadyTasksLists[ uxQueue ] ) ) )
\r
1154 prvListTaskWithinSingleList( pcWriteBuffer, ( xList * ) &( pxReadyTasksLists[ uxQueue ] ), tskREADY_CHAR );
\r
1156 }while( uxQueue > ( unsigned portSHORT ) tskIDLE_PRIORITY );
\r
1158 if( !listLIST_IS_EMPTY( pxDelayedTaskList ) )
\r
1160 prvListTaskWithinSingleList( pcWriteBuffer, ( xList * ) pxDelayedTaskList, tskBLOCKED_CHAR );
\r
1163 if( !listLIST_IS_EMPTY( pxOverflowDelayedTaskList ) )
\r
1165 prvListTaskWithinSingleList( pcWriteBuffer, ( xList * ) pxOverflowDelayedTaskList, tskBLOCKED_CHAR );
\r
1168 if( !listLIST_IS_EMPTY( &xTasksWaitingTermination ) )
\r
1170 prvListTaskWithinSingleList( pcWriteBuffer, ( xList * ) &xTasksWaitingTermination, tskDELETED_CHAR );
\r
1173 if( !listLIST_IS_EMPTY( &xSuspendedTaskList ) )
\r
1175 prvListTaskWithinSingleList( pcWriteBuffer, ( xList * ) &xSuspendedTaskList, tskSUSPENDED_CHAR );
\r
1182 /*----------------------------------------------------------*/
\r
1184 #if ( configUSE_TRACE_FACILITY == 1 )
\r
1186 void vTaskStartTrace( signed portCHAR * pcBuffer, unsigned portLONG ulBufferSize )
\r
1188 portENTER_CRITICAL();
\r
1190 pcTraceBuffer = ( signed portCHAR * )pcBuffer;
\r
1191 pcTraceBufferStart = pcBuffer;
\r
1192 pcTraceBufferEnd = pcBuffer + ( ulBufferSize - tskSIZE_OF_EACH_TRACE_LINE );
\r
1193 xTracing = pdTRUE;
\r
1195 portEXIT_CRITICAL();
\r
1199 /*----------------------------------------------------------*/
\r
1201 #if ( configUSE_TRACE_FACILITY == 1 )
\r
1203 unsigned portLONG ulTaskEndTrace( void )
\r
1205 unsigned portLONG ulBufferLength;
\r
1207 portENTER_CRITICAL();
\r
1208 xTracing = pdFALSE;
\r
1209 portEXIT_CRITICAL();
\r
1211 ulBufferLength = ( unsigned portLONG ) ( pcTraceBuffer - pcTraceBufferStart );
\r
1213 return ulBufferLength;
\r
1220 /*-----------------------------------------------------------
\r
1221 * SCHEDULER INTERNALS AVAILABLE FOR PORTING PURPOSES
\r
1222 * documented in task.h
\r
1223 *----------------------------------------------------------*/
\r
1226 void vTaskIncrementTick( void )
\r
1228 /* Called by the portable layer each time a tick interrupt occurs.
\r
1229 Increments the tick then checks to see if the new tick value will cause any
\r
1230 tasks to be unblocked. */
\r
1231 if( uxSchedulerSuspended == ( unsigned portBASE_TYPE ) pdFALSE )
\r
1234 if( xTickCount == ( portTickType ) 0 )
\r
1238 /* Tick count has overflowed so we need to swap the delay lists.
\r
1239 If there are any items in pxDelayedTaskList here then there is
\r
1241 pxTemp = pxDelayedTaskList;
\r
1242 pxDelayedTaskList = pxOverflowDelayedTaskList;
\r
1243 pxOverflowDelayedTaskList = pxTemp;
\r
1244 xNumOfOverflows++;
\r
1247 /* See if this tick has made a timeout expire. */
\r
1248 prvCheckDelayedTasks();
\r
1254 /* The tick hook gets called at regular intervals, even if the
\r
1255 scheduler is locked. */
\r
1256 #if ( configUSE_TICK_HOOK == 1 )
\r
1258 extern void vApplicationTickHook( void );
\r
1260 vApplicationTickHook();
\r
1265 #if ( configUSE_TICK_HOOK == 1 )
\r
1267 extern void vApplicationTickHook( void );
\r
1269 /* Guard against the tick hook being called when the missed tick
\r
1270 count is being unwound (when the scheduler is being unlocked. */
\r
1271 if( uxMissedTicks == 0 )
\r
1273 vApplicationTickHook();
\r
1278 traceTASK_INCREMENT_TICK( xTickCount );
\r
1280 /*-----------------------------------------------------------*/
\r
1282 #if ( ( INCLUDE_vTaskCleanUpResources == 1 ) && ( INCLUDE_vTaskSuspend == 1 ) )
\r
1284 void vTaskCleanUpResources( void )
\r
1286 unsigned portSHORT usQueue;
\r
1287 volatile tskTCB *pxTCB;
\r
1289 usQueue = ( unsigned portSHORT ) uxTopUsedPriority + ( unsigned portSHORT ) 1;
\r
1291 /* Remove any TCB's from the ready queues. */
\r
1296 while( !listLIST_IS_EMPTY( &( pxReadyTasksLists[ usQueue ] ) ) )
\r
1298 listGET_OWNER_OF_NEXT_ENTRY( pxTCB, &( pxReadyTasksLists[ usQueue ] ) );
\r
1299 vListRemove( ( xListItem * ) &( pxTCB->xGenericListItem ) );
\r
1301 prvDeleteTCB( ( tskTCB * ) pxTCB );
\r
1303 }while( usQueue > ( unsigned portSHORT ) tskIDLE_PRIORITY );
\r
1305 /* Remove any TCB's from the delayed queue. */
\r
1306 while( !listLIST_IS_EMPTY( &xDelayedTaskList1 ) )
\r
1308 listGET_OWNER_OF_NEXT_ENTRY( pxTCB, &xDelayedTaskList1 );
\r
1309 vListRemove( ( xListItem * ) &( pxTCB->xGenericListItem ) );
\r
1311 prvDeleteTCB( ( tskTCB * ) pxTCB );
\r
1314 /* Remove any TCB's from the overflow delayed queue. */
\r
1315 while( !listLIST_IS_EMPTY( &xDelayedTaskList2 ) )
\r
1317 listGET_OWNER_OF_NEXT_ENTRY( pxTCB, &xDelayedTaskList2 );
\r
1318 vListRemove( ( xListItem * ) &( pxTCB->xGenericListItem ) );
\r
1320 prvDeleteTCB( ( tskTCB * ) pxTCB );
\r
1323 while( !listLIST_IS_EMPTY( &xSuspendedTaskList ) )
\r
1325 listGET_OWNER_OF_NEXT_ENTRY( pxTCB, &xSuspendedTaskList );
\r
1326 vListRemove( ( xListItem * ) &( pxTCB->xGenericListItem ) );
\r
1328 prvDeleteTCB( ( tskTCB * ) pxTCB );
\r
1333 /*-----------------------------------------------------------*/
\r
1335 #if ( configUSE_APPLICATION_TASK_TAG == 1 )
\r
1337 void vTaskSetApplicationTaskTag( xTaskHandle xTask, pdTASK_HOOK_CODE pxTagValue )
\r
1341 /* If xTask is NULL then we are setting our own task hook. */
\r
1342 if( xTask == NULL )
\r
1344 xTCB = ( tskTCB * ) pxCurrentTCB;
\r
1348 xTCB = ( tskTCB * ) xTask;
\r
1351 /* Save the hook function in the TCB. A critical section is required as
\r
1352 the value can be accessed from an interrupt. */
\r
1353 portENTER_CRITICAL();
\r
1354 xTCB->pxTaskTag = pxTagValue;
\r
1355 portEXIT_CRITICAL();
\r
1359 /*-----------------------------------------------------------*/
\r
1361 #if ( configUSE_APPLICATION_TASK_TAG == 1 )
\r
1363 portBASE_TYPE xTaskCallApplicationTaskHook( xTaskHandle xTask, void *pvParameter )
\r
1366 portBASE_TYPE xReturn;
\r
1368 /* If xTask is NULL then we are calling our own task hook. */
\r
1369 if( xTask == NULL )
\r
1371 xTCB = ( tskTCB * ) pxCurrentTCB;
\r
1375 xTCB = ( tskTCB * ) xTask;
\r
1378 if( xTCB->pxTaskTag != NULL )
\r
1380 xReturn = xTCB->pxTaskTag( pvParameter );
\r
1391 /*-----------------------------------------------------------*/
\r
1393 void vTaskSwitchContext( void )
\r
1395 traceTASK_SWITCHED_OUT();
\r
1397 if( uxSchedulerSuspended != ( unsigned portBASE_TYPE ) pdFALSE )
\r
1399 /* The scheduler is currently suspended - do not allow a context
\r
1401 xMissedYield = pdTRUE;
\r
1405 taskFIRST_CHECK_FOR_STACK_OVERFLOW();
\r
1406 taskSECOND_CHECK_FOR_STACK_OVERFLOW();
\r
1408 /* Find the highest priority queue that contains ready tasks. */
\r
1409 while( listLIST_IS_EMPTY( &( pxReadyTasksLists[ uxTopReadyPriority ] ) ) )
\r
1411 --uxTopReadyPriority;
\r
1414 /* listGET_OWNER_OF_NEXT_ENTRY walks through the list, so the tasks of the
\r
1415 same priority get an equal share of the processor time. */
\r
1416 listGET_OWNER_OF_NEXT_ENTRY( pxCurrentTCB, &( pxReadyTasksLists[ uxTopReadyPriority ] ) );
\r
1418 traceTASK_SWITCHED_IN();
\r
1419 vWriteTraceToBuffer();
\r
1421 /*-----------------------------------------------------------*/
\r
1423 void vTaskPlaceOnEventList( const xList * const pxEventList, portTickType xTicksToWait )
\r
1425 portTickType xTimeToWake;
\r
1427 /* THIS FUNCTION MUST BE CALLED WITH INTERRUPTS DISABLED OR THE
\r
1428 SCHEDULER SUSPENDED. */
\r
1430 /* Place the event list item of the TCB in the appropriate event list.
\r
1431 This is placed in the list in priority order so the highest priority task
\r
1432 is the first to be woken by the event. */
\r
1433 vListInsert( ( xList * ) pxEventList, ( xListItem * ) &( pxCurrentTCB->xEventListItem ) );
\r
1435 /* We must remove ourselves from the ready list before adding ourselves
\r
1436 to the blocked list as the same list item is used for both lists. We have
\r
1437 exclusive access to the ready lists as the scheduler is locked. */
\r
1438 vListRemove( ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
\r
1441 #if ( INCLUDE_vTaskSuspend == 1 )
\r
1443 if( xTicksToWait == portMAX_DELAY )
\r
1445 /* Add ourselves to the suspended task list instead of a delayed task
\r
1446 list to ensure we are not woken by a timing event. We will block
\r
1448 vListInsertEnd( ( xList * ) &xSuspendedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
\r
1452 /* Calculate the time at which the task should be woken if the event does
\r
1453 not occur. This may overflow but this doesn't matter. */
\r
1454 xTimeToWake = xTickCount + xTicksToWait;
\r
1456 listSET_LIST_ITEM_VALUE( &( pxCurrentTCB->xGenericListItem ), xTimeToWake );
\r
1458 if( xTimeToWake < xTickCount )
\r
1460 /* Wake time has overflowed. Place this item in the overflow list. */
\r
1461 vListInsert( ( xList * ) pxOverflowDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
\r
1465 /* The wake time has not overflowed, so we can use the current block list. */
\r
1466 vListInsert( ( xList * ) pxDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
\r
1472 /* Calculate the time at which the task should be woken if the event does
\r
1473 not occur. This may overflow but this doesn't matter. */
\r
1474 xTimeToWake = xTickCount + xTicksToWait;
\r
1476 listSET_LIST_ITEM_VALUE( &( pxCurrentTCB->xGenericListItem ), xTimeToWake );
\r
1478 if( xTimeToWake < xTickCount )
\r
1480 /* Wake time has overflowed. Place this item in the overflow list. */
\r
1481 vListInsert( ( xList * ) pxOverflowDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
\r
1485 /* The wake time has not overflowed, so we can use the current block list. */
\r
1486 vListInsert( ( xList * ) pxDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
\r
1491 /*-----------------------------------------------------------*/
\r
1493 signed portBASE_TYPE xTaskRemoveFromEventList( const xList * const pxEventList )
\r
1495 tskTCB *pxUnblockedTCB;
\r
1496 portBASE_TYPE xReturn;
\r
1498 /* THIS FUNCTION MUST BE CALLED WITH INTERRUPTS DISABLED OR THE
\r
1499 SCHEDULER SUSPENDED. It can also be called from within an ISR. */
\r
1501 /* The event list is sorted in priority order, so we can remove the
\r
1502 first in the list, remove the TCB from the delayed list, and add
\r
1503 it to the ready list.
\r
1505 If an event is for a queue that is locked then this function will never
\r
1506 get called - the lock count on the queue will get modified instead. This
\r
1507 means we can always expect exclusive access to the event list here. */
\r
1508 pxUnblockedTCB = ( tskTCB * ) listGET_OWNER_OF_HEAD_ENTRY( pxEventList );
\r
1509 vListRemove( &( pxUnblockedTCB->xEventListItem ) );
\r
1511 if( uxSchedulerSuspended == ( unsigned portBASE_TYPE ) pdFALSE )
\r
1513 vListRemove( &( pxUnblockedTCB->xGenericListItem ) );
\r
1514 prvAddTaskToReadyQueue( pxUnblockedTCB );
\r
1518 /* We cannot access the delayed or ready lists, so will hold this
\r
1519 task pending until the scheduler is resumed. */
\r
1520 vListInsertEnd( ( xList * ) &( xPendingReadyList ), &( pxUnblockedTCB->xEventListItem ) );
\r
1523 if( pxUnblockedTCB->uxPriority >= pxCurrentTCB->uxPriority )
\r
1525 /* Return true if the task removed from the event list has
\r
1526 a higher priority than the calling task. This allows
\r
1527 the calling task to know if it should force a context
\r
1533 xReturn = pdFALSE;
\r
1538 /*-----------------------------------------------------------*/
\r
1540 void vTaskSetTimeOutState( xTimeOutType * const pxTimeOut )
\r
1542 pxTimeOut->xOverflowCount = xNumOfOverflows;
\r
1543 pxTimeOut->xTimeOnEntering = xTickCount;
\r
1545 /*-----------------------------------------------------------*/
\r
1547 portBASE_TYPE xTaskCheckForTimeOut( xTimeOutType * const pxTimeOut, portTickType * const pxTicksToWait )
\r
1549 portBASE_TYPE xReturn;
\r
1551 portENTER_CRITICAL();
\r
1553 #if ( INCLUDE_vTaskSuspend == 1 )
\r
1554 /* If INCLUDE_vTaskSuspend is set to 1 and the block time specified is
\r
1555 the maximum block time then the task should block indefinitely, and
\r
1556 therefore never time out. */
\r
1557 if( *pxTicksToWait == portMAX_DELAY )
\r
1559 xReturn = pdFALSE;
\r
1561 else /* We are not blocking indefinitely, perform the checks below. */
\r
1564 if( ( xNumOfOverflows != pxTimeOut->xOverflowCount ) && ( xTickCount >= pxTimeOut->xTimeOnEntering ) )
\r
1566 /* The tick count is greater than the time at which vTaskSetTimeout()
\r
1567 was called, but has also overflowed since vTaskSetTimeOut() was called.
\r
1568 It must have wrapped all the way around and gone past us again. This
\r
1569 passed since vTaskSetTimeout() was called. */
\r
1572 else if( ( xTickCount - pxTimeOut->xTimeOnEntering ) < *pxTicksToWait )
\r
1574 /* Not a genuine timeout. Adjust parameters for time remaining. */
\r
1575 *pxTicksToWait -= ( xTickCount - pxTimeOut->xTimeOnEntering );
\r
1576 vTaskSetTimeOutState( pxTimeOut );
\r
1577 xReturn = pdFALSE;
\r
1584 portEXIT_CRITICAL();
\r
1588 /*-----------------------------------------------------------*/
\r
1590 void vTaskMissedYield( void )
\r
1592 xMissedYield = pdTRUE;
\r
1596 * -----------------------------------------------------------
\r
1598 * ----------------------------------------------------------
\r
1600 * The portTASK_FUNCTION() macro is used to allow port/compiler specific
\r
1601 * language extensions. The equivalent prototype for this function is:
\r
1603 * void prvIdleTask( void *pvParameters );
\r
1606 static portTASK_FUNCTION( prvIdleTask, pvParameters )
\r
1608 /* Stop warnings. */
\r
1609 ( void ) pvParameters;
\r
1613 /* See if any tasks have been deleted. */
\r
1614 prvCheckTasksWaitingTermination();
\r
1616 #if ( configUSE_PREEMPTION == 0 )
\r
1618 /* If we are not using preemption we keep forcing a task switch to
\r
1619 see if any other task has become available. If we are using
\r
1620 preemption we don't need to do this as any task becoming available
\r
1621 will automatically get the processor anyway. */
\r
1626 #if ( ( configUSE_PREEMPTION == 1 ) && ( configIDLE_SHOULD_YIELD == 1 ) )
\r
1628 /* When using preemption tasks of equal priority will be
\r
1629 timesliced. If a task that is sharing the idle priority is ready
\r
1630 to run then the idle task should yield before the end of the
\r
1633 A critical region is not required here as we are just reading from
\r
1634 the list, and an occasional incorrect value will not matter. If
\r
1635 the ready list at the idle priority contains more than one task
\r
1636 then a task other than the idle task is ready to execute. */
\r
1637 if( listCURRENT_LIST_LENGTH( &( pxReadyTasksLists[ tskIDLE_PRIORITY ] ) ) > ( unsigned portBASE_TYPE ) 1 )
\r
1644 #if ( configUSE_IDLE_HOOK == 1 )
\r
1646 extern void vApplicationIdleHook( void );
\r
1648 /* Call the user defined function from within the idle task. This
\r
1649 allows the application designer to add background functionality
\r
1650 without the overhead of a separate task.
\r
1651 NOTE: vApplicationIdleHook() MUST NOT, UNDER ANY CIRCUMSTANCES,
\r
1652 CALL A FUNCTION THAT MIGHT BLOCK. */
\r
1653 vApplicationIdleHook();
\r
1657 } /*lint !e715 pvParameters is not accessed but all task functions require the same prototype. */
\r
1665 /*-----------------------------------------------------------
\r
1666 * File private functions documented at the top of the file.
\r
1667 *----------------------------------------------------------*/
\r
1671 static void prvInitialiseTCBVariables( tskTCB *pxTCB, const signed portCHAR * const pcName, unsigned portBASE_TYPE uxPriority )
\r
1673 /* Store the function name in the TCB. */
\r
1674 strncpy( ( char * ) pxTCB->pcTaskName, ( const char * ) pcName, ( unsigned portSHORT ) configMAX_TASK_NAME_LEN );
\r
1675 pxTCB->pcTaskName[ ( unsigned portSHORT ) configMAX_TASK_NAME_LEN - ( unsigned portSHORT ) 1 ] = '\0';
\r
1677 /* This is used as an array index so must ensure it's not too large. */
\r
1678 if( uxPriority >= configMAX_PRIORITIES )
\r
1680 uxPriority = configMAX_PRIORITIES - 1;
\r
1683 pxTCB->uxPriority = uxPriority;
\r
1684 #if ( configUSE_MUTEXES == 1 )
\r
1686 pxTCB->uxBasePriority = uxPriority;
\r
1690 vListInitialiseItem( &( pxTCB->xGenericListItem ) );
\r
1691 vListInitialiseItem( &( pxTCB->xEventListItem ) );
\r
1693 /* Set the pxTCB as a link back from the xListItem. This is so we can get
\r
1694 back to the containing TCB from a generic item in a list. */
\r
1695 listSET_LIST_ITEM_OWNER( &( pxTCB->xGenericListItem ), pxTCB );
\r
1697 /* Event lists are always in priority order. */
\r
1698 listSET_LIST_ITEM_VALUE( &( pxTCB->xEventListItem ), configMAX_PRIORITIES - ( portTickType ) uxPriority );
\r
1699 listSET_LIST_ITEM_OWNER( &( pxTCB->xEventListItem ), pxTCB );
\r
1701 #if ( portCRITICAL_NESTING_IN_TCB == 1 )
\r
1703 pxTCB->uxCriticalNesting = ( unsigned portBASE_TYPE ) 0;
\r
1707 #if ( configUSE_APPLICATION_TASK_TAG == 1 )
\r
1709 pxTCB->pxTaskTag = NULL;
\r
1713 /*-----------------------------------------------------------*/
\r
1715 static void prvInitialiseTaskLists( void )
\r
1717 unsigned portBASE_TYPE uxPriority;
\r
1719 for( uxPriority = 0; uxPriority < configMAX_PRIORITIES; uxPriority++ )
\r
1721 vListInitialise( ( xList * ) &( pxReadyTasksLists[ uxPriority ] ) );
\r
1724 vListInitialise( ( xList * ) &xDelayedTaskList1 );
\r
1725 vListInitialise( ( xList * ) &xDelayedTaskList2 );
\r
1726 vListInitialise( ( xList * ) &xPendingReadyList );
\r
1728 #if ( INCLUDE_vTaskDelete == 1 )
\r
1730 vListInitialise( ( xList * ) &xTasksWaitingTermination );
\r
1734 #if ( INCLUDE_vTaskSuspend == 1 )
\r
1736 vListInitialise( ( xList * ) &xSuspendedTaskList );
\r
1740 /* Start with pxDelayedTaskList using list1 and the pxOverflowDelayedTaskList
\r
1742 pxDelayedTaskList = &xDelayedTaskList1;
\r
1743 pxOverflowDelayedTaskList = &xDelayedTaskList2;
\r
1745 /*-----------------------------------------------------------*/
\r
1747 static void prvCheckTasksWaitingTermination( void )
\r
1749 #if ( INCLUDE_vTaskDelete == 1 )
\r
1751 portBASE_TYPE xListIsEmpty;
\r
1753 /* ucTasksDeleted is used to prevent vTaskSuspendAll() being called
\r
1754 too often in the idle task. */
\r
1755 if( uxTasksDeleted > ( unsigned portBASE_TYPE ) 0 )
\r
1757 vTaskSuspendAll();
\r
1758 xListIsEmpty = listLIST_IS_EMPTY( &xTasksWaitingTermination );
\r
1761 if( !xListIsEmpty )
\r
1765 portENTER_CRITICAL();
\r
1767 pxTCB = ( tskTCB * ) listGET_OWNER_OF_HEAD_ENTRY( ( ( xList * ) &xTasksWaitingTermination ) );
\r
1768 vListRemove( &( pxTCB->xGenericListItem ) );
\r
1769 --uxCurrentNumberOfTasks;
\r
1772 portEXIT_CRITICAL();
\r
1774 prvDeleteTCB( pxTCB );
\r
1780 /*-----------------------------------------------------------*/
\r
1782 static tskTCB *prvAllocateTCBAndStack( unsigned portSHORT usStackDepth )
\r
1786 /* Allocate space for the TCB. Where the memory comes from depends on
\r
1787 the implementation of the port malloc function. */
\r
1788 pxNewTCB = ( tskTCB * ) pvPortMalloc( sizeof( tskTCB ) );
\r
1790 if( pxNewTCB != NULL )
\r
1792 /* Allocate space for the stack used by the task being created.
\r
1793 The base of the stack memory stored in the TCB so the task can
\r
1794 be deleted later if required. */
\r
1795 pxNewTCB->pxStack = ( portSTACK_TYPE * ) pvPortMalloc( ( ( size_t )usStackDepth ) * sizeof( portSTACK_TYPE ) );
\r
1797 if( pxNewTCB->pxStack == NULL )
\r
1799 /* Could not allocate the stack. Delete the allocated TCB. */
\r
1800 vPortFree( pxNewTCB );
\r
1805 /* Just to help debugging. */
\r
1806 memset( pxNewTCB->pxStack, tskSTACK_FILL_BYTE, usStackDepth * sizeof( portSTACK_TYPE ) );
\r
1812 /*-----------------------------------------------------------*/
\r
1814 #if ( configUSE_TRACE_FACILITY == 1 )
\r
1816 static void prvListTaskWithinSingleList( const signed portCHAR *pcWriteBuffer, xList *pxList, signed portCHAR cStatus )
\r
1818 volatile tskTCB *pxNextTCB, *pxFirstTCB;
\r
1819 unsigned portSHORT usStackRemaining;
\r
1821 /* Write the details of all the TCB's in pxList into the buffer. */
\r
1822 listGET_OWNER_OF_NEXT_ENTRY( pxFirstTCB, pxList );
\r
1825 listGET_OWNER_OF_NEXT_ENTRY( pxNextTCB, pxList );
\r
1826 usStackRemaining = usTaskCheckFreeStackSpace( ( unsigned portCHAR * ) pxNextTCB->pxStack );
\r
1827 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
1828 strcat( ( portCHAR * ) pcWriteBuffer, ( portCHAR * ) pcStatusString );
\r
1830 } while( pxNextTCB != pxFirstTCB );
\r
1834 /*-----------------------------------------------------------*/
\r
1836 #if ( ( configUSE_TRACE_FACILITY == 1 ) || ( INCLUDE_uxTaskGetStackHighWaterMark == 1 ) )
\r
1838 unsigned portSHORT usTaskCheckFreeStackSpace( const unsigned portCHAR * pucStackByte )
\r
1840 register unsigned portSHORT usCount = 0;
\r
1842 while( *pucStackByte == tskSTACK_FILL_BYTE )
\r
1844 pucStackByte -= portSTACK_GROWTH;
\r
1848 usCount /= sizeof( portSTACK_TYPE );
\r
1854 /*-----------------------------------------------------------*/
\r
1856 #if ( INCLUDE_uxTaskGetStackHighWaterMark == 1 )
\r
1858 unsigned portBASE_TYPE uxTaskGetStackHighWaterMark( xTaskHandle xTask )
\r
1861 unsigned portCHAR *pcEndOfStack;
\r
1863 pxTCB = prvGetTCBFromHandle( xTask );
\r
1865 #if portSTACK_GROWTH < 0
\r
1867 pcEndOfStack = ( unsigned portCHAR * ) pxTCB->pxStack;
\r
1871 pcEndOfStack = ( unsigned portCHAR * ) pxTCB->pxEndOfStack;
\r
1875 return usTaskCheckFreeStackSpace( pcEndOfStack );
\r
1879 /*-----------------------------------------------------------*/
\r
1881 #if ( ( INCLUDE_vTaskDelete == 1 ) || ( INCLUDE_vTaskCleanUpResources == 1 ) )
\r
1883 static void prvDeleteTCB( tskTCB *pxTCB )
\r
1885 /* Free up the memory allocated by the scheduler for the task. It is up to
\r
1886 the task to free any memory allocated at the application level. */
\r
1887 vPortFree( pxTCB->pxStack );
\r
1888 vPortFree( pxTCB );
\r
1894 /*-----------------------------------------------------------*/
\r
1896 #if ( INCLUDE_xTaskGetCurrentTaskHandle == 1 )
\r
1898 xTaskHandle xTaskGetCurrentTaskHandle( void )
\r
1900 /* A critical section is not required as this is not called from
\r
1901 an interrupt and the current TCB will always be the same for any
\r
1902 individual execution thread. */
\r
1903 return pxCurrentTCB;
\r
1908 /*-----------------------------------------------------------*/
\r
1910 #if ( INCLUDE_xTaskGetSchedulerState == 1 )
\r
1912 portBASE_TYPE xTaskGetSchedulerState( void )
\r
1914 portBASE_TYPE xReturn;
\r
1916 if( xSchedulerRunning == pdFALSE )
\r
1918 xReturn = taskSCHEDULER_NOT_STARTED;
\r
1922 if( uxSchedulerSuspended == ( unsigned portBASE_TYPE ) pdFALSE )
\r
1924 xReturn = taskSCHEDULER_RUNNING;
\r
1928 xReturn = taskSCHEDULER_SUSPENDED;
\r
1936 /*-----------------------------------------------------------*/
\r
1938 #if ( configUSE_MUTEXES == 1 )
\r
1940 void vTaskPriorityInherit( xTaskHandle * const pxMutexHolder )
\r
1942 tskTCB * const pxTCB = ( tskTCB * ) pxMutexHolder;
\r
1944 if( pxTCB->uxPriority < pxCurrentTCB->uxPriority )
\r
1946 /* Adjust the mutex holder state to account for its new priority. */
\r
1947 listSET_LIST_ITEM_VALUE( &( pxTCB->xEventListItem ), configMAX_PRIORITIES - ( portTickType ) pxCurrentTCB->uxPriority );
\r
1949 /* If the task being modified is in the ready state it will need to
\r
1950 be moved in to a new list. */
\r
1951 if( listIS_CONTAINED_WITHIN( &( pxReadyTasksLists[ pxTCB->uxPriority ] ), &( pxTCB->xGenericListItem ) ) )
\r
1953 vListRemove( &( pxTCB->xGenericListItem ) );
\r
1955 /* Inherit the priority before being moved into the new list. */
\r
1956 pxTCB->uxPriority = pxCurrentTCB->uxPriority;
\r
1957 prvAddTaskToReadyQueue( pxTCB );
\r
1961 /* Just inherit the priority. */
\r
1962 pxTCB->uxPriority = pxCurrentTCB->uxPriority;
\r
1968 /*-----------------------------------------------------------*/
\r
1970 #if ( configUSE_MUTEXES == 1 )
\r
1972 void vTaskPriorityDisinherit( xTaskHandle * const pxMutexHolder )
\r
1974 tskTCB * const pxTCB = ( tskTCB * ) pxMutexHolder;
\r
1976 if( pxMutexHolder != NULL )
\r
1978 if( pxTCB->uxPriority != pxTCB->uxBasePriority )
\r
1980 /* We must be the running task to be able to give the mutex back.
\r
1981 Remove ourselves from the ready list we currently appear in. */
\r
1982 vListRemove( &( pxTCB->xGenericListItem ) );
\r
1984 /* Disinherit the priority before adding ourselves into the new
\r
1986 pxTCB->uxPriority = pxTCB->uxBasePriority;
\r
1987 listSET_LIST_ITEM_VALUE( &( pxTCB->xEventListItem ), configMAX_PRIORITIES - ( portTickType ) pxTCB->uxPriority );
\r
1988 prvAddTaskToReadyQueue( pxTCB );
\r
1994 /*-----------------------------------------------------------*/
\r
1996 #if ( portCRITICAL_NESTING_IN_TCB == 1 )
\r
1998 void vTaskEnterCritical( void )
\r
2000 portDISABLE_INTERRUPTS();
\r
2002 if( xSchedulerRunning != pdFALSE )
\r
2004 pxCurrentTCB->uxCriticalNesting++;
\r
2009 /*-----------------------------------------------------------*/
\r
2011 #if ( portCRITICAL_NESTING_IN_TCB == 1 )
\r
2013 void vTaskExitCritical( void )
\r
2015 if( xSchedulerRunning != pdFALSE )
\r
2017 if( pxCurrentTCB->uxCriticalNesting > 0 )
\r
2019 pxCurrentTCB->uxCriticalNesting--;
\r
2021 if( pxCurrentTCB->uxCriticalNesting == 0 )
\r
2023 portENABLE_INTERRUPTS();
\r
2030 /*-----------------------------------------------------------*/
\r