git.sur5r.net Git - freertos/blob - Source/tasks.c

   1 /*\r
   2         FreeRTOS.org V4.6.0 - Copyright (C) 2003-2007 Richard Barry.\r
   3 \r
   4         This file is part of the FreeRTOS.org distribution.\r
   5 \r
   6         FreeRTOS.org is free software; you can redistribute it and/or modify\r
   7         it under the terms of the GNU General Public License as published by\r
   8         the Free Software Foundation; either version 2 of the License, or\r
   9         (at your option) any later version.\r
  10 \r
  11         FreeRTOS.org is distributed in the hope that it will be useful,\r
  12         but WITHOUT ANY WARRANTY; without even the implied warranty of\r
  13         MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the\r
  14         GNU General Public License for more details.\r
  15 \r
  16         You should have received a copy of the GNU General Public License\r
  17         along with FreeRTOS.org; if not, write to the Free Software\r
  18         Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA\r
  19 \r
  20         A special exception to the GPL can be applied should you wish to distribute\r
  21         a combined work that includes FreeRTOS.org, without being obliged to provide\r
  22         the source code for any proprietary components.  See the licensing section\r
  23         of http://www.FreeRTOS.org for full details of how and when the exception\r
  24         can be applied.\r
  25 \r
  26         ***************************************************************************\r
  27         See http://www.FreeRTOS.org for documentation, latest information, license\r
  28         and contact details.  Please ensure to read the configuration and relevant\r
  29         port sections of the online documentation.\r
  30 \r
  31         Also see http://www.SafeRTOS.com for an IEC 61508 compliant version, along\r
  32         with development and support options.\r
  33         ***************************************************************************\r
  34 */\r
  35 \r
  36 /*\r
  37 Changes from V1.00:\r
  38         \r
  39         + Call to portRESTORE_CONTEXT has been removed.  The first context\r
  40           switch is now performed within sPortStartScheduler().\r
  41 \r
  42 Changes from V1.01:\r
  43 \r
  44         + More use of 8bit data types.\r
  45         + Function name prefixes changed where the data type returned has changed.\r
  46         + configUSE_TRACE_FACILITY is no longer defined by default.\r
  47 \r
  48 Changes from V1.2.0\r
  49 \r
  50         + Introduced ucTopReadyPriority.  This tracks the highest priority ready\r
  51           queue that contains a valid TCB and thus makes the context switch\r
  52           slightly faster.\r
  53 \r
  54         + prvAddTaskToReadyQueue() has been made a macro.\r
  55 \r
  56 Changes from V1.2.6\r
  57 \r
  58         + Added conditional compilation directives.\r
  59         + Extended API.\r
  60         + Rearranged function order.\r
  61         + Creating a task now causes a context switch if the task being created\r
  62           has a higher priority than the calling task - assuming the kernel is\r
  63           running.\r
  64         + vTaskDelete() now only causes a context switch if the calling task is\r
  65           the task being deleted.\r
  66 \r
  67 Changes from V2.0.0\r
  68 \r
  69         + Allow the type of the tick count to be 16 or 32 bits.\r
  70         + Introduce xPendingReadyList feature to allow the time interrupts have to\r
  71           be disabled to be minimised.\r
  72         + Remove the #if( INCLUDE_vTaskSuspendAll ) statements.  vTaskSuspendAll()\r
  73           is now always included as it is used by the scheduler itself.\r
  74 \r
  75 Changes from V2.1.0\r
  76 \r
  77         + Bug fix - pxCurrentTCB is now initialised before the call to\r
  78           prvInitializeTaskLists().  Previously pxCurrentTCB could be accessed\r
  79           while null.\r
  80 \r
  81 Changed from V2.1.1\r
  82 \r
  83         + Change to where lStackSize is declared within sTaskCreate() to prevent\r
  84           compiler warnings with 8051 port.\r
  85 \r
  86 Changes from V2.2.0\r
  87 \r
  88         + Explicit use of 'signed' qualifier on portCHAR types added.\r
  89         + Changed odd calculation of initial pxTopOfStack value when\r
  90           portSTACK_GROWTH < 0.\r
  91         + Removed pcVersionNumber definition.\r
  92 \r
  93 Changes from V2.5.3\r
  94 \r
  95         + cTaskResumeAll() modified to ensure it can be called prior to the task\r
  96           lists being initialised.\r
  97 \r
  98 Changes from V2.5.5\r
  99 \r
 100         + Added API function vTaskDelayUntil().\r
 101         + Added INCLUDE_vTaskDelay conditional compilation.\r
 102 \r
 103 Changes from V2.6.0\r
 104 \r
 105         + Updated the vWriteTraceToBuffer macro to always be 4 byte aligned so it\r
 106           can be used on ARM architectures.\r
 107         + tskMAX_TASK_NAME_LEN definition replaced with the port specific\r
 108           configMAX_TASK_NAME_LEN definition.\r
 109         + Removed the call to strcpy when copying across the task name into the\r
 110           TCB.\r
 111         + Added ucTasksDeleted variable to prevent vTaskSuspendAll() being called\r
 112           too often in the idle task.\r
 113 \r
 114 Changes between V3.0.0 and V2.6.1\r
 115 \r
 116         + When resuming the scheduler a yield is performed if either a tick has\r
 117           been missed, or a task is moved from the pending ready list into a ready\r
 118           list.  Previously a yield was not performed on this second condition.\r
 119         + Introduced the type portBASE_TYPE.  This necessitates several API\r
 120           changes.\r
 121         + Removed the sUsingPreemption variable.  The constant defined in\r
 122           portmacro.h is now used directly.\r
 123         + The idle task can now include an optional hook function - and no longer\r
 124           completes its time slice if other tasks with equal priority to it are\r
 125           ready to run.\r
 126         + See the FreeRTOS.org documentation for more information on V2.x.x to\r
 127           V3.x.x modifications.\r
 128 \r
 129 Changes from V3.1.1\r
 130 \r
 131         + Modified vTaskPrioritySet() and vTaskResume() to allow these functions to\r
 132           be called while the scheduler is suspended.\r
 133         + Corrected the task ordering within event lists.\r
 134 \r
 135 Changes from V3.2.0\r
 136 \r
 137         + Added function xTaskGetCurrentTaskHandle().\r
 138 \r
 139 Changes from V3.2.4\r
 140 \r
 141         + Changed the volatile declarations on some variables to reflect the \r
 142           changes to the list definitions.\r
 143         + Changed the order of the TCB definition so there is commonality between\r
 144           the task control block and a co-routine control block.\r
 145         + Allow the scheduler to be started even if no tasks other than the idle\r
 146           task has been created.  This allows co-routines to run even when no tasks\r
 147           have been created.\r
 148         + The need for a context switch is now signalled if a task woken by an \r
 149           event has a priority greater or equal to the currently running task.\r
 150           Previously this was only greater than.\r
 151 \r
 152 Changes from V4.0.0\r
 153 \r
 154         + Added the xMissedYield handling.\r
 155 \r
 156 Changes from V4.0.1\r
 157 \r
 158         + The function vTaskList() now suspends the scheduler rather than disabling\r
 159           interrupts during the creation of the task list.  \r
 160         + Allow a task to delete itself by passing in its own handle.  Previously \r
 161           this could only be done by passing in NULL.\r
 162         + The tick hook function is now called only within a tick isr.  Previously\r
 163           it was also called when the tick function was called during the scheduler\r
 164           unlocking process.\r
 165 \r
 166 Changes from V4.0.3\r
 167 \r
 168         + Extra checks have been placed in vTaskPrioritySet() to avoid unnecessary\r
 169           yields.\r
 170 \r
 171 Changed from V4.0.4\r
 172 \r
 173         + Bug fix:  The 'value' of the event list item is updated when the priority\r
 174           of a task is changed.  Previously only the priority of the TCB itself was\r
 175           changed.\r
 176         + When resuming a task a check is first made to see if the task is actually\r
 177           suspended.\r
 178         + vTaskPrioritySet() and vTaskResume() no longer use the event list item.\r
 179           This has not been necessary since V4.0.1 when the xMissedYield handling\r
 180           was added.\r
 181         + Implement xTaskResumeFromISR().\r
 182 \r
 183 Changes from V4.0.5\r
 184 \r
 185         + Added utility functions and xOverflowCount variable to facilitate the\r
 186           queue.c changes.\r
 187 \r
 188 Changes from V4.1.2\r
 189         \r
 190         + Tasks that block on events with a timeout of portMAX_DELAY are now\r
 191           blocked indefinitely if configINCLUDE_vTaskSuspend is defined. \r
 192           Previously portMAX_DELAY was just the longest block time possible.\r
 193 \r
 194 Changes from V4.1.3\r
 195 \r
 196         + Very small change made to xTaskCheckForTimeout() as a result of the \r
 197         SafeRTOS testing.  This corrects the case where the function can return an\r
 198         invalid value - but only in an extremely unlikely scenario.\r
 199 \r
 200 Changes since V4.3.1:\r
 201 \r
 202         + Added xTaskGetSchedulerState() function.\r
 203         + Added prvIsTaskSuspended() to take into account the Occurrence of\r
 204           vTaskResume() or vTaskResumeFromISR() being called passing in the\r
 205           handle of a task that appears in the Suspended list only because it\r
 206           is blocked on an event without a timeout being specified.\r
 207         + Updated xTaskCheckForTimeout() to take into account that tasks blocked\r
 208           using the Suspended list should never time out.\r
 209 */\r
 210 \r
 211 #include <stdio.h>\r
 212 #include <stdlib.h>\r
 213 #include <string.h>\r
 214 \r
 215 #include "FreeRTOS.h"\r
 216 #include "task.h"\r
 217 \r
 218 /*\r
 219  * Macro to define the amount of stack available to the idle task.\r
 220  */\r
 221 #define tskIDLE_STACK_SIZE      configMINIMAL_STACK_SIZE\r
 222 \r
 223 \r
 224 /*\r
 225  * Default a definitions for backwards compatibility with old\r
 226  * portmacro.h files.\r
 227  */\r
 228 #ifndef configMAX_TASK_NAME_LEN\r
 229         #define configMAX_TASK_NAME_LEN 16\r
 230 #endif\r
 231 \r
 232 #ifndef configIDLE_SHOULD_YIELD\r
 233         #define configIDLE_SHOULD_YIELD         1\r
 234 #endif\r
 235 \r
 236 #if configMAX_TASK_NAME_LEN < 1\r
 237         #undef configMAX_TASK_NAME_LEN\r
 238         #define configMAX_TASK_NAME_LEN 1\r
 239 #endif\r
 240 \r
 241 #ifndef INCLUDE_xTaskResumeFromISR\r
 242         #define INCLUDE_xTaskResumeFromISR 1\r
 243 #endif\r
 244 \r
 245 #ifndef INCLUDE_xTaskGetSchedulerState\r
 246         #define INCLUDE_xTaskGetSchedulerState 0\r
 247 #endif\r
 248 \r
 249 /*\r
 250  * Task control block.  A task control block (TCB) is allocated to each task,\r
 251  * and stores the context of the task.\r
 252  */\r
 253 typedef struct tskTaskControlBlock\r
 254 {\r
 255         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. */\r
 256         xListItem                               xGenericListItem;       /*< List item used to place the TCB in ready and blocked queues. */\r
 257         xListItem                               xEventListItem;         /*< List item used to place the TCB in event lists. */\r
 258         unsigned portBASE_TYPE  uxPriority;                     /*< The priority of the task where 0 is the lowest priority. */\r
 259         portSTACK_TYPE                  *pxStack;                       /*< Points to the start of the stack. */\r
 260         signed portCHAR                 pcTaskName[ configMAX_TASK_NAME_LEN ];/*< Descriptive name given to the task when created.  Facilitates debugging only. */\r
 261 \r
 262         #if ( configUSE_TRACE_FACILITY == 1 )\r
 263                 unsigned portBASE_TYPE  uxTCBNumber;            /*< This is used for tracing the scheduler and making debugging easier only. */\r
 264         #endif  \r
 265                 \r
 266         #if ( configUSE_MUTEXES == 1 )\r
 267                 unsigned portBASE_TYPE uxBasePriority;\r
 268         #endif\r
 269                 \r
 270 } tskTCB;\r
 271 \r
 272 /*lint -e956 */\r
 273 \r
 274 tskTCB * volatile pxCurrentTCB = NULL;                                  \r
 275 \r
 276 /* Lists for ready and blocked tasks. --------------------*/\r
 277 \r
 278 static xList pxReadyTasksLists[ configMAX_PRIORITIES ]; /*< Prioritised ready tasks. */\r
 279 static xList xDelayedTaskList1;                                                 /*< Delayed tasks. */\r
 280 static xList xDelayedTaskList2;                                                 /*< Delayed tasks (two lists are used - one for delays that have overflowed the current tick count. */\r
 281 static xList * volatile pxDelayedTaskList;                              /*< Points to the delayed task list currently being used. */\r
 282 static xList * volatile pxOverflowDelayedTaskList;              /*< Points to the delayed task list currently being used to hold tasks that have overflowed the current tick count. */\r
 283 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. */\r
 284 \r
 285 #if ( INCLUDE_vTaskDelete == 1 )\r
 286 \r
 287         static volatile xList xTasksWaitingTermination;         /*< Tasks that have been deleted - but the their memory not yet freed. */\r
 288         static volatile unsigned portBASE_TYPE uxTasksDeleted = ( unsigned portBASE_TYPE ) 0;\r
 289 \r
 290 #endif\r
 291 \r
 292 #if ( INCLUDE_vTaskSuspend == 1 )\r
 293 \r
 294         static xList xSuspendedTaskList;                                        /*< Tasks that are currently suspended. */\r
 295 \r
 296 #endif\r
 297 \r
 298 /* File private variables. --------------------------------*/\r
 299 static volatile unsigned portBASE_TYPE uxCurrentNumberOfTasks   = ( unsigned portBASE_TYPE ) 0;\r
 300 static volatile portTickType xTickCount                                                 = ( portTickType ) 0;\r
 301 static unsigned portBASE_TYPE uxTopUsedPriority                                 = tskIDLE_PRIORITY;\r
 302 static volatile unsigned portBASE_TYPE uxTopReadyPriority               = tskIDLE_PRIORITY;\r
 303 static volatile signed portBASE_TYPE xSchedulerRunning                  = pdFALSE;\r
 304 static volatile unsigned portBASE_TYPE uxSchedulerSuspended             = ( unsigned portBASE_TYPE ) pdFALSE;\r
 305 static volatile unsigned portBASE_TYPE uxMissedTicks                    = ( unsigned portBASE_TYPE ) 0;\r
 306 static volatile portBASE_TYPE xMissedYield                                              = ( portBASE_TYPE ) pdFALSE;\r
 307 static volatile portBASE_TYPE xNumOfOverflows                                   = ( portBASE_TYPE ) 0;\r
 308 /* Debugging and trace facilities private variables and macros. ------------*/\r
 309 \r
 310 /*\r
 311  * The value used to fill the stack of a task when the task is created.  This\r
 312  * is used purely for checking the high water mark for tasks.\r
 313  */\r
 314 #define tskSTACK_FILL_BYTE      ( 0xa5 )\r
 315 \r
 316 /*\r
 317  * Macros used by vListTask to indicate which state a task is in.\r
 318  */\r
 319 #define tskBLOCKED_CHAR         ( ( signed portCHAR ) 'B' )\r
 320 #define tskREADY_CHAR           ( ( signed portCHAR ) 'R' )\r
 321 #define tskDELETED_CHAR         ( ( signed portCHAR ) 'D' )\r
 322 #define tskSUSPENDED_CHAR       ( ( signed portCHAR ) 'S' )\r
 323 \r
 324 /*\r
 325  * Macros and private variables used by the trace facility.\r
 326  */\r
 327 #if ( configUSE_TRACE_FACILITY == 1 )\r
 328 \r
 329         #define tskSIZE_OF_EACH_TRACE_LINE                      ( ( unsigned portLONG ) ( sizeof( unsigned portLONG ) + sizeof( unsigned portLONG ) ) )\r
 330         static volatile signed portCHAR * volatile pcTraceBuffer;\r
 331         static signed portCHAR *pcTraceBufferStart;\r
 332         static signed portCHAR *pcTraceBufferEnd;\r
 333         static signed portBASE_TYPE xTracing = pdFALSE;\r
 334 \r
 335 #endif\r
 336 \r
 337 /*\r
 338  * Macro that writes a trace of scheduler activity to a buffer.  This trace\r
 339  * shows which task is running when and is very useful as a debugging tool.\r
 340  * As this macro is called each context switch it is a good idea to undefine\r
 341  * it if not using the facility.\r
 342  */\r
 343 #if ( configUSE_TRACE_FACILITY == 1 )\r
 344 \r
 345         #define vWriteTraceToBuffer()                                                                                                                                   \\r
 346         {                                                                                                                                                                                               \\r
 347                 if( xTracing )                                                                                                                                                          \\r
 348                 {                                                                                                                                                                                       \\r
 349                         static unsigned portBASE_TYPE uxPreviousTask = 255;                                                                             \\r
 350                                                                                                                                                                                                         \\r
 351                         if( uxPreviousTask != pxCurrentTCB->uxTCBNumber )                                                                               \\r
 352                         {                                                                                                                                                                               \\r
 353                                 if( ( pcTraceBuffer + tskSIZE_OF_EACH_TRACE_LINE ) < pcTraceBufferEnd )                         \\r
 354                                 {                                                                                                                                                                       \\r
 355                                         uxPreviousTask = pxCurrentTCB->uxTCBNumber;                                                                             \\r
 356                                         *( unsigned portLONG * ) pcTraceBuffer = ( unsigned portLONG ) xTickCount;              \\r
 357                                         pcTraceBuffer += sizeof( unsigned portLONG );                                                                   \\r
 358                                         *( unsigned portLONG * ) pcTraceBuffer = ( unsigned portLONG ) uxPreviousTask;  \\r
 359                                         pcTraceBuffer += sizeof( unsigned portLONG );                                                                   \\r
 360                                 }                                                                                                                                                                       \\r
 361                                 else                                                                                                                                                            \\r
 362                                 {                                                                                                                                                                       \\r
 363                                         xTracing = pdFALSE;                                                                                                                             \\r
 364                                 }                                                                                                                                                                       \\r
 365                         }                                                                                                                                                                               \\r
 366                 }                                                                                                                                                                                       \\r
 367         }\r
 368 \r
 369 #else\r
 370 \r
 371         #define vWriteTraceToBuffer()\r
 372 \r
 373 #endif\r
 374 \r
 375 \r
 376 /*\r
 377  * Place the task represented by pxTCB into the appropriate ready queue for\r
 378  * the task.  It is inserted at the end of the list.  One quirk of this is\r
 379  * that if the task being inserted is at the same priority as the currently\r
 380  * executing task, then it will only be rescheduled after the currently\r
 381  * executing task has been rescheduled.\r
 382  */\r
 383 #define prvAddTaskToReadyQueue( pxTCB )                                                                                                                                                 \\r
 384 {                                                                                                                                                                                                                               \\r
 385         if( pxTCB->uxPriority > uxTopReadyPriority )                                                                                                                            \\r
 386         {                                                                                                                                                                                                                       \\r
 387                 uxTopReadyPriority = pxTCB->uxPriority;                                                                                                                                 \\r
 388         }                                                                                                                                                                                                                       \\r
 389         vListInsertEnd( ( xList * ) &( pxReadyTasksLists[ pxTCB->uxPriority ] ), &( pxTCB->xGenericListItem ) );        \\r
 390 }               \r
 391 \r
 392 /*\r
 393  * Macro that looks at the list of tasks that are currently delayed to see if\r
 394  * any require waking.\r
 395  *\r
 396  * Tasks are stored in the queue in the order of their wake time - meaning\r
 397  * once one tasks has been found whose timer has not expired we need not look\r
 398  * any further down the list.\r
 399  */\r
 400 #define prvCheckDelayedTasks()                                                                                                                                                                          \\r
 401 {                                                                                                                                                                                                                                       \\r
 402 register tskTCB *pxTCB;                                                                                                                                                                                         \\r
 403                                                                                                                                                                                                                                         \\r
 404         while( ( pxTCB = ( tskTCB * ) listGET_OWNER_OF_HEAD_ENTRY( pxDelayedTaskList ) ) != NULL )                                              \\r
 405         {                                                                                                                                                                                                                               \\r
 406                 if( xTickCount < listGET_LIST_ITEM_VALUE( &( pxTCB->xGenericListItem ) ) )                                                                      \\r
 407                 {                                                                                                                                                                                                                       \\r
 408                         break;                                                                                                                                                                                                  \\r
 409                 }                                                                                                                                                                                                                       \\r
 410                 vListRemove( &( pxTCB->xGenericListItem ) );                                                                                                                            \\r
 411                 /* Is the task waiting on an event also? */                                                                                                                                     \\r
 412                 if( pxTCB->xEventListItem.pvContainer )                                                                                                                                         \\r
 413                 {                                                                                                                                                                                                                       \\r
 414                         vListRemove( &( pxTCB->xEventListItem ) );                                                                                                                              \\r
 415                 }                                                                                                                                                                                                                       \\r
 416                 prvAddTaskToReadyQueue( pxTCB );                                                                                                                \\r
 417         }                                                                                                                                                                                                                               \\r
 418 }                                                                                                                                                                                       \r
 419 \r
 420 /*\r
 421  * Several functions take an xTaskHandle parameter that can optionally be NULL,\r
 422  * where NULL is used to indicate that the handle of the currently executing\r
 423  * task should be used in place of the parameter.  This macro simply checks to\r
 424  * see if the parameter is NULL and returns a pointer to the appropriate TCB.\r
 425  */\r
 426 #define prvGetTCBFromHandle( pxHandle ) ( ( pxHandle == NULL ) ? ( tskTCB * ) pxCurrentTCB : ( tskTCB * ) pxHandle )\r
 427 \r
 428 \r
 429 /* File private functions. --------------------------------*/\r
 430 \r
 431 /*\r
 432  * Utility to ready a TCB for a given task.  Mainly just copies the parameters\r
 433  * into the TCB structure.\r
 434  */\r
 435 static void prvInitialiseTCBVariables( tskTCB *pxTCB, const signed portCHAR * const pcName, unsigned portBASE_TYPE uxPriority );\r
 436 \r
 437 /*\r
 438  * Utility to ready all the lists used by the scheduler.  This is called\r
 439  * automatically upon the creation of the first task.\r
 440  */\r
 441 static void prvInitialiseTaskLists( void );\r
 442 \r
 443 /*\r
 444  * The idle task, which as all tasks is implemented as a never ending loop.\r
 445  * The idle task is automatically created and added to the ready lists upon\r
 446  * creation of the first user task.\r
 447  *\r
 448  * The portTASK_FUNCTION_PROTO() macro is used to allow port/compiler specific\r
 449  * language extensions.  The equivalent prototype for this function is:\r
 450  *\r
 451  * void prvIdleTask( void *pvParameters );\r
 452  *\r
 453  */\r
 454 static portTASK_FUNCTION_PROTO( prvIdleTask, pvParameters );\r
 455 \r
 456 /*\r
 457  * Utility to free all memory allocated by the scheduler to hold a TCB,\r
 458  * including the stack pointed to by the TCB.\r
 459  *\r
 460  * This does not free memory allocated by the task itself (i.e. memory\r
 461  * allocated by calls to pvPortMalloc from within the tasks application code).\r
 462  */\r
 463 #if ( ( INCLUDE_vTaskDelete == 1 ) || ( INCLUDE_vTaskCleanUpResources == 1 ) )\r
 464         static void prvDeleteTCB( tskTCB *pxTCB );\r
 465 #endif\r
 466 \r
 467 /*\r
 468  * Used only by the idle task.  This checks to see if anything has been placed\r
 469  * in the list of tasks waiting to be deleted.  If so the task is cleaned up\r
 470  * and its TCB deleted.\r
 471  */\r
 472 static void prvCheckTasksWaitingTermination( void );\r
 473 \r
 474 /*\r
 475  * Allocates memory from the heap for a TCB and associated stack.  Checks the\r
 476  * allocation was successful.\r
 477  */\r
 478 static tskTCB *prvAllocateTCBAndStack( unsigned portSHORT usStackDepth );\r
 479 \r
 480 /*\r
 481  * Called from vTaskList.  vListTasks details all the tasks currently under\r
 482  * control of the scheduler.  The tasks may be in one of a number of lists.\r
 483  * prvListTaskWithinSingleList accepts a list and details the tasks from\r
 484  * within just that list.\r
 485  *\r
 486  * THIS FUNCTION IS INTENDED FOR DEBUGGING ONLY, AND SHOULD NOT BE CALLED FROM\r
 487  * NORMAL APPLICATION CODE.\r
 488  */\r
 489 #if ( configUSE_TRACE_FACILITY == 1 )\r
 490 \r
 491         static void prvListTaskWithinSingleList( const signed portCHAR *pcWriteBuffer, xList *pxList, signed portCHAR cStatus );\r
 492 \r
 493 #endif\r
 494 \r
 495 /*\r
 496  * When a task is created, the stack of the task is filled with a known value.\r
 497  * This function determines the 'high water mark' of the task stack by\r
 498  * determining how much of the stack remains at the original preset value.\r
 499  */\r
 500 #if ( configUSE_TRACE_FACILITY == 1 )\r
 501 \r
 502         unsigned portSHORT usTaskCheckFreeStackSpace( const unsigned portCHAR * pucStackByte );\r
 503 \r
 504 #endif\r
 505 \r
 506 /*\r
 507  * Checks that a task being resumed (unsuspended) is actually in the Suspended\r
 508  * state.\r
 509  */\r
 510 #if ( INCLUDE_vTaskSuspend == 1 )\r
 511 \r
 512         static portBASE_TYPE prvIsTaskSuspended( const tskTCB * const pxTCB );  \r
 513 \r
 514 #endif\r
 515 \r
 516 /*lint +e956 */\r
 517 \r
 518 \r
 519 \r
 520 \r
 521 \r
 522 /*-----------------------------------------------------------\r
 523  * TASK CREATION API documented in task.h\r
 524  *----------------------------------------------------------*/\r
 525 \r
 526 signed portBASE_TYPE xTaskCreate( pdTASK_CODE pvTaskCode, const signed portCHAR * const pcName, unsigned portSHORT usStackDepth, void *pvParameters, unsigned portBASE_TYPE uxPriority, xTaskHandle *pxCreatedTask )\r
 527 {\r
 528 signed portBASE_TYPE xReturn;\r
 529 tskTCB * pxNewTCB;\r
 530 #if ( configUSE_TRACE_FACILITY == 1 )\r
 531         static unsigned portBASE_TYPE uxTaskNumber = 0; /*lint !e956 Static is deliberate - this is guarded before use. */\r
 532 #endif\r
 533 \r
 534         /* Allocate the memory required by the TCB and stack for the new task.\r
 535         checking that the allocation was successful. */\r
 536         pxNewTCB = prvAllocateTCBAndStack( usStackDepth );\r
 537 \r
 538         if( pxNewTCB != NULL )\r
 539         {               \r
 540                 portSTACK_TYPE *pxTopOfStack;\r
 541 \r
 542                 /* Setup the newly allocated TCB with the initial state of the task. */\r
 543                 prvInitialiseTCBVariables( pxNewTCB, pcName, uxPriority );\r
 544 \r
 545                 /* Calculate the top of stack address.  This depends on whether the\r
 546                 stack grows from high memory to low (as per the 80x86) or visa versa.\r
 547                 portSTACK_GROWTH is used to make the result positive or negative as\r
 548                 required by the port. */\r
 549                 #if portSTACK_GROWTH < 0\r
 550                 {\r
 551                         pxTopOfStack = pxNewTCB->pxStack + ( usStackDepth - 1 );\r
 552                 }\r
 553                 #else\r
 554                 {\r
 555                         pxTopOfStack = pxNewTCB->pxStack;       \r
 556                 }\r
 557                 #endif\r
 558 \r
 559                 /* Initialize the TCB stack to look as if the task was already running,\r
 560                 but had been interrupted by the scheduler.  The return address is set\r
 561                 to the start of the task function. Once the stack has been initialised\r
 562                 the     top of stack variable is updated. */\r
 563                 pxNewTCB->pxTopOfStack = pxPortInitialiseStack( pxTopOfStack, pvTaskCode, pvParameters );\r
 564 \r
 565                 /* We are going to manipulate the task queues to add this task to a\r
 566                 ready list, so must make sure no interrupts occur. */\r
 567                 portENTER_CRITICAL();\r
 568                 {\r
 569                         uxCurrentNumberOfTasks++;\r
 570                         if( uxCurrentNumberOfTasks == ( unsigned portBASE_TYPE ) 1 )\r
 571                         {\r
 572                                 /* As this is the first task it must also be the current task. */\r
 573                                 pxCurrentTCB =  pxNewTCB;\r
 574 \r
 575                                 /* This is the first task to be created so do the preliminary\r
 576                                 initialisation required.  We will not recover if this call\r
 577                                 fails, but we will report the failure. */\r
 578                                 prvInitialiseTaskLists();\r
 579                         }\r
 580                         else\r
 581                         {       \r
 582                                 /* If the scheduler is not already running, make this task the\r
 583                                 current task if it is the highest priority task to be created\r
 584                                 so far. */\r
 585                                 if( xSchedulerRunning == pdFALSE )\r
 586                                 {\r
 587                                         if( pxCurrentTCB->uxPriority <= uxPriority )\r
 588                                         {\r
 589                                                 pxCurrentTCB = pxNewTCB;        \r
 590                                         }\r
 591                                 }\r
 592                         }                               \r
 593 \r
 594                         /* Remember the top priority to make context switching faster.  Use\r
 595                         the priority in pxNewTCB as this has been capped to a valid value. */\r
 596                         if( pxNewTCB->uxPriority > uxTopUsedPriority )\r
 597                         {\r
 598                                 uxTopUsedPriority = pxNewTCB->uxPriority;\r
 599                         }\r
 600 \r
 601                         #if ( configUSE_TRACE_FACILITY == 1 )\r
 602                         {\r
 603                                 /* Add a counter into the TCB for tracing only. */\r
 604                                 pxNewTCB->uxTCBNumber = uxTaskNumber;\r
 605                                 uxTaskNumber++;\r
 606                         }\r
 607                         #endif\r
 608 \r
 609                         prvAddTaskToReadyQueue( pxNewTCB );\r
 610 \r
 611                         xReturn = pdPASS;\r
 612                 }\r
 613                 portEXIT_CRITICAL();\r
 614         }\r
 615         else\r
 616         {\r
 617                 xReturn = errCOULD_NOT_ALLOCATE_REQUIRED_MEMORY;\r
 618         }\r
 619 \r
 620         if( xReturn == pdPASS )\r
 621         {\r
 622                 if( ( void * ) pxCreatedTask != NULL )\r
 623                 {\r
 624                         /* Pass the TCB out - in an anonymous way.  The calling function/\r
 625                         task can use this as a handle to delete the task later if\r
 626                         required.*/\r
 627                         *pxCreatedTask = ( xTaskHandle ) pxNewTCB;\r
 628                 }\r
 629 \r
 630                 if( xSchedulerRunning != pdFALSE )\r
 631                 {\r
 632                         /* If the created task is of a higher priority than the current task\r
 633                         then it should run now. */\r
 634                         if( pxCurrentTCB->uxPriority < uxPriority )\r
 635                         {\r
 636                                 taskYIELD();\r
 637                         }\r
 638                 }\r
 639         }\r
 640 \r
 641         return xReturn;\r
 642 }\r
 643 /*-----------------------------------------------------------*/\r
 644 \r
 645 #if ( INCLUDE_vTaskDelete == 1 )\r
 646 \r
 647         void vTaskDelete( xTaskHandle pxTaskToDelete )\r
 648         {\r
 649         tskTCB *pxTCB;\r
 650 \r
 651                 taskENTER_CRITICAL();\r
 652                 {\r
 653                         /* Ensure a yield is performed if the current task is being \r
 654                         deleted. */\r
 655                         if( pxTaskToDelete == pxCurrentTCB )\r
 656                         {\r
 657                                 pxTaskToDelete = NULL;\r
 658                         }\r
 659 \r
 660                         /* If null is passed in here then we are deleting ourselves. */\r
 661                         pxTCB = prvGetTCBFromHandle( pxTaskToDelete );\r
 662 \r
 663                         /* Remove task from the ready list and place in the     termination list.\r
 664                         This will stop the task from be scheduled.  The idle task will check\r
 665                         the termination list and free up any memory allocated by the\r
 666                         scheduler for the TCB and stack. */\r
 667                         vListRemove( &( pxTCB->xGenericListItem ) );\r
 668 \r
 669                         /* Is the task waiting on an event also? */                                                                                             \r
 670                         if( pxTCB->xEventListItem.pvContainer )\r
 671                         {\r
 672                                 vListRemove( &( pxTCB->xEventListItem ) );\r
 673                         }\r
 674 \r
 675                         vListInsertEnd( ( xList * ) &xTasksWaitingTermination, &( pxTCB->xGenericListItem ) );\r
 676 \r
 677                         /* Increment the ucTasksDeleted variable so the idle task knows\r
 678                         there is a task that has been deleted and that it should therefore\r
 679                         check the xTasksWaitingTermination list. */\r
 680                         ++uxTasksDeleted;\r
 681                 }\r
 682                 taskEXIT_CRITICAL();\r
 683 \r
 684                 /* Force a reschedule if we have just deleted the current task. */\r
 685                 if( xSchedulerRunning != pdFALSE ) \r
 686                 {\r
 687                         if( ( void * ) pxTaskToDelete == NULL )\r
 688                         {\r
 689                                 taskYIELD();\r
 690                         }\r
 691                 }\r
 692         }\r
 693 \r
 694 #endif\r
 695 \r
 696 \r
 697 \r
 698 \r
 699 \r
 700 \r
 701 /*-----------------------------------------------------------\r
 702  * TASK CONTROL API documented in task.h\r
 703  *----------------------------------------------------------*/\r
 704 \r
 705 #if ( INCLUDE_vTaskDelayUntil == 1 )\r
 706 \r
 707         void vTaskDelayUntil( portTickType * const pxPreviousWakeTime, portTickType xTimeIncrement )\r
 708         {\r
 709         portTickType xTimeToWake;\r
 710         portBASE_TYPE xAlreadyYielded, xShouldDelay = pdFALSE;\r
 711 \r
 712                 vTaskSuspendAll();\r
 713                 {\r
 714                         /* Generate the tick time at which the task wants to wake. */\r
 715                         xTimeToWake = *pxPreviousWakeTime + xTimeIncrement;\r
 716 \r
 717                         if( xTickCount < *pxPreviousWakeTime )\r
 718                         {\r
 719                                 /* The tick count has overflowed since this function was\r
 720                                 lasted called.  In this case the only time we should ever\r
 721                                 actually delay is if the wake time has also     overflowed,\r
 722                                 and the wake time is greater than the tick time.  When this\r
 723                                 is the case it is as if neither time had overflowed. */\r
 724                                 if( ( xTimeToWake < *pxPreviousWakeTime ) && ( xTimeToWake > xTickCount ) )\r
 725                                 {\r
 726                                         xShouldDelay = pdTRUE;\r
 727                                 }\r
 728                         }\r
 729                         else\r
 730                         {\r
 731                                 /* The tick time has not overflowed.  In this case we will\r
 732                                 delay if either the wake time has overflowed, and/or the\r
 733                                 tick time is less than the wake time. */\r
 734                                 if( ( xTimeToWake < *pxPreviousWakeTime ) || ( xTimeToWake > xTickCount ) )\r
 735                                 {\r
 736                                         xShouldDelay = pdTRUE;\r
 737                                 }\r
 738                         }\r
 739 \r
 740                         /* Update the wake time ready for the next call. */\r
 741                         *pxPreviousWakeTime = xTimeToWake;\r
 742 \r
 743                         if( xShouldDelay )\r
 744                         {\r
 745                                 /* We must remove ourselves from the ready list before adding\r
 746                                 ourselves to the blocked list as the same list item is used for\r
 747                                 both lists. */\r
 748                                 vListRemove( ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );\r
 749 \r
 750                                 /* The list item will be inserted in wake time order. */\r
 751                                 listSET_LIST_ITEM_VALUE( &( pxCurrentTCB->xGenericListItem ), xTimeToWake );\r
 752 \r
 753                                 if( xTimeToWake < xTickCount )\r
 754                                 {\r
 755                                         /* Wake time has overflowed.  Place this item in the\r
 756                                         overflow list. */\r
 757                                         vListInsert( ( xList * ) pxOverflowDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );\r
 758                                 }\r
 759                                 else\r
 760                                 {\r
 761                                         /* The wake time has not overflowed, so we can use the\r
 762                                         current block list. */\r
 763                                         vListInsert( ( xList * ) pxDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );\r
 764                                 }\r
 765                         }\r
 766                 }\r
 767                 xAlreadyYielded = xTaskResumeAll();\r
 768 \r
 769                 /* Force a reschedule if xTaskResumeAll has not already done so, we may\r
 770                 have put ourselves to sleep. */\r
 771                 if( !xAlreadyYielded )\r
 772                 {\r
 773                         taskYIELD();\r
 774                 }\r
 775         }       \r
 776         \r
 777 #endif\r
 778 /*-----------------------------------------------------------*/\r
 779 \r
 780 #if ( INCLUDE_vTaskDelay == 1 )\r
 781 \r
 782         void vTaskDelay( portTickType xTicksToDelay )\r
 783         {\r
 784         portTickType xTimeToWake;\r
 785         signed portBASE_TYPE xAlreadyYielded = pdFALSE;\r
 786 \r
 787                 /* A delay time of zero just forces a reschedule. */\r
 788                 if( xTicksToDelay > ( portTickType ) 0 )\r
 789                 {\r
 790                         vTaskSuspendAll();\r
 791                         {\r
 792                                 /* A task that is removed from the event list while the\r
 793                                 scheduler is suspended will not get placed in the ready\r
 794                                 list or removed from the blocked list until the scheduler\r
 795                                 is resumed.\r
 796                                 \r
 797                                 This task cannot be in an event list as it is the currently\r
 798                                 executing task. */\r
 799 \r
 800                                 /* Calculate the time to wake - this may overflow but this is\r
 801                                 not a problem. */\r
 802                                 xTimeToWake = xTickCount + xTicksToDelay;\r
 803 \r
 804                                 /* We must remove ourselves from the ready list before adding\r
 805                                 ourselves to the blocked list as the same list item is used for\r
 806                                 both lists. */\r
 807                                 vListRemove( ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );\r
 808 \r
 809                                 /* The list item will be inserted in wake time order. */\r
 810                                 listSET_LIST_ITEM_VALUE( &( pxCurrentTCB->xGenericListItem ), xTimeToWake );\r
 811 \r
 812                                 if( xTimeToWake < xTickCount )\r
 813                                 {\r
 814                                         /* Wake time has overflowed.  Place this item in the\r
 815                                         overflow list. */\r
 816                                         vListInsert( ( xList * ) pxOverflowDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );\r
 817                                 }\r
 818                                 else\r
 819                                 {\r
 820                                         /* The wake time has not overflowed, so we can use the\r
 821                                         current block list. */\r
 822                                         vListInsert( ( xList * ) pxDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );\r
 823                                 }\r
 824                         }\r
 825                         xAlreadyYielded = xTaskResumeAll();\r
 826                 }\r
 827                 \r
 828                 /* Force a reschedule if xTaskResumeAll has not already done so, we may\r
 829                 have put ourselves to sleep. */\r
 830                 if( !xAlreadyYielded )\r
 831                 {\r
 832                         taskYIELD();\r
 833                 }\r
 834         }\r
 835         \r
 836 #endif\r
 837 /*-----------------------------------------------------------*/\r
 838 \r
 839 #if ( INCLUDE_uxTaskPriorityGet == 1 )\r
 840 \r
 841         unsigned portBASE_TYPE uxTaskPriorityGet( xTaskHandle pxTask )\r
 842         {\r
 843         tskTCB *pxTCB;\r
 844         unsigned portBASE_TYPE uxReturn;\r
 845 \r
 846                 taskENTER_CRITICAL();\r
 847                 {\r
 848                         /* If null is passed in here then we are changing the\r
 849                         priority of the calling function. */\r
 850                         pxTCB = prvGetTCBFromHandle( pxTask );\r
 851                         uxReturn = pxTCB->uxPriority;\r
 852                 }\r
 853                 taskEXIT_CRITICAL();\r
 854 \r
 855                 return uxReturn;\r
 856         }\r
 857 \r
 858 #endif\r
 859 /*-----------------------------------------------------------*/\r
 860 \r
 861 #if ( INCLUDE_vTaskPrioritySet == 1 )\r
 862 \r
 863         void vTaskPrioritySet( xTaskHandle pxTask, unsigned portBASE_TYPE uxNewPriority )\r
 864         {\r
 865         tskTCB *pxTCB;\r
 866         unsigned portBASE_TYPE uxCurrentPriority, xYieldRequired = pdFALSE;\r
 867 \r
 868                 /* Ensure the new priority is valid. */\r
 869                 if( uxNewPriority >= configMAX_PRIORITIES )\r
 870                 {\r
 871                         uxNewPriority = configMAX_PRIORITIES - 1;\r
 872                 }\r
 873 \r
 874                 taskENTER_CRITICAL();\r
 875                 {\r
 876                         /* If null is passed in here then we are changing the\r
 877                         priority of the calling function. */\r
 878                         pxTCB = prvGetTCBFromHandle( pxTask );\r
 879                         \r
 880                         #if ( configUSE_MUTEXES == 1 )\r
 881                         {\r
 882                                 uxCurrentPriority = pxTCB->uxBasePriority;\r
 883                         }\r
 884                         #else\r
 885                         {\r
 886                                 uxCurrentPriority = pxTCB->uxPriority;\r
 887                         }\r
 888                         #endif\r
 889 \r
 890                         if( uxCurrentPriority != uxNewPriority )\r
 891                         {\r
 892                                 /* The priority change may have readied a task of higher\r
 893                                 priority than the calling task. */\r
 894                                 if( uxNewPriority > uxCurrentPriority ) \r
 895                                 {\r
 896                                         if( pxTask != NULL )\r
 897                                         {\r
 898                                                 /* The priority of another task is being raised.  If we\r
 899                                                 were raising the priority of the currently running task\r
 900                                                 there would be no need to switch as it must have already\r
 901                                                 been the highest priority task. */\r
 902                                                 xYieldRequired = pdTRUE;\r
 903                                         }\r
 904                                 }\r
 905                                 else if( pxTask == NULL )\r
 906                                 {\r
 907                                         /* Setting our own priority down means there may now be another\r
 908                                         task of higher priority that is ready to execute. */\r
 909                                         xYieldRequired = pdTRUE;\r
 910                                 }\r
 911                         \r
 912                                 \r
 913 \r
 914                                 #if ( configUSE_MUTEXES == 1 )\r
 915                                 {\r
 916                                         /* Only change the priority being used if the task is not\r
 917                                         currently using an inherited priority. */\r
 918                                         if( pxTCB->uxBasePriority == pxTCB->uxPriority )\r
 919                                         {\r
 920                                                 pxTCB->uxPriority = uxNewPriority;\r
 921                                         }\r
 922                                         \r
 923                                         /* The base priority gets set whatever. */\r
 924                                         pxTCB->uxBasePriority = uxNewPriority;                                  \r
 925                                 }\r
 926                                 #else\r
 927                                 {\r
 928                                         pxTCB->uxPriority = uxNewPriority;\r
 929                                 }\r
 930                                 #endif\r
 931 \r
 932                                 listSET_LIST_ITEM_VALUE( &( pxTCB->xEventListItem ), ( configMAX_PRIORITIES - ( portTickType ) uxNewPriority ) );\r
 933 \r
 934                                 /* If the task is in the blocked or suspended list we need do\r
 935                                 nothing more than change it's priority variable. However, if\r
 936                                 the task is in a ready list it needs to be removed and placed\r
 937                                 in the queue appropriate to its new priority. */\r
 938                                 if( listIS_CONTAINED_WITHIN( &( pxReadyTasksLists[ uxCurrentPriority ] ), &( pxTCB->xGenericListItem ) ) )\r
 939                                 {\r
 940                                         /* The task is currently in its ready list - remove before adding\r
 941                                         it to it's new ready list.  As we are in a critical section we\r
 942                                         can do this even if the scheduler is suspended. */\r
 943                                         vListRemove( &( pxTCB->xGenericListItem ) );\r
 944                                         prvAddTaskToReadyQueue( pxTCB );\r
 945                                 }                       \r
 946                                 \r
 947                                 if( xYieldRequired == pdTRUE )\r
 948                                 {\r
 949                                         taskYIELD();\r
 950                                 }                               \r
 951                         }\r
 952                 }\r
 953                 taskEXIT_CRITICAL();\r
 954         }\r
 955 \r
 956 #endif\r
 957 /*-----------------------------------------------------------*/\r
 958 \r
 959 #if ( INCLUDE_vTaskSuspend == 1 )\r
 960 \r
 961         void vTaskSuspend( xTaskHandle pxTaskToSuspend )\r
 962         {\r
 963         tskTCB *pxTCB;\r
 964 \r
 965                 taskENTER_CRITICAL();\r
 966                 {\r
 967                         /* Ensure a yield is performed if the current task is being \r
 968                         suspended. */\r
 969                         if( pxTaskToSuspend == pxCurrentTCB )\r
 970                         {\r
 971                                 pxTaskToSuspend = NULL;\r
 972                         }\r
 973 \r
 974                         /* If null is passed in here then we are suspending ourselves. */\r
 975                         pxTCB = prvGetTCBFromHandle( pxTaskToSuspend );\r
 976 \r
 977                         /* Remove task from the ready/delayed list and place in the     suspended list. */\r
 978                         vListRemove( &( pxTCB->xGenericListItem ) );\r
 979 \r
 980                         /* Is the task waiting on an event also? */                                                                                             \r
 981                         if( pxTCB->xEventListItem.pvContainer )\r
 982                         {\r
 983                                 vListRemove( &( pxTCB->xEventListItem ) );\r
 984                         }\r
 985 \r
 986                         vListInsertEnd( ( xList * ) &xSuspendedTaskList, &( pxTCB->xGenericListItem ) );\r
 987                 }\r
 988                 taskEXIT_CRITICAL();\r
 989 \r
 990                 /* We may have just suspended the current task. */\r
 991                 if( ( void * ) pxTaskToSuspend == NULL )\r
 992                 {\r
 993                         taskYIELD();\r
 994                 }\r
 995         }\r
 996 \r
 997 #endif\r
 998 /*-----------------------------------------------------------*/\r
 999 \r
1000 #if ( INCLUDE_vTaskSuspend == 1 )\r
1001 \r
1002         static portBASE_TYPE prvIsTaskSuspended( const tskTCB * const pxTCB )\r
1003         {\r
1004         portBASE_TYPE xReturn = pdFALSE;\r
1005 \r
1006                 /* Is the task we are attempting to resume actually in the\r
1007                 suspended list? */\r
1008                 if( listIS_CONTAINED_WITHIN( &xSuspendedTaskList, &( pxTCB->xGenericListItem ) ) != pdFALSE )\r
1009                 {\r
1010                         /* Has the task already been resumed from within an ISR? */\r
1011                         if( listIS_CONTAINED_WITHIN( &xPendingReadyList, &( pxTCB->xEventListItem ) ) != pdTRUE )\r
1012                         {                       \r
1013                                 /* Is it in the suspended list because it is in the\r
1014                                 Suspended state?  It is possible to be in the suspended\r
1015                                 list because it is blocked on a task with no timeout\r
1016                                 specified. */\r
1017                                 if( listIS_CONTAINED_WITHIN( NULL, &( pxTCB->xEventListItem ) ) == pdTRUE )\r
1018                                 {\r
1019                                         xReturn = pdTRUE;\r
1020                                 }\r
1021                         }\r
1022                 }\r
1023 \r
1024                 return xReturn;\r
1025         }\r
1026 \r
1027 #endif\r
1028 /*-----------------------------------------------------------*/\r
1029 \r
1030 #if ( INCLUDE_vTaskSuspend == 1 )\r
1031 \r
1032         void vTaskResume( xTaskHandle pxTaskToResume )\r
1033         {\r
1034         tskTCB *pxTCB;\r
1035 \r
1036                 /* Remove the task from whichever list it is currently in, and place\r
1037                 it in the ready list. */\r
1038                 pxTCB = ( tskTCB * ) pxTaskToResume;\r
1039 \r
1040                 /* The parameter cannot be NULL as it is impossible to resume the\r
1041                 currently executing task. */\r
1042                 if( pxTCB != NULL )\r
1043                 {\r
1044                         taskENTER_CRITICAL();\r
1045                         {\r
1046                                 if( prvIsTaskSuspended( pxTCB ) == pdTRUE )\r
1047                                 {\r
1048                                         /* As we are in a critical section we can access the ready\r
1049                                         lists even if the scheduler is suspended. */\r
1050                                         vListRemove(  &( pxTCB->xGenericListItem ) );\r
1051                                         prvAddTaskToReadyQueue( pxTCB );\r
1052 \r
1053                                         /* We may have just resumed a higher priority task. */\r
1054                                         if( pxTCB->uxPriority >= pxCurrentTCB->uxPriority )\r
1055                                         {\r
1056                                                 /* This yield may not cause the task just resumed to run, but\r
1057                                                 will leave the lists in the correct state for the next yield. */\r
1058                                                 taskYIELD();\r
1059                                         }\r
1060                                 }\r
1061                         }\r
1062                         taskEXIT_CRITICAL();\r
1063                 }\r
1064         }\r
1065 \r
1066 #endif\r
1067 \r
1068 /*-----------------------------------------------------------*/\r
1069 \r
1070 #if ( ( INCLUDE_xTaskResumeFromISR == 1 ) && ( INCLUDE_vTaskSuspend == 1 ) )\r
1071 \r
1072         portBASE_TYPE xTaskResumeFromISR( xTaskHandle pxTaskToResume )\r
1073         {\r
1074         portBASE_TYPE xYieldRequired = pdFALSE;\r
1075         tskTCB *pxTCB;\r
1076 \r
1077                 pxTCB = ( tskTCB * ) pxTaskToResume;\r
1078 \r
1079                 if( prvIsTaskSuspended( pxTCB ) == pdTRUE )\r
1080                 {\r
1081                         if( uxSchedulerSuspended == ( unsigned portBASE_TYPE ) pdFALSE )\r
1082                         {\r
1083                                 xYieldRequired = ( pxTCB->uxPriority >= pxCurrentTCB->uxPriority );\r
1084                                 vListRemove(  &( pxTCB->xGenericListItem ) );   \r
1085                                 prvAddTaskToReadyQueue( pxTCB );\r
1086                         }\r
1087                         else\r
1088                         {\r
1089                                 /* We cannot access the delayed or ready lists, so will hold this\r
1090                                 task pending until the scheduler is resumed, at which point a\r
1091                                 yield will be performed if necessary. */\r
1092                                 vListInsertEnd( ( xList * ) &( xPendingReadyList ), &( pxTCB->xEventListItem ) );\r
1093                         }\r
1094                 }\r
1095 \r
1096                 return xYieldRequired;\r
1097         }\r
1098 \r
1099 #endif\r
1100 \r
1101 \r
1102 \r
1103 \r
1104 /*-----------------------------------------------------------\r
1105  * PUBLIC SCHEDULER CONTROL documented in task.h\r
1106  *----------------------------------------------------------*/\r
1107 \r
1108 \r
1109 void vTaskStartScheduler( void )\r
1110 {\r
1111 portBASE_TYPE xReturn;\r
1112 \r
1113         /* Add the idle task at the lowest priority. */\r
1114         xReturn = xTaskCreate( prvIdleTask, ( signed portCHAR * ) "IDLE", tskIDLE_STACK_SIZE, ( void * ) NULL, tskIDLE_PRIORITY, ( xTaskHandle * ) NULL );\r
1115 \r
1116         if( xReturn == pdPASS )\r
1117         {\r
1118                 /* Interrupts are turned off here, to ensure a tick does not occur\r
1119                 before or during the call to xPortStartScheduler().  The stacks of\r
1120                 the created tasks contain a status word with interrupts switched on\r
1121                 so interrupts will automatically get re-enabled when the first task\r
1122                 starts to run.\r
1123                 \r
1124                 STEPPING THROUGH HERE USING A DEBUGGER CAN CAUSE BIG PROBLEMS IF THE\r
1125                 DEBUGGER ALLOWS INTERRUPTS TO BE PROCESSED. */\r
1126                 portDISABLE_INTERRUPTS();\r
1127 \r
1128                 xSchedulerRunning = pdTRUE;\r
1129                 xTickCount = ( portTickType ) 0;\r
1130 \r
1131                 /* Setting up the timer tick is hardware specific and thus in the\r
1132                 portable interface. */\r
1133                 if( xPortStartScheduler() )\r
1134                 {\r
1135                         /* Should not reach here as if the scheduler is running the\r
1136                         function will not return. */\r
1137                 }\r
1138                 else\r
1139                 {\r
1140                         /* Should only reach here if a task calls xTaskEndScheduler(). */\r
1141                 }\r
1142         }\r
1143 }\r
1144 /*-----------------------------------------------------------*/\r
1145 \r
1146 void vTaskEndScheduler( void )\r
1147 {\r
1148         /* Stop the scheduler interrupts and call the portable scheduler end\r
1149         routine so the original ISRs can be restored if necessary.  The port\r
1150         layer must ensure interrupts enable     bit is left in the correct state. */\r
1151         portDISABLE_INTERRUPTS();\r
1152         xSchedulerRunning = pdFALSE;\r
1153         vPortEndScheduler();\r
1154 }\r
1155 /*----------------------------------------------------------*/\r
1156 \r
1157 void vTaskSuspendAll( void )\r
1158 {\r
1159         portENTER_CRITICAL();\r
1160                 ++uxSchedulerSuspended;\r
1161         portEXIT_CRITICAL();\r
1162 }\r
1163 /*----------------------------------------------------------*/\r
1164 \r
1165 signed portBASE_TYPE xTaskResumeAll( void )\r
1166 {\r
1167 register tskTCB *pxTCB;\r
1168 signed portBASE_TYPE xAlreadyYielded = pdFALSE;\r
1169 \r
1170         /* It is possible that an ISR caused a task to be removed from an event\r
1171         list while the scheduler was suspended.  If this was the case then the\r
1172         removed task will have been added to the xPendingReadyList.  Once the\r
1173         scheduler has been resumed it is safe to move all the pending ready\r
1174         tasks from this list into their appropriate ready list. */\r
1175         portENTER_CRITICAL();\r
1176         {\r
1177                 --uxSchedulerSuspended;\r
1178 \r
1179                 if( uxSchedulerSuspended == ( unsigned portBASE_TYPE ) pdFALSE )\r
1180                 {                       \r
1181                         if( uxCurrentNumberOfTasks > ( unsigned portBASE_TYPE ) 0 )\r
1182                         {\r
1183                                 portBASE_TYPE xYieldRequired = pdFALSE;\r
1184                                 \r
1185                                 /* Move any readied tasks from the pending list into the\r
1186                                 appropriate ready list. */\r
1187                                 while( ( pxTCB = ( tskTCB * ) listGET_OWNER_OF_HEAD_ENTRY(  ( ( xList * ) &xPendingReadyList ) ) ) != NULL )\r
1188                                 {\r
1189                                         vListRemove( &( pxTCB->xEventListItem ) );\r
1190                                         vListRemove( &( pxTCB->xGenericListItem ) );\r
1191                                         prvAddTaskToReadyQueue( pxTCB );\r
1192                                         \r
1193                                         /* If we have moved a task that has a priority higher than\r
1194                                         the current task then we should yield. */\r
1195                                         if( pxTCB->uxPriority >= pxCurrentTCB->uxPriority )\r
1196                                         {\r
1197                                                 xYieldRequired = pdTRUE;\r
1198                                         }\r
1199                                 }\r
1200 \r
1201                                 /* If any ticks occurred while the scheduler was suspended then\r
1202                                 they should be processed now.  This ensures the tick count does not\r
1203                                 slip, and that any delayed tasks are resumed at the correct time. */\r
1204                                 if( uxMissedTicks > ( unsigned portBASE_TYPE ) 0 )\r
1205                                 {\r
1206                                         while( uxMissedTicks > ( unsigned portBASE_TYPE ) 0 )\r
1207                                         {\r
1208                                                 vTaskIncrementTick();\r
1209                                                 --uxMissedTicks;\r
1210                                         }\r
1211 \r
1212                                         /* As we have processed some ticks it is appropriate to yield\r
1213                                         to ensure the highest priority task that is ready to run is\r
1214                                         the task actually running. */\r
1215                                         xYieldRequired = pdTRUE;\r
1216                                 }\r
1217                                 \r
1218                                 if( ( xYieldRequired == pdTRUE ) || ( xMissedYield == pdTRUE ) )\r
1219                                 {\r
1220                                         xAlreadyYielded = pdTRUE;\r
1221                                         xMissedYield = pdFALSE;\r
1222                                         taskYIELD();\r
1223                                 }\r
1224                         }\r
1225                 }\r
1226         }\r
1227         portEXIT_CRITICAL();\r
1228 \r
1229         return xAlreadyYielded;\r
1230 }\r
1231 \r
1232 \r
1233 \r
1234 \r
1235 \r
1236 \r
1237 /*-----------------------------------------------------------\r
1238  * PUBLIC TASK UTILITIES documented in task.h\r
1239  *----------------------------------------------------------*/\r
1240 \r
1241 \r
1242 \r
1243 portTickType xTaskGetTickCount( void )\r
1244 {\r
1245 portTickType xTicks;\r
1246 \r
1247         /* Critical section required if running on a 16 bit processor. */\r
1248         taskENTER_CRITICAL();\r
1249         {\r
1250                 xTicks = xTickCount;\r
1251         }\r
1252         taskEXIT_CRITICAL();\r
1253 \r
1254         return xTicks;\r
1255 }\r
1256 /*-----------------------------------------------------------*/\r
1257 \r
1258 unsigned portBASE_TYPE uxTaskGetNumberOfTasks( void )\r
1259 {\r
1260 unsigned portBASE_TYPE uxNumberOfTasks;\r
1261 \r
1262         taskENTER_CRITICAL();\r
1263                 uxNumberOfTasks = uxCurrentNumberOfTasks;\r
1264         taskEXIT_CRITICAL();\r
1265 \r
1266         return uxNumberOfTasks;\r
1267 }\r
1268 /*-----------------------------------------------------------*/\r
1269 \r
1270 #if ( ( configUSE_TRACE_FACILITY == 1 ) && ( INCLUDE_vTaskDelete == 1 ) && ( INCLUDE_vTaskSuspend == 1 ) )\r
1271 \r
1272         void vTaskList( signed portCHAR *pcWriteBuffer )\r
1273         {\r
1274         unsigned portBASE_TYPE uxQueue;\r
1275 \r
1276                 /* This is a VERY costly function that should be used for debug only.\r
1277                 It leaves interrupts disabled for a LONG time. */\r
1278 \r
1279         vTaskSuspendAll();\r
1280                 {\r
1281                         /* Run through all the lists that could potentially contain a TCB and\r
1282                         report the task name, state and stack high water mark. */\r
1283 \r
1284                         pcWriteBuffer[ 0 ] = ( signed portCHAR ) 0x00;\r
1285                         strcat( ( portCHAR * ) pcWriteBuffer, ( const portCHAR * ) "\r\n" );\r
1286 \r
1287                         uxQueue = uxTopUsedPriority + 1;\r
1288 \r
1289                         do\r
1290                         {\r
1291                                 uxQueue--;\r
1292 \r
1293                                 if( !listLIST_IS_EMPTY( &( pxReadyTasksLists[ uxQueue ] ) ) )\r
1294                                 {\r
1295                                         prvListTaskWithinSingleList( pcWriteBuffer, ( xList * ) &( pxReadyTasksLists[ uxQueue ] ), tskREADY_CHAR );                     \r
1296                                 }\r
1297                         }while( uxQueue > ( unsigned portSHORT ) tskIDLE_PRIORITY );\r
1298 \r
1299                         if( !listLIST_IS_EMPTY( pxDelayedTaskList ) )\r
1300                         {\r
1301                                 prvListTaskWithinSingleList( pcWriteBuffer, ( xList * ) pxDelayedTaskList, tskBLOCKED_CHAR );\r
1302                         }\r
1303 \r
1304                         if( !listLIST_IS_EMPTY( pxOverflowDelayedTaskList ) )\r
1305                         {\r
1306                                 prvListTaskWithinSingleList( pcWriteBuffer, ( xList * ) pxOverflowDelayedTaskList, tskBLOCKED_CHAR );\r
1307                         }\r
1308 \r
1309                         if( !listLIST_IS_EMPTY( &xTasksWaitingTermination ) )\r
1310                         {\r
1311                                 prvListTaskWithinSingleList( pcWriteBuffer, ( xList * ) &xTasksWaitingTermination, tskDELETED_CHAR );\r
1312                         }\r
1313 \r
1314                         if( !listLIST_IS_EMPTY( &xSuspendedTaskList ) )\r
1315                         {\r
1316                                 prvListTaskWithinSingleList( pcWriteBuffer, ( xList * ) &xSuspendedTaskList, tskSUSPENDED_CHAR );\r
1317                         }\r
1318                 }\r
1319         xTaskResumeAll();\r
1320         }\r
1321 \r
1322 #endif\r
1323 /*----------------------------------------------------------*/\r
1324 \r
1325 #if ( configUSE_TRACE_FACILITY == 1 )\r
1326 \r
1327         void vTaskStartTrace( signed portCHAR * pcBuffer, unsigned portLONG ulBufferSize )\r
1328         {\r
1329                 portENTER_CRITICAL();\r
1330                 {\r
1331                         pcTraceBuffer = ( volatile signed portCHAR * volatile )pcBuffer;\r
1332                         pcTraceBufferStart = pcBuffer;\r
1333                         pcTraceBufferEnd = pcBuffer + ( ulBufferSize - tskSIZE_OF_EACH_TRACE_LINE );\r
1334                         xTracing = pdTRUE;\r
1335                 }\r
1336                 portEXIT_CRITICAL();\r
1337         }\r
1338 \r
1339 #endif\r
1340 /*----------------------------------------------------------*/\r
1341 \r
1342 #if ( configUSE_TRACE_FACILITY == 1 )\r
1343 \r
1344         unsigned portLONG ulTaskEndTrace( void )\r
1345         {\r
1346         unsigned portLONG ulBufferLength;\r
1347 \r
1348                 portENTER_CRITICAL();\r
1349                         xTracing = pdFALSE;\r
1350                 portEXIT_CRITICAL();\r
1351 \r
1352                 ulBufferLength = ( unsigned portLONG ) ( pcTraceBuffer - pcTraceBufferStart );\r
1353 \r
1354                 return ulBufferLength;\r
1355         }\r
1356 \r
1357 #endif\r
1358 \r
1359 \r
1360 \r
1361 /*-----------------------------------------------------------\r
1362  * SCHEDULER INTERNALS AVAILABLE FOR PORTING PURPOSES\r
1363  * documented in task.h\r
1364  *----------------------------------------------------------*/\r
1365 \r
1366 \r
1367 inline void vTaskIncrementTick( void )\r
1368 {\r
1369         /* Called by the portable layer each time a tick interrupt occurs.\r
1370         Increments the tick then checks to see if the new tick value will cause any\r
1371         tasks to be unblocked. */\r
1372         if( uxSchedulerSuspended == ( unsigned portBASE_TYPE ) pdFALSE )\r
1373         {\r
1374                 ++xTickCount;\r
1375                 if( xTickCount == ( portTickType ) 0 )\r
1376                 {\r
1377                         xList *pxTemp;\r
1378 \r
1379                         /* Tick count has overflowed so we need to swap the delay lists.  \r
1380                         If there are any items in pxDelayedTaskList here then there is \r
1381                         an error! */\r
1382                         pxTemp = pxDelayedTaskList;\r
1383                         pxDelayedTaskList = pxOverflowDelayedTaskList;\r
1384                         pxOverflowDelayedTaskList = pxTemp;\r
1385             xNumOfOverflows++;\r
1386                 }\r
1387 \r
1388                 /* See if this tick has made a timeout expire. */\r
1389                 prvCheckDelayedTasks();\r
1390         }\r
1391         else\r
1392         {\r
1393                 ++uxMissedTicks;\r
1394 \r
1395                 /* The tick hook gets called at regular intervals, even if the \r
1396                 scheduler is locked. */\r
1397                 #if ( configUSE_TICK_HOOK == 1 )\r
1398                 {\r
1399                         extern void vApplicationTickHook( void );\r
1400 \r
1401                         vApplicationTickHook();\r
1402                 }\r
1403                 #endif\r
1404         }\r
1405 \r
1406         #if ( configUSE_TICK_HOOK == 1 )\r
1407         {\r
1408                 extern void vApplicationTickHook( void );\r
1409 \r
1410                 /* Guard against the tick hook being called when the missed tick\r
1411                 count is being unwound (when the scheduler is being unlocked. */\r
1412                 if( uxMissedTicks == 0 )\r
1413                 {\r
1414                         vApplicationTickHook();\r
1415                 }\r
1416         }\r
1417         #endif\r
1418 }\r
1419 /*-----------------------------------------------------------*/\r
1420 \r
1421 #if ( ( INCLUDE_vTaskCleanUpResources == 1 ) && ( INCLUDE_vTaskSuspend == 1 ) )\r
1422 \r
1423         void vTaskCleanUpResources( void )\r
1424         {\r
1425         unsigned portSHORT usQueue;\r
1426         volatile tskTCB *pxTCB;\r
1427 \r
1428                 usQueue = ( unsigned portSHORT ) uxTopUsedPriority + ( unsigned portSHORT ) 1;\r
1429 \r
1430                 /* Remove any TCB's from the ready queues. */\r
1431                 do\r
1432                 {\r
1433                         usQueue--;\r
1434 \r
1435                         while( !listLIST_IS_EMPTY( &( pxReadyTasksLists[ usQueue ] ) ) )\r
1436                         {\r
1437                                 listGET_OWNER_OF_NEXT_ENTRY( pxTCB, &( pxReadyTasksLists[ usQueue ] ) );\r
1438                                 vListRemove( ( xListItem * ) &( pxTCB->xGenericListItem ) );\r
1439 \r
1440                                 prvDeleteTCB( ( tskTCB * ) pxTCB );\r
1441                         }\r
1442                 }while( usQueue > ( unsigned portSHORT ) tskIDLE_PRIORITY );\r
1443 \r
1444                 /* Remove any TCB's from the delayed queue. */\r
1445                 while( !listLIST_IS_EMPTY( &xDelayedTaskList1 ) )\r
1446                 {\r
1447                         listGET_OWNER_OF_NEXT_ENTRY( pxTCB, &xDelayedTaskList1 );\r
1448                         vListRemove( ( xListItem * ) &( pxTCB->xGenericListItem ) );\r
1449 \r
1450                         prvDeleteTCB( ( tskTCB * ) pxTCB );\r
1451                 }\r
1452 \r
1453                 /* Remove any TCB's from the overflow delayed queue. */\r
1454                 while( !listLIST_IS_EMPTY( &xDelayedTaskList2 ) )\r
1455                 {\r
1456                         listGET_OWNER_OF_NEXT_ENTRY( pxTCB, &xDelayedTaskList2 );\r
1457                         vListRemove( ( xListItem * ) &( pxTCB->xGenericListItem ) );\r
1458 \r
1459                         prvDeleteTCB( ( tskTCB * ) pxTCB );\r
1460                 }\r
1461 \r
1462                 while( !listLIST_IS_EMPTY( &xSuspendedTaskList ) )\r
1463                 {\r
1464                         listGET_OWNER_OF_NEXT_ENTRY( pxTCB, &xSuspendedTaskList );\r
1465                         vListRemove( ( xListItem * ) &( pxTCB->xGenericListItem ) );\r
1466 \r
1467                         prvDeleteTCB( ( tskTCB * ) pxTCB );\r
1468                 }               \r
1469         }\r
1470 \r
1471 #endif\r
1472 /*-----------------------------------------------------------*/\r
1473 \r
1474 void vTaskSwitchContext( void )\r
1475 {\r
1476         if( uxSchedulerSuspended != ( unsigned portBASE_TYPE ) pdFALSE )\r
1477         {\r
1478                 /* The scheduler is currently suspended - do not allow a context\r
1479                 switch. */\r
1480                 xMissedYield = pdTRUE;\r
1481                 return;\r
1482         }\r
1483 \r
1484         /* Find the highest priority queue that contains ready tasks. */\r
1485         while( listLIST_IS_EMPTY( &( pxReadyTasksLists[ uxTopReadyPriority ] ) ) )\r
1486         {\r
1487                 --uxTopReadyPriority;\r
1488         }\r
1489 \r
1490         /* listGET_OWNER_OF_NEXT_ENTRY walks through the list, so the tasks of the\r
1491         same priority get an equal share of the processor time. */\r
1492         listGET_OWNER_OF_NEXT_ENTRY( pxCurrentTCB, &( pxReadyTasksLists[ uxTopReadyPriority ] ) );\r
1493         vWriteTraceToBuffer();\r
1494 }\r
1495 /*-----------------------------------------------------------*/\r
1496 \r
1497 void vTaskPlaceOnEventList( const xList * const pxEventList, portTickType xTicksToWait )\r
1498 {\r
1499 portTickType xTimeToWake;\r
1500 \r
1501         /* THIS FUNCTION MUST BE CALLED WITH INTERRUPTS DISABLED OR THE\r
1502         SCHEDULER SUSPENDED. */\r
1503 \r
1504         /* Place the event list item of the TCB in the appropriate event list.\r
1505         This is placed in the list in priority order so the highest priority task\r
1506         is the first to be woken by the event. */\r
1507         vListInsert( ( xList * ) pxEventList, ( xListItem * ) &( pxCurrentTCB->xEventListItem ) );\r
1508 \r
1509         /* We must remove ourselves from the ready list before adding ourselves\r
1510         to the blocked list as the same list item is used for both lists.  We have\r
1511         exclusive access to the ready lists as the scheduler is locked. */\r
1512         vListRemove( ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );\r
1513 \r
1514 \r
1515         #if ( INCLUDE_vTaskSuspend == 1 )\r
1516         {                        \r
1517                 if( xTicksToWait == portMAX_DELAY )\r
1518                 {\r
1519                         /* Add ourselves to the suspended task list instead of a delayed task\r
1520                         list to ensure we are not woken by a timing event.  We will block\r
1521                         indefinitely. */\r
1522                         vListInsertEnd( ( xList * ) &xSuspendedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );\r
1523                 }\r
1524                 else\r
1525                 {\r
1526                         /* Calculate the time at which the task should be woken if the event does\r
1527                         not occur.  This may overflow but this doesn't matter. */\r
1528                         xTimeToWake = xTickCount + xTicksToWait;\r
1529                 \r
1530                         listSET_LIST_ITEM_VALUE( &( pxCurrentTCB->xGenericListItem ), xTimeToWake );\r
1531                 \r
1532                         if( xTimeToWake < xTickCount )\r
1533                         {\r
1534                                 /* Wake time has overflowed.  Place this item in the overflow list. */\r
1535                                 vListInsert( ( xList * ) pxOverflowDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );\r
1536                         }\r
1537                         else\r
1538                         {\r
1539                                 /* The wake time has not overflowed, so we can use the current block list. */\r
1540                                 vListInsert( ( xList * ) pxDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );\r
1541                         }\r
1542                 }\r
1543         }\r
1544         #else\r
1545         {\r
1546                         /* Calculate the time at which the task should be woken if the event does\r
1547                         not occur.  This may overflow but this doesn't matter. */\r
1548                         xTimeToWake = xTickCount + xTicksToWait;\r
1549                 \r
1550                         listSET_LIST_ITEM_VALUE( &( pxCurrentTCB->xGenericListItem ), xTimeToWake );\r
1551                 \r
1552                         if( xTimeToWake < xTickCount )\r
1553                         {\r
1554                                 /* Wake time has overflowed.  Place this item in the overflow list. */\r
1555                                 vListInsert( ( xList * ) pxOverflowDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );\r
1556                         }\r
1557                         else\r
1558                         {\r
1559                                 /* The wake time has not overflowed, so we can use the current block list. */\r
1560                                 vListInsert( ( xList * ) pxDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );\r
1561                         }\r
1562         }\r
1563         #endif\r
1564 }\r
1565 /*-----------------------------------------------------------*/\r
1566 \r
1567 signed portBASE_TYPE xTaskRemoveFromEventList( const xList * const pxEventList )\r
1568 {\r
1569 tskTCB *pxUnblockedTCB;\r
1570 portBASE_TYPE xReturn;\r
1571 \r
1572         /* THIS FUNCTION MUST BE CALLED WITH INTERRUPTS DISABLED OR THE\r
1573         SCHEDULER SUSPENDED.  It can also be called from within an ISR. */\r
1574 \r
1575         /* The event list is sorted in priority order, so we can remove the\r
1576         first in the list, remove the TCB from the delayed list, and add\r
1577         it to the ready list.\r
1578         \r
1579         If an event is for a queue that is locked then this function will never\r
1580         get called - the lock count on the queue will get modified instead.  This\r
1581         means we can always expect exclusive access to the event list here. */\r
1582         pxUnblockedTCB = ( tskTCB * ) listGET_OWNER_OF_HEAD_ENTRY( pxEventList );\r
1583         vListRemove( &( pxUnblockedTCB->xEventListItem ) );\r
1584 \r
1585         if( uxSchedulerSuspended == ( unsigned portBASE_TYPE ) pdFALSE )\r
1586         {\r
1587                 vListRemove( &( pxUnblockedTCB->xGenericListItem ) );\r
1588                 prvAddTaskToReadyQueue( pxUnblockedTCB );\r
1589         }\r
1590         else\r
1591         {\r
1592                 /* We cannot access the delayed or ready lists, so will hold this\r
1593                 task pending until the scheduler is resumed. */\r
1594                 vListInsertEnd( ( xList * ) &( xPendingReadyList ), &( pxUnblockedTCB->xEventListItem ) );\r
1595         }\r
1596 \r
1597         if( pxUnblockedTCB->uxPriority >= pxCurrentTCB->uxPriority )\r
1598         {\r
1599                 /* Return true if the task removed from the event list has\r
1600                 a higher priority than the calling task.  This allows\r
1601                 the calling task to know if it should force a context\r
1602                 switch now. */\r
1603                 xReturn = pdTRUE;\r
1604         }\r
1605         else\r
1606         {\r
1607                 xReturn = pdFALSE;\r
1608         }\r
1609 \r
1610         return xReturn;\r
1611 }\r
1612 /*-----------------------------------------------------------*/\r
1613 \r
1614 void vTaskSetTimeOutState( xTimeOutType * const pxTimeOut )\r
1615 {\r
1616     pxTimeOut->xOverflowCount = xNumOfOverflows;\r
1617     pxTimeOut->xTimeOnEntering = xTickCount;\r
1618 }\r
1619 /*-----------------------------------------------------------*/\r
1620 \r
1621 portBASE_TYPE xTaskCheckForTimeOut( xTimeOutType * const pxTimeOut, portTickType * const pxTicksToWait )\r
1622 {\r
1623 portBASE_TYPE xReturn;\r
1624 \r
1625         #if ( INCLUDE_vTaskSuspend == 1 )\r
1626                 /* If INCLUDE_vTaskSuspend is set to 1 and the block time specified is\r
1627                 the maximum block time then the task should block indefinitely, and\r
1628                 therefore never time out. */\r
1629                 if( *pxTicksToWait == portMAX_DELAY )\r
1630                 {\r
1631                         xReturn = pdFALSE;\r
1632                 }\r
1633                 else /* We are not blocking indefinitely, perform the checks below. */\r
1634         #endif\r
1635 \r
1636     if( ( xNumOfOverflows != pxTimeOut->xOverflowCount ) && ( xTickCount >= pxTimeOut->xTimeOnEntering ) )\r
1637     {\r
1638         /* The tick count is greater than the time at which vTaskSetTimeout()\r
1639                 was called, but has also overflowed since vTaskSetTimeOut() was called.\r
1640         It must have wrapped all the way around and gone past us again. This\r
1641         passed since vTaskSetTimeout() was called. */\r
1642         xReturn = pdTRUE;\r
1643     }\r
1644     else if( ( xTickCount - pxTimeOut->xTimeOnEntering ) < *pxTicksToWait )\r
1645     {\r
1646         /* Not a genuine timeout. Adjust parameters for time remaining. */\r
1647         *pxTicksToWait -= ( xTickCount - pxTimeOut->xTimeOnEntering );\r
1648         vTaskSetTimeOutState( pxTimeOut );\r
1649         xReturn = pdFALSE;\r
1650     }\r
1651     else\r
1652     {\r
1653         xReturn = pdTRUE;\r
1654     }\r
1655 \r
1656     return xReturn;\r
1657 }\r
1658 /*-----------------------------------------------------------*/\r
1659 \r
1660 void vTaskMissedYield( void )\r
1661 {\r
1662         xMissedYield = pdTRUE;\r
1663 }\r
1664 \r
1665 /*\r
1666  * -----------------------------------------------------------\r
1667  * The Idle task.\r
1668  * ----------------------------------------------------------\r
1669  *\r
1670  * The portTASK_FUNCTION() macro is used to allow port/compiler specific\r
1671  * language extensions.  The equivalent prototype for this function is:\r
1672  *\r
1673  * void prvIdleTask( void *pvParameters );\r
1674  *\r
1675  */\r
1676 static portTASK_FUNCTION( prvIdleTask, pvParameters )\r
1677 {\r
1678         /* Stop warnings. */\r
1679         ( void ) pvParameters;\r
1680 \r
1681         for( ;; )\r
1682         {\r
1683                 /* See if any tasks have been deleted. */\r
1684                 prvCheckTasksWaitingTermination();\r
1685 \r
1686                 #if ( configUSE_PREEMPTION == 0 )\r
1687                 {\r
1688                         /* If we are not using preemption we keep forcing a task switch to\r
1689                         see if any other task has become available.  If we are using\r
1690                         preemption we don't need to do this as any task becoming available\r
1691                         will automatically get the processor anyway. */\r
1692                         taskYIELD();    \r
1693                 }\r
1694                 #endif\r
1695 \r
1696                 #if ( ( configUSE_PREEMPTION == 1 ) && ( configIDLE_SHOULD_YIELD == 1 ) )\r
1697                 {\r
1698                         /* When using preemption tasks of equal priority will be\r
1699                         timesliced.  If a task that is sharing the idle priority is ready\r
1700                         to run then the idle task should yield before the end of the\r
1701                         timeslice.\r
1702                         \r
1703                         A critical region is not required here as we are just reading from\r
1704                         the list, and an occasional incorrect value will not matter.  If\r
1705                         the ready list at the idle priority contains more than one task\r
1706                         then a task other than the idle task is ready to execute. */\r
1707                         if( listCURRENT_LIST_LENGTH( &( pxReadyTasksLists[ tskIDLE_PRIORITY ] ) ) > ( unsigned portBASE_TYPE ) 1 )\r
1708                         {\r
1709                                 taskYIELD();\r
1710                         }\r
1711                 }\r
1712                 #endif\r
1713 \r
1714                 #if ( configUSE_IDLE_HOOK == 1 )\r
1715                 {\r
1716                         extern void vApplicationIdleHook( void );\r
1717 \r
1718                         /* Call the user defined function from within the idle task.  This\r
1719                         allows the application designer to add background functionality\r
1720                         without the overhead of a separate task.\r
1721                         NOTE: vApplicationIdleHook() MUST NOT, UNDER ANY CIRCUMSTANCES,\r
1722                         CALL A FUNCTION THAT MIGHT BLOCK. */\r
1723                         vApplicationIdleHook();\r
1724                 }\r
1725                 #endif\r
1726         }\r
1727 } /*lint !e715 pvParameters is not accessed but all task functions require the same prototype. */\r
1728 \r
1729 \r
1730 \r
1731 \r
1732 \r
1733 \r
1734 \r
1735 /*-----------------------------------------------------------\r
1736  * File private functions documented at the top of the file.\r
1737  *----------------------------------------------------------*/\r
1738 \r
1739 \r
1740 \r
1741 static void prvInitialiseTCBVariables( tskTCB *pxTCB, const signed portCHAR * const pcName, unsigned portBASE_TYPE uxPriority )\r
1742 {\r
1743         /* Store the function name in the TCB. */\r
1744         strncpy( ( char * ) pxTCB->pcTaskName, ( const char * ) pcName, ( unsigned portSHORT ) configMAX_TASK_NAME_LEN );\r
1745         pxTCB->pcTaskName[ ( unsigned portSHORT ) configMAX_TASK_NAME_LEN - ( unsigned portSHORT ) 1 ] = '\0';\r
1746 \r
1747         /* This is used as an array index so must ensure it's not too large. */\r
1748         if( uxPriority >= configMAX_PRIORITIES )\r
1749         {\r
1750                 uxPriority = configMAX_PRIORITIES - 1;\r
1751         }\r
1752 \r
1753         pxTCB->uxPriority = uxPriority;\r
1754         #if ( configUSE_MUTEXES == 1 )\r
1755         {\r
1756                 pxTCB->uxBasePriority = uxPriority;\r
1757         }\r
1758         #endif\r
1759 \r
1760         vListInitialiseItem( &( pxTCB->xGenericListItem ) );\r
1761         vListInitialiseItem( &( pxTCB->xEventListItem ) );\r
1762 \r
1763         /* Set the pxTCB as a link back from the xListItem.  This is so we can get\r
1764         back to the containing TCB from a generic item in a list. */\r
1765         listSET_LIST_ITEM_OWNER( &( pxTCB->xGenericListItem ), pxTCB );\r
1766 \r
1767         /* Event lists are always in priority order. */\r
1768         listSET_LIST_ITEM_VALUE( &( pxTCB->xEventListItem ), configMAX_PRIORITIES - ( portTickType ) uxPriority );\r
1769         listSET_LIST_ITEM_OWNER( &( pxTCB->xEventListItem ), pxTCB );\r
1770 }\r
1771 /*-----------------------------------------------------------*/\r
1772 \r
1773 static void prvInitialiseTaskLists( void )\r
1774 {\r
1775 unsigned portBASE_TYPE uxPriority;\r
1776 \r
1777         for( uxPriority = 0; uxPriority < configMAX_PRIORITIES; uxPriority++ )\r
1778         {\r
1779                 vListInitialise( ( xList * ) &( pxReadyTasksLists[ uxPriority ] ) );\r
1780         }\r
1781 \r
1782         vListInitialise( ( xList * ) &xDelayedTaskList1 );\r
1783         vListInitialise( ( xList * ) &xDelayedTaskList2 );\r
1784         vListInitialise( ( xList * ) &xPendingReadyList );\r
1785 \r
1786         #if ( INCLUDE_vTaskDelete == 1 )\r
1787         {\r
1788                 vListInitialise( ( xList * ) &xTasksWaitingTermination );\r
1789         }\r
1790         #endif\r
1791 \r
1792         #if ( INCLUDE_vTaskSuspend == 1 )\r
1793         {\r
1794                 vListInitialise( ( xList * ) &xSuspendedTaskList );\r
1795         }\r
1796         #endif\r
1797 \r
1798         /* Start with pxDelayedTaskList using list1 and the pxOverflowDelayedTaskList\r
1799         using list2. */\r
1800         pxDelayedTaskList = &xDelayedTaskList1;\r
1801         pxOverflowDelayedTaskList = &xDelayedTaskList2;\r
1802 }\r
1803 /*-----------------------------------------------------------*/\r
1804 \r
1805 static void prvCheckTasksWaitingTermination( void )\r
1806 {                                                       \r
1807         #if ( INCLUDE_vTaskDelete == 1 )\r
1808         {                               \r
1809                 portBASE_TYPE xListIsEmpty;\r
1810 \r
1811                 /* ucTasksDeleted is used to prevent vTaskSuspendAll() being called\r
1812                 too often in the idle task. */\r
1813                 if( uxTasksDeleted > ( unsigned portBASE_TYPE ) 0 )\r
1814                 {\r
1815                         vTaskSuspendAll();\r
1816                                 xListIsEmpty = listLIST_IS_EMPTY( &xTasksWaitingTermination );                          \r
1817                         xTaskResumeAll();\r
1818 \r
1819                         if( !xListIsEmpty )\r
1820                         {\r
1821                                 tskTCB *pxTCB;\r
1822 \r
1823                                 portENTER_CRITICAL();\r
1824                                 {                       \r
1825                                         pxTCB = ( tskTCB * ) listGET_OWNER_OF_HEAD_ENTRY( ( ( xList * ) &xTasksWaitingTermination ) );\r
1826                                         vListRemove( &( pxTCB->xGenericListItem ) );\r
1827                                         --uxCurrentNumberOfTasks;\r
1828                                         --uxTasksDeleted;\r
1829                                 }\r
1830                                 portEXIT_CRITICAL();\r
1831 \r
1832                                 prvDeleteTCB( pxTCB );\r
1833                         }\r
1834                 }\r
1835         }\r
1836         #endif\r
1837 }\r
1838 /*-----------------------------------------------------------*/\r
1839 \r
1840 static tskTCB *prvAllocateTCBAndStack( unsigned portSHORT usStackDepth )\r
1841 {\r
1842 tskTCB *pxNewTCB;\r
1843 \r
1844         /* Allocate space for the TCB.  Where the memory comes from depends on\r
1845         the implementation of the port malloc function. */\r
1846         pxNewTCB = ( tskTCB * ) pvPortMalloc( sizeof( tskTCB ) );\r
1847 \r
1848         if( pxNewTCB != NULL )\r
1849         {\r
1850                 /* Allocate space for the stack used by the task being created.\r
1851                 The base of the stack memory stored in the TCB so the task can\r
1852                 be deleted later if required. */\r
1853                 pxNewTCB->pxStack = ( portSTACK_TYPE * ) pvPortMalloc( ( ( size_t )usStackDepth ) * sizeof( portSTACK_TYPE ) );\r
1854 \r
1855                 if( pxNewTCB->pxStack == NULL )\r
1856                 {\r
1857                         /* Could not allocate the stack.  Delete the allocated TCB. */\r
1858                         vPortFree( pxNewTCB );                  \r
1859                         pxNewTCB = NULL;                        \r
1860                 }               \r
1861                 else\r
1862                 {\r
1863                         /* Just to help debugging. */\r
1864                         memset( pxNewTCB->pxStack, tskSTACK_FILL_BYTE, usStackDepth * sizeof( portSTACK_TYPE ) );\r
1865                 }\r
1866         }\r
1867 \r
1868         return pxNewTCB;\r
1869 }\r
1870 /*-----------------------------------------------------------*/\r
1871 \r
1872 #if ( configUSE_TRACE_FACILITY == 1 )\r
1873 \r
1874         static void prvListTaskWithinSingleList( const signed portCHAR *pcWriteBuffer, xList *pxList, signed portCHAR cStatus )\r
1875         {\r
1876         volatile tskTCB *pxNextTCB, *pxFirstTCB;\r
1877         static portCHAR pcStatusString[ 50 ];\r
1878         unsigned portSHORT usStackRemaining;\r
1879 \r
1880                 /* Write the details of all the TCB's in pxList into the buffer. */\r
1881                 listGET_OWNER_OF_NEXT_ENTRY( pxFirstTCB, pxList );\r
1882                 do\r
1883                 {\r
1884                         listGET_OWNER_OF_NEXT_ENTRY( pxNextTCB, pxList );\r
1885                         usStackRemaining = usTaskCheckFreeStackSpace( ( unsigned portCHAR * ) pxNextTCB->pxStack );\r
1886                         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
1887                         strcat( ( portCHAR * ) pcWriteBuffer, ( portCHAR * ) pcStatusString );\r
1888 \r
1889                 } while( pxNextTCB != pxFirstTCB );\r
1890         }\r
1891 \r
1892 #endif\r
1893 /*-----------------------------------------------------------*/\r
1894 \r
1895 #if ( configUSE_TRACE_FACILITY == 1 )\r
1896         unsigned portSHORT usTaskCheckFreeStackSpace( const unsigned portCHAR * pucStackByte )\r
1897         {\r
1898         register unsigned portSHORT usCount = 0;\r
1899 \r
1900                 while( *pucStackByte == tskSTACK_FILL_BYTE )\r
1901                 {\r
1902                         pucStackByte -= portSTACK_GROWTH;\r
1903                         usCount++;\r
1904                 }\r
1905 \r
1906                 usCount /= sizeof( portSTACK_TYPE );\r
1907 \r
1908                 return usCount;\r
1909         }\r
1910 #endif\r
1911 /*-----------------------------------------------------------*/\r
1912 \r
1913 \r
1914 \r
1915 #if ( ( INCLUDE_vTaskDelete == 1 ) || ( INCLUDE_vTaskCleanUpResources == 1 ) )\r
1916 \r
1917         static void prvDeleteTCB( tskTCB *pxTCB )\r
1918         {\r
1919                 /* Free up the memory allocated by the scheduler for the task.  It is up to\r
1920                 the task to free any memory allocated at the application level. */\r
1921                 vPortFree( pxTCB->pxStack );\r
1922                 vPortFree( pxTCB );\r
1923         }\r
1924 \r
1925 #endif\r
1926 \r
1927 \r
1928 /*-----------------------------------------------------------*/\r
1929 \r
1930 #if ( INCLUDE_xTaskGetCurrentTaskHandle == 1 )\r
1931 \r
1932         xTaskHandle xTaskGetCurrentTaskHandle( void )\r
1933         {\r
1934         xTaskHandle xReturn;\r
1935 \r
1936                 portENTER_CRITICAL();\r
1937                 {\r
1938                         xReturn = ( xTaskHandle ) pxCurrentTCB;\r
1939                 }\r
1940                 portEXIT_CRITICAL();\r
1941 \r
1942                 return xReturn;\r
1943         }\r
1944 \r
1945 #endif\r
1946 \r
1947 /*-----------------------------------------------------------*/\r
1948 \r
1949 #if ( INCLUDE_xTaskGetSchedulerState == 1 )\r
1950 \r
1951         portBASE_TYPE xTaskGetSchedulerState( void )\r
1952         {\r
1953         portBASE_TYPE xReturn;\r
1954         \r
1955                 if( xSchedulerRunning == pdFALSE )\r
1956                 {\r
1957                         xReturn = taskSCHEDULER_NOT_STARTED;\r
1958                 }\r
1959                 else\r
1960                 {\r
1961                         if( uxSchedulerSuspended == ( unsigned portBASE_TYPE ) pdFALSE )\r
1962                         {\r
1963                                 xReturn = taskSCHEDULER_RUNNING;\r
1964                         }\r
1965                         else\r
1966                         {\r
1967                                 xReturn = taskSCHEDULER_SUSPENDED;\r
1968                         }\r
1969                 }\r
1970                 \r
1971                 return xReturn;\r
1972         }\r
1973 \r
1974 #endif\r
1975 \r
1976 #if ( configUSE_MUTEXES == 1 )\r
1977         \r
1978         void vTaskPriorityInherit( xTaskHandle * const pxMutexHolder )\r
1979         {\r
1980         tskTCB * const pxTCB = ( tskTCB * ) pxMutexHolder;\r
1981 \r
1982                 if( pxTCB->uxPriority < pxCurrentTCB->uxPriority )\r
1983                 {\r
1984                         /* Adjust the mutex holder state to account for its new priority. */\r
1985                         listSET_LIST_ITEM_VALUE( &( pxTCB->xEventListItem ), configMAX_PRIORITIES - ( portTickType ) pxCurrentTCB->uxPriority );\r
1986 \r
1987                         /* If the task being modified is in the read state it will need to\r
1988                         be moved in to a new list. */\r
1989                         if( listIS_CONTAINED_WITHIN( &( pxReadyTasksLists[ pxTCB->uxPriority ] ), &( pxTCB->xGenericListItem ) ) )\r
1990                         {\r
1991                                 vListRemove( &( pxTCB->xGenericListItem ) );\r
1992 \r
1993                                 /* Inherit the priority before being moved into the new list. */\r
1994                                 pxTCB->uxPriority = pxCurrentTCB->uxPriority;\r
1995                                 prvAddTaskToReadyQueue( pxTCB );\r
1996                         }\r
1997                         else\r
1998                         {\r
1999                                 /* Just inherit the priority. */\r
2000                                 pxTCB->uxPriority = pxCurrentTCB->uxPriority;\r
2001                         }\r
2002                 }\r
2003         }\r
2004 \r
2005 #endif\r
2006 \r
2007 #if ( configUSE_MUTEXES == 1 )  \r
2008 \r
2009         void vTaskPriorityDisinherit( xTaskHandle * const pxMutexHolder )\r
2010         {\r
2011         tskTCB * const pxTCB = ( tskTCB * ) pxMutexHolder;\r
2012 \r
2013                 if( pxMutexHolder != NULL )\r
2014                 {\r
2015                         if( pxTCB->uxPriority != pxTCB->uxBasePriority )\r
2016                         {\r
2017                                 /* We must be the running task to be able to give the mutex back.\r
2018                                 Remove ourselves from the ready list we currently appear in. */\r
2019                                 vListRemove( &( pxTCB->xGenericListItem ) );\r
2020 \r
2021                                 /* Disinherit the priority before adding ourselves into the new\r
2022                                 ready list. */\r
2023                                 pxTCB->uxPriority = pxTCB->uxBasePriority;\r
2024                                 listSET_LIST_ITEM_VALUE( &( pxTCB->xEventListItem ), configMAX_PRIORITIES - ( portTickType ) pxTCB->uxPriority );\r
2025                                 prvAddTaskToReadyQueue( pxTCB );\r
2026                         }\r
2027                 }\r
2028         }\r
2029 \r
2030 #endif\r
2031 \r
2032         \r
2033 \r
2034         \r
2035 \r