tasks.c

modbus开发程序包

			vListInsertEnd( ( xList * ) &xSuspendedTaskList, &( pxTCB->xGenericListItem ) );
		}
		taskEXIT_CRITICAL();

		/* We may have just suspended the current task. */
		if( ( void * ) pxTaskToSuspend == NULL )
		{
			taskYIELD();
		}
	}

#endif
/*-----------------------------------------------------------*/

#if ( INCLUDE_vTaskSuspend == 1 )

	void vTaskResume( xTaskHandle pxTaskToResume )
	{
	tskTCB *pxTCB;

		/* Remove the task from whichever list it is currently in, and place
		it in the ready list. */
		pxTCB = ( tskTCB * ) pxTaskToResume;

		/* The parameter cannot be NULL as it is impossible to resume the
		currently executing task. */
		if( pxTCB != NULL )
		{
			taskENTER_CRITICAL();
			{
				/* Is the task we are attempting to resume actually suspended? */
				if( listIS_CONTAINED_WITHIN( &xSuspendedTaskList, &( pxTCB->xGenericListItem ) ) != pdFALSE )
				{
					/* Has the task already been resumed from within an ISR? */
					if( listIS_CONTAINED_WITHIN( &xPendingReadyList, &( pxTCB->xEventListItem ) ) != pdTRUE )
					{			
						/* As we are in a critical section we can access the ready 
						lists even if the scheduler is suspended. */
						vListRemove(  &( pxTCB->xGenericListItem ) );
						prvAddTaskToReadyQueue( pxTCB );

						/* We may have just resumed a higher priority task. */
						if( pxTCB->uxPriority >= pxCurrentTCB->uxPriority )
						{
							/* This yield may not cause the task just resumed to run, but
							will leave the lists in the correct state for the next yield. */
							taskYIELD();
						}
					}
				}
			}
			taskEXIT_CRITICAL();
		}
	}

#endif

/*-----------------------------------------------------------*/

#if ( ( INCLUDE_xTaskResumeFromISR == 1 ) && ( INCLUDE_vTaskSuspend == 1 ) )

	portBASE_TYPE xTaskResumeFromISR( xTaskHandle pxTaskToResume )
	{
	portBASE_TYPE xYieldRequired = pdFALSE;
	tskTCB *pxTCB;

		pxTCB = ( tskTCB * ) pxTaskToResume;

		/* Is the task we are attempting to resume actually suspended? */
		if( listIS_CONTAINED_WITHIN( &xSuspendedTaskList, &( pxTCB->xGenericListItem ) ) != pdFALSE )
		{
			/* Has the task already been resumed from within an ISR? */
			if( listIS_CONTAINED_WITHIN( &xPendingReadyList, &( pxTCB->xEventListItem ) ) != pdTRUE )
			{
				if( uxSchedulerSuspended == ( unsigned portBASE_TYPE ) pdFALSE )
				{
					xYieldRequired = ( pxTCB->uxPriority >= pxCurrentTCB->uxPriority );
					vListRemove(  &( pxTCB->xGenericListItem ) );	
					prvAddTaskToReadyQueue( pxTCB );
				}
				else
				{
					/* We cannot access the delayed or ready lists, so will hold this
					task pending until the scheduler is resumed, at which point a 
					yield will be preformed if necessary. */
					vListInsertEnd( ( xList * ) &( xPendingReadyList ), &( pxTCB->xEventListItem ) );
				}
			}
		}

		return xYieldRequired;
	}

#endif




/*-----------------------------------------------------------
 * PUBLIC SCHEDULER CONTROL documented in task.h
 *----------------------------------------------------------*/


void vTaskStartScheduler( void )
{
portBASE_TYPE xReturn;

	/* Add the idle task at the lowest priority. */
	xReturn = xTaskCreate( prvIdleTask, ( signed portCHAR * ) "IDLE", tskIDLE_STACK_SIZE, ( void * ) NULL, tskIDLE_PRIORITY, ( xTaskHandle * ) NULL );

	if( xReturn == pdPASS )
	{
		/* Interrupts are turned off here, to ensure a tick does not occur
		before or during the call to xPortStartScheduler().  The stacks of
		the created tasks contain a status word with interrupts switched on
		so interrupts will automatically get re-enabled when the first task
		starts to run.
		
		STEPPING THROUGH HERE USING A DEBUGGER CAN CAUSE BIG PROBLEMS IF THE
		DEBUGGER ALLOWS INTERRUPTS TO BE PROCESSED. */
		portDISABLE_INTERRUPTS();

		xSchedulerRunning = pdTRUE;
		xTickCount = ( portTickType ) 0;

		/* Setting up the timer tick is hardware specific and thus in the
		portable interface. */
		if( xPortStartScheduler() )
		{
			/* Should not reach here as if the scheduler is running the
			function will not return. */
		}
		else
		{
			/* Should only reach here if a task calls xTaskEndScheduler(). */
		}
	}
}
/*-----------------------------------------------------------*/

void vTaskEndScheduler( void )
{
	/* Stop the scheduler interrupts and call the portable scheduler end
	routine so the original ISRs can be restored if necessary.  The port
	layer must ensure interrupts enable	bit is left in the correct state. */
	portDISABLE_INTERRUPTS();
	xSchedulerRunning = pdFALSE;
	vPortEndScheduler();
}
/*----------------------------------------------------------*/

void vTaskSuspendAll( void )
{
	portENTER_CRITICAL();
		++uxSchedulerSuspended;
	portEXIT_CRITICAL();
}
/*----------------------------------------------------------*/

signed portBASE_TYPE xTaskResumeAll( void )
{
register tskTCB *pxTCB;
signed portBASE_TYPE xAlreadyYielded = pdFALSE;

	/* It is possible that an ISR caused a task to be removed from an event
	list while the scheduler was suspended.  If this was the case then the
	removed task will have been added to the xPendingReadyList.  Once the
	scheduler has been resumed it is safe to move all the pending ready
	tasks from this list into their appropriate ready list. */
	portENTER_CRITICAL();
	{
		--uxSchedulerSuspended;

		if( uxSchedulerSuspended == ( unsigned portBASE_TYPE ) pdFALSE )
		{			
			if( uxCurrentNumberOfTasks > ( unsigned portBASE_TYPE ) 0 )
			{
				portBASE_TYPE xYieldRequired = pdFALSE;
				
				/* Move any readied tasks from the pending list into the
				appropriate ready list. */
				while( ( pxTCB = ( tskTCB * ) listGET_OWNER_OF_HEAD_ENTRY(  ( ( xList * ) &xPendingReadyList ) ) ) != NULL )
				{
					vListRemove( &( pxTCB->xEventListItem ) );
					vListRemove( &( pxTCB->xGenericListItem ) );
					prvAddTaskToReadyQueue( pxTCB );
					
					/* If we have moved a task that has a priority higher than
					the current task then we should yield. */
					if( pxTCB->uxPriority >= pxCurrentTCB->uxPriority )
					{
						xYieldRequired = pdTRUE;
					}
				}

				/* If any ticks occurred while the scheduler was suspended then
				they should be processed now.  This ensures the tick count does not
				slip, and that any delayed tasks are resumed at the correct time. */
				if( uxMissedTicks > ( unsigned portBASE_TYPE ) 0 )
				{
					while( uxMissedTicks > ( unsigned portBASE_TYPE ) 0 )
					{
						vTaskIncrementTick();
						--uxMissedTicks;
					}

					/* As we have processed some ticks it is appropriate to yield
					to ensure the highest priority task that is ready to run is
					the task actually running. */
					xYieldRequired = pdTRUE;
				}
				
				if( ( xYieldRequired == pdTRUE ) || ( xMissedYield == pdTRUE ) )
				{
					xAlreadyYielded = pdTRUE;
					xMissedYield = pdFALSE;
					taskYIELD();
				}
			}
		}
	}
	portEXIT_CRITICAL();

	return xAlreadyYielded;
}






/*-----------------------------------------------------------
 * PUBLIC TASK UTILITIES documented in task.h
 *----------------------------------------------------------*/



portTickType xTaskGetTickCount( void )
{
portTickType xTicks;

	/* Critical section required if running on a 16 bit processor. */
	taskENTER_CRITICAL();
	{
		xTicks = xTickCount;
	}
	taskEXIT_CRITICAL();

	return xTicks;
}
/*-----------------------------------------------------------*/

unsigned portBASE_TYPE uxTaskGetNumberOfTasks( void )
{
unsigned portBASE_TYPE uxNumberOfTasks;

	taskENTER_CRITICAL();
		uxNumberOfTasks = uxCurrentNumberOfTasks;
	taskEXIT_CRITICAL();

	return uxNumberOfTasks;
}
/*-----------------------------------------------------------*/

#if ( ( configUSE_TRACE_FACILITY == 1 ) && ( INCLUDE_vTaskDelete == 1 ) && ( INCLUDE_vTaskSuspend == 1 ) )

	void vTaskList( signed portCHAR *pcWriteBuffer )
	{
	unsigned portBASE_TYPE uxQueue;

		/* This is a VERY costly function that should be used for debug only.
		It leaves interrupts disabled for a LONG time. */

        vTaskSuspendAll();
		{
			/* Run through all the lists that could potentially contain a TCB and
			report the task name, state and stack high water mark. */

			pcWriteBuffer[ 0 ] = ( signed portCHAR ) 0x00;
			strcat( ( portCHAR * ) pcWriteBuffer, ( const portCHAR * ) "\r\n" );

			uxQueue = uxTopUsedPriority + 1;

			do
			{
				uxQueue--;

				if( !listLIST_IS_EMPTY( &( pxReadyTasksLists[ uxQueue ] ) ) )
				{
					prvListTaskWithinSingleList( pcWriteBuffer, ( xList * ) &( pxReadyTasksLists[ uxQueue ] ), tskREADY_CHAR );			
				}
			}while( uxQueue > ( unsigned portSHORT ) tskIDLE_PRIORITY );

			if( !listLIST_IS_EMPTY( pxDelayedTaskList ) )
			{
				prvListTaskWithinSingleList( pcWriteBuffer, ( xList * ) pxDelayedTaskList, tskBLOCKED_CHAR );
			}

			if( !listLIST_IS_EMPTY( pxOverflowDelayedTaskList ) )
			{
				prvListTaskWithinSingleList( pcWriteBuffer, ( xList * ) pxOverflowDelayedTaskList, tskBLOCKED_CHAR );
			}

			if( !listLIST_IS_EMPTY( &xTasksWaitingTermination ) )
			{
				prvListTaskWithinSingleList( pcWriteBuffer, ( xList * ) &xTasksWaitingTermination, tskDELETED_CHAR );
			}

			if( !listLIST_IS_EMPTY( &xSuspendedTaskList ) )
			{
				prvListTaskWithinSingleList( pcWriteBuffer, ( xList * ) &xSuspendedTaskList, tskSUSPENDED_CHAR );
			}
		}
        xTaskResumeAll();
	}

#endif
/*----------------------------------------------------------*/

#if ( configUSE_TRACE_FACILITY == 1 )

	void vTaskStartTrace( signed portCHAR * pcBuffer, unsigned portLONG ulBufferSize )
	{
		portENTER_CRITICAL();
		{
			pcTraceBuffer = ( volatile signed portCHAR * volatile )pcBuffer;
			pcTraceBufferStart = pcBuffer;
			pcTraceBufferEnd = pcBuffer + ( ulBufferSize - tskSIZE_OF_EACH_TRACE_LINE );
			xTracing = pdTRUE;
		}
		portEXIT_CRITICAL();
	}

#endif
/*----------------------------------------------------------*/

#if ( configUSE_TRACE_FACILITY == 1 )

	unsigned portLONG ulTaskEndTrace( void )
	{
	unsigned portLONG ulBufferLength;

		portENTER_CRITICAL();
			xTracing = pdFALSE;
		portEXIT_CRITICAL();

		ulBufferLength = ( unsigned portLONG ) ( pcTraceBuffer - pcTraceBufferStart );

		return ulBufferLength;
	}

#endif



/*-----------------------------------------------------------
 * SCHEDULER INTERNALS AVAILABLE FOR PORTING PURPOSES
 * documented in task.h
 *----------------------------------------------------------*/


inline void vTaskIncrementTick( void )
{
	/* Called by the portable layer each time a tick interrupt occurs.
	Increments the tick then checks to see if the new tick value will cause any
	tasks to be unblocked. */
	if( uxSchedulerSuspended == ( unsigned portBASE_TYPE ) pdFALSE )
	{
		++xTickCount;
		if( xTickCount == ( portTickType ) 0 )
		{
			xList *pxTemp;

			/* Tick count has overflowed so we need to swap the delay lists.  
			If there are any items in pxDelayedTaskList here then there is 
			an error! */
			pxTemp = pxDelayedTaskList;
			pxDelayedTaskList = pxOverflowDelayedTaskList;
			pxOverflowDelayedTaskList = pxTemp;
            xNumOfOverflows++;
		}

		/* See if this tick has made a timeout expire. */
		prvCheckDelayedTasks();
	}
	else
	{
		++uxMissedTicks;

		/* The tick hook gets called at regular intervals, even if the 
		scheduler is locked. */
		#if ( configUSE_TICK_HOOK == 1 )
		{
			extern void vApplicationTickHook( void );

			vApplicationTickHook();
		}
		#endif
	}

	#if ( configUSE_TICK_HOOK == 1 )
	{
		extern void vApplicationTickHook( void );

		/* Guard against the tick hook being called when the missed tick
		count is being unwound (when the scheduler is being unlocked. */
		if( uxMissedTicks == 0 )
		{
			vApplicationTickHook();
		}
	}
	#endif
}
/*-----------------------------------------------------------*/

#if ( ( INCLUDE_vTaskCleanUpResources == 1 ) && ( INCLUDE_vTaskSuspend == 1 ) )

	void vTaskCleanUpResources( void )
	{
	unsigned portSHORT usQueue;
	volatile tskTCB *pxTCB;

		usQueue = ( unsigned portSHORT ) uxTopUsedPriority + ( unsigned portSHORT ) 1;

		/* Remove any TCB's from the ready queues. */
		do
		{
			usQueue--;

			while( !listLIST_IS_EMPTY( &( pxReadyTasksLists[ usQueue ] ) ) )
			{
				listGET_OWNER_OF_NEXT_ENTRY( pxTCB, &( pxReadyTasksLists[ usQueue ] ) );
				vListRemove( ( xListItem * ) &( pxTCB->xGenericListItem ) );

				prvDeleteTCB( ( tskTCB * ) pxTCB );
			}
		}while( usQueue > ( unsigned portSHORT ) tskIDLE_PRIORITY );

		/* Remove any TCB's from the delayed queue. */
		while( !listLIST_IS_EMPTY( &xDelayedTaskList1 ) )
		{
			listGET_OWNER_OF_NEXT_ENTRY( pxTCB, &xDelayedTaskList1 );
			vListRemove( ( xListItem * ) &( pxTCB->xGenericListItem ) );

			prvDeleteTCB( ( tskTCB * ) pxTCB );
		}

		/* Remove any TCB's from the overflow delayed queue. */
		while( !listLIST_IS_EMPTY( &xDelayedTaskList2 ) )
		{
			listGET_OWNER_OF_NEXT_ENTRY( pxTCB, &xDelayedTaskList2 );
			vListRemove( ( xListItem * ) &( pxTCB->xGenericListItem ) );