zrestorepriorityrecursive.c

zilog的实时操作系统RZK,可以移植到多种处理器上

/*
* File				:	ZRestorePriorityRecursive.c
*
* Description		:	This file contains definition of RestorePriorityRecursive routine.
*
* Copyright 2004 ZiLOG Inc.  ALL RIGHTS RESERVED.
*
* This file contains unpublished confidential and proprietary information
* of ZiLOG, Inc.
* NO PART OF THIS WORK MAY BE DUPLICATED, STORED, PUBLISHED OR DISCLOSED 
* IN ANY FORM WITHOUT THE PRIOR WRITTEN CONSENT OF ZiLOG, INC.
* This is not a license and no use of any kind of this work is authorized
* in the absence of a written license granted by ZiLOG, Inc. in ZiLOG's 
* sole discretion 
*/
#include "ZSysgen.h"
#include "ZTypes.h"
#include "ZThread.h"  
#include "ZQueue.h"
#include "ZSemaphore.h"
#include "ZInterrupt.h"

#define pThread ((RZK_TCB_t*)hThread)

extern RZK_DISPATCHQ_t  DispatchQueue[DMAX_PRIORITY_P1];
extern const UINT32 pMap[32];
extern volatile UINT32 DQPriorityBitMap;

/** extern functions */
extern void RemoveFromResourceQueue(RZK_HANDLE_t hControlBlock, RZK_THREADHANDLE_t hThreadToRemove);
extern void AppendToResourceQueue(RZK_HANDLE_t hObject,RZK_THREADHANDLE_t hThread);
extern void UpdatePriorityRecursive( RZK_HANDLE_t hThread  );
extern void QueueNodeRemove(RZK_TCB_t *pObjectToRemove );
extern void QueueAppend(RZK_TCB_t *pInsertionPosition ,RZK_TCB_t *pObjectToAppend);
extern void GetInheritedPriority(RZK_HANDLE_t hThread,RZK_HANDLE_t hBlockingThread);

/* Function			:	RestorePriorityRecursive
*
* Description		:	This function restores the priority of the threads recursively
*						due to priority inheritance
* 
* Inputs			:	hThread - pointer to the thread whose priority 
*								  has to be updated.
*
* Outputs			:	Void.
*							
*
* Dependencies		:	None.
*/
void RestorePriorityRecursive(RZK_HANDLE_t hThread)
{
	/*LOCAL VARIABLES*/
	RZK_THREAD_PRIORITY_t uTempPrio, uNewPrio;

	/* Gets inherited priority of the thread */
	GetInheritedPriority(pThread,NULL);
	uTempPrio = pThread->cDispPriority;

	/* Check whether inherited priority is greater than original priority.
	If so assign original priority else assign inherited priority to newprio */
	uNewPrio =(pThread->cInheritedPriority > pThread->uOriginalPriority)? pThread-> uOriginalPriority : pThread->cInheritedPriority;

	if(uTempPrio != uNewPrio)
	{
		pThread->cDispPriority = uNewPrio;
	
		if(pThread->uBlockingReason & (BLOCK_PENDMESSAGEQUEUE | BLOCK_PENDMAILBOX | BLOCK_ACQUIRESEMAPHORE | BLOCK_REGIONWAIT))
		{
			RemoveFromResourceQueue(pThread-> pBlockingResource,pThread);
			AppendToResourceQueue(pThread-> pBlockingResource,pThread);
			if(((RZK_SEMAPHORE_t*)pThread-> pBlockingResource)->uState & OBJECT_PRIORITY_INHERITANCE)
				UpdatePriorityRecursive(pThread);
		}
	
		/* Change the position in the dispatch queue and dqbitmap */	
		if(pThread->uState & THREAD_RUNNING)
		{
			UINTRMASK mInterruptMask;

			mInterruptMask = RZKDisableInterrupts();

			QueueNodeRemove( ( RZK_TCB_t * ) hThread);

			/* Update DQPriorityBitmap if dispatch queue is altered */
			if(DispatchQueue[uTempPrio].pPrevious == (RZK_TCB_t *) &DispatchQueue[uTempPrio])
				DQPriorityBitMap &= (~pMap[uTempPrio]);

			QueueAppend(DispatchQueue[uNewPrio].pPrevious,pThread);
		       DQPriorityBitMap |= pMap[uNewPrio];

			RZKEnableInterrupts(mInterruptMask);						   
		}
	}
}/* end of restorepriorityrecursive*/