zgetinheritedpriority.c

zilog的实时操作系统RZK,可以移植到多种处理器上

/*
* File				:	ZGetInheritedPriority.c
*
* Description		:	This file defines GetInheritedPriority 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* This file contains unpublished confidential and proprietary information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 "ZSemaphore.h"

#define pThread ((RZK_TCB_t*)hThread)
#define pBlockingThread ((RZK_TCB_t*)hBlockingThread)

/* Function			:	GetInheritedPriority
*
* Description		:	This function finds the highest priority thread recursively
*						among the threads blocked on semaphores acquired by a particular thread
*						and assigns it to the inherited prioirty of the thread.
* 
* Inputs			:	hThread - pointer to the thread whose priority 
*								  has to be updated.
*						hBlockingThread - pointer to the thread which is blocking on the
*									the  object owned by hThread
*
* Outputs			:	None.
*							
*
* Dependencies		:	None.
*/
void GetInheritedPriority(RZK_HANDLE_t hThread,RZK_HANDLE_t hBlockingThread)
{
	RZK_SEMAPHORE_t *pTempObject;

	/* Assign max priority to cInheritedPriority */
	pThread->cInheritedPriority = DMAX_PRIORITY;
	if(pThread->pOwnedResNext == NULL)
		return;
	else
	{
		pTempObject = ( RZK_SEMAPHORE_t * ) pThread->pOwnedResNext;
		while(pTempObject != NULL)
		{
			/* Check whther any threads are there in object's queue and thread's priority 
			is less than inherited priority */
			if((pTempObject->pResNext != NULL) && (pTempObject->pResNext != pBlockingThread) && 
			(pTempObject->pResNext->cDispPriority < pThread->cInheritedPriority))
			{
				pThread->cInheritedPriority = pTempObject->pResNext-> cDispPriority;
			}
			pTempObject = pTempObject-> pOwnedResNext;
			
		}
	}

}/* end of GetInheritedPriority */