os_sem.c

lpc2368-keil环境下的ucos的移植例程

		default:
			OS_EXIT_CRITICAL();
			*err = OS_ERR_INVALID_OPT;
			return (pevent);
	}
}
#endif

/*$PAGE*/
/*
*********************************************************************************************************
*   										PEND ON SEMAPHORE
*
* Description: This function waits for a semaphore.
*
* Arguments  : pevent   	 is a pointer to the event control block associated with the desired
*   						 semaphore.
*
*   		   timeout  	 is an optional timeout period (in clock ticks).  If non-zero, your task will
*   						 wait for the resource up to the amount of time specified by this argument.
*   						 If you specify 0, however, your task will wait forever at the specified
*   						 semaphore or, until the resource becomes available (or the event occurs).
*
*   		   err  		 is a pointer to where an error message will be deposited.  Possible error
*   						 messages are:
*
*   						 OS_NO_ERR  		 The call was successful and your task owns the resource
*   											 or, the event you are waiting for occurred.
*   						 OS_TIMEOUT 		 The semaphore was not received within the specified
*   											 timeout.
*   						 OS_ERR_EVENT_TYPE   If you didn't pass a pointer to a semaphore.
*   						 OS_ERR_PEND_ISR	 If you called this function from an ISR and the result
*   											 would lead to a suspension.
*   						 OS_ERR_PEVENT_NULL  If 'pevent' is a NULL pointer.
*
* Returns    : none
*********************************************************************************************************
*/

void OSSemPend(OS_EVENT *pevent, INT16U timeout, INT8U *err)
{
#if OS_CRITICAL_METHOD == 3 						  /* Allocate storage for CPU status register      */
	OS_CPU_SR  cpu_sr;
#endif    


	if (OSIntNesting > 0)
	{
		/* See if called from ISR ...   				 */
		*err = OS_ERR_PEND_ISR; 					  /* ... can't PEND from an ISR                    */
		return;
	}
#if OS_ARG_CHK_EN > 0
	if (pevent == (OS_EVENT *) 0)
	{
		/* Validate 'pevent'							 */
		*err = OS_ERR_PEVENT_NULL;
		return;
	}
	if (pevent->OSEventType != OS_EVENT_TYPE_SEM)
	{
		/* Validate event block type					 */
		*err = OS_ERR_EVENT_TYPE;
		return;
	}
#endif
	OS_ENTER_CRITICAL();
	if (pevent->OSEventCnt > 0)
	{
		/* If sem. is positive, resource available ...   */
		pevent->OSEventCnt--;   					  /* ... decrement semaphore only if positive.     */
		OS_EXIT_CRITICAL();
		*err = OS_NO_ERR;
		return;
	}
	/* Otherwise, must wait until event occurs  	 */
	OSTCBCur->OSTCBStat |= OS_STAT_SEM; 			  /* Resource not available, pend on semaphore     */
	OSTCBCur->OSTCBDly = timeout;   				/* Store pend timeout in TCB					 */
	OS_EventTaskWait(pevent);   					  /* Suspend task until event or timeout occurs    */
	OS_EXIT_CRITICAL();
	OS_Sched(); 									  /* Find next highest priority task ready  	   */
	OS_ENTER_CRITICAL();
	if (OSTCBCur->OSTCBStat & OS_STAT_SEM)
	{
		/* Must have timed out if still waiting for event*/
		OS_EventTO(pevent);
		OS_EXIT_CRITICAL();
		*err = OS_TIMEOUT;  						  /* Indicate that didn't get event within TO      */
		return;
	}
	OSTCBCur->OSTCBEventPtr = (OS_EVENT *) 0;
	OS_EXIT_CRITICAL();
	*err = OS_NO_ERR;
}
/*$PAGE*/
/*
*********************************************************************************************************
*   									  POST TO A SEMAPHORE
*
* Description: This function signals a semaphore
*
* Arguments  : pevent   	 is a pointer to the event control block associated with the desired
*   						 semaphore.
*
* Returns    : OS_NO_ERR		   The call was successful and the semaphore was signaled.
*   		   OS_SEM_OVF   	   If the semaphore count exceeded its limit.  In other words, you have
*   							   signalled the semaphore more often than you waited on it with either
*   							   OSSemAccept() or OSSemPend().
*   		   OS_ERR_EVENT_TYPE   If you didn't pass a pointer to a semaphore
*   		   OS_ERR_PEVENT_NULL  If 'pevent' is a NULL pointer.
*********************************************************************************************************
*/

INT8U OSSemPost(OS_EVENT *pevent)
{
#if OS_CRITICAL_METHOD == 3 							   /* Allocate storage for CPU status register */
	OS_CPU_SR  cpu_sr;  							 
#endif    


#if OS_ARG_CHK_EN > 0
	if (pevent == (OS_EVENT *) 0)
	{
		/* Validate 'pevent'						*/
		return (OS_ERR_PEVENT_NULL);
	}
	if (pevent->OSEventType != OS_EVENT_TYPE_SEM)
	{
		/* Validate event block type				*/
		return (OS_ERR_EVENT_TYPE);
	}
#endif
	OS_ENTER_CRITICAL();
	if (pevent->OSEventGrp != 0x00)
	{
		/* See if any task waiting for semaphore	*/
		OS_EventTaskRdy(pevent, (void *) 0, OS_STAT_SEM);   /* Ready highest prio task waiting on event */
		OS_EXIT_CRITICAL();
		OS_Sched(); 									   /* Find highest priority task ready to run  */
		return (OS_NO_ERR);
	}
	if (pevent->OSEventCnt < 65535)
	{
		/* Make sure semaphore will not overflow		 */
		pevent->OSEventCnt++;   					  /* Increment semaphore count to register event   */
		OS_EXIT_CRITICAL();
		return (OS_NO_ERR);
	}
	OS_EXIT_CRITICAL(); 							  /* Semaphore value has reached its maximum	   */
	return (OS_SEM_OVF);
}
/*$PAGE*/
/*
*********************************************************************************************************
*   									   QUERY A SEMAPHORE
*
* Description: This function obtains information about a semaphore
*
* Arguments  : pevent   	 is a pointer to the event control block associated with the desired
*   						 semaphore
*
*   		   pdata		 is a pointer to a structure that will contain information about the
*   						 semaphore.
*
* Returns    : OS_NO_ERR		   The call was successful and the message was sent
*   		   OS_ERR_EVENT_TYPE   If you are attempting to obtain data from a non semaphore.
*   		   OS_ERR_PEVENT_NULL  If 'pevent' is a NULL pointer.
*********************************************************************************************************
*/

#if OS_SEM_QUERY_EN > 0
INT8U OSSemQuery(OS_EVENT *pevent, OS_SEM_DATA *pdata)
{
#if OS_CRITICAL_METHOD == 3 							   /* Allocate storage for CPU status register */
	OS_CPU_SR  cpu_sr;
#endif    
	INT8U     *psrc;
	INT8U     *pdest;


#if OS_ARG_CHK_EN > 0
	if (pevent == (OS_EVENT *) 0)
	{
		/* Validate 'pevent'						*/
		return (OS_ERR_PEVENT_NULL);
	}
	if (pevent->OSEventType != OS_EVENT_TYPE_SEM)
	{
		/* Validate event block type				*/
		return (OS_ERR_EVENT_TYPE);
	}
#endif
	OS_ENTER_CRITICAL();
	pdata->OSEventGrp = pevent->OSEventGrp; 			   /* Copy message mailbox wait list		   */
	psrc = &pevent->OSEventTbl[0];
	pdest = &pdata->OSEventTbl[0];
#if OS_EVENT_TBL_SIZE > 0
	*pdest++ = *psrc++;
#endif

#if OS_EVENT_TBL_SIZE > 1
	*pdest++ = *psrc++;
#endif

#if OS_EVENT_TBL_SIZE > 2
	*pdest++ = *psrc++;
#endif

#if OS_EVENT_TBL_SIZE > 3
	*pdest++ = *psrc++;
#endif

#if OS_EVENT_TBL_SIZE > 4
	*pdest++ = *psrc++;
#endif

#if OS_EVENT_TBL_SIZE > 5
	*pdest++ = *psrc++;
#endif

#if OS_EVENT_TBL_SIZE > 6
	*pdest++ = *psrc++;
#endif

#if OS_EVENT_TBL_SIZE > 7
	*pdest = *psrc;
#endif
	pdata->OSCnt = pevent->OSEventCnt;  			  /* Get semaphore count					  */
	OS_EXIT_CRITICAL();
	return (OS_NO_ERR);
}
#endif  												   /* OS_SEM_QUERY_EN   					   */
#endif  												   /* OS_SEM_EN 							   */