cxsemfsh.c

CMEX source code RTOS for atmel atmega128

/*********************************************************

Copyright (c) CMX Company. 1999. All rights reserved

*********************************************************/
/* version 5.30 */

#define CMXMODULE 1

#include <cxfuncs.h>	/* get cmx include header file */
#include <cxextern.h>	/* get cmx include header file */

#ifdef CMXTRACKER
#include <cmxtrack.h>	/* get cmx include header file */
#endif

/*
mode = 0 = do not flush if task owns semaphore
mode = 1 = do flush if task owns semaphore
also reset count to original value
*/
byte K_Semaphore_Reset(byte sem_num,byte mode)	
{
	SEM *sem_ptr;

	if (sem_num >= MAX_SEMAPHORES)
		{
		return(K_ERROR);	/* return good status to caller */
		}
	K_I_Disable_Sched();
	sem_ptr = &sem_array[sem_num];	/* CMX semaphore handler. */
	if (sem_ptr->fwlink == NULL)
		{
		K_I_Func_Return();	/* release task block */
		return(K_ERROR);	/* return good status to caller */
		}
	if (sem_ptr->fwlink != (tcbpointer)sem_ptr)	/* see if another task already "owns" this semaphore. */
		{
		if (!mode)
			{
			K_I_Func_Return();	/* release task block. */
			return(K_ERROR);
			}
		else
			{
			do {
				sem_ptr->fwlink->tcbstate = RESUME | TIME_EXPIRED;	/* allow task to run again */
				if (sem_ptr->fwlink->priority < active_priority)
					PREEMPTED;	/* yes, so set the preempted scheduling flag */
				if ((sem_ptr->fwlink = sem_ptr->fwlink->fwlink) == (tcbpointer)sem_ptr)
					sem_ptr->bwlink = (tcbpointer)sem_ptr;
				}
			while(sem_ptr->fwlink != (tcbpointer)sem_ptr);
			}
		}
	sem_ptr->sem_count = sem_ptr->sem_n;
	K_I_Func_Return();	/* release task block. */
	return(K_OK);
}