/*
-SPIN.C
-Spinlock semaphores
*/

/******************spin.c stuff*********************************/
void Wait(int *semaphore)
{
	asm(" sei");  /* Test and set is atomic */
	
	while((*semaphore)<=0)	/* disabled */
	{      
         asm(" cli\n"		/* disabled */
		     " nop\n"		/* enabled  */
             " sei");		/* enabled  */
	}           
     
	(*semaphore)--;			/* disabled */
    asm(" cli");			/* disabled */
}							/* enabled  */


//NB: for below signal function, disabling interrupts is not
//    necessary because (*semaphore)++ is an atomic operation
//    i just disabled interrupts because one might one to debug
//    using LEDs or other means when signal is called.
void Signal(int *semaphore)
{
	asm(" sei");  /* increment is atomic */
	(*semaphore)++;
	asm(" cli");
}
/**************************************************************/