/* ****************BLOCK.C********
  Jonathan W. Valvano   Feb 26, 1997
  Blocking semaphores ***needs to be modified to make it blocking**** */
void Wait(sema4Ptr semaphore){
     asm(" sei");  /* Test and set is atomic */
	 PORTC|=0x10;
     while((semaphore->value)<=0){ /* disabled */
         asm(" cli\n"              /* disabled */
		     " nop\n"              /* enabled  */
             " sei");}             /* enabled  */
     (semaphore->value)--;         /* disabled */
	 PORTC&=0xEF;
     asm(" cli");                  /* disabled */
}                                  /* enabled  */
void Signal(sema4Ptr semaphore){
     asm(" sei");  /* increment is atomic */
	 PORTC|=0x20;
     (semaphore->value)++;
	 PORTC&=0xDF;
     asm(" cli");
}