Chaves

 
class Key {

		 boolean locked;

		 Queue waiting;

}

void lock(Key k) {

		 InterruptStatus is = saveInterruptStatus();
		 disableInterrupts();

		 if(k.locked) {

		 		 k.waiting.put(currentProcess);

		 		 currentProcess.state = WAITING;

		 		 transfer(currentProcess.coroutine, kernel);

		 }

		 k.locked = true;

		 is.restore();

}

void unlock(Key k) {

		 InterruptStatus is = saveInterruptStatus();
		 disableInterrupts();

		 if(k.waiting.empty()) {

		 		 k.locked = false;

		 } else {

		 		 Process p = k.waiting.get();

		 		 p.state = READY;

		 		 ready.put(p);

		 }

		 is.restore();

}