According to some embodiments, a resource is allocated in accordance with a masked request vector. For example, a masking unit may receive a request vector and provide a masked request vector, wherein each bit in the request vector represents a requestor and indicates if that requestor is requesting a resource. A first priority encoder may receive the masked request vector from the masking unit and output a signal indicating a selected requestor. According to some embodiments, a second priority encoder may receive the un-masked request vector and output a signal indicating an alternate selected requestor.