A data processing apparatus including a memory circuit and a data accessing circuit is provided, in which the memory circuit includes multiple cache ways configured to store data. In response to a first logic state of an enabling signal, if a tag of an address of an access requirement is the same as a corresponding tag of the multiple cache ways, the data accessing circuit determines that a cache hit occurs. In response to a second logic state of the enabling signal, if the address is within one or more predetermined address intervals specified by the data accessing circuit, the data accessing circuit determines that the cache hit occurs, and if the address is outside the one or more predetermined address intervals, the data accessing circuit determines that a cache miss occurs.