Program read only memory for data processing device, supplies first address data or second address data to program datum memory unit when control signal is not available or available respectively

摘要

An address processing unit (24) applies a computational process on a portion of first address data based on a computational code in order to generate second address data. The second address data are supplied to a program datum memory unit (22) when a control signal is available. The first address data are supplied to the program datum memory when the control signal is not available. Independent claims are also included for the following: (a) a program distinction system; (b) an address selection method; (c) a program distinction method.