Patent ID: 6915413

Claim:
A micro-controller having a program memory for storing a program, the program memory including a dictionary memory for storing instruction codes which appear in the program, and a compressed code memory for storing compressed codes each converted from each of the instruction codes included in the program, each said compressed code having a word length sufficiently long to identify all instruction codes included in the program, each said compressed code having a value indicative of an address in said dictionary memory at which an associated instruction code is stored, the micro-controller comprising: first reading means, responsive to an instruction code read request which specifies an address of a compressed code, to read the compressed code stored in the specified address in said compressed code memory, and to subsequently read an instruction code stored in an address indicated by the compressed code in said dictionary memory; second reading means, responsive to an instruction code read request which specifies an address of a compressed code, to read data stored at the specified address in either said dictionary memory or said compressed code memory; and selecting means for selectively forcing either said first reading means or said second reading means to function.