Code memory compression with online decompression

This paper presents a new architecture for the compression of application programs stored in embedded ROM memories. Several methods based on dictionaries have been studied and compared, but the proposed architecture satisfies several hard constraints, such as instruction by instruction decompression at run time, a single physical memory to avoid wasted silicon area due to interconnection, the possibility to modify the program with the same compressed physical memory and no address translation table. Compression factors are depending on the application programs, but are between 10 to 30% including the cost of dictionaries.