A main CPU and a sub CPU take share of executing a tone generating process to generate multiple tone signals on a real-time basis without using an exclusive tone generator. The main CPU and sub CPU are formed on a one-chip LSI, thus facilitating realization of a compact electronic musical instrument....http://www.google.com/patents/US5584034?utm_source=gb-gplus-sharePatent US5584034 - Apparatus for executing respective portions of a process by main and sub CPUS
