Development and evolution of hardware behaviors

A new system is proposed towards the computational frame-work of evolutionary hardware that adaptively changes its structure and behavior according to the environment. In the proposed system, hardware specifications, which produce hardware structures and behaviors, are automatically generated as Hardware Description Language (HDL) programs. Using a rewriting system, the system introduces a program development process, that imitates the natural development process from pollinated egg to adult and gives the HDL-program flexible evolvability. Also discussed is a method to evolve the language itself by modifying the corresponding rewriting system. This method is intended to serve as hierarchal mechanism of evolution and to contribute to the evolvability of large-scale hardware. Although this paper's discussion is mainly involves in HDL-programs because our goal is hardware evolution, the techniques described here are applicable to ordinary computer programs written in such conventional formats as “C” language.