Experiments with an efficient heuristic algorithm for local microcode generation

A local microcode generation method for a control-unit synthesis is presented. The register-transfer behavior of a data path is specified by a dTOL system (an L-system-type parallel formal language), and local microcode generation is formulated as a parsing problem of the corresponding DTOL language. The authors propose an efficient, goal-oriented, search algorithm to parse a behavioral specification, and discuss several heuristics for improving the performance of the method. Five data paths, designed by well-known synthesis tools, were used to study the performance of the method. The results of the study and some problems arising in a few of the designs are discussed