The new design method for compositional microprogram control units with code sharing is proposed. The method targets on reduction in the number of PAL macrocells in the combinational part of control unit. Some additional control microinstructions containing codes of the classes of pseudoequivalent chains are used for operational linear chains modification. Proposed method is illustrated by an example. Various graph-scheme of algorithm (GSA) research results are illustrated with the diagrams. Most desirable GSA characteristics for using proposed method were obtained. Key words: control unit, algorithm, transition, hardware amount, code sharing.
