Synthesis of compositional microprogram control units with code sharing

Abstract

The chapter is devoted to the design methods based on the so-called code sharing compositional microprogram control unit (CMCU)!with code sharing, in which the microinstruction address is represented by concatenation of the OLC code and the code of its component. This representation makes possible using special methods of Moore FSM optimization adapted to the peculiarities of CMCU. In this case, the OLC codes are viewed as analogs of the states codes of Moore FSM. This approach permits to reduce the number of inputs and outputs of the combinational part of CMCU. Additional decrease can be achieved due to the application of elementary OLCs having only one input. In this case, the address of first component of each OLC is represented by all zeros and permits to diminish the number of functions generated by FSM.