Earticle

In order to reduce hardware amount in a control unit, the CMCU (compositional microprogram control unit) that makes use of a property of operational linear chain by adopting counter into next-state logic, and DIA (dedicated input area) that splits control memory into two parts having different microinstruction formats are reviewed, and then the concept of TMI field of a DIA is extended to e-DIA in order to supplement the operation of a DIA. The occurrence of idle cycles is removed and microoperation missing or duplication in some cases is protected by applying the e-DIA to CMCU. CMCU with e-DIA is implemented using VHDL, and the improvements are validated through simulation.