Methods of interpretation of control algorithms

Abstract

AbstractThe chapter introduces such basic topics, as principles of microprogram control and specification of the control unit behavior using the graph-scheme of algorithm. Next, some methods of control algorithm interpretation, such as finite-state machines (FSM) and microprogram control units (MCU), are discussed. Last part of the chapter is devoted to the organization principles of compositional microprogram control units, which can be viewed as compositions of finite-state machine and microprogram control unit. These control units provide efficient interpretation of the so-called linear GSA , in which long sequences of operator vertices can be found. These sequences are called operational linear chains (OLC). Microinstructions corresponding to the components of OLC are addressed using the principle of natural microinstruction addressing. It permits to use the counter to keep microinstruction addresses and to simplify the combinational part of control unit, as compared with the classical Moore FSM. The Mealy FSM is used in CMCU to address microinstructions. It permits to calculate the transition address during one cycle of control unit’s operation. Due to this feature, performance of the CMCU (proportional to the number of cycles needed to execute the control algorithm) is better than performance of the equivalent MCU with natural microinstruction addressing.KeywordsControl AlgorithmOperator VertexLogical ConditionLogic CircuitStructure TableThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.