An Extensible Object-Oriented Mixed-Mode Functional Simulation System

A LISP-based functional simulation system supporting a general concept of function and abstraction is described. SIMMER was developed primarily to support research into the relation of structure to function and associated description languages, and also to provide assistance to the designer analyzing especially difficult circuits. It consists of a general object-oriented message-passing functional simulator; a user-extensible intermediate-level base language for describing complex systems; and a supporting integrated database (not described). We introduce the versional module, a generalized notion of state, and busses as active functional objects. Message-passing LISP objects are used to represent physical and abstract entities.