High-level functional (or behavioral) simulation models are difficult, time-consuming, and expensive to develop. We report on a method for automatically generating the program code for a high-level functional simulation model. The high-level model is produced directly from the program code for the circuit components' functional models and a netlist description of their connectivity. A prototype has been implemented in LISP for the SIMMER functional simulator.

CONSTELLATION, a general LISP-based tool for structure recognition and manipulation, is described. CONSTELLATION is a design refinement tool for the later stages of the design process, when a complete (or nearly so) design is available. It is intended to recognize local sub-structures in the design and carry out specific associated manipulations. The recognition phase is driven by a design precedent. This is a pattern which an experienced designer points out in an existing design, together with an associated action to perform. The action is normally stated in the system's native Y hardware description language, though we also support the use of LISP or mixtures. CONSTELLATION has also been interfaced to a general abstract functional simulator (SIMMER[11]). It is in experimental use in a production environment where we are exploring its applications to rationalizing existing flat designs, interactive structure editing performance enhancements, identifying candidates for new cell-generators, and in-circuit functional simulation.

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.