Precedent-Based Manipulation of VLSI Structures

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 rationaling existing flat designs, interactive structure editing performance enhancements, identifying candidates for new cell-generators, and in-circuit functional simulation.