An object-based representation for the evolution of VLSI designs

Abstract The information involved in the development of VLSI designs is both vast and conceptually complex. This paper presents an object-based representation of the information needed to support design development processes. In this representation, attributes that are invariant under certain classes of design operations are identified and grouped into objects. The resulting structure allows different implementations to be simultaneously and compactly maintained; it also supports parameterized designs. A taxonomy of objects is established so that appropriate design techniques are inherited. To allow customized design environments, control knowledge is kept separate from both the domain knowledge and the description of the design. Historical information that may be used for redesign, learning, and explanation is also retained. Although we believe that the representation applies to design quite generally, the taxonomy and vocabulary of the examples are taken from the VLSI arena and implementation is discussed in the context of LISP and KEE™ frame-based software.