How to build a hardware description and measurement system on an object-oriented programming language.

This paper describes new techniques for applying the mechanisms of in object-oriented programming languages to hardware description. Some object-oriented language mechanisms, like inheritance, directly simplify CAD programs; others, like data abstraction, allow us to create more powerful CAD mechanisms based on them. We describe: how to extend class inheritance and integrate it with procedural construction to simplify the description of hardware; how to create measurement methods that can measure a module whose components are described at different levels of abstraction; and how to implement a consistency maintenance engine that ensures the consistency of the data kept for the design. We have implemented these features in Fred, an object- oriented modeling system for VLSI modules. Fred is implemented in Flavors, an object-oriented extension of Lisp; we also discuss how to implement its features in other languages.