CPA (conditions, precedence relations and assertions), a framework for specifying the behavior of control-oriented digital systems, is described. CPA allows the expression of sequential behavior, data transformations and timing constraints in an integrated representation. It supports the abstract, declarative specification of behavior independent of any particular implementation. Thus it is especially useful for verifying a design against a set of externally-defined requirements.>

A novel method for using bottom-up design information in the synthesis of integrated circuits from abstract behavioral description is reported. There are two important ways in which this method differs from traditional top-down synthesis techniques. First, it draws on a newly developed procedural database to collect detailed information on the physical and logical properties of the primitives available for building the design. Second, it partitions each design it considers into clusters that have physical as well as logical significance. This method for representing and organizing knowledge about candidate designs makes it possible to estimate physical placement and wiring, even at the abstract register-transfer (RT) level. This allows a more accurate evaluation of RT designs without doing a full logic-level or transistor-level layout. Partitioning also leads to a simple method for systematically exploring the space of possible designs to find the one that best meets the designer's objectives and constraints.>

The Design Automation Assistant is a knowledge-based expert-system, KBES, that generates a technology-independent list of operators, registers, data paths and control signals from an algorithmic description of a VLSI system. One merit of codifying knowledge in a KBES is that it can be easily quantified and qualified. This paper takes a retrospective on that codified knowledge base, examining what has been learned about VLSI design. It discusses both the major steps in the implementation design process and the extent to which each rule embodies domain knowledge. Finally, the paper provides an example design with typical rules from each of the major steps in the implementation design process.