From VHDL to efficient and first-time-right designs

Abstract

In this article we provide a practical transformational approach to the synthesis of correct synchronous digital hardware designs from high-level specifications. We do this while taking into account the complete life cycle of a design from early prototype to full custom implementation. Besides time-to-market, both flexibility with respect to target architecture and efficiency issues are addressed by the methodology. The utilization of user-selected behaviorpreserving transformation steps ensures first-time-right designs while exploiting the experience, flexibility, and creativity of the designer.To ensure that design transformations are indeed behavior-preserving a novel mechanized approach to the specification and verification of design transformations on control data flow graphs which is independent of a specific behavioral model or graph size has been developed.As a demonstration of an industrial application we use a video processing algorithm needed for the conversion from a line-interlaced to progressively scanned video format. Both a video signal processor-based prototype implementation as well as a very efficient full custom implementation are developed starting from a single high-level behavioral specification of the algorithm in VHDL. Results are compared with those previously obtained using different tools and methodologies.

On the fundamental limitations of transformational design

“…Starting from an initial specification in some hardware description language, programming language or specification language, an implementation (often described in the same language) is derived by repeatedly applying so-called correctness-preserving transformations. Transformations to apply are either selected manually [Bolognesi 1992;Voeten et al 1996;Middelhoek 1997;Huijs 1996;Middelhoek and Rajan 1996] or automatically as in the case of high-level synthesis [Chaiyakul et al • Jeroen P. M. Voeten 1993; Janssen et al 1994;Campasano 1989]. 1 Each transformation can modify certain aspects of a design (such as implementation cost, size and performance) but preserves other aspects (such as functionality).…”