Functional vector generation for assertion-based verification at behavioral level using interval analysis

Abstract

The 2001 International Technology Roadmap for Semiconductors (ITRS) predicts that it is unlikely that verification will be manageable for designs envisioned beyond 2007 without design-for-verifiability. Some CAD vendors have promoted assertion-based verification (ABV) as one of the first commercial design-for-verification techniques. In order to handle complex design, this methodology has to be complemented with tools that automatically generate vectors or counterexamples that violate/verify proposed assertions or constraints. This paper presents an assertion checking technique for behavioral models that combines a non-linear solver and state exploration techniques and avoids expanding behavior into logic equations. The kernel of the technique is a modified interval analysis (MODIA) that avoids most of the problems of classical interval analysis (IA) and improves reuse during vector generation. The results show that the proposed technique is able to handle very efficiently data-dominated designs, which research and commercial assertion/property checkers are unable or need more CPU effort to verify.