Temporal Coverage Analysis for Dynamic Verification

Abstract

Dynamic verification is widely used to ensure the logical correctness of system design. Verification progress is usually gauged by coverage metrics. Most coverage metrics measure the sub-structures of design under verification that are exercised. More importantly, the probability of a bug being detected is approximated by probabilistic coverage analysis. However, existing analysis methods do not consider the temporal nature of digital systems, i.e., it only applies to combinational circuit but not sequential circuit. In this brief, we propose a probabilistic analysis framework which takes into account the temporal behavior of system design. We propose an effective analysis algorithm which can estimate the probability of a bug being detected for sequential circuit. Experimental results on 17489 random instances show that our method is both efficient and accurate. The analysis has time complexity quadratic to the number of coverage bins and linear to the number of simulation cycles. The analysis result has an average relative error of about 7.38%. In practice, our analysis result can be used to measure the completeness of verification.