Specification-based compaction of directed tests for functional validation of pipelined processors

Abstract

Functional validation is a major bottleneck in microprocessor design methodology. Simulation is the widely used method for functional validation using billions of random and biased-random test programs. Although directed tests require a smaller test set compared to random tests to achieve the same functional coverage goal, there is a lack of automated techniques for directed test generation. Furthermore, the number of directed tests can still be prohibitively large. This paper presents a methodology for specification-based coverage analysis and test generation. The primary contribution of this paper is a compaction technique that can drastically reduce the required number of directed test programs to achieve a coverage goal. Our experimental results using a MIPS processor and an industrial processor (e500) demonstrate more than 90% reduction in number of directed tests without sacrificing the functional coverage goal.

Test compaction techniques for assertion-based test generation

“…One proposed approach is to compact directed tests from properties for validating a pipeline processor. This is achieved by analyzing the finite state machine model of the processor by identifying and removing redundant and unreachable states along with illegal transitions in order to minimize the overall state space of the model [Koo and Mishra 2008].…”

Functional Test Compaction

“…In contrast to these test compaction approaches, a property compaction technique needs to be applied before test generation. Therefore, a test generator only needs to generate a reduced set of tests without sacrificing the coverage requirement [17]. This approach can reduce the generation cost as well as the overall validation effort.…”

Functional Test Generation Using Efficient Property Clustering and Learning Techniques

“…Due to the overlap between different fault models, some of the generated properties may lead to redundant tests. Therefore, property compaction can be employed to reduce the number of properties without affecting coverage goals [21].…”