A Formal Verification Methodology for Checking Data Integrity

Formal verification techniques have been playing an important role in pre-silicon validation processes. One of the most important points considered in performing formal verification is to define good verification scopes; we should define clearly what to be verified formally upon designs under test. We considered the following three practical requirements when we defined the scope of formal verification. It should be: (a) hard to verify; (b) small to handle; and (c) easy to understand. Our novel approach is to break down generic properties for the system into stereotype properties in block level and to define requirements for Verifiable RTL. Consequently, each designer instead of verification experts can describe properties of the design easily, and formal model checking can be applied systematically and thoroughly to all the leaf modules. During the development of a component chip for server platforms, we focused on RAS (reliability availability and serviceability) features and described more than 2000 properties in PSL. As a result of the formal verification, we found several critical logic bugs in a short time with limited resources, and successfully verified all of them. This paper presents a study of the functional verification methodology.