We consider a fully SAT-based method of unbounded symbolic model checking based on computing Craig interpolants. In benchmark studies using a set of large industrial circuit verification instances, this method is greatly more efficient than BDD-based symbolic model checking, and compares favorably to some recent SAT-based model checking methods on positive instances.

Interpolation and SAT-based model checking

In recent years, formal methods have emerged as an alternative approach to ensuring the quality and correctness of hardware designs, overcoming some of the limitations of traditional validation techniques such as simulation and testing.There are two main aspects to the application of formal methods in a design process: the formal framework used to specify desired properties of a design and the verification techniques and tools used to reason about the relationship between a specification and a corresponding implementation. We survey a variety of frameworks and techniques proposed in the literature and applied to actual designs. The specification frameworks we describe include temporal logics, predicate logic, abstraction and refinement, as well as containment between o-regular languages. The verification techniques presented include model checking, automata-theoretic techniques, automated theorem proving, and approaches that integrate the above methods.In order to provide insight into the scope and limitations of currently available techniques, we present a selection of case studies where formal methods were applied to industrial-scale designs, such as microprocessors, floating-point hardware, protocols, memory subsystems, and communications hardware.

Formal verification in hardware design: a survey

A Qualitative Physics Based on Confluences

From the Publisher:
This book provides an introduction to the foundations of this interdisciplinary research area, emphasizing its applications in computer aided circuit design

Algorithms and data structures in VLSI design

RuleBase is a formal verification tool, developed by the IBM Haifa Research Laboratory. It is the result of three years of experience in practical formal verification of hardware which, we believe, has been a key factor in bringing the tool to its current level of maturity. We present the tool, including several unique features, and summarize our usage experience.

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RuleBase: an industry-oriented formal verification tool

We propose a methodology to formally prove protocol compliance for communication blocks in System-on-Chip (SoC) designs. In this methodology, a set of operational properties is specified with respect to the states of a central finite state machine (FSM). This central FSM is called main FSM and controls the overall behavior of the design. In order to prove a set of compliance properties, we developed an approach that combines property checking on a bounded circuit model with an approximate reachability analysis. The property checker determines whether a property is valid for an arbitrary state of the design regardless of its reachability. In order to avoid false negatives, reachability constraints are added to the property, which are generated by an approximate FSM traversal algorithm. We show how the existence of a main FSM can be exploited systematically in the reachability analysis and how to partition both the transition relation and the state space such that the computational complexity is reduced drastically. This makes formal verification of protocol compliance tractable even for large designs with several thousand state variables. Our approach has been applied successfully to verify several industrial designs.

Unbounded Protocol Compliance Verification Using Interval Property Checking With Invariants

This paper describes an innovative and powerful methodology for the complete formal verification of modules and intellectual property (IP), and its application to the verification of processor IP. Unlike other formal approaches, the methodology is a self-contained approach to hardware verification, independent of simulation. The methodology eliminates all gaps in the verification plan and in the property set. It thus ensures that the IP is free of functional errors − the highest possible verification quality. Its underlying technology has been field-proven on hundreds of modules and IP, two of which are described, including the TriCore2 processor, Infineon's next generation high-end processor for embedded and safety-critical applications.

Complete Formal Verification of TriCore2 and Other Processors

This paper describes how model checking has been integrated into an industrial hardware design process. We present an application oriented specification language for assumption/commitment style properties and an abstraction algorithm that generates an intuitive and efficient representation of synchronous circuits. These approaches are embedded in our Circuit Verification Environment CVE. They are demonstrated on two industrial applications.

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Model Checking in Industrial Hardware Design

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A New Formal Verification Approach for Hardware-dependent Embedded System Software

A method is specified for determining the quality of a quantity of properties describing a machine, including a step for determining the existence of at least one sub-quantity of interrelated properties (P0, P1, . . . Pn) of the form Pi=(forall t. Ai(t)=>Zi(t)), wherein Ai(t) present an initial state and Zi(t) a target state for a corresponding property and at least one initial state Ai is dependant on internal signals and including a step for checking whether at least one aspect of the input/output behaviour of the machine described by the properties, which cannot be derived from an individual property Pi, is described to such an accurate extent that one property Q exists, which represents this aspect without being dependant on the internal signals. The procedure is capable of providing a measurement and can particularly be used in the verification and specification of circuits.

Jörg Bormann

Papers

Unbounded Protocol Compliance Verification Using Interval Property Checking With Invariants

Complete Formal Verification of TriCore2 and Other Processors

Model Checking in Industrial Hardware Design

A New Formal Verification Approach for Hardware-dependent Embedded System Software

Method for the determination of the quality of a set of properties, usable for the verification and specification of circuits