: The expressive power of higher order logic makes it possible to define a wide variety of data types within the logic and to prove theorems that state the properties of these types concisely and abstractly. This paper describes how such defined data types can be used to support formal reasoning in higher order logic about the behaviour of hardware designs. First printed: May 1988 Reprinted with revisions: April 1990 An earlier version of this paper appears in: The Fusion of Hardware Design and Verification, ed. G.J. Milne (North-Holland, 1988), pp. 27--50. Contents Introduction 5 1 Hardware Verification using Higher Order Logic 5 1.1 Notation : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : 5 1.2 Specifying Hardware Behaviour : : : : : : : : : : : : : : : : : : 6 1.3 Specifying Hardware Structure : : : : : : : : : : : : : : : : : : 7 1.4 Formulating Correctness : : : : : : : : : : : : : : : : : : : : : : 8 2 Recursive Types in Higher Order Logic 8 2.1 Type Definit...

. In this paper a methodology for verifying RISC cores is presented. This methodology is based on a hierarchical model of interpreters. This model allows us to define formal specifications at each level of abstraction and successively prove the correctness between the neighbouring abstraction levels, so that the overall specification is correct with respect to its hardware implementation. The correctness proofs have been split into two steps so that the parallelism in the execution due to the pipelining of instructions, is accounted for. The first step shows that the instructions are correctly processed by the pipeline and the second step shows that the semantic of each instruction is correct. We have implemented the specification of the entire model and performed parts of the proofs in HOL. 1 Introduction Completely automating the verification of general complex systems is practically impossible. Hence appropriate heuristics for specific classes of circuits such as finite state machi...