Intel Corporation

John Moondanos

Ziyad Hanna

Zurab Khasidashvili

Daher Kaiss

Carl Seger

An approach for cut-point frontier selection and/or counter-example generation. Both a lazy and an eager cut-point frontier are identified. A reconvergence (or non-reconvergence) ratio is then computed for each of the frontiers and the one with the smaller (larger) reconvergence (non-reconvergence) ratio is selected as the next cut-point frontier. For another aspect, to generate a counter-example, in response to identifying a difference in output signals for a given cut-point frontier, values of eigenvariables and reconverging primary inputs are used to compute the corresponding values of the non-reconverging primary inputs. These corresponding values are then computed to be compatible with the internal signal values implied by the cut-point frontier selections that were made to expose the difference in the outputs.

Method and apparatus for cut-point frontier selection and for counter-example generation in formal equivalence verification

A method for facilitating the sequential verification of loop-free circuits by reducing the sequential verification problem to combinational verification, by constructing and comparing Timed Binary Decision. Diagrams (TBDDs) and Timed Binary Expression Diagrams (TBEDs). The TBEDs can be compared by using both BDDs and SAT solvers.

Application of the retimed normal form to the formal equivalence verification of abstract RTL descriptions for pipelined designs

The present invention provides a method and system for comparing a pair of circuit models without the need for performing a false negative check when cut-points are introduced. An exemplary method includes generating a BDD for each of a plurality of signals of each circuit model from an initial cut-point frontier towards an output of each circuit model until a BDD of one of the plurality of signals reaches a predetermined maximum size, selecting a new cut-point signal frontier, and generating a normalized function for each cut-point signal on the new cut-point frontier of each circuit model.

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John Moondanos