Synopsys, Inc.

Nec Laboratories America, Inc.

Sudipta Kundu

Malay K Ganai

Carl Preston Pixley

Alfred Koelbl

Per Mattias Bjesse

Naiyong Jin

Hanish Singla

Nishant Chauhan

Mitesh Jain

A method or system for clock gating verification of a circuit design. The system identifies a set of sequential components of the circuit design, and a set of nets of the circuit design. Each net is configured to provide a signal to a clock pin of a sequential component. The system then identifies a subset of nets that are associated with toggle signals, each of which transitions between two different signal values. For each of the subset of nets, the system determines one or more toggle cover properties. The system also determines a depth of at least one net in the subset of nets, and performs sign off for the clock gating verification based on the toggle cover properties and the depth of the at least one net.

Performing automatic sign-off for clock gating verification using toggle cover properties

A security verification system performs security verification of a circuit design. The security verification system simplifies formal security verification of the circuit design by replacing circuit blocks of the circuit with black box circuit blocks. The security verification system instruments the circuit design so that black-boxing can be performed for security verification without changing the security decision over the data paths. The security verification system uses dependence information of the inputs and outputs of the black box to connect inputs of the circuit block with outputs of the circuit block. The black-box circuit block keeps the logic inside the cone of influence of clocks and resets. The system performs security verification of the circuit design by proving a non-interference property of the instrumented circuit design.

Scalable formal security verification of circuit designs

A system and method for providing formal property verification across circuit design versions is described. In one embodiment, the system receives a first version and a second version of a circuit design. The received first version has a first set of constraints, a first set of next-state functions representing the first version of the circuit design, and a first property that has been verified as true for the first version of the circuit design. The received second version has a second set of constraints, a second set of next-state functions representing the second version of the circuit design, and a second property for the second version of the circuit design. The described embodiments further construct a composite circuit design based on the first set of constraints, the first set of next-state functions, and the first property and further based on the second set of constraints, the second set of next-state functions, and the second property. A third property is constructed for the composite circuit design in which the first property implies the second property. Some described embodiments output a proof or a counterexample for the second circuit design, based on the proof of the third property for the composite circuit design, since a user of the system and method is trying to verify the second circuit design, not the composite circuit design.

Accelerating formal property verification across design versions using sequential equivalence checking

Disclosed is a technology for parallelized design verification of two circuit designs at a register transfer level. A plurality of potential equivalent sub-circuit pairs is identified from the circuit designs to create a proof-tree structure. The proof-tree structure includes a root-proof, a plurality of parent-proofs downchain of said root-proof and a plurality of child-proofs downchain of at least one of the parent-proofs. Each one of the child-proofs is associated with a first equivalency status of one of the potential equivalent sub-circuit pairs. The parent-proofs are associated with second equivalency statuses dependent upon the first equivalency statuses of downchain child-proofs. The root-proof is associated with a third functional equivalency status of the two circuit designs dependent upon the second equivalency statuses of downchain parent-proofs. This Abstract is not intended to limit the scope of the claims.

Deep insight for debug using internal equivalence visualization and counter-example for sequential equivalence checking

A design is verified by using equivalence checking to compare a word-level description of the design to a bit-level description of the design. A word-level data flow graph (DFG) based on the word-level description and a bit-level DFG is obtained. Structural analysis is used to reduce the graphs and partition them into smaller portions for the equivalence checking. The analysis includes searching the bit-level DFG to find partial-product encoding and removing redundancy from the bit-level DFG. A reference model with architectural information from the bit-level DFG is created based on the word-level DFG. The reference model is reduced and equivalence checked against the bit-level DFG to determine if the word-level description is equivalent to the bit-level description.

Equivalence checking using structural analysis on data flow graphs

Methods and systems for generating verification conditions and verifying the correctness of a concurrent system of program threads are described. The methods and systems determine and employ mutually atomic transactions to reduce verification problem sizes and state space for concurrent systems. The embodiments provide both an adequate and an optimal set of token-passing constraints for a bounded unrolling of threads.

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Hillsboro, OR, United States of America

Sudipta Kundu