Nec Corporation

Nec Usa, Inc.

Subhrajit Bhattacharya

Anand Raghunathan

Pranav N Ashar

Aarti Gupta

Sujit Dey

Akira Mukaiyama

A method of checking correctness of scheduling of a circuit where a schedule for the circuit is obtained from a behavioral description. The method comprising extracting loop invariants to determine a sufficient set of acyclic threads when loops are present, performing symbolic simulation to extract the above loop invariants, and proving equivalence of the acyclic threads. Systems, computer systems and computer program products that incorporate the techniques of verification and correctness checking according to the present invention have also been disclosed.

Verification of scheduling in the presence of loops using uninterpreted symbolic simulation

A complete procedure for verifying register-transfer logic against its scheduled behavior in a high-level synthesis environment is provided. A new method that is both complete and practical for verification is provided. Hardware verification is known to be a hard problem and the proposed verification technique leverages off the fact that high-level synthesis--performed manually or by means of high-level synthesis software--proceeds from the algorithmic description of the design to structural RTL through a sequence of very well defined steps, each limited in its scope. Equivalence checking task is partitioned into two simpler subtasks, verifying the validity of register sharing, and verifying correct synthesis of the RYL interconnect and control. While state space traversal is unavoidable for verifying validity of the register sharing, irrelevant portions of the design are automatically abstracted out, significantly simplifying the task that must be performed by a back-end model checker.

Method for verification of RTL generated from scheduled behavior in a

An alternative method for testing circuits (H-SCAN) which retains the main advantage of full scan testing, namely, the ability to use combinational automatic test pattern generation (ATPG), while eliminating the high area overhead the long test application time associated with full, scan test methods. The method provides a practical test methodology that can be easily applied to any RT-level specification. The method uses existing connections of registers and other structures available in a high-level specification of a circuit without necessitating the use of scan flip-flops. Test application time is reduced by using the parallelism inherent in the circuit design to load multiple flip-flops in a single clock cycle, without having to add parallel scan chains as done in traditional parallel scan approaches.

Growing community of inventors

Plainsboro, NJ, United States of America

Subhrajit Bhattacharya