Mentor Graphics Corporation

Samsung Electronics Co., Ltd.

Xiaoxin Fan

Wu-Tung Cheng

Robert Brady Benware

Huaxing Tang

Yu Jane Huang

Shashank Nemawarkar

Manish Sharma

James David Dundas

Madhu Saravana Sibi Govindan

According to one general aspect, an apparatus may include a main-branch target buffer (BTB). The apparatus may include a micro-BTB separate from and smaller than the main-BTB, and configured to produce prediction information associated with a branching instruction. The apparatus may include a micro-BTB confidence counter configured to measure a correctness of the prediction information produced by the micro-BTB. The apparatus may further include a micro-BTB misprediction rate counter configured to measure a rate of mispredictions produced by the micro-BTB. The apparatus may also include a micro-BTB enablement circuit configured to enable a usage of the micro-BTB's prediction information, based, at least in part, upon the values of the micro-BTB confidence counter and the micro-BTB misprediction rate counter.

Method and apparatus to control the use of hierarchical branch predictors based on the effectiveness of their results

Aspects of the invention relate to techniques for fault diagnosis based on dynamic circuit design partitioning. According to various implementations of the invention, a sub-circuit is extracted from a circuit design based on failure information of one or more integrated circuit devices. The extraction process may comprise combining fan-in cones of failing observation points included in the failure information. The extraction process may further comprise adding fan-in cones of one or more passing observation points to the combined fan-in cones of the failing observation points. Clock information of test patterns and/or layout information of the circuit design may be extracted and used in the sub-circuit extraction process. The extracted sub-circuit may then be used for diagnosing the one or more integrated circuit devices.

Dynamic design partitioning for diagnosis

Aspects of the invention relate to techniques for chain fault diagnosis based on dynamic circuit design partitioning. Fan-out cones for scan cells of one or more faulty scan chains of a circuit design are determined and combined to derive a forward-tracing cone. Fan-in cones for scan cells of the one or more faulty scan chains and for failing observation points of the circuit design are determined and combined to derive a backward-tracing cone. By determining intersection of the forward-tracing cone and the backward-tracing cone, a chain diagnosis sub-circuit for the test failure file is generated. Using the process, a plurality of chain diagnosis sub-circuits may be generated for a plurality of test failure files. Scan chain fault diagnosis may then be performed on the plurality of chain diagnosis sub-circuits with a plurality of computers.

Dynamic design partitioning for scan chain diagnosis

Aspects of the invention relate to techniques for fault diagnosis based on circuit design partitioning. According to various implementations of the invention, a circuit design of a failing die is first partitioned into a plurality of sub-circuits. The sub-circuits may be formed based on fan-in cones of observation points. Shared gate ratios may be used as a metric for adding fan-in cones of observation points into a sub-circuit. Based on test patterns and the sub-circuits, sub-circuit test patterns are determined. Fault diagnosis is then performed on the sub-circuits. The sub-circuit fault diagnosis comprises extracting sub-circuit failure information from the failure information for the failing die. The sub-circuit fault diagnosis may employ fault-free values for boundary gates in the sub-circuits.

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Austin, TX, United States of America

Xiaoxin Fan