Synopsys, Inc.

Cadence Design Systems, Inc.

Tela Innovations, Inc.

Cho Moon

Subramanyam Sripada

Harish Kriplani

Sonia Singhal

Krishna Prasad Belkhale

Puneet Gupta

Andrew B Kahng

Nahmsuk Oh

Loa Mize

Paul J Donehue

Bon Woong Ku

A method of performing an optimization within a circuit layout design is provided. The method includes determining, from multiple nets of the circuit layout design, a target net that has one or more performance characteristics that are outside a range of constraints, determining, from the multiple nets, a non-critical net that has the one or more performance characteristics that are within the range of the constraints, and adjusting, by a processor, one or more of a shape and a location of one or more of the non-critical net and the target net, such that the one or more performance characteristics of the non-critical net is changed and remains within the range of the constraints.

Timing-aware surgical optimization for engineering change order in chip design

Modes of a circuit are merged together to reduce the number of modes. Subsets of modes are identified such that modes belonging to each subset are mergeable. A set of modes is mergeable if every pair of modes in the set is mergeable. Constraints of modes belonging to each pair of modes are compared to determine whether two modes are mergeable. To allow two modes to be merged, a constraint is transformed such that it affects the same paths in the merged mode and the first mode but excludes paths from the second mode. Determining whether two modes are mergeable may include verifying whether a clock in one mode blocks propagation of a clock in another mode and whether a value specified in a constraint in a mode is within specified tolerance of the value of a corresponding constraint in another mode.

Automatic reduction of modes of electronic circuits for timing analysis

Individual mode timing constraints associated with a set of netlists are combined into merged mode timing constraints. An initial merged mode constraint is generated by combining timing constraints from individual modes. The initial merged mode includes the union of all timing constraints from individual modes that add timing relationships and the intersection of all timing constraints from the individual modes that remove timing relationships. Extraneous timing relationships are identified in the merged mode and eliminated by introducing timing constraints in the merged mode. Equivalence between the merged mode and the individual modes is verified by comparing timing relationships in the merged mode with timing relationships in the individual modes. The merged mode is considered equivalent to the individual modes if every timing relationship present in an individual mode is present in the merged mode and every timing relationship present in the merged mode is present in any of individual modes.

Automatic generation of merged mode constraints for electronic circuits

Automatic verification of merged mode constraints for electronic circuits

Timing behaviors associated with constraints of circuits are compared to identify mismatches between circuit configurations. Aggregate sets of timing constraints associated with timing nodes are determined for timing paths between start points and end points. Precedence rules are applied to aggregate sets of timing constraints by applying precedence rules to interacting timing constraints. Aggregate sets of constraints for corresponding timing nodes are matched to determine if timing constraint mismatches exist between circuits. If aggregate timing constraints associated with start point, end point pairs are found to match, reconvergent points between the start point and end points are analyzed to see if aggregate constraints of timing nodes connected to reconvergent/divergent points match if timing exception matches are involved. Graph traversal algorithms allow efficient computation of aggregate timing constraints for timing nodes.

Comparing timing constraints of circuits

A method of designing a digital circuit is described, so that it is likely to pass a signoff time test. The method begins with the running of a basic static time test on a partially developed version of the digital circuit, next a signoff time test is run for the partially developed version of the digital system. The differences between the results of the basic static time test and the signoff time test are noted and the prospective basic static time test passing conditions are altered so that if a similar system passes the basic static time test with the altered passing conditions it will be more likely to pass the signoff time test. Then, the partially developed version of the digital system is altered to yield a second partially developed version and the first static time test is run, with the altered passing conditions on the second partially developed version.

Method of designing a digital circuit by correlating different static timing analyzers

A method and an apparatus to perform static timing analysis and optimization for multi-mode clock circuit networks have been disclosed. In one embodiment, the method includes determining a plurality of sensitization conditions associated with one or more clock signals in a circuit network operable in a plurality of modes and automatically eliminating false paths from a plurality of clock paths of the circuit network based on the plurality of sensitization conditions. Other embodiments have been claimed and described.

Systems, methods, and apparatus to perform static timing analysis and optimization for multi-mode clock circuit networks

Disclosed is a method and system for handling timing constraints or assertions for timing model extraction. One disclosed approach for assertion handling is by automatically preserving the integrity of original assertions by retaining existing pins or creating new internal pins. The assertions are viewed as part of the model, and a set of new assertions are generated automatically as part of the timing model extraction process and can be stored as part of the model. Assertions can be associated with input ports, output ports, internal pins, or hierarchical pins and can even span multiple blocks. This disclosed approach allows for application of assertions associated with timing models when the model is instantiated and detachment of assertions when the model is de-instantiated, and thus removes one of main problems associated with timing models.

Assertion handling for timing model extraction

Disclosed is a method and system for extracting a timing model. One disclosed approach to extract a timing model is by reducing the timing graph. Original timing behavior is preserved in the timing model including arrival times, slew times, timing violations and even latch time borrowing that is independent of clock waveforms. Also, original timing constraints can be captured in the model and be applied automatically when the model is used. Anchor points are automatically identified and retained to obtain a model that is smaller than the original netlist.

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San Diego, CA, United States of America

Cho Moon