Patents by Inventor James C. Gregerson
James C. Gregerson has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Publication number: 20170061067Abstract: Timing window manipulation for noise reduction includes: selecting a path of a circuit design having a timing violation from a timing analysis of a victim window; determining an aggressor net coupled to a victim net along the path; determining a propagation path through the determined aggressor net; propagating a victim window value backward through the propagation path, the victim window value associated with the victim net; and modifying circuit characteristics of the circuit design within a switching window associated with the aggressor net based at least on the propagated victim window value.Type: ApplicationFiled: July 19, 2016Publication date: March 2, 2017Inventors: JAMES C. GREGERSON, KERIM KALAFALA, TSZ-MEI KO, GREGORY M. SCHAEFFER
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Publication number: 20170061059Abstract: Timing window manipulation for noise reduction includes: selecting a path of a circuit design having a timing violation from a timing analysis of a victim window; determining an aggressor net coupled to a victim net along the path; determining a propagation path through the determined aggressor net; propagating a victim window value backward through the propagation path, the victim window value associated with the victim net; and modifying circuit characteristics of the circuit design within a switching window associated with the aggressor net based at least on the propagated victim window value.Type: ApplicationFiled: August 26, 2015Publication date: March 2, 2017Inventors: JAMES C. GREGERSON, KERIM KALAFALA, TSZ-MEI KO, GREGORY M. SCHAEFFER
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Patent number: 9542524Abstract: Disclosed are a system and a method for performing a timing analysis of an integrated circuit (IC). An internal timing constraint of a logic device in a first signal pathway of a hierarchical entity in an IC design is determined based on a reference value and, if necessary, on library information. A first boundary timing constraint associated with the first signal pathway is derived based on the internal timing constraint and a second boundary timing constraint associated with the first signal pathway is derived based on the first boundary timing constraint and a target slack value for the internal timing constraint. A static timing analysis is performed using the second boundary timing constraint. Based on the analysis, a timing abstraction for the hierarchical entity is generated. A timing model for the IC design is generated using the timing abstraction and other timing abstractions for other hierarchical entities in the design.Type: GrantFiled: January 27, 2015Date of Patent: January 10, 2017Assignee: International Business Machines CorporationInventors: James C. Gregerson, David J. Hathaway, Kerim Kalafala, Tsz-Mei Ko, Alex Rubin
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Publication number: 20160217245Abstract: Disclosed are a system and a method for performing a timing analysis of an integrated circuit (IC). An internal timing constraint of a logic device in a first signal pathway of a hierarchical entity in an IC design is determined based on a reference value and, if necessary, on library information. A first boundary timing constraint associated with the first signal pathway is derived based on the internal timing constraint and a second boundary timing constraint associated with the first signal pathway is derived based on the first boundary timing constraint and a target slack value for the internal timing constraint. A static timing analysis is performed using the second boundary timing constraint. Based on the analysis, a timing abstraction for the hierarchical entity is generated. A timing model for the IC design is generated using the timing abstraction and other timing abstractions for other hierarchical entities in the design.Type: ApplicationFiled: January 27, 2015Publication date: July 28, 2016Inventors: James C. Gregerson, David J. Hathaway, Kerim Kalafala, Tsz-Mei Ko, Alex Rubin
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Patent number: 9318171Abstract: A computer-system implemented method for dual asynchronous and synchronous memory operation in a memory subsystem includes establishing a synchronous channel between a memory controller and a memory buffer chip. A mode selector determines a reference clock source for a memory domain phase-locked loop of the memory buffer chip based on an operating mode of the memory buffer chip. An output of a nest domain phase-locked loop is provided as the reference clock source to the memory domain phase-locked loop in the memory buffer chip based on the operating mode being synchronous. The nest domain phase-locked loop is operable synchronous to a memory controller phase-locked loop of the memory controller. A separate reference clock is provided independent of the nest domain phase-locked loop as the reference clock to the memory domain phase-locked loop based on the operating mode being asynchronous.Type: GrantFiled: September 30, 2014Date of Patent: April 19, 2016Assignee: International Business Machines CorporationInventors: Gary A. Van Huben, Patrick J. Meaney, John S. Dodson, Scot H. Rider, James C. Gregerson, Eric E. Retter, Irving G. Baysah, Glenn D. Gilda, Lawrence D. Curley, Vesselina K. Papazova
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Patent number: 9142272Abstract: Embodiments relate to a dual asynchronous and synchronous memory system. One aspect is a system that includes a memory controller and a memory buffer chip coupled to the memory controller via a synchronous channel. The memory buffer chip includes a memory buffer unit configured to synchronously communicate with the memory controller in a nest domain, and a memory buffer adaptor configured to communicate with at least one memory interface port in a memory domain. The at least one memory interface port is operable to access at least one memory device. A boundary layer is connected to the nest domain and the memory domain, where the boundary layer is configurable to operate in a synchronous transfer mode between the nest and memory domains and to operate in an asynchronous transfer mode between the nest and memory domains.Type: GrantFiled: March 15, 2013Date of Patent: September 22, 2015Assignee: International Business Machines CorporationInventors: Gary A. Van Huben, Patrick J. Meaney, John S. Dodson, Scot H. Rider, James C. Gregerson, Eric E. Retter, Irving G. Baysah, Glenn D. Gilda, Lawrence D. Curley, Vesselina K. Papazova
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Publication number: 20150019831Abstract: A computer-system implemented method for dual asynchronous and synchronous memory operation in a memory subsystem includes establishing a synchronous channel between a memory controller and a memory buffer chip. A mode selector determines a reference clock source for a memory domain phase-locked loop of the memory buffer chip based on an operating mode of the memory buffer chip. An output of a nest domain phase-locked loop is provided as the reference clock source to the memory domain phase-locked loop in the memory buffer chip based on the operating mode being synchronous. The nest domain phase-locked loop is operable synchronous to a memory controller phase-locked loop of the memory controller. A separate reference clock is provided independent of the nest domain phase-locked loop as the reference clock to the memory domain phase-locked loop based on the operating mode being asynchronous.Type: ApplicationFiled: September 30, 2014Publication date: January 15, 2015Inventors: Gary A. Van Huben, Patrick J. Meaney, John S. Dodson, Scot H. Rider, James C. Gregerson, Eric E. Retter, Irving G. Baysah, Glenn D. Gilda, Lawrence D. Curley, Vesselina K. Papazova
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Publication number: 20140281326Abstract: Embodiments relate to a dual asynchronous and synchronous memory system. One aspect is a system that includes a memory controller and a memory buffer chip coupled to the memory controller via a synchronous channel. The memory buffer chip includes a memory buffer unit configured to synchronously communicate with the memory controller in a nest domain, and a memory buffer adaptor configured to communicate with at least one memory interface port in a memory domain. The at least one memory interface port is operable to access at least one memory device. A boundary layer is connected to the nest domain and the memory domain, where the boundary layer is configurable to operate in a synchronous transfer mode between the nest and memory domains and to operate in an asynchronous transfer mode between the nest and memory domains.Type: ApplicationFiled: March 15, 2013Publication date: September 18, 2014Applicant: International Business Machines CorporationInventors: Gary A. Van Huben, Patrick J. Meaney, John S. Dodson, Scot H. Rider, James C. Gregerson, Eric E. Retter, Irving G. Baysah, Glenn D. Gilda, Lawrence D. Curley, Vesselina K. Papazova
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Patent number: 8560989Abstract: Systems and methods for statistical clock cycle computation and closing timing of an integrated circuit design to a maximum clock cycle or period. The method includes loading a design and timing model for at least one circuit path of an integrated circuit or a region of the integrated circuit into a computing device. The method further includes performing a statistical static timing analysis (SSTA) of the at least one circuit path using the loaded design and timing model to obtain slack canonical data. The method further includes calculating a maximum circuit clock cycle for the integrated circuit or the specified region of the integrated circuit in linear canonical form based upon the slack canonical data obtained from the SSTA.Type: GrantFiled: December 6, 2011Date of Patent: October 15, 2013Assignee: International Business Machines CorporationInventors: Nathan Buck, Brian Dreibelbis, John P. Dubuque, Eric A. Foreman, James C. Gregerson, Peter A. Habitz, Jeffrey G. Hemmett, Debjit Sinha, Natesan Venkateswaran, Chandramouli Visweswariah, Michael H. Wood, Vladimir Zolotov
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Publication number: 20130145333Abstract: Systems and methods for statistical clock cycle computation and closing timing of an integrated circuit design to a maximum clock cycle or period. The method includes loading a design and timing model for at least one circuit path of an integrated circuit or a region of the integrated circuit into a computing device. The method further includes performing a statistical static timing analysis (SSTA) of the at least one circuit path using the loaded design and timing model to obtain slack canonical data. The method further includes calculating a maximum circuit clock cycle for the integrated circuit or the specified region of the integrated circuit in linear canonical form based upon the slack canonical data obtained from the SSTA.Type: ApplicationFiled: December 6, 2011Publication date: June 6, 2013Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATIONInventors: Nathan BUCK, Brian DREIBELBIS, John P. DUBUQUE, Eric A. FOREMAN, James C. GREGERSON, Peter A. HABITZ, Jeffrey G. HEMMETT, Debjit SINHA, Natesan VENKATESWARAN, Chandramouli VISWESWARIAH, Michael H. WOOD, Vladimir ZOLOTOV
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Patent number: 8458632Abstract: Aspects of the present invention provide solutions for projecting slack in an integrated circuit. A statistical static timing analysis (SSTA) is computed to get a set of Gaussian distributions over a plurality of variation sources in the integrated circuit. Based on the Gaussian distributions, a truncated subset and a remainder subset of the Gaussian distributions are identified. Then data factors that represent a ratio between the remainder subset and the truncated subset are obtained. These data factors are applied to the SSTA to root sum square (RSS) project the slack for the integrated circuit that takes into account the absence of the truncated subset.Type: GrantFiled: August 3, 2011Date of Patent: June 4, 2013Assignee: International Business Machines CorporationInventors: Eric A. Foreman, James C. Gregerson, Peter A. Habitz, Jeffrey G. Hemmett, Debjit Sinha, Natesan Venkateswaran, Chandramouli Visweswariah, Xiaoyue Wang, Vladimer Zolotov
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Publication number: 20130036395Abstract: Aspects of the present invention provide solutions for projecting slack in an integrated circuit. A statistical static timing analysis (SSTA) is computed to get a set of Gaussian distributions over a plurality of variation sources in the integrated circuit. Based on the Gaussian distributions, a truncated subset and a remainder subset of the Gaussian distributions are identified. Then data factors that represent a ratio between the remainder subset and the truncated subset are obtained. These data factors are applied to the SSTA to root sum square (RSS) project the slack for the integrated circuit that takes into account the absence of the truncated subset.Type: ApplicationFiled: August 3, 2011Publication date: February 7, 2013Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATIONInventors: Eric A. Foreman, James C. Gregerson, Peter A. Habitz, Jeffrey G. Hemmett, Debjit Sinha, Natesan Venkateswaran, Chandramouli Visweswariah, Xiaoyue Wang, Vladmimir Zolotov
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Patent number: 8086988Abstract: Disclosed is a computer-implemented method for designing a chip to optimize yielding parts in different bins as a function of multiple diverse metrics and further to maximize the profit potential of the resulting chip bins. The method separately calculates joint probability distributions (JPD), each JPD being a function of a different metric (e.g., performance, power consumption, etc.). Based on the JPDs, corresponding yield curves are generated. A profit function then reduces the values of all of these metrics (e.g., performance values, power consumption values, etc.) to a common profit denominator (e.g., to monetary values indicating profit that may be associated with a given metric value). The profit function and, more particularly, the monetary values can be used to combine the various yield curves into a combined profit-based yield curve from which a profit model can be generated.Type: GrantFiled: May 18, 2009Date of Patent: December 27, 2011Assignee: International Business Machines CorporationInventors: Nathan Buck, Howard H. Chen, James P. Eckhardt, Eric A. Foreman, James C. Gregerson, Peter A. Habitz, Susan K. Lichtensteiger, Chandramouli Visweswariah, Tad J. Wilder
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Patent number: 7873926Abstract: Methods for analyzing timing of an integrated circuit using block-based static statistical timing analysis and for practical worst test definition and debug. The method includes building a timing graph, determining a slack for each of the nodes in the timing graph, and identifying a statistically worst slack for at least one of the nodes. The method further includes replacing this statistically worst slack with a proxy worst slack.Type: GrantFiled: March 31, 2008Date of Patent: January 18, 2011Assignee: International Business Machines CorporationInventors: Nathan C. Buck, Eric A. Foreman, James C. Gregerson, Jeffrey G. Hemmett
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Publication number: 20100293512Abstract: Disclosed is a computer-implemented method for designing a chip to optimize yielding parts in different bins as a function of multiple diverse metrics and further to maximize the profit potential of the resulting chip bins. The method separately calculates joint probability distributions (JPD), each JPD being a function of a different metric (e.g., performance, power consumption, etc.). Based on the JPDs, corresponding yield curves are generated. A profit function then reduces the values of all of these metrics (e.g., performance values, power consumption values, etc.) to a common profit denominator (e.g., to monetary values indicating profit that may be associated with a given metric value). The profit function and, more particularly, the monetary values can be used to combine the various yield curves into a combined profit-based yield curve from which a profit model can be generated.Type: ApplicationFiled: May 18, 2009Publication date: November 18, 2010Applicant: International Business Machines CorporationInventors: Nathan Buck, Howard H. Chen, James P. Eckhardt, Eric A. Foreman, James C. Gregerson, Peter A. Habitz, Susan K. Lichtensteiger, Chandramouli Visweswariah, Tad J. Wilder
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Patent number: 7694254Abstract: Run-time reduction is achieved in timing performance of a logical design, such as a digital integrated circuit. A portion of the logical design that is expected to be stable with respect to timing performance, such as a clock tree, is identified. Timing sensitivities, including sensitivities to sources of variability, of the identified portion of the logical design are determined at a given instant. The timing sensitivities of the identified portion of the logical design are saved for re-use. The saved timing sensitivities are re-used throughout the timing analysis and in subsequent timing analyses.Type: GrantFiled: January 3, 2007Date of Patent: April 6, 2010Assignee: International Business Machines CorporationInventors: James C. Gregerson, Kerim Kalafala, Alexander Suess
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Publication number: 20090249270Abstract: Methods for analyzing timing of an integrated circuit using block-based static statistical timing analysis and for practical worst test definition and debug. The method includes building a timing graph, determining a slack for each of the nodes in the timing graph, and identifying a statistically worst slack for at least one of the nodes. The method further includes replacing this statistically worst slack with a proxy worst slack.Type: ApplicationFiled: March 31, 2008Publication date: October 1, 2009Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATIONInventors: Nathan C. Buck, Eric A. Foreman, James C. Gregerson, Jeffrey G. Hemmett
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Publication number: 20080307374Abstract: A logical design including multiple logical blocks is mapped onto an integrated circuit chip. A chip level floor plan is created on the chip, including temporary areas on the chip set aside for accommodating logical blocks having logical content including timing requirements based on the logical design. The temporary areas are translated into physical cells on the chip with pins assigned for inputs and outputs for the logical blocks. The logical blocks are mapped to the physical cells on the chip in a time sensitive manner using timing assertions to form temporary logical partitions. Blocks on the chip, including the temporary logical partitions, are connected based on the timing assertions. A timing analysis is performed on the chip to determine timing slack associated with each temporary logical partition. A determination is made whether the timing slack is acceptable.Type: ApplicationFiled: June 5, 2007Publication date: December 11, 2008Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATIONInventors: James C. Gregerson, Leonard M. Greenberg, Steven J. Hnatko, Kirk D. Lamb, James H. McCullen
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Publication number: 20080163147Abstract: Run-time reduction is achieved in timing performance of a logical design, such as a digital integrated circuit. A portion of the logical design that is expected to be stable with respect to timing performance, such as a clock tree, is identified. Timing sensitivities, including sensitivities to sources of variability, of the identified portion of the logical design are determined at a given instant. The timing sensitivities of the identified portion of the logical design are saved for re-use. The saved timing sensitivities are re-used throughout the timing analysis and in subsequent timing analyses.Type: ApplicationFiled: January 3, 2007Publication date: July 3, 2008Applicant: International Business Machines CorporationInventors: James C. Gregerson, Kerim Kalafala, Alexander Suess
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Patent number: 5446913Abstract: A method and system for enhancing processing efficiency in a data processing system which includes multiple scalar instruction processors and a vector instruction processor. An ordered sequence of intermixed scalar and vector instructions is processed in a nonsequential order by coupling those instructions to selected processors. As each instruction is finished an indication of that state is stored within a finish instruction array. The first vector instruction within the ordered sequence is initiated within the vector instruction processor only after an indication that each scalar instruction preceding the first vector instruction is finished. A vector advance signal is generated by the vector instruction processor each time processing of a vector instruction is initiated.Type: GrantFiled: December 16, 1992Date of Patent: August 29, 1995Assignee: International Business Machines CorporationInventors: Norman C. Chou, Edward J. D'Avignon, James C. Gregerson, James R. Robinson, Michael S. Siegel, Michael A. Smoolca, Albert J. Van Norstrand, Jr.