Patents Represented by Attorney, Agent or Law Firm Lynn Augspurger
  • Patent number: 7739633
    Abstract: Testing a model of a logic circuit model. The testing includes generating valid random input stimulus sequences for a logic circuit model. Enumerating critical resource requirements, enumerating critical resource availabilities does this, and selecting of stimulus sequences and determining legal times for execution of said stimulus sequences based on resource availability. This includes generating a plurality of possible combinations of input stimulus sequences and generating an array representation of critical resource requirements. These are used to generate an array representation of critical resources availabilities.
    Type: Grant
    Filed: March 6, 2008
    Date of Patent: June 15, 2010
    Assignee: International Business Machines Corporation
    Inventors: Faisal A. Ahmad, Kevin C. Gower, Anish T. Patel
  • Patent number: 6904585
    Abstract: A method for identifying and modifying, in a VLSI chip design, wire routes within a region of wiring congestion that can be routed around that region without inducing timing violations by the insertion and proper placement of inverters. Circuits and nets are examined in the vicinity of the wiring congestion to determine those nets with high potential to drive a route outside the region. Circuit locations are analyzed to determine if the net connecting them creates a path through the region of wiring congestion. Timing slacks are derived from the timing reports for such nets and compared against a timing value representing the additional delay of using an inverter pair to drive the wire route outside the region of wiring congestion. If a net has sufficient timing slack, it is buffered with an inverter pair which is then placed in a manner as to force the wire routes for the modified path around the region of wiring congestion, thereby reducing the wire utilization within the region.
    Type: Grant
    Filed: April 4, 2003
    Date of Patent: June 7, 2005
    Assignee: International Business Machines Corporation
    Inventors: Mark A. Brittain, Kenneth D. Klapproth, Vu T. Le, Joseph J. Palumbo
  • Patent number: 6836865
    Abstract: A method for preparing a logic structure for random pattern testing is disclosed. In an exemplary embodiment of the invention, the method includes configuring a select mechanism within a data scan chain, the select mechanism configured between a first register in the data scan chain and a second register. A parallel data path is routed within the scan chain, the parallel data path beginning from an input side of the first register, running through the select mechanism, and ending at an input side of the second register. Thus configured, the select mechanism is capable of switching a source path of input data to said second register from a normal data path to the parallel data path. When the parallel data path is selected as the source path of input data to the second register, data loaded into the second register matches data loaded into the first register.
    Type: Grant
    Filed: October 9, 2001
    Date of Patent: December 28, 2004
    Assignee: International Business Machines Corporation
    Inventors: Mary P. Kusko, William V. Huott, Bryan J. Robbins, Timothy Charest
  • Patent number: 6829627
    Abstract: A computer system with a floating point unit (“FPU”) for supporting multiple floating point architectures is provided. The system includes a format converter for converting between the internal data flow format and the architected external data types by multiplexing the exponent and system includes a floating point unit having an internal data-flow according to an internal floating point format for performing floating point operations. The internal format has a number of exponent bits and a number of fraction bits sufficient to support each of the floating point architectures. The format converters the exponent value of each floating point architecture into the internal floating point format so that data operand of any of the floating point architectures point is converted into the internal floating point format for subsequent arithmetic operations, and the result of the operation is converted back into the original floating point architecture for output.
    Type: Grant
    Filed: January 18, 2001
    Date of Patent: December 7, 2004
    Assignee: International Business Machines Corporation
    Inventors: Christopher A. Krygowski, Eric M. Schwarz
  • Patent number: 6822885
    Abstract: A high speed latch and compare function providing rapid cache comparison through the use of a dual rail comparison circuit having transmission gate exclusive or (XOR) circuits.
    Type: Grant
    Filed: April 14, 2003
    Date of Patent: November 23, 2004
    Assignee: International Business Machines Corporation
    Inventors: Paul A. Bunce, John D. Davis, Donald W. Plass
  • Patent number: 6816824
    Abstract: Low-conductance and high-conductance IV characteristics (models) are created using the low and high end of their body voltage ranges, respectively. The body voltage of the device (FET) is initialized to the low end of range at time zero, and then a transient, two dimensional sweep of gate and drain voltages is performed. Drain currents are measured in this two dimensional region and are used to create a piecewise, linear IV model of device. The process is repeated for the highest body voltage. This process differs significantly from prior art bulk device characterization techniques, which did not have to initialize body voltage or perform a transient analysis. The body voltage is modulating during the switching event due to the gate-to-body and diffusion-to-body coupling; and thus only a transient analysis can properly model these coupling effects.
    Type: Grant
    Filed: April 19, 1999
    Date of Patent: November 9, 2004
    Assignee: International Business Machines Corporation
    Inventors: Ching-Te K. Chuang, Brian W. Curran, George E. Smith, III
  • Patent number: 6788112
    Abstract: A sense amplifier for a memory device comprising: a first sensing stage comprising a first sensing device and a second sensing device operably connected to a first sense line and a second sense line respectively, to reduce the capacitive load on the first sense line and second sense line. A source terminal of the sensing device is connected to a switchable current sink with drain terminal thereof connected to an input of a second sensing stage. The sense amplifier also includes a second sensing stage comprising cross-coupled inverters responsive to the first sensing stage, the second sensing stage is activated by a sense enable signal following a selected delay, and an output driver responsive to the second sensing stage.
    Type: Grant
    Filed: May 12, 2003
    Date of Patent: September 7, 2004
    Assignee: International Business Machines Corporation
    Inventors: Yuen H. Chan, Rajiv Joshi, Antonio R. Pelella, John R. Rawlins, Jatinder K. Wadhwa
  • Patent number: 6751708
    Abstract: A method is disclosed for instructing a computing system to ensure that a line is present in an instruction cache that includes selecting a line-touch instruction, recognizing the line-touch instruction as a type of branch instruction where the branch is not taken, executing the line-touch instruction to fetch a target line from a target address into the instruction cache, and interlocking the execution of the line-touch instruction with the completion of the fetch of the target line in order to prevent execution of the instruction following the line-touch instruction until after the target line has reached the cache.
    Type: Grant
    Filed: January 9, 2002
    Date of Patent: June 15, 2004
    Assignee: International Business Machines Corporation
    Inventors: John S. Liptay, Mark A. Check, Mark S. Farrell, Bruce C. Giamei, Charles F. Webb
  • Patent number: 6751765
    Abstract: An exemplary embodiment of the invention is a method for LBIST testing integrated circuit. The method includes generating a plurality of multi-bit test patterns and grouping the multi-bit test patterns by a plurality of test pattern partitions including a first test pattern partition having a first number of bits and a second test pattern partition having second number of bits greater than the first number. The first test pattern partition is applied to the integrated circuit to generate a first signature that is compared to a first reference signature to detect a failure. The second test pattern partition is applied to the integrated circuit to generate a second signature that is compared to a second reference signature to detect a failure in the integrated circuit.
    Type: Grant
    Filed: November 27, 2000
    Date of Patent: June 15, 2004
    Assignee: International Business Machines Corporation
    Inventors: Richard F. Rizzolo, Rocco E. DeStefano, Joseph E. Eckelman, Thomas G. Foote, Steven Michnowski, Franco Motika, Phillip J. Nigh, Bryan J. Robbins
  • Patent number: 6748565
    Abstract: An exemplary embodiment of the invention is a method and apparatus for configuring system cycle time in a data processing system with at least one master latch clock generating a master latch clock signal and at least one slave latch clock generating a slave latch clock signal. Timing errors are detected during system hardware testing. Adjustments to the system timing are calculated based on error for at least one of a master latch clock signal and a slave latch clock signal. The on-cycle edge of at least one of the master latch clock signal and slave latch clock signal is adjusted based on the calculations while maintaining a corresponding mid-cycle edge of at least one of the master latch clock signal and the slave latch clock signal.
    Type: Grant
    Filed: October 2, 2000
    Date of Patent: June 8, 2004
    Assignee: International Business Machines Corporation
    Inventors: Glenn E. Holmes, Timothy G. McNamara, William J. Scarpero, Jr.
  • Patent number: 6745313
    Abstract: A method is disclosed for selecting data in a computer system having a cache memory and a branch history table, where the method includes predicting an address corresponding to the data, selecting data at the predicted address in the cache memory, translating an address corresponding to the data, comparing the translated address with the predicted address, and if they are different, re-selecting data at the translated address in the cache memory and appending the translated address to the branch history table.
    Type: Grant
    Filed: January 9, 2002
    Date of Patent: June 1, 2004
    Assignee: International Business Machines Corporation
    Inventors: John S. Liptay, Mark A. Check, Brian R. Prasky, Chung-Lung Kevin Shum
  • Patent number: 6697833
    Abstract: A method is disclosed for efficiently multiplying de-normalized floating-point numbers without necessarily incurring additional delay over the multiplication of normalized numbers, wherein the de-normalized numbers are initially assumed to be normalized. The method includes providing multiplier and multiplicand floating-point numbers, each defining a fraction and an exponent; encoding the multiplier fraction; multiplexing the multiplier fraction; and multiplying the multiplier fraction by the multiplicand fraction to form a first set of partial products.
    Type: Grant
    Filed: January 18, 2001
    Date of Patent: February 24, 2004
    Assignee: International Business Machines Corporation
    Inventors: Christopher A. Krygowski, Eric M. Schwarz
  • Patent number: 6671838
    Abstract: An exemplary embodiment of the invention is a built-in self-test (BIST) method and apparatus for testing the logic circuits on an integrated circuit. Random test pattern data is generated by a random pattern generator. A random resistant fault analysis (RRFA) program is used to determine the weighting requirements, on a per channel basis, for testing the logic circuits. The weighting requirements from the RRFA program are applied to the random test pattern data resulting in weighted test pattern data. The weighted test pattern data is then programmably applied to the scan chain.
    Type: Grant
    Filed: September 27, 2000
    Date of Patent: December 30, 2003
    Assignee: International Business Machines Corporation
    Inventors: Timothy J. Koprowski, Mary P. Kusko, Lawrence K. Lange, Bryan J. Robbins
  • Patent number: 6671794
    Abstract: A method and system for detecting address generation interlock in a pipelined data processor is disclosed. The method comprises accumulating a plurality of vectors over a predefined number of processor clock cycles, with subsequent vectors corresponding to subsequent clock cycles; accumulating the status of one or more general registers in the plurality of vectors with the same bit location in each vector of the plurality of vectors corresponding to a particular general register; generating a list of pending general register updates from a logical combination of the plurality of vectors; and determining the existence of address generation interlock from the list of pending general register updates.
    Type: Grant
    Filed: October 2, 2000
    Date of Patent: December 30, 2003
    Assignee: International Business Machines Corporation
    Inventors: Bruce C. Giamei, Mark A. Check, John S. Liptay
  • Patent number: 6671793
    Abstract: An exemplary embodiment of the invention is a method and system for managing a result returned from a translator co-processor to a recovery unit of a central processor. The computer system has a pipelined computer processor and a pipelined central processor, which executes an instruction set in a hardware controlled execution unit and executes an instruction set in a milli-mode architected state with a millicode sequence of instructions in the hardware controlled execution unit. The central processor initiates a request to the translator co-processor a cycle after decode of a perform translator operation instruction in the millicode sequence. The translator co-processor processes the perform translator operation instruction to generate a perform translator operation result. The translator co-processor returns the results to a recovery unit of the central processor. The recovery unit stores the perform translator operation result in a system register.
    Type: Grant
    Filed: October 2, 2000
    Date of Patent: December 30, 2003
    Assignee: International Business Machines Corporation
    Inventors: Scott B. Swaney, Mark S. Farrell, John D. MacDougall, Hans-Juergen Muenster, Charles F. Webb
  • Patent number: 6662296
    Abstract: An exemplary embodiment of the present invention is a method and system for reducing the number of branch instructions required to test combinations of millicode branch points. The method is implemented via a pipe-lined computer processor executing a millicode routine. The processor interrogates a millicode condition code; interrogates a first field of the TMBP instruction, the results of which determine a logical function to be performed on the millicode condition code; interrogates a second field of the TMBP instruction which specifies a first millicode branch point; interrogates a third field of the TMBP instruction, which specifies a second millicode branch point; and sets a millicode condition code based upon the results of the interrogating and used for executing subsequent TMBP instructions or conditional branch instructions.
    Type: Grant
    Filed: October 2, 2000
    Date of Patent: December 9, 2003
    Assignee: International Business Machines Corporation
    Inventors: Mark S. Farrell, John S. Liptay, Charles F. Webb
  • Patent number: 6629280
    Abstract: An exemplary embodiment of the invention is a method and apparatus for delaying the start of an array built-in self-test (ABIST) until after the ABIST memory arrays have been started. The length of the delay is determined by the value in a programmable delay located on the integrated circuit. The initiation of the ABIST test is delayed by the time specified in the programmable delay.
    Type: Grant
    Filed: September 25, 2000
    Date of Patent: September 30, 2003
    Assignee: International Business Machines Corporation
    Inventors: Timothy J. Koprowski, William V. Huott, Timothy G. McNamara, Pradip Patel
  • Patent number: 6629298
    Abstract: A method (and a system for using the method) for automating a slew rate analysis between two or more circuits on a semiconductor chip. The method includes the steps of: receiving as input one or more input parameters characterizing the physical medium through which the signal propagation occurs (the net) and the electrical characteristics of signals transmitted between the circuits; and providing as output one or more output parameters characterizing the appropriate solution for physical implementation of the circuit(s) and net(s) which satisfy the performance requirements of the system. The receiving step can comprise any one of: providing a hierarchical signal name cross-reference defining a name for the signal for a given hierarchy level of the circuits; providing a set of one or more boolean equations used to generate the one or more output parameters from the one or more input parameters; providing a physical design information for the circuits; and providing a timing information for the signals.
    Type: Grant
    Filed: November 10, 1999
    Date of Patent: September 30, 2003
    Assignee: International Business Machines Corporation
    Inventors: Peter J. Camporese, Adam R. Jatkowski, Leon J. Sigal, Patrick M. Williams
  • Patent number: 6629281
    Abstract: This invention describes a method and apparatus, contained within an integrated circuit, for isolating failure by precisely controlling the number of clocks applied during built-in self-test (BIST). A programmable clock counter, on the integrated circuit, stores a specified number of clock cycles and sends a signal to stop a BIST engine once the specified number of clock cycles have been generated. The intermediate results can then be mapped bit by bit in order to isolate the cause of failure.
    Type: Grant
    Filed: September 26, 2000
    Date of Patent: September 30, 2003
    Assignee: International Business Machines Corporation
    Inventors: Timothy G. McNamara, William V. Huott, Timothy J. Koprowski
  • Patent number: 6618844
    Abstract: A method of evaluating decoupling capacitor placement for Very Large Scale Integrated Chips (VLSI) is disclosed. Included in the method is an analysis of the usage for each decoupling capacitor, the distance from the devices, and the locations of the devices and decoupling capacitors. Also addressed are the orientations and size of the components.
    Type: Grant
    Filed: June 29, 2001
    Date of Patent: September 9, 2003
    Assignee: International Business Machines Corporation
    Inventors: Allan H. Dansky, Wiren D. Becker, Howard H. Smith, Peter J. Camporese, Kwok Fai Eng, Dale E. Hoffman, Bhupindra Singh