International Business Machines Corporation

Jeremy T Hopkins

Samuel I Ward

Thomas Edward Rosser

Benjiman L Goodman

Ruchir Puri

Haoxing Ren

Joachim Keinert

Nathaniel Douglas Hieter

David Anthony Papa

David L Rude

Smita Krishnaswamy

John Mack Isakson

Julie Ann Rosser

Nilesh A Modi

Decoupling capacitors (dcaps) are placed in an IC design by assigning different dcap utilization rates to logic cones, applying the rates to corresponding dcap regions surrounding cells in the cones, identifying any overlap of regions from different logic cones, and inserting a dcap at the overlapping region having the highest dcap utilization rate. The best location for the dcap is computed using a hypergraph wherein the cells are edges and the regions are nodes. Any node that is dominated by another node is removed and its edge is extended to the dominating node. The dcap is inserted in the region having the most edges (the edges can be weighted). The process is repeated iteratively, updating the hypergraph by removing nodes connected to dcap location, and inserting the next dcap at a region corresponding to the node which then has the greatest number of connected edges.

Decoupling capacitor insertion using hypergraph connectivity analysis

Spare cells are placed in an IC design using stability values associated with logic cones of the design. A desired spare cell utilization rate is assigned to a cone based on its stability value, and an actual spare cell utilization rate for the cone bounding box is calculated. If the actual utilization rate is less than the desired utilization rate, additional spare cells are inserted as needed to attain the desired utilization rate. The stability value is provided by a logic or circuit designer, or derived from historical information regarding the logic cone in a previous design iteration. Spare cells are placed for each logic cone in the design until a global spare cell utilization target is exceeded. The spare cell placement method can be an integrated part of a placement directed synthesis which is followed by early mode padding and design routing.

Stability-dependent spare cell insertion

Spare cells are placed in an IC design by assigning different spare utilization rates to logic cones, applying the rates to corresponding spare cell regions surrounding cells in the cones, identifying any overlap of regions from different logic cones, and inserting a spare cell at the overlapping region having the highest spare utilization rate. The best location for the spare cell is computed using a hypergraph wherein the cells are edges and the regions are nodes. Any node that is dominated by another node is removed and its edge is extended to the dominating node. The spare cell is inserted in the region having the most edges (the edges can be weighted). The process is repeated iteratively, updating the hypergraph by removing nodes connected to spare cell location, and inserting the next spare cell at a region corresponding to the node which then has the greatest number of connected edges.

Cone-aware spare cell placement using hypergraph connectivity analysis

A technique for implementing an engineering change order includes determining spares that are available to implement a modification to a circuit design. One of the available spares is then selected to implement the modification to the circuit design based on performance criteria associated with each of the available spares.

Techniques for selecting spares to implement a design change in an integrated circuit

A computer executed method is disclosed which accepts an original circuit with an original logic, accepts a modified circuit, and synthesizes a difference circuit. The difference circuit represents changes that implement the modified circuit's logic for the original circuit. The synthesis may locate an output-side boundary in the original logic in such a manner that the original logic is free of logic changes in between the output-side boundary and the primary output elements of the original circuit. The disclosed synthesis may also locate an input-side boundary in the original logic in such a manner that the original logic is free of logic changes in between the input-side boundary and the primary input elements of the original circuit. A computer program products are also disclosed. The computer program product contains a computer useable medium having a computer readable program code embodied therein. The computer readable program code when executed on a computer causes the computer to carry out the methods of finding input and output side boundaries in an original logic, and synthesizing in between those boundaries a difference circuit representing logic changes.

Logic difference synthesis

Disclosed are a method, a system and a computer program product for determining and reporting minterms to aid in implementing an engineering change order (ECO). A Minterm Tracing and Reporting (MTR) utility, which executes on a computer system, receives two or more timing points of an optimized netlist, where one or more of the two or more timing points are received from one or more of a user, a memory medium, and/or a network. For example, a timing point is a primary input, a primary output, or a latch point. After receiving the two or more timing points of the optimized netlist, the MTR utility determines two or more minterms of the optimized netlist. In determining the minterms, from one timing point to a next timing point: a polarity at the timing point may be determined, and a forward trace from the timing point to the next timing point is performed to determine the two or more minterms of the optimized netlist. In the forward trace from the timing point to the next timing point, the MTR utility determines two or more logical cones and one or more intersections of the logical cones. The MTR utility reports (e.g., communicates) each of the determined minterms, the determined polarities, and the one or more intersections of logical cones to one or more of a computer-executable application, a network, a memory medium, and/or a display.

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Round Rock, TX, United States of America

Jeremy T Hopkins