Chris H Chu

US Patent:

7266796, Sep 4, 2007

Filed:

Apr 8, 2005

Appl. No.:

11/102381

Inventors:

Chris Chong-Nuen Chu - Ames IA, US
Natarajan Viswanathan - Ames IA, US

Assignee:

Iowa State University Research Foundation, Inc. - Ames IA

International Classification:

G06F 17/50

US Classification:

716 9, 716 2, 716 7, 716 11

Abstract:

A method for efficient analytical placement of standard cell designs includes obtaining a placement of cells using a wirelength objective function, modifying the placement of cells by cell shifting to redistribute cells to thereby reduce cell overlap, and refining the placement of cells to thereby reduce wirelength using a half-perimeter bounding rectangle-measure. Preferably the wirelength the wirelength objective function is a quadratic objective function which is solved using a hybrid net model. The hybrid net model preferably uses a clique model for two-pin and three-pin nets and a star model for nets having at least four pins. The use of the hybrid net model reduces a number of non-zero entries in a connectivity matrix.