Invention Grant
- Patent Title: Alignment net insertion for straightening the datapath in a force-directed placer
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Application No.: US13826631Application Date: 2013-03-14
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Publication No.: US09251306B2Publication Date: 2016-02-02
- Inventor: Myung-Chul Kim , Natarajan Viswanathan , Samuel I. Ward
- Applicant: GLOBALFOUNDRIES Inc.
- Applicant Address: KY Grand Cayman
- Assignee: GLOBALFOUNDRIES Inc.
- Current Assignee: GLOBALFOUNDRIES Inc.
- Current Assignee Address: KY Grand Cayman
- Agency: Heslin Rothenberg Farley & Mesiti P.C.
- Main IPC: G06F17/50
- IPC: G06F17/50

Abstract:
An automated method for aligning a critical datapath in an integrated circuit design inserts an artificial alignment net in the netlist which interconnects all cells in the bit stack of the datapath. The cells are placed using a wirelength optimization which assigns weights to wire sections based on the alignment direction. The rate of change of the alignment weighting value can vary during different stages of global placement. The invention is particularly suited for a force-directed placer which uses a linear system solver to obtain a globally optimum solution for placement of the cells having some overlap among the cells, and thereafter spreads the cells to reduce the overlap. Pseudo nets are also inserted which interconnect a cell and an expected location of the cell after spreading for that iteration.
Public/Granted literature
- US20130205272A1 ALIGNMENT NET INSERTION FOR STRAIGHTENING THE DATAPATH IN A FORCE-DIRECTED PLACER Public/Granted day:2013-08-08
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