Invention Grant
- Patent Title: Legalization of VLSI circuit placement with blockages using hierarchical row slicing
- Patent Title (中): VLSI电路放置合法化使用分层行分片
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Application No.: US12108599Application Date: 2008-04-24
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Publication No.: US07934188B2Publication Date: 2011-04-26
- Inventor: Charles J. Alpert , Michael W. Dotson , Gi-Joon Nam , Shyam Ramji , Natarajan Viswanathan
- Applicant: Charles J. Alpert , Michael W. Dotson , Gi-Joon Nam , Shyam Ramji , Natarajan Viswanathan
- Applicant Address: US NY Armonk
- Assignee: International Business Machines Corporation
- Current Assignee: International Business Machines Corporation
- Current Assignee Address: US NY Armonk
- Agent Libby Z. Handelsman; Jack V. Musgrove
- Main IPC: G06F17/50
- IPC: G06F17/50

Abstract:
A hierarchical method of legalizing the placement of logic cells in the presence of blockages selectively classifies the blockages into at least two different sets based on size (large and small). Movable logic cells are relocated first among coarse regions between large blockages to remove overlaps among the cells and the large blockages without regard to small blockages (while satisfying capacity constraints of the coarse regions), and thereafter the movable logic cells are relocated among fine regions between small blockages to remove all cell overlaps (while satisfying capacity constraints of the fine regions). The coarse and fine regions may be horizontal slices of the placement region having a height corresponding to a single circuit row height of the design. Cells are relocated with minimal perturbation from the previous placement, preserving wirelength and timing optimizations. The legalization technique may utilize more than two levels of granularity with multiple relocation stages.
Public/Granted literature
- US20090271752A1 Legalization of VLSI circuit placement with blockages using hierarchical row slicing Public/Granted day:2009-10-29
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