Alignment net insertion for straightening the datapath in a force-directed placer
US9251306B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 14, 2013 |
| Grant date | Feb 2, 2016 |
| Priority date | — |
| Expiry date | May 5, 2033 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F30/00
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.