METHOD TO REDUCE THE WIRELENGTH OF ANALYTICAL PLACEMENT TECHNIQUES BY MODULATION OF SPREADING FORCES VECTORS

摘要

A method of force directed placement programming is presented. The method includes sorting objects of a netlist for placement by magnitude of their spreading force and selecting a plurality of the objects. The method further includes waiving (or nullifying) the spreading force for the selected objects in a subsequent non-linear program solver step of the force directed placement program. The positions of the objects after the subsequent non-linear program solver step are based only on their connections to other objects in the netlist. The selected objects no longer retain their relative ordering as obtained during a previous non-linear program solve step of the force directed placement program. An alternative method of force directed placement programming is also present, which includes identifying objects from a netlist for placement that have a very high spreading force magnitude. The method further includes controlling the spreading force magnitude for the objects identified in the force directed placement programming to reduce wirelength in a chip design without sacrificing spreading of the objects.