A hierarchical floorplanning approach

A hierarchical floorplanner for general cell layout that exploits accurate shape functions that describe constraints on the leaf cells in order to produce good floorplans is presented. The leaf cells may have highly constrained shapes, or more flexible shapes. The floorplanner trades off the locations, sizes shapes, and pin positions of the cell against each other in order to minimize the layout area and the amount of interconnections. To the extent that the shape functions are accurate, there is no need for design iterations. By imposing a hierarchy in the form of a multiwave cluster tree, the number of floorplanning options is restricted and the problem is simplified by allowing the floorplanner to operate on one hierarchical cell at a time. The shape functions and the hierarchical approach make it possible to directly compute locations, sizes, shapes, and pin positions for the leaf cells