Slicing floorplans with range constraint

In floorplanning, it is important to allow users to specify placement constraints. Floorplanning with preplaced constraint was considered recently in Murata et al. (1997) and Young and Wong (1998). In this paper, we address a more general kind of placement constraint called range constraint in which a module must be placed within a given rectangular region in the floorplan. This is a more general formulation of the placement constraint problem and any preplaced constraint can be written as a range constraint. We extend the Wong-Liu algorithm (1986) to handle range constraint. Our main contribution is a novel shape curve computation which takes range constraint into consideration. Experimental results show that the extended floorplanner performs very well and, in particular, it out-performs the floorplanner proposed by Young and Wong (1998) when specialized to handle preplaced modules.