On extending slicing floorplans to handle L/T-shaped modules and abutment constraints

In oorplanning it is common that a designer wants to have certain modules abutting with one another in the nal pack ing Unfortunately few oorplanning algorithm can han dle abutment constraints although this feature is useful in practice The problem of controlling the relative positions of an arbitrary number of modules is non trivial Slicing oorplans have an advantageous feature that the topologi cal structure of the packing can be found without knowing the module dimensions This feature is good for handling placement constraints in general In this paper we make use of it to solve the abutment problem in the presence of L shaped and T shaped modules This is done by a proce dure which explores the topological structure of the packing and nd the neighborhood relationship between every pair of modules in linear time This enables us to check and x the abutment constraints and to handle the L shaped and T shaped modules There are many previous works on recti linear block packing but none of them can handle rectilinear blocks with soft modules e ciently Our main contribution is a method which can handle abutment constraints in the presence of L shaped or T shaped modules in such a way that the shape exibility of the soft modules can still be fully exploited to obtain a tight packing We tested our oorplanner with some benchmark data and the results are promising We can pack modules of which are L shaped or T shaped with twelve abutment constraints in about minutes giving less than deadspace using a MHz UltraSPARC workstation