An Incremental Floorplanning Algorithm with Less Flexibility First Principles

To support incremental changes on the existing floorplan derived from some changes in the high level synthesis is becoming an increasingly important problem in order to cope with the complexity of the merging of VLSI design phases and the necessary of alternation between synthesis and physical design. In this paper, we present an incremental floorplanning algorithm with less flexibility first (LFF) principles (LFF_IFP algorithm). LFF principle is a deterministic algorithm through human's accumulated experience. In this paper, the horizontal and vertical constraint graphs are built up based on the packing of the initial floorplanning result within linear time, and the accumulated slack distances among blocks are computed. The flexibility of blocks to be inserted to the initial floorplan ('incremental block' is also called here for short) is computed and every slack space belongs to the block in the initial floorplan also has different degree of flexibility for a given incremental block. The experimental results demonstrate that the algorithm is effective and promising in building block layout application