Rectilinear Shape Formation Method on Block Placement

Kazuhisa OKADA  Takayuki YAMANOUCHI  Takashi KAMBE  

IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E81-A   No.3   pp.446-454
Publication Date: 1998/03/25
Online ISSN: 
Print ISSN: 0916-8508
Type of Manuscript: Special Section PAPER (Special Section of Selected Papers from the 10th Karuizawa Workshop on Circuits and Systems)
floorplan,  rectilinear,  soft block,  placement,  

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In the floorplan design problem, soft blocks can take various rectilinear shapes. The conventional floorplanning methods, however, restrict their shapes only to rectangle. As a result, waste area often remains in the layout. Some floorplanning methods have been developed to handle rectilinear hard blocks, however, no floorplanning methods have been developed to optimize rectilinear soft blocks. In this paper, we propose a floorplanning method which places rectilinear soft blocks. The advantages of the method are reducing both waste area and wire length. We present Separate-Rejoin method which efficiently forms rectilinear shapes for soft blocks. The result is obtained quickly because the method is based on the slicing structure in spite of handling rectilinear block. Thus, our method is suitable for practical use in terms of layout area, wire length and processing time. We applied our method to a benchmark example and an industrial data. For the benchmark example, our method reduces waste area by 25% and wire length by 13% in comparison with the conventional rectangular soft block approach.