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A Graph Based Soft Module Handling in Floorplan Hiroaki ITOGA Chikaaki KODAMA Kunihiro FUJIYOSHI Publication IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences Vol.E88-A No.12 pp.3390-3397 Publication Date: 2005/12/01 Online ISSN: DOI: 10.1093/ietfec/e88-a.12.3390 Print ISSN: 0916-8508 Type of Manuscript: Special Section PAPER (Special Section on VLSI Design and CAD Algorithms) Category: Floorplan and Placement Keyword: floorplan, soft module, compaction graph, slack, Full Text: PDF(378.4KB)>>
Summary: In the VLSI layout design, a floorplan is often obtained to define rough arrangement of modules in the early design stage. In the stage, the aspect ratio of each soft module is also determined. The aspect ratio can be changed in the designated range keeping its area of each module. In this paper, in order to determine the aspect ratio, we propose a graph-based one dimensional compaction method which determines the aspect ratio quickly under the constraint that topology of a floorplan must not be changed. The proposed method is divided into two steps: (1) Selection of a minimal set of soft modules to adjust the aspect ratio. (2) Decision on the aspect ratio. (1) is formulated as the minimal cut problem in graph theory. We solve the problem by transforming it to the shortest path problem. (2) is divided into two operations. One is to determine the increment limit in height or width of each soft module and the other is to determine the aspect ratio of each soft module by Newton-Raphson method. The experimental comparisons show effectiveness of the proposed method. | ||||||||||
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