A Timing-Driven Global Routing Algorithm with Pin Assignment, Block Reshaping, and Positioning for Building Block Layout

Tetsushi KOIDE  Shin'ichi WAKABAYASHI  

IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E81-A   No.12   pp.2476-2484
Publication Date: 1998/12/25
Online ISSN: 
Print ISSN: 0916-8508
Type of Manuscript: Special Section PAPER (Special Section on VLSI Design and CAD Algorithms)
Category: Layout Optimization
building block layout,  global routing,  pin assignment,  timing constraint,  simulated evolution,  

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This paper presents a timing-driven global routing algorithm based on coarse pin assignment, block reshaping, and positioning for VLSI building block layout. As opposed to conventional approaches, we combine pin assignment and global routing problems into one problem. The proposed algorithm determines global routes, coarse pin assignments, and block shapes and positions so as to minimize the chip area and total wire length of nets under the given timing constraints. It is based on an iterative improvement paradigm and performs rip-up and rerouting, block reshaping, and positioning in the manner of simulated evolution taking shapes of soft blocks and routing congestion into consideration until the solution is not further improved. The Elmore delay model is adopted for the interconnection delay model. Experimental results show the effectiveness of the proposed algorithm.