Fast wire length estimation by net bundling for block placement

The wire length estimation is the bottleneck of packing based block placers. To cope with this problem, we present a fast wire length estimation method in this paper. The key idea is to bundle the 2-pin nets between block pairs, and measure the wire length bundle by bundle, instead of net by net. Previous bundling method [5] introduces a huge error which compromises the performance. We present an errorfree bundling approach which utilizes the piecewise linear wire length function of a pair of blocks. With the function implemented into a lookup table, the wire length can be computed promptly and precisely by binary search. Furthermore, we show that 3-pin nets can also be bundled, resulting in a further speedup. The effectiveness of our method is verified by experiments. Categories and Subject Descriptors B.7.2 [Integrated Circuits]: Design Aids—Placement and Routing; J.6 [Computer Applications]: Computer-Aided Engineering—Computer-aided design (CAD) General Terms Algorithm, Experim...

• Type: Conference
• Year: 2006
• Where: ICCAD
• Authors: Tan Yan, Hiroshi Murata
• Keywords: Hardware, ICCAD 2006, Wire Length Bundle, Wire Length Estimation, Wire Length Function