NTUplace3: An analytical placer for large-scale mixed-size designs with preplaced blocks and density constraints

作者：Chen Tung Chieh^*; Jiang Zhe Wei; Hsu Tien Chang; Chen Hsin Chen; Chang Yao Wen

来源：IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems, 2008, 27(7): 1228-1240.

DOI：10.1109/TCAD.2008.923063

• legalization (LG)
• physical design
• placement

In addition to wirelength, modern placers need to consider various constraints such as preplaced blocks and density. We propose a high-quality analytical placement algorithm considering wirelength, preplaced blocks, and density based on the log-sum-exp wirelength model proposed by Naylor et al. and the multilevel framework. To handle preplaced blocks, we use a two-stage smoothing technique, i.e., Gaussian smoothing followed by level smoothing, to facilitate block spreading during global placement (GP). The density is controlled by white-space reallocation using partitioning and cut-line shifting during GP and cell sliding during detailed placement. We further use the conjugate gradient method with dynamic step-size control to speed up the GP and macro shifting to find better macro positions. Experimental results show that our placer obtains very high-quality results.

• 出版日期2008-7
• 单位中国科学院电工研究所