Quadratic Placement Algorithm Using Gaussian Blurring and Fixed Point Technique

• Main Authors: Huang, Chuan-Chia, 黃川嘉
• Other Authors: Chen, Hung-Ming
• Format: Others
• Language: en_US
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/04916193067270789150

碩士 === 國立交通大學 === 電子工程學系 電子研究所 === 102 === State of the art global placers adopt different cell spreading algorithms to handle density of placement. In this work, we found there exist different placement behavior when placing cells across and around fixed macros among state of the art global placers. Our findings also suggest that placement behavior around fixed macros has significant impact toward routability of the design that cannot be observed through conventional evaluation metrics. For quadratic placers, the methodologies adopted in SimPL and Kraftwerk2 represent two distinct class of cell spreading algorithms. Based on our implementations of the two frameworks, we answer to the question on whether if there exist different level of controllability in terms of global view and local view among different cell spreading algorithms. We further investigate the impact of placement behavior on routability of the design. To address both global view and local view of the placement, we propose a two stage global placement framework. The first stage aims to assign large portion of cells with precise amount of white space by moving cells across fixed macros. The second stage aims to determine accurate relative order of cells and move cells around fixed macros. Our proposed placement framework achieves equivalent placement quality compared to ComPLx with placement behavior around fixed macros that is inherently desirable to routability.