A fast rectangular spreading technique in global placement

Cell shifting is an efficient technique of removing overlap and accelerating the convergence of quadratic placement approach. However, this technique does not take the cells´ spreading direction into consideration. In our implement of cell shifting, the four corners of the rectilinear region tend to be less occupied by cells, thereby reducing the utilization of the whole region. To solve this problem, in this paper, we present a cell shifting aware of spreading direction of cells, rectangular spreading, to drive cells to spread in a rectangular contour. It can afford placement with better distribution of cells in four corners. Besides, we give a detailed description of our implement of cell shifting.