Pin assignment with global routing for VLSI building block layout

In this paper, we will consider global routing and pin assignment in VLSI building block layout, and present an efficient algorithm which integrates global routing, pin assignment, block reshaping and positioning. The general flow of the proposed algorithm is the same as the one proposed in by Cong in 1991 [1] and consists of two main phases. The first phase is to determine not only global routes and coarse pin assignment in the same way as [1], but also shapes and positions of blocks. The second phase is to compute the final pin assignment for channels. We generalize the channel pin assignment (CPA) problem in [1], in which the CPA problem is formulated for only channels formed by two blocks, to the CPA problem for channels formed by multiple blocks. We will propose a linear time optimal channel pin assignment algorithm, which is an extension of the algorithm in [1]. Experimental results show the effectiveness of the proposed algorithm.