Routing space estimation and assignment for macro-cell placement

In general, the routing space between two adjacent macro-cells is estimated and assigned after completing the placement of all the macro-cells. In thi s paper, the routing space in a macro-cell placement is divided into straig ht channels. First, based on a probabilistic analysis, a new routing space estimation approach for a channel is proposed. For the assignment of routin g space between two adjacent macro-cells, it is desired that this assignmen t does not change the topological relation between any pair of adjacent mac rocells in a macro-cell placement. Hence, the assignment of a previous chan nel will not be modified by the assignment of a recent channel during the a ssignment process of routing space. A safe routing space assignment approac h is further proposed for obtaining a complete macro-cell placement. It is proved that the time complexity of a safe routing space assignment is O(N l og N), where N is the number of macro-cells in a macrocell netlist. Finally , the experimental results show that the proposed estimation and assignment of routing space is effective in a macro-cell placement.