Finding optimal module orientation in macro cell placement

A report is presented on an ILP (integer linear programming) formulation for finding the optimal module orientations in macro cell placement. Compared to earlier approaches which work only for two-terminal nets based on Euclidean metric for wire length estimation, the proposed method handles multi-terminal nets based on the Manhattan metric of the minimum bounding box of the pin positions, which is more accurate. Experimental results of benchmark examples have shown 7 to 11% reductions of half-perimeter cost wiring length