Track assignment in the Pathway datapath layout assembler

The authors present a novel dynamic programming algorithm for optimizing the assignment of signals to metal2 tracks, in datapaths. The algorithm is part of the Pathway datapath layout assembler, which was used in the design of the NS32SF641 microprocessor. Using this system, it was possible to produce layout as compact as hand-crafted layout, in a fraction of the time. The proposed algorithm for track assignment minimizes datapath height. The runtime was reduced to an acceptable level, without any significant degradation of the solution, by a heuristic limitation of the solution space. The most serious shortcoming of the track assignment algorithm described is the limitation of the model upon which it is based-that each net occupy only one track in any cell.<>