SPFD-based one-to-many rewiring

ABSTRACT

This presentation gives a new SPFD-based method to make a target wire redundant with higher possibility than the previous rewiring methods. After placement and routing, we obtain or estimate how much the existing and candidate wires interferes such physical design, and thus, we find out the most critical one of the existing wires. In order to remove it, the previous methods add new input wires to only one LUT. Actually, in the context of gate/cell-based logic optimization, it is well-known that input wire addition to many gates/cells is likely to make the critical one redundant. However, in an FPGA circuit, since an LUT can realize an arbitrary function for a specified number of inputs, such wire addition has never been considered to be useful. In this presentation, we provides with an SPFD-based condition for such wire addition to improve the FPGA circuit performance. We also present several experimental results to show the effectiveness of the proposed condition.