WireMap: FPGA technology mapping for improved routability

This paper presents a new technology mapper, WireMap. The mapper uses an edge flow heuristic to improve the routability of a mapped design. The heuristic is applied during the iterative mapping optimization to reduce the total number of pin-to-pin connections (or edges). The average edge reduction of 9.3% is achieved while maintaining depth and LUT count of state-of-theart technology mapping. Placing and routing the resulting netlists leads to an 8.5% reduction in the total wire length, a 6.0% reduction in minimum channel width, and a 2.3% reduction in critical path delay. Applying WireMap has an additional advantage of reducing an average number of inputs of LUTs without increasing the total LUT count and depth. The percentages of 5- and 6-LUTs in a typical design are reduced, while the percentages of 2-, 3-, and 4-LUTs are increased. These smaller LUTs can be merged into pairs and implemented using the dual output LUT structure found in commercial FPGAs. WireMap leads to 9.4% fewer ...

• Type: Conference
• Year: 2008
• Where: FPGA
• Authors: Stephen Jang, Billy Chan, Kevin Chung, Alan Mishchenko
• Keywords: Edge Flow, FPGA, FPGA 2008, LUT Count, Total Lut Count