SmartOpt: an industrial strength framework for logic synthesis

ABSTRACT

In recent years, the maximum logic capacity of each successive FPGA family has been increasing by more than 50%, which motivates scalable solutions. Meanwhile, academic research in logic synthesis has been fruitful, but these advances have been demonstrated on academic architectures and benchmark designs which are not representative of modern industrial FPGAs. This paper presents a framework (SmartOpt) for mapping complex FPGA architectures to a simple netlist model, which can be supported by academic tools. SmartOpt was applied to leverage the algorithms implemented in the ABC package and to study their relative contributions. This work is integrated into the Xilinx ISE 11.1 software flow for FPGAs and shows significant improvements in both the LUT count and performance of large industrial circuits described in HDL. Xilinx Synthesis Technology (XST) reference flow was compared experimentally against the same flow augmented by SmartOpt. When applied to a set of 20 large industrial Virtex-5 benchmarks ranging from 17K to 69K 6-LUTs, the augmented flow produced 8.3% fewer LUTs and led to 2.1% higher operating frequency while keeping runtimes reasonable. With dual-LUT-merging, the LUT count is reduced by 22.7%, while increasing the operating frequency only by 0.7%.

REFERENCES

• 1: Altera. Stratix III Device Handbook, http://www.altera.com/literature/hb/stx3/stratix3_handbook.pdf
• 2: Xilinx Virtex-5 Product Table. http://www.xilinx.com/products/silicon_solutions/fpgas/virtex/virtex5/v5product_table.pdf
• 3: Berkeley Logic Interchange Format (BLIF), http://vlsi.colorado.edu/~vis/blif.ps
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INDEX TERMS

Primary Classification:
  B. Hardware
  B.6 LOGIC DESIGN
      B.6.3 Design Aids
          Subjects: Optimization

Additional Classification:
  B. Hardware
  B.7 INTEGRATED CIRCUITS
      B.7.1 Types and Design Styles
          Subjects: Gate arrays

General Terms:
Algorithms, Design, Experimentation, Performance

Keywords:
abc, blif, edge flow, fpga, interface, smartopt, technology mapping