On the viability of FPGA-based integrated coprocessors

Abstract

The paper examines the viability of using integrated programmable logic as a coprocessor to support a host CPU core. This adaptive coprocessor is compared to a VLIW machine in term of both die area occupied and performance. The parametric bounds necessary to justify the adoption of an FPGA-based coprocessor are established. An abstract field programmable gate array model is used to investigate the area and delay characteristics of arithmetic circuits implemented on FPGA architectures to determine the potential speedup of FPGA-based coprocessors. Analysis shows that integrated FPGA arrays are suitable as coprocessor platforms for realising algorithms that require only limited numbers of multiplication instructions. Inherent FPGA characteristics limit the data-path widths that can be supported efficiently for these applications. An FPGA-based adaptive coprocessor requires a large minimum die area before any advantage over a VLIW machine of a comparable size can be realised.