AConFPGA: A Multiple-Output Boolean Function Approximation DSE Technique Targeting FPGAs

New relaxed quality standards laid down by approximate computing enrich the design pool with architectures dissipating less power, consuming fewer resources or with smaller latencies. In LUT-based FPGA logic approximation, the number of LUTs and latency associated to a design can be optimized by allowing the approximation of circuit results. In this paper, we present techniques for automatic design space exploration (DSE) of Boolean function falsifications and the ability and impact to reduce resources usage as well as the length of critical paths on LUT-based FPGAs. Our experiments give evidence that resource reductions of about 20% are easily achievable for error rates amounting to less than 0.05% w.r.t. accurate designs.