Resource sharing in pipelined CDFG synthesis

Efficient use of limited available resources on an FPGA remains a crucial problem for synthesizing pipelined designs. Resource sharing addresses this challenge. In this paper, we propose resource sharing techniques that can be incorporated into an automated synthesis flow to generate pipelined designs. Given a synthesized pipelined design, we create a direct relationship between available time slack on modules and the multiplexing overhead due to sharing. This flexibility is maximally exploited without violating any throughput constraints. We propose different techniques to address resource sharing problems of varying restrictions. Specifically, we propose an optimal algorithm for constant-slack resource sharing and a heuristic for the general intrapipeline stage resource sharing. On an average the demand on arithmetic functional units can be reduced by 39.5% for a set of benchmarks from the multimedia domain using our resource sharing technique.