FRIDA: Reconfigurable Arrays for Dynamically Scheduled High-Level Synthesis

Reconfigurable computing fabrics include FPGAs and CGRAs. FPGAs offer flexible bit-level reconfigurability and can map almost any program via high-level synthesis (HLS) compilers, but they incur high area and speed overheads compared to ASICs. CGRAs, in contrast, provide ASIC-like performance but limited flexibility, typically supporting only feedforward programs with unambiguous memory accesses, far from the capabilities of HLS compilers. This work introduces a new class of reconfigurable arrays inspired by modern dynamically scheduled HLS (DHLS) tools. Unlike traditional HLS, DHLS compilers no longer produce explicit state machines, eliminating the need for look-up tables. Instead, they delegate scheduling decisions to a set of coarse-grained primitives. Our arrays leverage these primitives as processing elements and combine FPGA-style interconnect topology for high routing flexibility with CGRA-like bus-based interconnect. We present a framework to explore these arrays and evaluate a preliminary architecture using DHLS benchmarks. The results show an average of ~2× speed improvement, but unfortunately only a ~20% area reduction compared to an FPGA implemented on the same technology node.