An Efficient SRAM-Based Reconfigurable Architecture for Embedded Processors

Nowadays, embedded processors are widely used in wide range of domains from low-power to safety-critical applications. By providing prominent features such as variant peripheral support and flexibility to partial or major design modifications, field-programmable gate arrays (FPGAs) are commonly used to implement either an entire embedded system or a hardware description language-based processor, known as soft-core processor. FPGA-based designs, however, suffer from high power consumption, large die area, and low performance that hinders common use of soft-core processors in low-power embedded systems. In this paper, we present an efficient reconfigurable architecture to implement soft-core embedded processors in SRAM-based FPGAs by using characteristics such as low utilization and fragmented accessibility of comprising units. To this end, we integrate the low utilized functional units into efficiently designed look-up table (LUT)-based reconfigurable units (RUs). To further improve the efficiency of the proposed architecture, we used a set of efficient configurable hard logics that implement frequent Boolean functions while the other functions will still be employed by LUTs. We have evaluated effectiveness of the proposed architecture by implementing the Berkeley RISC-V processor and running MiBench benchmarks. We have also examined the applicability of the proposed architecture on an alternative open-source processor (i.e., LEON2) and a digital signal processing core. Experimental results show that the proposed architecture as compared to the conventional LUT-based soft-core processors improves area footprint, static power, energy consumption, and total execution time by 30.7%, 32.5%, 36.9%, and 6.3%, respectively.