A computation- and communication- infrastructure for modular special instructions in a dynamically reconfigurable processor

Processors with a reconfigurable instruction set combine the performance of dedicated application accelerators with a flexibility that goes beyond that of traditional application specific instruction set processors (ASIPs). The latter are optimized for certain application domains and thus typically do not provide a high performance and/or efficiency when deployed in other domains. State-of-the-art reconfigurable processors on the other side still use the concept of monolithic Special Instructions (SIs, i.e. the application accelerators). In our work, we instead present modular SIs as a hierarchy of elementary data paths and different SI implementations that facilitate a high flexibility and performance. This is a novel concept that achieves a speedup of 26.6x compared to a general purpose processor and 1.24x compared to a state-of-the-art reconfigurable processor (that is statically optimized for the predetermined benchmark situation) when executing an H.264 video encoder. We introduce a novel infrastructure for computation and communication that actually enables the implementation of modular SIs and offers various parameters to match specific requirements. The infrastructure is implemented and tested on an FPGA-based prototype to demonstrate its feasibility.