Increasing computational density of application-specific systems

Application-specific systems are increasingly being deployed on reconfigurable computing platforms such as the field-programmable gate array (FPGA). These systems can integrate many disparate computing elements, and often contain soft processors hosting application components. Soft processors are sequential, synchronous devices with low computational density, and are not capable of exploiting the concurrency available on the FPGA. We present a method for increasing the computational density of application-specific systems by eliminating soft processors within these systems. This method eliminates soft processors by replacing programs that would be hosted on soft processors with custom, self-contained, circuitizable finite-state machine with datapath (FSMD) components that are automatically generated. We show that FS-MDs produced using this method eliminate the computational overhead associated with fetching and decoding instructions. We further show that this method, when applied to interrupt-driven programs, can produce concurrent FSMDs that arbitrate for shared datapath resources. We discuss how these FSMDs are capable of leveraging the spatial computational capabilities of the FPGA and are therefore more aptly suited for deployment within application-specific systems. We show that these FSMDs eliminate overhead associated with interrupt context switching, decrease interrupt servicing latencies, and eliminate interrupt livelock. We discuss implications and limitations of this method, and describe a prototype that implements the method for programs targeted for the Intel 8051.