Micro-Coded Datapaths: Populating the Space Between Finite State Machine and Processor

Domain-specific design flows can enable an efficient path to implementation, as well as making the design process intuitive and the designs reusable. When targeting FPGAs, there are few techniques in high level synthesis that enable thorough exploration of the inherent flexibility of the FPGA fabric as an implementation medium. In this paper, we propose a new methodology, based on micro-coded datapaths, that enables design space exploration of processing engine architectures implemented in programmable logic that range from a fixed finite state machine to a soft processor. As a use case, these processing engines can be embedded within programmable logic threads that are used to carry out network packet processing. We demonstrate the application of this methodology on a network address translation application, and show that micro-coded data paths indeed enable both human designers and automated tools to explore the design space in a structured way, thus exploiting the full potential of the FPGA technology.