Hardware software co-design in Haskell

We present a library in Haskell for programming Field Programmable Gate Arrays (FPGAs), including hardware software co-design. Code for software (in C) and hardware (in VHDL) is generated from a single program, along with the code to support communication between hardware and software. We present type-based techniques for the simultaneous implementation of more than one embedded domain specific language (EDSL). We build upon a generic representation of imperative programs that is loosely coupled to instruction and expression types, allowing the individual parts to be developed and improved separately. Code generation is implemented as a series of translations between progressively smaller, typed EDSLs, safeguarding against errors that arise in untyped translations. Initial case studies show promising performance.