Implementation of an Embedded Hardware Description Language Using Haskell

This paper describes an ongoing implementation of an embedded hardware description language (HDL) using Haskell as a host language. Traditionally, “functional” HDL’s are made using lazy lists to model signals, so circuits are functions from lists of input values to lists of output values. We use another known approach for embedded languages, in which circuits are data structures rather than functions. This style of implementation permits one to inspect the structure of the circuit, allowing one to perform different interpretations for the same description. The approach we present can also be applied to other domain-specific embedded languages. We provide an elegant implementation of memories and a set of new signal types.