A logical model of a minimal RISC-V CPU written in Haskell.

This is an exercise to learn Nix, Haskell, and RISC-V. It is not intended to be useful, fast, or even complete.

The goal is to understand the inner workings of the RISC-V architecture from the bottom-up and learn Haskell concepts on the way. A possible outcome would be an emulator that can run RV32I assembly.

• Install Nix
  • follow instructions on https://nixos.org/download
• Enable flakes
  • follow instructions on https://nixos.wiki/wiki/Flakes#Enable_flakes
• (Optional) install direnv

• The structure of the project is dictated by the tools we are using, namely Nix and Cabal. This repository is both a Nix flake and a Cabal package and as such contains the following folders/files:
  • app/: Haskell source code for an executable that can be built and run by cabal run.
  • src/: Haskell library folder, each file inside is a Haskell module.
  • test/: Haskell source code for an executable that is built and run by cabal test, used to test the functions defined in src/.
  • CHANGELOG.md: This file will only become relevant in case of a release.
  • flake.nix: This is a Nix flake providing dependencies for the project.
  • flake.lock: File specifying the exact versions of dependencies, created by the nix flake lock command.
  • LICENSE: The Apache 2.0 license.
  • riscvs-hs.cabal: Cabal package description.
  • shell.nix: For compatibility with Nix without flakes as well as other tools.

• If you're using VSCode, you can use Nix environment selector to connect it with the Nix shell.

The RISC-V Instruction Set Manual