use Nix devenv to manage project environment

.envrc

@@ -0,0 +1,3 @@
+source_url "https://raw.githubusercontent.com/cachix/devenv/95f329d49a8a5289d31e0982652f7058a189bfca/direnvrc" "sha256-d+8cBpDfDBj41inrADaJt+bDWhOktwslgoP5YiGJ1v0="
+
+use devenv

.gitignore

@@ -1,5 +1,6 @@
 .idea/
 .vscode/
+.devenv/
 /CFA/sim/work/**
 *.wlf
 *.mpf
@@ -13,4 +14,12 @@
 *.png
 !im.tif
 *.bmp
-*.out
+*.out# Devenv
+.devenv*
+devenv.local.nix
+
+# direnv
+.direnv
+
+# pre-commit
+.pre-commit-config.yaml

Color/SaturationCorrection.sv

@@ -116,8 +116,8 @@ module SaturationCorrection #(
 
               calState <= 3;
             end else if (calState == 3) begin
-              alpha <= (saturation_inc[31] == 0) ? ((saturation_inc + saturation >= 256)
-                    ? (65536 / saturation) - 256 : (65536 / (256 - saturation_inc)) - 256)
+              alpha <= (saturation_inc[31] == 0) ? ((saturation_inc + saturation >= 255)
+                    ? (65536 / saturation) - 255 : (65536 / (256 - saturation_inc)) - 255)
                     : (saturation_inc);
 
               calState <= 4;

devenv.lock

@@ -0,0 +1,122 @@
+{
+  "nodes": {
+    "devenv": {
+      "locked": {
+        "dir": "src/modules",
+        "lastModified": 1725637114,
+        "owner": "cachix",
+        "repo": "devenv",
+        "rev": "c31e347a96dbb7718a0279afa993752a7dfc6a39",
+        "treeHash": "e0dfcbbfb0974603336900406b364bd4d1308fa4",
+        "type": "github"
+      },
+      "original": {
+        "dir": "src/modules",
+        "owner": "cachix",
+        "repo": "devenv",
+        "type": "github"
+      }
+    },
+    "flake-compat": {
+      "flake": false,
+      "locked": {
+        "lastModified": 1696426674,
+        "owner": "edolstra",
+        "repo": "flake-compat",
+        "rev": "0f9255e01c2351cc7d116c072cb317785dd33b33",
+        "treeHash": "2addb7b71a20a25ea74feeaf5c2f6a6b30898ecb",
+        "type": "github"
+      },
+      "original": {
+        "owner": "edolstra",
+        "repo": "flake-compat",
+        "type": "github"
+      }
+    },
+    "gitignore": {
+      "inputs": {
+        "nixpkgs": [
+          "pre-commit-hooks",
+          "nixpkgs"
+        ]
+      },
+      "locked": {
+        "lastModified": 1709087332,
+        "owner": "hercules-ci",
+        "repo": "gitignore.nix",
+        "rev": "637db329424fd7e46cf4185293b9cc8c88c95394",
+        "treeHash": "ca14199cabdfe1a06a7b1654c76ed49100a689f9",
+        "type": "github"
+      },
+      "original": {
+        "owner": "hercules-ci",
+        "repo": "gitignore.nix",
+        "type": "github"
+      }
+    },
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1716977621,
+        "owner": "cachix",
+        "repo": "devenv-nixpkgs",
+        "rev": "4267e705586473d3e5c8d50299e71503f16a6fb6",
+        "treeHash": "6d9f1f7ca0faf1bc2eeb397c78a49623260d3412",
+        "type": "github"
+      },
+      "original": {
+        "owner": "cachix",
+        "ref": "rolling",
+        "repo": "devenv-nixpkgs",
+        "type": "github"
+      }
+    },
+    "nixpkgs-stable": {
+      "locked": {
+        "lastModified": 1725693463,
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "68e7dce0a6532e876980764167ad158174402c6f",
+        "treeHash": "ee872ee4d2426a6c3e1e4b3fa844550ce1b52b29",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixos-24.05",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "pre-commit-hooks": {
+      "inputs": {
+        "flake-compat": "flake-compat",
+        "gitignore": "gitignore",
+        "nixpkgs": [
+          "nixpkgs"
+        ],
+        "nixpkgs-stable": "nixpkgs-stable"
+      },
+      "locked": {
+        "lastModified": 1725513492,
+        "owner": "cachix",
+        "repo": "pre-commit-hooks.nix",
+        "rev": "7570de7b9b504cfe92025dd1be797bf546f66528",
+        "treeHash": "4b46d77870afecd8f642541cb4f4927326343b59",
+        "type": "github"
+      },
+      "original": {
+        "owner": "cachix",
+        "repo": "pre-commit-hooks.nix",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "devenv": "devenv",
+        "nixpkgs": "nixpkgs",
+        "pre-commit-hooks": "pre-commit-hooks"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}

devenv.nix

@@ -0,0 +1,59 @@
+{ pkgs, lib, config, inputs, ... }:
+
+{
+  # https://devenv.sh/basics/
+  env.GREET = "devenv";
+
+  # https://devenv.sh/packages/
+  packages = with pkgs; [
+    git
+    verilator
+    systemc
+    verible
+    svls
+    gtkwave
+  ];
+
+  # https://devenv.sh/languages/
+  languages.rust.enable = true;
+  languages.c.enable = true;
+  languages.cplusplus.enable = true;
+
+  # https://devenv.sh/processes/
+  # processes.cargo-watch.exec = "cargo-watch";
+
+  # https://devenv.sh/services/
+  # services.postgres.enable = true;
+
+  # https://devenv.sh/scripts/
+  scripts.addEnv.exec = ''
+    export SYSTEMC_INCLUDE="${pkgs.systemc}/include"
+    echo $SYSTEMC_INCLUDE
+    export SYSTEMC_LIBDIR="${pkgs.systemc}/lib"
+    echo $SYSTEMC_LIBDIR
+  '';
+
+  enterShell = ''
+    addEnv
+    echo
+
+    git --version
+    echo
+
+    verilator --version
+    echo
+
+    gcc --version
+  '';
+
+  # https://devenv.sh/tests/
+  enterTest = ''
+    echo "Running tests"
+    git --version | grep --color=auto "${pkgs.git.version}"
+  '';
+
+  # https://devenv.sh/pre-commit-hooks/
+  # pre-commit.hooks.shellcheck.enable = true;
+
+  # See full reference at https://devenv.sh/reference/options/
+}

devenv.yaml

@@ -0,0 +1,15 @@
+# yaml-language-server: $schema=https://devenv.sh/devenv.schema.json
+inputs:
+  nixpkgs:
+    url: github:cachix/devenv-nixpkgs/rolling
+
+# If you're using non-OSS software, you can set allowUnfree to true.
+# allowUnfree: true
+
+# If you're willing to use a package that's vulnerable
+# permittedInsecurePackages:
+#  - "openssl-1.1.1w"
+
+# If you have more than one devenv you can merge them
+#imports:
+# - ./backend