diff --git a/npc/flake.lock b/npc/flake.lock
new file mode 100644
index 0000000..9d7ed7c
--- /dev/null
+++ b/npc/flake.lock
@@ -0,0 +1,61 @@
+{
+  "nodes": {
+    "flake-utils": {
+      "inputs": {
+        "systems": "systems"
+      },
+      "locked": {
+        "lastModified": 1701680307,
+        "narHash": "sha256-kAuep2h5ajznlPMD9rnQyffWG8EM/C73lejGofXvdM8=",
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "rev": "4022d587cbbfd70fe950c1e2083a02621806a725",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "type": "github"
+      }
+    },
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1703013332,
+        "narHash": "sha256-+tFNwMvlXLbJZXiMHqYq77z/RfmpfpiI3yjL6o/Zo9M=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "54aac082a4d9bb5bbc5c4e899603abfb76a3f6d6",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixos-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "flake-utils": "flake-utils",
+        "nixpkgs": "nixpkgs"
+      }
+    },
+    "systems": {
+      "locked": {
+        "lastModified": 1681028828,
+        "narHash": "sha256-Vy1rq5AaRuLzOxct8nz4T6wlgyUR7zLU309k9mBC768=",
+        "owner": "nix-systems",
+        "repo": "default",
+        "rev": "da67096a3b9bf56a91d16901293e51ba5b49a27e",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-systems",
+        "repo": "default",
+        "type": "github"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}
diff --git a/npc/flake.nix b/npc/flake.nix
new file mode 100644
index 0000000..3c5c8af
--- /dev/null
+++ b/npc/flake.nix
@@ -0,0 +1,24 @@
+{
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
+    flake-utils.url = "github:numtide/flake-utils";
+  };
+
+  outputs = { self, ... }@inputs: with inputs;
+    flake-utils.lib.eachDefaultSystem (system:
+     let pkgs = nixpkgs.legacyPackages.${system}; in
+      {
+        devShells.default = pkgs.mkShell {
+          packages = with pkgs; [
+            verilator
+            gtkwave
+            gcc
+            bear
+          ];
+          shellHook = ''
+            export NEMU_HOME=/home/xin/repo/ysyx-workbench/nemu
+          '';
+        };
+      }
+    );
+}