diff --git a/.gitea/workflows/build.yml b/.gitea/workflows/build.yml
new file mode 100644
index 0000000..2ad575b
--- /dev/null
+++ b/.gitea/workflows/build.yml
@@ -0,0 +1,24 @@
+name: Build nix packages
+on: [push]
+
+jobs:
+  npc-test:
+    runs-on: nix
+    steps:
+      - uses: https://github.com/cachix/cachix-action@v14
+        with:
+          name: ysyx
+          authToken: '${{ secrets.CACHIX_SIGNING_KEY }}'
+      - uses: actions/checkout@v4
+      - name: Cache develop environment
+        id: cache-nix-develop
+        uses: actions/cache@v4
+        with:
+          path: |
+            /nix/store
+            /nix/var/nix/db
+          key: nix-develop-${{ hashFiles('flake.*') }}
+      - name: Build am-kernels
+        run: |
+          nix build .#{am-kernels}
+          nix build .#rv32Cross.{am-kernels-nemu, am-kernels-npc}
diff --git a/.gitignore b/.gitignore
index fe30a49..fa429be 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,15 +1,43 @@
-!*/
-!*.h
-!*.c
-!*.cc
-!*.S
-!Makefile
-!README
-!README.md
-!LICENSE
-.*
-_*
-*~
 build/
-!.gitignore
 out/
+.cache/
+.envrc
+.vscode/
+# Created by https://www.toptal.com/developers/gitignore/api/c++
+# Edit at https://www.toptal.com/developers/gitignore?templates=c++
+
+### C++ ###
+# Prerequisites
+*.d
+
+# Compiled Object files
+*.slo
+*.lo
+*.o
+*.obj
+
+# Precompiled Headers
+*.gch
+*.pch
+
+# Compiled Dynamic libraries
+*.so
+*.dylib
+*.dll
+
+# Fortran module files
+*.mod
+*.smod
+
+# Compiled Static libraries
+*.lai
+*.la
+*.a
+*.lib
+
+# Executables
+*.exe
+*.out
+*.app
+
+# End of https://www.toptal.com/developers/gitignore/api/c++