diff --git a/.gitmodules b/.gitmodules
new file mode 100644
index 0000000..235d98c
--- /dev/null
+++ b/.gitmodules
@@ -0,0 +1,6 @@
+[submodule "ext/cryptocores"]
+	path = ext/cryptocores
+	url = https://git.goodcleanfun.de/tmeissner/cryptocores.git
+[submodule "ext/libvhdl"]
+	path = ext/libvhdl
+	url = https://git.goodcleanfun.de/tmeissner/libvhdl.git
diff --git a/ext/cryptocores b/ext/cryptocores
new file mode 160000
index 0000000..302ad79
--- /dev/null
+++ b/ext/cryptocores
@@ -0,0 +1 @@
+Subproject commit 302ad79ceddc851b88bfc119848c449634d261eb
diff --git a/ext/libvhdl b/ext/libvhdl
new file mode 160000
index 0000000..84d9a28
--- /dev/null
+++ b/ext/libvhdl
@@ -0,0 +1 @@
+Subproject commit 84d9a28afbf773fd3cdd2c7c83b2034fbcd1b033