diff --git a/flap/runtime/runtime.c b/flap/runtime/runtime.c
index 5e6adf5..e428878 100644
--- a/flap/runtime/runtime.c
+++ b/flap/runtime/runtime.c
@@ -35,3 +35,7 @@ int64_t write_block(intptr_t *block, int64_t n, intptr_t v) {
   block[n] = v;
   return 0;
 }
+
+void add_eight_int(int64_t x1,int64_t x2,int64_t x3,int64_t x4,int64_t x5, int64_t x6,int64_t x7,int64_t x8) {
+  return observe_int(x1+x2+x3+x4+x5+x6+x7+x8);
+}