diff --git a/sm4/sm4_gcm.go b/sm4/sm4_gcm.go
index 4318b8d..8cf74d3 100644
--- a/sm4/sm4_gcm.go
+++ b/sm4/sm4_gcm.go
@@ -1,5 +1,6 @@
 //go:build amd64
 // +build amd64
+
 package sm4
 
 import (