diff --git a/app/internal/callfn/callfn.go b/app/internal/callfn/callfn.go
index ed4cac3..023558d 100644
--- a/app/internal/callfn/callfn.go
+++ b/app/internal/callfn/callfn.go
@@ -2,7 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build android,arm
+// +build android
+// +build arm 386 amd64
 
 // Package callfn provides an android entry point.
 //
diff --git a/app/internal/callfn/callfn_386.s b/app/internal/callfn/callfn_386.s
new file mode 100644
index 0000000..d2bb54f
--- /dev/null
+++ b/app/internal/callfn/callfn_386.s
@@ -0,0 +1,11 @@
+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+#include "textflag.h"
+#include "funcdata.h"
+
+TEXT ·CallFn(SB),$0-4
+	MOVL fn+0(FP), AX
+	CALL AX
+	RET
diff --git a/app/internal/callfn/callfn_amd64.s b/app/internal/callfn/callfn_amd64.s
new file mode 100644
index 0000000..8769604
--- /dev/null
+++ b/app/internal/callfn/callfn_amd64.s
@@ -0,0 +1,11 @@
+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+#include "textflag.h"
+#include "funcdata.h"
+
+TEXT ·CallFn(SB),$0-8
+	MOVQ fn+0(FP), AX
+	CALL AX
+	RET