diff --git a/cpu/bf537/serial.c b/cpu/bf537/serial.c
index e04d08a..f7a2483 100644
--- a/cpu/bf537/serial.c
+++ b/cpu/bf537/serial.c
@@ -52,6 +52,8 @@
 #include <asm/io.h>
 #include "serial.h"
 
+DECLARE_GLOBAL_DATA_PTR;
+
 unsigned long pll_div_fact;
 
 void calc_baud(void)
@@ -74,7 +76,6 @@
 void serial_setbrg(void)
 {
 	int i;
-	DECLARE_GLOBAL_DATA_PTR;
 
 	calc_baud();