diff --git a/nemu/src/device/timer.c b/nemu/src/device/timer.c
index 98ced99..9e680ec 100644
--- a/nemu/src/device/timer.c
+++ b/nemu/src/device/timer.c
@@ -19,6 +19,7 @@
 
 static uint32_t *rtc_port_base = NULL;
 
+__attribute_noinline__
 static void rtc_io_handler(uint32_t offset, int len, bool is_write) {
   assert(offset == 0 || offset == 4);
   if (!is_write && offset == 4) {