diff --git a/nemu/src/device/timer.c b/nemu/src/device/timer.c
index 27e4e01..a582580 100644
--- a/nemu/src/device/timer.c
+++ b/nemu/src/device/timer.c
@@ -26,6 +26,7 @@ static void rtc_io_handler(uint32_t offset, int len, bool is_write) {
     printf("rtc_io_handle %ld\n", us);
     rtc_port_base[0] = (uint32_t)us;
     rtc_port_base[1] = us >> 32;
+    printf("rtc_port_handle %d, %d [%p]\n", rtc_port_base[0], rtc_port_base[1], rtc_port_base);
   }
 }