diff --git a/riscv/main.c b/riscv/main.c
index ed9b092..91b21a1 100644
--- a/riscv/main.c
+++ b/riscv/main.c
@@ -46,6 +46,9 @@ int main()
   int b=2;
   typedef void (*fun_t)(void);
   fun_t fun = (fun_t)0;
+  set_csr(mstatus, 0x00000008);
+  set_csr(mie, (1 << 3) | (1 << 7));
+  set_csr(mip, (1 << 3));
   fun();
   int c = add(a, b);
   my_printf("Hello World! %s\n", "Andy");
@@ -55,10 +58,10 @@ int main()
   fun();
   my_printf("mul(%d, %d)=%d\n", a, b, a * b);
   my_printf("ram_val test: %s\n", g_string);
-  set_csr(mstatus, 0x00000008);
-  set_csr(mie, (1 << 3));
-  set_csr(mip, (1 << 3));
   cpu_test();
 
+  my_printf("enter while 1\n");
+  while (1) {
+  }
   return 0;
 }
\ No newline at end of file