diff --git a/src/kservice.c b/src/kservice.c
index 7c62901e36..dd95fe029a 100644
--- a/src/kservice.c
+++ b/src/kservice.c
@@ -1375,8 +1375,7 @@ const rt_uint8_t __lowest_bit_bitmap[] =
  */
 int __rt_ffs(int value)
 {
-    rt_uint32_t result = (rt_uint32_t)value;
-    return __lowest_bit_bitmap[ (result & (result - 1) ^ result) % 37];
+    return __lowest_bit_bitmap_new[(rt_uint32_t)(value & (value - 1) ^ value) % 37];
 }
 #else
 const rt_uint8_t __lowest_bit_bitmap[] =