diff --git a/library/bignum_core.c b/library/bignum_core.c
index ba6c0c1..a99b3be 100644
--- a/library/bignum_core.c
+++ b/library/bignum_core.c
@@ -71,12 +71,10 @@
     int i;
     size_t j;
 
-    if (A_limbs != 0) {
-        for (i = (int) A_limbs - 1; i >= 0; i--) {
-            if (A[i] != 0) {
-                j = biL - mbedtls_mpi_core_clz(A[i]);
-                return (i * biL) + j;
-            }
+    for (i = ((int) A_limbs) - 1; i >= 0; i--) {
+        if (A[i] != 0) {
+            j = biL - mbedtls_mpi_core_clz(A[i]);
+            return (i * biL) + j;
         }
     }