c3-lang/libtommath

diff --git a/bn_mp_decr.c b/bn_mp_decr.c
index 9dd271a..ea63034 100644
--- a/bn_mp_decr.c
+++ b/bn_mp_decr.c
@@ -23,7 +23,7 @@ int mp_decr(mp_int *a)
       return MP_OKAY;
    } else if (a->dp[0] > 1uL) {
       a->dp[0]--;
-      if (a->dp[0] == 0) {
+      if (a->dp[0] == 0u) {
          mp_zero(a);
       }
       return MP_OKAY;