py/mpz: Normalize (remove leading zeros) xor operation result.

1 files changed, 5 insertions, 1 deletions

diff --git a/py/mpz.c b/py/mpz.c
index e0475d60a1..2a4fb4659d 100644
--- a/py/mpz.c
+++ b/py/mpz.c
@@ -285,7 +285,11 @@ STATIC mp_uint_t mpn_xor(mpz_dig_t *idig, const mpz_dig_t *jdig, mp_uint_t jlen,
         *idig = *jdig;
     }
 
-    return idig - oidig;
+    // remove trailing zeros
+    for (--idig; idig >= oidig && *idig == 0; --idig) {
+    }
+
+    return idig + 1 - oidig;
 }
 
 /* computes i = i * d1 + d2