vm: fix updating size inside bignum_gcd loop.

diff --git a/vm/bignum.cpp b/vm/bignum.cpp
index df706c1718ed9273b8d8b7a1a3e9e44b078e704f..82a23117aea8010e92a08b5c8559b61d00b1f11f 100755 (executable)
--- a/vm/bignum.cpp
+++ b/vm/bignum.cpp
@@ -1903,8 +1903,8 @@ bignum * factor_vm::bignum_gcd(bignum * a, bignum * b)
         BIGNUM_ASSERT (t == 0);
 
         // update size_a and size_b to remove any zeros at end
-        while (size_a > 0 && *(scan_a + size_a - 1) == 0) size_a--;
-        while (size_b > 0 && *(scan_b + size_b - 1) == 0) size_b--;
+        while (size_a > 0 && *(--scan_a) == 0) size_a--;
+        while (size_b > 0 && *(--scan_b) == 0) size_b--;
     }
 
     e = bignum_trim (a);