Fix decimal128 0 comp

Author: mborland

include/boost/decimal/detail/comparison.hpp

@@ -97,8 +97,11 @@ constexpr auto equal_parts_impl(T1 lhs_sig, U1 lhs_exp, bool lhs_sign,
 
     // Check the value of delta exp to avoid to large a value for pow10
     // Also if only one of the significands is 0 then we know the values have to be mismatched
-    if (delta_exp > detail::precision_v<DecimalType> || delta_exp < -detail::precision_v<DecimalType> ||
-        ((new_lhs_sig == static_cast<comp_type>(0)) ^ (new_rhs_sig == static_cast<comp_type>(0))))
+    if (new_lhs_sig == static_cast<comp_type>(0) && new_rhs_sig == static_cast<comp_type>(0))
+    {
+        return true;
+    }
+    if (delta_exp > detail::precision_v<DecimalType> || delta_exp < -detail::precision_v<DecimalType>)
     {
         return false;
     }