fix another case, quick tests passing

Author: tgross35

src/math/log.rs

@@ -308,12 +308,15 @@ impl DInt64 {
         }
 
         match self.cmp(&other) {
-            Ordering::Less => {
+            Ordering::Equal => {
                 if (self.sign ^ other.sign) != 0 {
                     return DInt64::ZERO;
                 }
+                let mut ret = self.clone();
+                ret.ex += 1;
+                return ret;
             }
-            Ordering::Equal => {
+            Ordering::Less => {
                 return other.add(self);
             }
             Ordering::Greater => (),