diff --git a/UBigInt.pas b/UBigInt.pas
index a49ea16..4c8505e 100644
--- a/UBigInt.pas
+++ b/UBigInt.pas
@@ -237,10 +237,17 @@ class function TBigInt.SubtractAbsoluteValues(constref AA, AB: TBigInt; const AR
 var
   a, b: TBigInt;
   carry: Cardinal;
-  i, j, lastNonZeroDigitIndex, len: Integer;
+  compare, i, j, lastNonZeroDigitIndex, len: Integer;
 begin
   // Establishes the operand order, such that Abs(a) is not less than Abs(b).
-  if (AA.CompareToAbsoluteValues(AB) >= 0) then
+  compare := AA.CompareToAbsoluteValues(AB);
+  if compare = 0 then
+  begin
+    Result := Zero;
+    Exit;
+  end;
+
+  if compare > 0 then
   begin
     a := AA;
     b := AB;