public static void negate(Slice decimal)
    {
        setNegative(decimal, !isNegative(decimal));
    }
@Test
    public void testAddReturnOverflow()
    {
        assertAddReturnOverflow(TWO, TWO);
        assertAddReturnOverflow(MAX_DECIMAL_UNSCALED_VALUE, MAX_DECIMAL_UNSCALED_VALUE);
        assertAddReturnOverflow(MAX_DECIMAL_UNSCALED_VALUE.negate(), MAX_DECIMAL_UNSCALED_VALUE);
        assertAddReturnOverflow(MAX_DECIMAL_UNSCALED_VALUE, MAX_DECIMAL_UNSCALED_VALUE.negate());
        assertAddReturnOverflow(MAX_DECIMAL_UNSCALED_VALUE.negate(), MAX_DECIMAL_UNSCALED_VALUE.negate());
    }