presto-spi/src/main/java/io/prestosql/spi/type/UnscaledDecimal128Arithmetic.java/UnscaledDecimal128Arithmetic/add
class UnscaledDecimal128Arithmetic:    public static void add(Slice left, Slice right, Slice result)
    {
        long overflow = addWithOverflow(left, right, result);
        if (overflow != 0) {
            throwOverflowException();
        }
    }