presto-spi/src/main/java/io/prestosql/spi/type/UnscaledDecimal128Arithmetic.java/UnscaledDecimal128Arithmetic/compare
class UnscaledDecimal128Arithmetic:    public static int compare(long leftRawLow, long leftRawHigh, long rightRawLow, long rightRawHigh)
    {
        boolean leftStrictlyNegative = isStrictlyNegative(leftRawLow, leftRawHigh);
        boolean rightStrictlyNegative = isStrictlyNegative(rightRawLow, rightRawHigh);

        if (leftStrictlyNegative != rightStrictlyNegative) {
            return leftStrictlyNegative ? -1 : 1;
        }
        else {
            long leftHigh = unpackUnsignedLong(leftRawHigh);
            long rightHigh = unpackUnsignedLong(rightRawHigh);
            return compareUnsigned(leftRawLow, leftHigh, rightRawLow, rightHigh) * (leftStrictlyNegative ? -1 : 1);
        }
    }