presto-main/src/main/java/io/prestosql/type/RealOperators.java/RealOperators/castToDouble
class RealOperators:    @ScalarOperator(CAST)
    @SqlType(StandardTypes.DOUBLE)
    public static double castToDouble(@SqlType(StandardTypes.REAL) long value)
    {
        return (double) intBitsToFloat((int) value);
    }