presto-main/src/main/java/io/prestosql/operator/scalar/MathFunctions.java/MathFunctions/signFloat
class MathFunctions:    @Description("signum")
    @ScalarFunction("sign")
    @SqlType(StandardTypes.REAL)
    public static long signFloat(@SqlType(StandardTypes.REAL) long num)
    {
        return floatToRawIntBits((Math.signum(intBitsToFloat((int) num))));
    }