presto-main/src/main/java/io/prestosql/operator/scalar/MathFunctions.java/MathFunctions/floorFloat
class MathFunctions:    @Description("round down to nearest integer")
    @ScalarFunction("floor")
    @SqlType(StandardTypes.REAL)
    public static long floorFloat(@SqlType(StandardTypes.REAL) long num)
    {
        return floatToRawIntBits((float) floor(intBitsToFloat((int) num)));
    }