[pypy-dev] Re: Ints vs Longs

[Florian Schulze]

On Mon, 13 Oct 2003 10:58:14 +0100, Michael Hudson <mwh at python.net> wrote:

> Florian Schulze <florian.proff.schulze at gmx.net> writes:
>
>> I just wondered what happens when ints overflow.
>
> In PyPy, um, I'm not sure :-) We don't have a long type in the
> StdObjSpace yet, so I guess you'll get an overflow error.
>
>> This question also applies to Psyco.
>
> Psyco correctly detects overflow and returns a long.
>
> For mulitplication, at least, this is easier in machine code than C...

That's because there is an overflow flag ;)

>> Is a long returned? How much of a speed penalty does occure due to
>> this?
>
> I don't know.  It's probably quite substantial.

Hmm, now that you mentioned that Psyco uses machinecode, I think the 
penalty is not *that* high. It depends on how well the processor handles 
the branching, I guess.

Florian