On 18.03.2009 21:08 Uhr, ron minnich wrote:
> On Wed, Mar 18, 2009 at 12:48 PM, Ward Vandewege <[email protected]> wrote:
>
>
>> Confirmed, removing -fomit-frame-pointer fixes the boot with FILO.
>>
>
> so you might want to look at the filo entry point and see if it
> expecting some reasonable value in %ebp. If so, we can probably fix
> the boot code to always set something sane in %ebp, no matter how
> coreboot is compiled.
>
> Really, though, I don't think coreboot runs for a long enough time
> that omitting frame pointers is a huge performance win. It would just
> be nice to confirm WHY this is happening.
>
> ron
>
>
I think we're doing this because of code size rather than speed.
-fomit-frame-pointer
Don't keep the frame pointer in a register for functions that
don't
need one. This avoids the instructions to save, set up and
restore
frame pointers; it also makes an extra register available in many
functions.
[...]
Enabled at levels -O, -O2, -O3, -Os.
The reason I brought this into v2 is that the "so much cooler" v3 has
been using it for quite a while ;-)
--
coresystems GmbH • Brahmsstr. 16 • D-79104 Freiburg i. Br.
Tel.: +49 761 7668825 • Fax: +49 761 7664613
Email: [email protected] • http://www.coresystems.de/
Registergericht: Amtsgericht Freiburg • HRB 7656
Geschäftsführer: Stefan Reinauer • Ust-IdNr.: DE245674866
--
coreboot mailing list: [email protected]
http://www.coreboot.org/mailman/listinfo/coreboot
