Re: Recommended compile flags for Lenny armel on NSLU2

[Alan Snelgrove <alansnelgrove@mac.com>]

> On 9/22/08, Alan Snelgrove <alansnelgrove@mac.com> wrote:
> >  CFLAGS=" -O4 -pipe -fomit-frame-pointer -ffast-math -mcpu=xscale
> > -mabi=aapcs-linux -mfloat-abi=softfp -mfpu=vfp"
> -mabi=aapcs-linux is the default for armel
>
> You may find that you get better performance from -O2, which performs
> all speed optimisations that do not significantly increase the size of
> the generated code. Or even from -Os, come to that.
> Looking at the GCC machine descriptions, I doubt that -ffast-math
> actually does anything on ARM.
>
> >  While the '-mfloat-abi=softfp' option compiling MPlayer OK it  
> > reported
> > "Illegal instruction" when run.
> Xscales don't have a VFP floating point coprocessor, so that's  
> correct.
>
> > But when I used '-mfloat-abi=soft' it compiled and runs OK.
> -mfloat-abi=soft is also the default in armel
>
> >  Mplayer doesn't detect ARMv5TE unless CFLAGS contains '-mcpu=xscale'
> Yes, the Debian compiler has been patched to default to armv4t, so
> that any package you compile will run on any Debian armel system.
>
>    M

Thanks for you reply Martin,
It did not cross my mind that the Debian compiler had been patched  
for armel.

So the -mfpu=vfp and -mcpu=xscale may still be useful?

Alan