Re: Recommended compile flags for Lenny armel on NSLU2
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
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