[SOLVED] x86 on amd64

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OtonVM · Post by **OtonVM** » Thu Jun 08, 2006 6:02 pm

Hello!

A really quick yes/no question: Can I install a pure 32bit system with the amd64 livecd?

Thank you!

Enlight · Post by **Enlight** » Thu Jun 08, 2006 6:05 pm

yes! do as if you had an athlon-xp.

ksp7498 · Post by **ksp7498** » Thu Jun 08, 2006 6:12 pm

^ yeah just do it as an athlon xp and add on sse2 support. -march=athlon-xp -msse2 would work great.

OtonVM · Post by **OtonVM** » Thu Jun 08, 2006 6:24 pm

Ok, thank you both! It's just that the i686 livecd fails to detect stuff whareas amd64 works...

Enlight · Post by **Enlight** » Fri Jun 09, 2006 9:06 am

ksp7498 wrote:^ yeah just do it as an athlon xp and add on sse2 support. -march=athlon-xp -msse2 would work great.

and -msse3 if you have the pni flag in /proc/cpuinfo

LinuxMan · Post by **LinuxMan** » Fri Jun 09, 2006 10:44 am

No. Need -march=athlon64 -msse3 . With these CFLAGS build 32bit executable but with optimizations for athlon64

Enlight · Post by **Enlight** » Fri Jun 09, 2006 11:49 am

LinuxMan wrote:No. Need -march=athlon64 -msse3 . With these CFLAGS build 32bit executable but with optimizations for athlon64

you're right as "-march=athlon64" is like -"mtune=athlon64 -mmmx msse{,2,3} -m3dnow{,ext}"

Now I fscking wonder if "-mtune={athlon-xp,athlon64}" are similar or if alignements variables changes, and in this case, wich one works best for a 32 bit install (or multilib with -m32).

OtonVM · Post by **OtonVM** » Fri Jun 09, 2006 1:41 pm

For now I put CFLAGS="-O2 -march=athlon-xp -pipe -msse2 -msse3" and I'm pretty happy with them. I have no need for all the optimization on this world. This should be enough and stable. I found many things that didn't compile with athlon64 and I was getting sick of it. That's why I'm doing this in the first place.

CaptainDangeax · Post by **CaptainDangeax** » Sun Jun 11, 2006 5:57 pm

If you're using a 32bits kernel, DON'T set march=k8 or march=athlon64, you will generate 64bits progs and they won't run. As said before, the best is -march=athlon-xp with the corrects switches.

OtonVM · Post by **OtonVM** » Sun Jun 11, 2006 6:04 pm

Exactly!

htranou · Post by **htranou** » Sun Jun 11, 2006 7:34 pm

CaptainDangeax wrote:If you're using a 32bits kernel, DON'T set march=k8 or march=athlon64, you will generate 64bits progs and they won't run. As said before, the best is -march=athlon-xp with the corrects switches.

Actually, you can. If GCC was built to build for i686 (or whatever x86 you put), it will only build those. I have a 32bit system with march=athlon64, and it works fine.

Though, athlon64 was only introduced in GCC 3.4, but since 3.4 is now in the stable tree...