A question on GCC march setting

satimis · 08-21-2006, 10:28 AM

Hi folks,

AMD Athlon64 PC

I'm reading "Gentoo Linux AMD64 Handbook"
http://www.gentoo.org/doc/en/handboo...book-amd64.xml
and come to following section;
5.e. Configuring the Compile Options
http://www.gentoo.org/doc/en/handboo...?part=1&chap=5

Code Listing 17: The GCC march setting

Code:

# AMD64 users who want to use a native 64 bit system should use -march=k8
#EM64T users should use -march=nocona
-march=athlon-xp

If I want to use native 64 bit system and set "-march=k8", can 32 bit Linux software run on Gentoo?

What does "-march=athlon-xp" refer to?

TIA

B.R.
satimis

weibullguy · 08-21-2006, 10:35 AM

Quote:

athlon-xp
Improved AMD Athlon CPU with MMX, 3dNOW!, enhanced 3dNOW! and full SSE instruction set support.

Quote:

k8
AMD K8 core based CPUs with x86-64 instruction set support. (This supersets MMX, SSE, SSE2, 3dNOW!, enhanced 3dNOW! and 64-bit instruction set extensions.)

These are described in the gcc manual in section 3.17.

Yes, 32-bit applications will run in 64-bit Gentoo.