Gentoo on Athlon64

Config · Posted: Fri Jan 02, 2004 7:04 pm Post subject: Gentoo on Athlon64

I just recently ordered an Athlon64 3000+, which is going to arrive pretty soon - and of course, Gentoo is going to be the OS installed on it.
From what I've read, there are 3 modes it can run on:
- Compat (32-bit mode)
- 64-compat (Enabling 64-bit extensions, but keeping 32-bit compatibility)
- 64-bit (Only 64-bit apps run on it)

Of course, Gentoo true 64-bit would be nice, but I've read too, that an app is has to be ported to it - if this is the case, there aren't so many apps to choose from.
So in what mode would you install Gentoo? And what are some of the drawbacks? Thanks a lot
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mad man moon · Posted: Sat Jan 03, 2004 11:21 am Post subject:

I would take 64-compat. There you get the best of two worlds:
Most apps are still not ported to 64bit, but you can still use them.
Your able to use the ported apps with better performance than in 32bit mode.
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the lone crouton · Tux's lil' helper Joined: 11 Aug 2003 Posts: 119

Does the source need to be "ported?" Surely you just compile it with k8 in you CFLAGS???

jshaw523 · n00b Joined: 29 Dec 2003 Posts: 12 Location: Columbus, OH

If the software is well written then it should be a simple matter of just compiling things with the right cflags... but unfortunetly some software isn't well written. Occasionally you will have people that do things like memcpy to copy arrays and what not that might not have the same desired results when you change the integer from 32bit words to 64bit words. Occasionally some people will sneak asm into there C code because they wanted to do something quickly and they will reference the old 32bit or even 16bit registers on the x86. While I don't know that referencing the old 32 bit registers causes a problem (referencing the old 16 bit registers doesn't cause a problem on 32 bit x86 CPU's) it might. So in short, just compiling the code with an x86-64 version of GCC doesn't mean everything out there will work right. Because of this I would definitly go with 64-compat mode so you can go back to 32 bit if you have trouble getting an application to compile or run correctly.

Master_Of_Disaster · Posted: Sat Jan 10, 2004 1:34 am Post subject:

It seems that -march=k8 doesn't work yet...

floffe · Posted: Sat Jan 10, 2004 2:01 am Post subject:

I think it should be -march=athlon-4 (or possibly march=athlon64). The gcc 3.3.2 manual has this option with the other cpu options, but it is not specified what it does.