On Sun, Sep 18, 2005 at 08:49:12PM -0700, maxim wexler wrote
> 
> 
> --- Mark Knecht <[EMAIL PROTECTED]> wrote:
> 
> > On 9/18/05, maxim wexler <[EMAIL PROTECTED]> wrote:
> > <SNIP>
> > > flags           : fpu vme de pse tsc msr pae mce cx8
> > > apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr
> > > sse sse2 syscall nx mmxext 3dnowext 3dnow
> > <SNIP>
> > 
> > So Walter's point would be that you could add
> > 
> > mmx mmxext sse sse2 3dnow 3dnowext
> > 
> > to your use flags, either globally in your make.conf
> 
> what about all those others?

  Only flags that are supported by the compiler are useful.  So you have
to do the following...

  1) find which compiler you're running
[m3000][root][~] gcc --version
gcc (GCC) 3.3.6 (Gentoo 3.3.6, ssp-3.3.6-1.0, pie-8.7.8)

  2) Today, I'm running gcc 3.3.6.  Go to http://gcc.gnome.org and select
version 3.3.6 and dive into the X86+AMD cpu-specific options, which is...
> http://gcc.gnu.org/onlinedocs/gcc-3.3.6/gcc/i386-and-x86_002d64-Options.html#i386-and-x86_002d64-Options
The "Sempron" is basically an Athlon with less cache.  The thing I hate
is that it doesn't say *WHICH* Athlon.  Use the generic "athlon" cpu
type (you might be able to get away with Athlon-XP).  Compare your
"flags" line with the supported options.  3dnow, mmx, sse, and sse2 show
up in both lists, so you can use them in CFLAGS.  Your line will
probably be identical to mine (assuming you're running 32-bit mode)...

CFLAGS="-O2 -pipe -fomit-frame-pointer -march=athlon -m3dnow -mmmx -msse -msse2 
-mfpmath=sse"

  3) Go to http://www.gentoo.org/dyn/use-index.xml for a list of global
USE flags.  Compare that with your flags line.  3dnow, mmx, and sse show
up both in that list and in the flags line of your /proc/cpuinfo output
so you can add them to USE in /etc/make.conf.

  4) Check /usr/portage/profiles/use.local.desc for any mplayer-specific
USE flags.  You could go through the file manually looking for mplayer
flags.  A quickie way to do that is to issue the command...

grep /mplayer /usr/portage/profiles/use.local.desc

3dnowext, mmxext, and sse2 show up in that list, so you can USE them.  I
would recommend entering them in /etc/portage/package.use.  Depending on
your video card, etc, you may want some of the other mplayer flags. 

  5) You asked about the other flags in the flags line.  While they
don't go into CFLAGS, they're nice to know about when you're building
your kernel.  E.g. it indicates support for apic and mtrr.  It also
indicates support for ancient MCA cards, but you most likely don't have
them, so you won't want to turn on MCA support in your kernel.

-- 
Walter Dnes <[EMAIL PROTECTED]>
My musings on technology and security at http://tech_sec.blog.ca
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