Re: [PATCH] Fix -march=athlon-tbird bug WRT SSE

["David O'Brien" <obrien at FreeBSD dot org>]

On Thu, Jul 28, 2005 at 01:18:43PM -0400, Kelley Cook wrote:
> > 2005-07-28 David O'Brien <obrien@FreeBSD.org>
> 
> >	* config/i386/i386.h: Athlon-tbird does not have SSE support.
> 
> Personally, I would think that completely dropping the "athlon-tbird", 
> "athlon-4", "k8", "athlon-mp", "opteron", and "athlon-fx" aliases would
> make more sense as they don't add anything useful to GCC.

athlon-4 does mean something above Athlon - SSE support.  I no opinion
about dropping "athlon-tbird" completely.

Why are "K8" and "opteron" not useful to GCC?  These certainly are - GCC
code for -march=athlon is not the same as -march=k8/opteron.
 
> For a specific example the Athlon rev B. (aka Thunderbird) was just a 
> process shrink of the original Athlon that the doubled the cache size and 
> came on a PGA instead of a slot card.

Actually there were Slot-A Thunderbirds also.  The Thunderbird had on-die
L2 cache, vs. the original Athlon's off-die 1/2 speed L2.

> GCC doesn't use cache size in any of 
> its calculations while clearly packaging and trace size aren't relevant.
> 
> This would leave "athlon", "athlon-xp", "x86-64", and "athlon64" in the two 
> family trees.
> 
> Athlon is the original instruction set.
> 
> Athlon-xp is Athlon + SSE
> 
> Athlon64 is the K8 chip, which is AMD's current implementation of x86-64 
> (which includes 3DNow!)

Opteron is also the K8 chip, which is AMD's current current
implementation of x86-64 (which includes 3DNow!).
 
> Note that there are no Xeon nor Celeron references on the Intel side.

But there are pentium4m and pentium3m, which are useless vs. pentium4 and
pentium3.

-- 
-- David  (obrien@FreeBSD.org)