[openbeos] Re: app_server: MMX/SSE help wanted

On 2004-08-08 17:29:04 [+0000], Kian Duffy wrote:
> On Sun, 08 Aug 2004 19:22:10 +0000, Christian Packmann 
> <christian.packmann@xxxxxx> wrote:
>> On 2004-08-08 17:00:18 [+0000], Kian Duffy wrote:
 
>>> Well, if it was a true clone of Intel's SSE, it wouldn't crash BeOS. 
>>> It is a bad clone of it, hence the crash

>> Okay, then let me know the instruction sequence on which an XP crashes, 
>> but a PIII/PIV doesn't. I've already checked the Intel docs 
>> (admittedly, not page to page), and so far I haven't found anything 
>> which would indicate an incompatibility.
 
> I'd suggest you find someone with an Athlon XP to ask, I no longer posess 
> any AMD kit due

I do have an Athlon XP, it just hasn't misbehaved so far in regard to SSE 
code. That's why I'd be interested in getting such instruction sequences. 

I've heard the myth about the 'incompatible' Athlon XP dozens of times, but 
never an explanation which I could verify empirically. I'm just a little 
tired of that bit of misinformation floating around, that's all.

> to the number of times my Duron went on fire (at rated 
> speed with above rated cooling).

Probably wrong cooler or mounting error. I once had a mainboard with 
premounted Duron+cooler, and that also ran very hot, 60-70°. Now I've got a 
XP2100+ and good cooler, the XP reaches ca. 55° under full load in summer; 
in winter it's overclocked without problems.

>>> And hence the problems with the MMX optomised version of the Windows
>>> 95 game "POD" on AMD systems.

>> What kind of problems, especially problems relating to the XP?

> The problems I had were not on an XP (I no longer use AMD kit, see 
> above), but on a Spitfire Duron. Basically, the game GPF'ed on loading 
> due to a misintrpretation of a MMX instruction. As I no longer have an 
> AMD system (or a Windows system), I can't check exactly what it was.
> 
> You needed the specific MMX version that came with Dell Dimension 
> H-series systems for that behaviour to happen, older versions were not 
> MMX enabled and later MMX versions worked on AMD CPU's with MMX.

This sounds more like a program error than h/w error. I've never heard of a 
problem in the MMX engine of the K7 core. And searching Google for "POD MMX 
AMD problem" just turned up hits on problems with the Forcefeedback driver, 
which are solved by patching the driver.

If the MMX core really was buggy you'd hear a lot more complaints, as all 
software using that specific MMX command would be crashing. And MMX is 
being used pretty widely now, not only for graphics/sound processing but 
for prime search (Prime95, Seventeen or Bust), probably SETI, RC5, OGR and 
others as well.

Bye,
Chris

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