[Soekris] net6501 : CPU architecture ?

Nix nix at esperi.org.uk
Tue May 14 17:56:46 CEST 2013


On 14 May 2013, Kyle Brantley uttered the following:

> On 5/13/2013 1:14 PM, Conrad Kostecki wrote:
>> I don't understand. How can a 32-Bit CPU work in 64-Bit Mode? I can't
>> image, that the BIOS makes the difference. Linux shows the flags lm,
>> which indicated, that it supports "AMD64/EM64T"?
>>
>
> The CPU was produced as a 64-bit chip, but for reasons X or Y or Z,
> the manufacturer is only going to support 32-bit. Maybe there are bugs
> with respect to 64-bit, maybe it's a marketing thing.

I think it's more that it's slow. IIRC, 64-bit integer multiply is a
*lot* slower than on other 64-bit parts: there may be other sloth. I
wouldn't be surprised to find that it was slower than 32-bit even
accounting for cache effects, where other 64-bit-capable CPUs are
faster.

> In short, as per Intel, using the 6501 in a 64-bit mode is
> unsupported.

... so unsupported that Intel hackers have been adding Atom-specific
64-bit variants of the string routines into glibc of late. :)

I suspect it's unsupported in the sense that "we want it to work, we
rely on it working, but if you're not a geek don't bother." --- but
anyone on this list has their geek credentials just on account of
knowing that Soekris exists :)

(I must say, having a houe move coming up I'm glad my firewall is a
Soekris. It's the only machine I own that I can be *sure* will get to
the far end of the car journey without risk of failure. Solid-state
FTW!)

-- 
NULL && (void)


More information about the Soekris-tech mailing list