Re: i686 quirk for AMD Geode

H. Peter Anvin
2009-11-10T21:26:45Z

On 11/10/2009 01:12 PM, Willy Tarreau wrote:
> yes, just like with emulated FPU or trapped unaligned accesses. It's
> just like flying fishes. They exist but they aren't the most common
> ones. If people encounter these cases on a specific program, then
> they just have to recompile it if it is a problem. At least they
> don't rebuild the whole distro. And once again, I've been using
> cmpxchg/bswap emulation for years on my i386 without feeling any
> need for a rebuild, and CMOV emulation for years now on my mini-itx
> C3 without any problem either. These are real experiences, not just
> fears of imaginary problems. Yes I can design a program to run 400
> times slower on these machines if I want. I just don't feel the need
> to do so and apparently existing programs' authors didn't either.

Willy, perhaps you can come up with a list of features you think should
be emulated, together with an explanation of why you opted for that list
of features and *did not* opt for others.

Note: emulated FPU is a special subcase. The FPU operations are
heavyweight enough that the overhead of trapping versus library calls is
relatively insignificant.

-hpa