Re: Problems with IEEE rounding mode on x86_64

[Brian Gough <bjg at network-theory dot co dot uk>]

At Tue, 17 Apr 2007 21:57:56 +0200,
Reinhold Bader wrote:
>  I've tried the example ieeeround.c from the GSL reference manual on
>  an x86_64 system and find that setting the GSL_IEEE_MODE
>  environment variable does not have any effect at all. E.g.
> 
>   export GSL_IEEE_MODE="round-up"
> 
>  does not yield a divergent series as described in the manual.
> 
>  For x86 and IA64 things are OK, however. The effect seems to be
>  limited to Opteron and EM64T type systems, using 64 bit libraries.
> 
>  Is this a known effect? Do these systems not conform to IEEE?
>  Normally, if a feature isn't supported, the error handler should be
>  invoked, but this does not happen.

Hello,

The configure script is not currently able to distinguish between
different x86-like chips.  If that is done I believe it just needs a
few additional asm instructions in ieee-utils/fp-gnux86.c to support
the different types of FPU.

I don't have access to any 64-bit systems so I have not been able to
do it.

-- 
Brian Gough