Re: FWD: FLOATING-POINT CONSISTENCY, -FFLOAT-STORE, AND X86

[Marc Lehmann <pcg at goof dot com>]

On Wed, Dec 16, 1998 at 03:50:22PM -0500, Tim Hollebeek wrote:
> Marc Lehmann writes ...
> > 
> > I still don't see what the 64 bit precision idea gives us, in terms of
> > performance. First, it doesn't give us full ieee, second, it kills
> > performance, depending on where the rounding mode is set (before each
> > assignment? resetting it to normal before each long double assignment?)
> 
> 64 bit rounding is a wonderful solution .... assuming the only
> floating point type you ever use is 'double'.

And the only floatingpoint type your highly optimized libm uses is double,
OR the algorithms work stable with both data types.

> As such, it makes sense as a practical user level solution, but I'm afraid
> it's almost useless as a general purpose solution.

I fear it won't even make sense as a practical user level solution. I should
hjave a look at glibc's libm to see wether rounding would affect it
negatively.

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