an FPU problem - nextafter too small?

[Dmitrii Pasechnik <dima@cs.uu.nl>]

I'm running the latest stable Debian 2.2 on Alpha XL266.
(alphaev56 processor)

There appears to be a problem with the values returned by
the function nextafter (see <math.h>).
Namely, this value (nextafter(0.,1.) returns 4.9407e-324)
is too small for doing arithmetic operations on it,
that is, for instance, 2.*nextafter(0.,1.) produces a floating point
exception.
This is with gcc (version 2.95.2 20000220 (Debian GNU/Linux))
and no extra options (except -lm).

The smallest possible value x that still allows for 2.*x with my setup
is about 1.e-307.
 
Is this a feature or a bug (in gcc or in glibc ?) ?
Thanks in advance,
Dmitrii.
-- 
Dmitrii Pasechnik
e-mail: d.pasechnik@twi.tudelft.nl 
http://ssor.twi.tudelft.nl/~dima/