mpf exponent range

[Zimmermann Paul]

       Dear Torbjörn,

> Do people on this list have any opinions about
> the exponent range, of mpf, in particular, if we should make input and
> output work for the entire allowed number range?

my opinion is yes. If input/output functions do not work for the entire
allowed number range, this should be documented, so that the user knows
what are the exact limits.

By the way the documentation says:

      The exponent of each float is a fixed precision, one machine word on
   most systems.  In the current implementation the exponent is a count of
   limbs, so for example on a 32-bit system this means a range of roughly
   2^-68719476768 to 2^68719476736, or on a 64-bit system this will be
   greater.

It would be nice to make precise the bounds on a 64-bit system. I guess
the maximum is 2^(2^63*64), but what is the minimum?

Paul Zimmermann