out-of-bound write

[Zimmermann Paul]

       Hi Torbjörn,

> While the documentation is very imprecise about the space requirements,
> it seems to promise some maximum needs for normalised input strings (in
> the sense of absence of leading zeros) but using ambiguous wording.

the documentation is very precise:

   "If the most significant input byte is non-zero then the high limb at rp
    will be non-zero, and only that exact number of limbs will be required
    there."

If the output fits into rn limbs, this means that exactly rn limbs are
required (and no more) to be allocated. I don't see what is imprecise here.

Paul