s it.
<li> <code>mpz_add_ui</code> contains two <code>__GMPN_COPY</code>s, one from
     <code>mpn_add_1</code> and one from <code>mpn_sub_1</code>.  If those two
     routines were opened up a bit maybe that code could be shared.  When a
     copy needs to be done there's no carry to append for the add, and if the
     copy is non-empty no high zero for the sub.
</ul>


<h4>Old and Obsolete Stuff</h4>

<p> The following tasks apply to chips or systems that are old and/or obsolete.
It's unlikely anything wi