ll processors too).
<li> S390: <code>BSWAP_LIMB_FETCH</code> looks like it could be done with
     <code>lrvg</code>, as per glibc sysdeps/s390/s390-64/bits/byteswap.h.
     This is only for 64-bit mode or something is it, since 32-bit mode has
     other code?  Also, is it worth using for <code>BSWAP_LIMB</code> too, or
     would that mean a store and re-fetch?  Presumably that's what comes out
     in glibc.
<li> Improve <code>count_leading_zeros</code> for 64-bit machines:
  <pre>
	   if ((x &gt&gt 32) 