| mantissa for $ffffffff. If both are true, return d0 clr
| and store the lower n bits of the least lword of FPTEMP
| to d0 for write out. If not, it is a real operr, and set d0.
| mantissa for $ffffffff. If both are true, return d0 clr
| and store the lower n bits of the least lword of FPTEMP
| to d0 for write out. If not, it is a real operr, and set d0.