using these to load long doubles, but they aren't implemented in hardware
on (at least) UltraSPARC I and II machines.
Emulate popc in the user trap handler as well.
Re-arrange slightly to make support functions more accessible.
Reviewed by: tmm
support for fcmp and fcmpe instructions with a condition code
specification other than %fcc0.
This (primarily the first part) seems to fix a lot of problems that
people were seeing, e.g. perl and gawk failures.
Reported and analyzed by: wollman
