for a start, look at the sparc64 entries in doc/HACKS.  floating point
is definately a problem.  there are multiple issues here from what i
know.  our fpu emulation has bugs.  gcc has bugs in both the softfloat
and hardfloat code it outputs.  we are missing the _Q_*(?) functions
that the ELF abi specifies.  there are also issues with optimisation
blowouts (eg, see the sha1.c entry in HACKS.)


a scan of archives will also find other issues i think.