Some results

[Henry Cejtin]

The signal stuff I understand (I think).  I'm pretty sure that unless you do
some magic, the signal handler stuff is going to use the running processes
stack.  This clearly is going to fail if %esp isn't pointing to a convenient
place.  There are system calls (again, I'm pretty sure) to force a switch to
a different stack, which we will have to use for the small code that actually
runs in responce to a Unix signal.  I'll investigate and send more after I have
checked it out.