have f16-f31 as part of the context. The PCB has been reorganized to
better match how we save and restore the (preserved) registers. This
commit also moves the context restoriation to its own function (named
pcb_restore), as we did with pcb_save.
Only minimal effort has been put in writing optimal assembly. The
expectation is that there will be more rounds of changes.
o Create pcb_save as the backend for savectx and cpu_switch.
o While here, use explicit bundling for pcb_save and optimize
for compactness (~87% density).
o Not part of the commit is a backend pcb_restore. restorectx()
still jumps halfway into cpu_switch().
exceptions from both kernel and user mode.
* Fix context switching so that we can switch back to a proc which we
switched away from (we were saving the state in the wrong place).
* Implement lazy switching of the high-fp state. This needs to be looked
at again for SMP to cope with the case of a process migrating from one
processor to another while it has the high-fp state.
* Make setregs() work properly. I still think this should be called
cpu_exec() or something.
* Various other minor fixes.
With this lot, we can execve() /sbin/init and we get all the way up to its
first syscall. At that point, we stop because syscall handling is not done
yet.
disk drivers along with a load of fixes to context switching, fork
handling and a load of other stuff I can't remember now. This takes us as
far as start_init() before it dies. I guess now I will have to finish off
the VM system and syscall handling :-).
not work on any real hardware (or fully work on any simulator). Much more
needs to happen before this is actually functional but its nice to see
the FreeBSD copyright message appear in the ia64 simulator.
