Olaf Seibert <rhialto@polderland.nl> writes:
> One thing SIMH maybe could do is change the meaning of an uncommon
> sort of instruction that's effectively a No OPeration, which could be
> inserted in the busy-wait. SIMH could treat it like a WAIT
> instruction.

Lars Brinkhoff <lars.spam@nocrew.org> writes:
> This sounds like a good idea.  I, for one, would really like to
> eliminate the busy-wait.  Would this, or one of the other suggestions,
> be acceptable?

Changing the semantics of VAX instructions (even effective NOPs) still
sounds like a bad idea to me.  And it's completely unnecessary, since
simulators like SIMH can be updated to simply detect the existing busy
wait loop and do the right thing, without needing any changes to the OS.