der Mouse pointed;

> Unless the "supervisor mode" under discussion isn't a privilege level
> wedged in between the usual userland and OS-kernel modes (which latter
> is called "supervisor mode" by some other CPUs, such as the 68k, that
> have only two privilege modes).

It was my mistake.  The R4000 supervior mode is just another mode switch
which allows to use a certain 64bit address range.  Not similar to "ring
protection" with "call-gate" processors.

I'm very curious about how Alpha w/ VMS PAL can run OpenVMS.

Toru Nishimura/ALKYL Technology