On Fri, Feb 3, 2017 at 1:17 PM, Paul Koning <paulkon...@comcast.net> wrote:
> > > On Feb 3, 2017, at 4:07 PM, Josh Dersch <dersc...@gmail.com> wrote: > > > > On Fri, Feb 3, 2017 at 12:31 PM, Paul Koning <paulkon...@comcast.net> > wrote: > > > >> > >> > >> > >> I'm not sure there is one. DEC OS designers typically would assume that > >> they are dealing with non-broken systems. Systems with MMU all have > EIS... > >> > > > > Is this actually true? I've been working on getting my PDP-11/40 running > > recently, and I don't recall anything in the documentation indicating > that > > an EIS was required if you had an MMU installed. > > What I meant is that the 11/40 has EIS standard, according to the PDP11 > architecture handbook. So an OS that depends on MMU would be designed for > 11/40, 11/45, etc. all of which have EIS. And since EIS instructions are > quite helpful they will be used. Not necessarily MUL, in a kernel, but > definitely SOB. > EIS was an option on the 11/40, it was not standard. https://pdos.csail.mit.edu/6.828/2005/readings/pdp11-40.pdf, section 2.4. - Josh > > paul > > >
