> 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.
paul
