PDP-11/83 w/FPU?

[Paul Anderson]

Are you referring to the M7238 EIS on the 11/40?

On Wed, Apr 17, 2019 at 11:45 PM Josh Dersch via cctalk <
cctalk at classiccmp.org> wrote:

> On Wed, Apr 17, 2019 at 2:58 PM Paul Koning via cctalk <
> cctalk at classiccmp.org> wrote:
>
> >
> >
> > > On Apr 17, 2019, at 4:36 PM, Ethan Dicks via cctalk <
> > cctalk at classiccmp.org> wrote:
> > >
> > > On Wed, Apr 17, 2019 at 2:48 PM W2HX via cctalk <cctalk at classiccmp.org
> >
> > wrote:
> > >> ?Hi friends. I am putting together a PDP-11 set up. i have a few CPUs
> > available to me, a 11/23+, an 11/73 and I also have available to me an
> > 11/83, M8190-AE .
> > >>
> > >> I would like to try to run as many different OS's as may interest me,
> > including some unixes as possible (bsd...etc).  My question is, are there
> > any OSes that need the floating point option?
> > >
> > > I know old UNIX (v2) needs a KE11-A or KE11-B (a Unibus peripheral
> > > integer math option), which really wasn't something people
> > > bought/installed in an 11/34 or later.  v5, v6, and v7 UNIX shouldn't
> > > require any sort of math hardware.
> >
> > I think that was typically called "EAE" (extended arithmetic element), a
> > Unibus peripheral that implemented integer mul/div and maybe a few other
> > odds and ends.  RSTS V4 had optional support for that.  It only applies
> to
> > 11/20 and 11/05 since all the other machines have the relevant
> instructions
> > built into the CPU.  (Later versions of RSTS required that.)
> >
>
> The EAE was also an option on the 11/40.
>
> At any rate, on the 11/73 and 83 CPU, the microcode emulates the floating
> point instructions if an actual FPA isn't fitted, so everything should just
> work (just a bit slower).
>
> - Josh
>