[Simh] VAX 8200/8250

[Bob Supnik]

The 8200 (V11) doesn't have a console processor; the console is 
implemented in microcode (as in the F11/J11) and some macrocode (as in 
MicroVAX II). That's one of the reasons the V11's microstore was 15KW, 
plus a 1 KW patch store, and MicroVAX II's was 1.6KW, with no patch 
store. (The other drivers of V11 microword consumption were the string, 
decimal, and soft floating instructions.) V11 and MicroVAX II have 
essentially identical microwords, although the capabilities of the main 
data path differ slightly, particularly around shifting.

I did not work on the V11 microcode directly. Close to release, when it 
was clear that the patch store would be half empty, I developed a patch 
to optimize CALL/RET using techniques lifted from the 8800 (Nautilus) 
microcode; these were also included in CVAX. I don't have a listing of 
the V11 microcode.

/Bob

On 4/6/2019 6:14 PM, simh-request at trailing-edge.com wrote:
> Message: 2
> Date: Sat, 6 Apr 2019 18:20:37 +0100
> From: Matt Burke<matt at 9track.net>
> To: Simh Trailing-Edge Mailing List<simh at trailing-edge.com>
> Subject: [Simh] VAX 8200/8250
> Message-ID:<bae094bf-ffeb-2905-24bb-26377cede77b at 9track.net>
> Content-Type: text/plain; charset=utf-8
>
> Here is a new simulator for the VAX 8200/8250 systems. Most of the key
> features are there including the DWBUA BI-Unibus adapter which allows
> all the existing Unibus devices to be used. The console RX50 is also
> implemented.
>
> The console processor is not simulated so it uses the same VMB trick as
> the VAX-11/7xx simulators i.e. you boot directly from a device "boot
> rq0" rather than "boot cpu".
>
> You can get the code from:
>
> https://github.com/9track/simh/tree/vax820
>
> And Windows executable from:
>
> http://www.9track.net/simh/vax820
>
> Please try it out and let me know how you get on.
>
>
> Matt