[Simh] VAX 8200/8250

[Timothy Stark]

Does simh use threads to handle MP processors?  I have other SIMH versions (vaxmp and turbovax) that uses threads to take advantage of CPU cores. 

I looked through your 782 code and did not see any threads handle that vaxmp and turbovax uses.

Tim

-----Original Message-----
From: Simh <simh-bounces at trailing-edge.com> On Behalf Of Matt Burke
Sent: Saturday, April 6, 2019 6:18 PM
To: simh at trailing-edge.com
Subject: Re: [Simh] VAX 8200/8250

On 06/04/2019 21:28, Timothy Stark wrote:
> I was surprised to see that!  Very good news!!  Good job!  I will try that soon.
>
> For 8250/8350, you need two MP processors.  Does vax820 emulate two MP processors like VAX-11/782?
>
No, but I have got another branch which does. It's a fairly nasty hack just to test the theory. Basically the two processors are run in lock-step and it saves/restores the context of each CPU between instruction cycles. There's a lot of overhead in that so the performance is quite poor once you start the secondary CPU.

Bob Supnik created a simulator for the SiCortex SC1 several years ago which shows a better way to do multiple processors in lock-step but that would involve significant changes to the VAX CPU and MMU modules.

Matt
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