[Simh] simh vt11 support

[Mark Pizzolato]

On Saturday, January 9, 2016 at 1:01 PM, Will Senn wrote:
> I am starting to narrow this down. The simh source code contains a
> directory for lunar11. It has a document, README.TXT that contains SimH
> directions:
> 
>      sim> ! Set CPU to a Unibus system type
>      sim> set cpu 11/70
>      sim> ! Enable DLI device so VT device autoconfigures
>      sim> ! with a starting vector of 320
>      sim> set dli enable
>      sim> set dli line=2
>      sim> ! Enable VT device
>      sim> set vt enable
>      sim> load lunar.lda
>      sim> dep 32530 1
>      sim> run
> 
> Lunar lander only needs a small screen area, and can run using a
> simulated "VR14" display, which can fit on many computer screens
> without scaling:
> 
>      sim> set vt crt=vr14
>      sim> set vt scale=1
> 
> However, running recent pdp11 and referring to vt results in:
> sim> set vt enable
> Non-existent device
> 
> The source file pdp11_vt.c seems to supply the necessary device:
> pdp11_vt.c: PDP-11 VT11/VS60 Display Processor Simulation
> ...
> vt           VT11/VS60 Display Processor
> 
> /*
>   * this file is just a thin layer of glue to the simulator-
>   * independent XY Display simulation
>   */
> 
> But after compiling, VT doesn't appear to exist as a valid device. What
> am I doing wrong - is the VT device part of the pdp11 simulator or isn't it?

Well, depending on your build environment you may or may not have the support for the required graphics.  

Apart from that I merely merged the work that I found that Phil Budne and Doug Gwyn wrote.  I started down the path of actually getting it running nicely with the current codebase but got distracted by other things and haven't gotten back to it.  Once it was running cleanly I was going to add the code for Lunar what would happen automatically when you "BOOT VT".  Adding the boot is simple getting the graphics running well seemed harder....

If anyone comes back with adjustments that work well, please contact me.

- Mark