[Simh] SIMH and LGP-30

[B Degnan]

Sorry...I hit send before editing my message, hopefully you get my points. 


b

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 From: "B Degnan" <billdeg at buzz1.com>
Sent: Monday, February 09, 2015 3:00 PM
To: simh at trailing-edge.com
Subject: [Simh] SIMH and LGP-30

Hi, 

While there is some chatter on the teletype, I thought I'd ask my first 
question. 

I have been able to get a number of the SIMH emulators to work and I am 
simply thrilled about the experience. 

Looking for a challenge I worked for about 5 hours last night on the SIMH 
for LGP-30....I can talk to the box a little but I was having a little 
trouble reproducing the Flexowriter operations for loading in programs 
manually via Flexowriter keyboard.   Can anyone help point me in the right 
direction.  Here is a little of what I did, below... 

SET CPU LGP30 

I am working through the LGP-30 "Programming Class" manual and they say 
things like: 

Depress "manual input" --> which I believe is: SET CPU MANUAL then D A 
value (what value?) 

Type C3838 (C5614) on keyboard --> I need to use: SET CPU INPUT=TTI but 
what to enter the value? 

Depress "Fill instruction" button --> I believe this is accomplshe by SET 
CPU FILL (fills IR from A) 

Type 000B31K4 (B4953) on keyboard  ----> How ??? using various combinations 
of D A + value.  I am wondering about the use of the ' character such as 
with   

Depress "one operation" button ----> ?? 

Depress "execute instruction" button ---> SET CPU EXEC = value (assuming 
knows correct IR?) 

B4953 should be in 5614 by entering everything in decimal form.   

If I example 5614 the system returns all zeros, so whatever I was doing did 
not work. 

I played around a lot with D A command combinations and I was able to get 
the simulator to respond to a point so I know the thing will work once I 
learn the secrets. (I.e. from the manual)       sim> d -n 64 10640        
sim> ex -mn 64        64:   B 400        sim> ex -mt 100  0100: B 0616 

Can anyone share more manual input testing and program execution tips?  
Nothing fancy just something simple so I can start writing and running 
little programs.  I figure then I could punch my own tapes and run them.  I 
also understand in principle about the role drum memory, but I may not be 
applying this understanding to programming.  I also assume the bootstrap is 
not in  memory already. 

I looked over 
https://github.com/simh/simh/blob/5551a0dd9c0e9e3161ba974c1665c09380381a1b/L
GP/lgp_cpu.c 

and I read about the DOS-based simulator, but I prefer to use SIMH 

Best, 

Bill Degnan 

Landenberg, PA 

  

 
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