PDP-11

other less used processors, such as PDP-11, TMS9900, eZ80 etc
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akuyou
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PDP-11

Post by akuyou » Fri Apr 26, 2019 1:19 pm

This CPU is in the 'Looks fascinating, but I don't think I'll ever have the time' category... but I thought Id give the system a mention, and put some of the good links I've found for it (probably just as a memo to myself in the future!)

There was an article on the PDP-11 on the register a few years ago:
https://www.theregister.co.uk/2013/06/1 ... ntil_2050/

There is a great summary card here:
https://ia800609.us.archive.org/15/item ... _Jul75.pdf

Maybe these would also be of interest:
https://ia800707.us.archive.org/2/items ... ndbook.pdf
https://gordonbell.azurewebsites.net/Di ... 201969.pdf

And why not emulate one with a PI... with an over the top physical interface!?
https://www.theregister.co.uk/2018/05/2 ... 1_revival/

I've run some UKNC documents through Google Translate... results here:
http://www.chibiakumas.com/pdp11/UkncTranslated.7z

there's a UKNC emulator here:
https://github.com/nzeemin/ukncbtl/releases

I only came across this platform because one of my patreon backers is trying to convert ChibiAkumas to the PDP-11... which sounds like a crazy daunting task... so I can only wish him luck, and admire his vision!
https://github.com/aberranth/chibiakumas
Chibi Akuma(s) Comedy-Horror 8-bit Bullet Hell shooter! // 「チビ悪魔」可笑しいゴシックSTG ! // Work in Progress: ChibiAliens

Interested in CPU's :Z80,6502,68000,6809,ARM,8086,RISC-V
Learning: 65816,ARM,8086,6809

aberrant
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Re: PDP-11

Post by aberrant » Sun Aug 11, 2019 1:11 am

Thanks, Kith for creating the topic about PDP-11 compatible machines! What is great about PDP machines that the hardware and the assembler were designed with one thing in mind - easiness for the man to write programs in machine language. And it was the last platform designed with that thought in mind. That is why PDP-11 assembler is so beautiful in comparison to other assemblers.
Unfortunately, I've started my programming carrier two years ago, and I focused on my primary programming language which Ruby(BTW, it's another awesome programming language), and I give not nearly enough attention to the assembler. But while I grow as Ruby developer, I starting to have more time for the retro dev :) And I did not forget about my first computer. Definitely, I will finish the conversion of ChibiAkuma to PDP-11. One thing I'd like to mention that the PDP-11 compatible machine I do the conversion for is not DEC machine. It is PDP-11 compatible machine created in the Soviet Union. No one outside of the ex-Soviet countries knows about the machine. Anyway, KIth, thank you for all of the tutorials you made (CPC tutorials in particular). You are really supporting me and inspire people to develop games for obsolete platforms. There is no much activity around your videos and on the forum, but you are really inspiring and support people who still fond of all kind of retro platforms. Basically, I just want to say - thanks man, you really keep fire burning!

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akuyou
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Re: PDP-11

Post by akuyou » Tue Aug 20, 2019 11:12 pm

@aberrant
Can you suggest an emulator and assembler for a PDP-11 beginner?

I've been having a quick play this morning with Macro-11 and E11, but I can't find a 'hello world' example that compiles and works, more worrying, MACRO-11 crashes during compiling some of the samples (with no output) which isn't very helpful.

If I can get some simple stuff working on some free tools, I'll do a small series of tutorials on this platform.
Chibi Akuma(s) Comedy-Horror 8-bit Bullet Hell shooter! // 「チビ悪魔」可笑しいゴシックSTG ! // Work in Progress: ChibiAliens

Interested in CPU's :Z80,6502,68000,6809,ARM,8086,RISC-V
Learning: 65816,ARM,8086,6809

tricky
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Re: PDP-11

Post by tricky » Sat Aug 31, 2019 8:21 pm

You can run a PDP-11 processor as a co-pro on a beeb and it might be supported by one of the emulators.
Keep an eye out for JGH on the stardot forums, he seems to know quite a bit about PDP-11s.

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akuyou
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Re: PDP-11

Post by akuyou » Sun Sep 01, 2019 8:00 am

I've now had some success with the pdpy11 assembler, and got some simple code running on E11

https://github.com/imachug/pdpy11
Chibi Akuma(s) Comedy-Horror 8-bit Bullet Hell shooter! // 「チビ悪魔」可笑しいゴシックSTG ! // Work in Progress: ChibiAliens

Interested in CPU's :Z80,6502,68000,6809,ARM,8086,RISC-V
Learning: 65816,ARM,8086,6809

aberrant
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Re: PDP-11

Post by aberrant » Mon Oct 21, 2019 11:41 am

Once again, I'm trying to start converting ChibiAkumas to PDP-11 (UKNC)))

Right now I'm trying to convert the T38-SC1.D01 loading screen to UKNC. When I try to view the result on the UKNC, garbage appears instead of the image.

I suspect the T38-SC1.D01 file is not just a memory dump. Besides, for some reason, it has a strange size 16336 bytes

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akuyou
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Re: PDP-11

Post by akuyou » Tue Oct 22, 2019 1:32 am

The file probably has an AMSDOS header on it - skip the first 128 bytes ... it should be 16000 for the 320x200 4bpp screen... so there may be some other junk at the end... that said I can load the file straight into Winape basic (assuming you're using the same version I'm looking at)

BUT I'll make you a proposition!

If you can give me a simple 'Bitmap test' source I can get to compile on the UKNC that shows a simple image onscreen... I'll get my sprite editor to output UKNC format data, so you can convert the files more easily?

Then I can use the result in my tutorials... sounds tempting?
Chibi Akuma(s) Comedy-Horror 8-bit Bullet Hell shooter! // 「チビ悪魔」可笑しいゴシックSTG ! // Work in Progress: ChibiAliens

Interested in CPU's :Z80,6502,68000,6809,ARM,8086,RISC-V
Learning: 65816,ARM,8086,6809

aberrant
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Joined: Fri Apr 26, 2019 6:37 am

Re: PDP-11

Post by aberrant » Tue Oct 22, 2019 7:41 pm

Yeah it would be great))

I included a couple of pictures in the archive.
screen.scr simple picture to demonstrate how screen represented in RAM
rebels.scr is for redundancy

And here is some commentaries:
  • Byte order is Little-Endian.
  • screen.scr colors are: 0b00 - black, 0b01 - red, 0b10 - green, 0b11 - blue
  • Code: Select all

    This is how pixels stored within a word:
    word bit  || 15 | 14 | 13 | 12 | 11 | 10 |  9 |  8 ||  7 |  6 |  5 |  4 |  3 |  2 |  1 |  0 ||
    pixel     ||  7 |  6 |  5 |  4 |  3 |  2 |  1 |  0 ||  7 |  6 |  5 |  4 |  3 |  2 |  1 |  0 ||
    color bit ||  1 |  1 |  1 |  1 |  1 |  1 |  1 |  1 ||  0 |  0 |  0 |  0 |  0 |  0 |  0 |  0 ||
    
  • Screen lines follow one after another in RAM. First line at the top and last one at the bottom.
Attachments
sample.zip
(11.36 KiB) Downloaded 13 times

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akuyou
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Re: PDP-11

Post by akuyou » Wed Oct 23, 2019 9:20 am

Sorry, I'm not at that stage yet!

I haven't managed to compile ANYTHING on the UKNC - I need something I can compile and run...

I was ideally going to create a UKNC ROM cartridge (as it's probably easier than a disk) - but I have no idea of the format.

I also can't make head nor tail of how to page in (or write to) the video RAM because all the documentation is in Russian... If I had an ASM that compiled and did *something* I could probably make a start - but right now I can't even get the emulator to run my code.

Once I get that far, then screen layout will be easy.
Chibi Akuma(s) Comedy-Horror 8-bit Bullet Hell shooter! // 「チビ悪魔」可笑しいゴシックSTG ! // Work in Progress: ChibiAliens

Interested in CPU's :Z80,6502,68000,6809,ARM,8086,RISC-V
Learning: 65816,ARM,8086,6809

aberrant
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Joined: Fri Apr 26, 2019 6:37 am

Re: PDP-11

Post by aberrant » Wed Oct 23, 2019 8:54 pm

Oh, I misunderstood you. I'll have to set up everything on a Windows machine (my dev environment is Linux) and then describe what you need to build and run some simple program. I'll do that in the next couple of days.

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