jsbeeb - a Javascript emulator

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ComanderJameson
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Re: jsbeeb - a Javascript emulator

Postby ComanderJameson » Tue Apr 29, 2014 5:53 pm

Once I ironed out the instruction timings with the VIAs, Frogman runs just fine on both a standard Beeb and VBeeb emulator.
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Matt Godbolt
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Re: jsbeeb - a Javascript emulator

Postby Matt Godbolt » Tue Apr 29, 2014 6:27 pm

Sweet - congratulations! Are you emulating a BBC Master? Frogman doesn't want to run on a BBC B it seems - Rich and I tracked it back to us overwriting some of the DFS working space which seems to be OK on the Master somehow...

Sorry the game's so terrible :)

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ComanderJameson
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Re: jsbeeb - a Javascript emulator

Postby ComanderJameson » Tue Apr 29, 2014 6:44 pm

Hey I've seen a lot worse!

Nope, it emulates just a bog standard BBC Micro. Frogman runs fine no matter which filing system is installed ADFS, Watford. I wonder what the difference is?

Now I'd like to get hold of some disc images with different encryption and see how it handles it. Any idea where I can find these? On STH?

Thanks!
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Matt Godbolt
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Re: jsbeeb - a Javascript emulator

Postby Matt Godbolt » Tue Apr 29, 2014 6:49 pm

I'd check out Kevin's protection. He's let me and Rich release it as an image and it's part of the unit tests of jsbeeb. Check out the image at https://github.com/mattgodbolt/jsbeeb/b ... d?raw=true - it's an SSD with some simple loaders.

In each case the "B.xxx" is a BASIC program that loads up the protection system for 'xxx' and runs it in a harness. The test is successful if the PC ever makes it to &E00.

There's no game or anything, just literally the protection system.

So far jsbeeb will decode Alien8, but fails to do either Lunar Jetman or Nightshade.

Also perhaps of interest is the disk image: https://github.com/mattgodbolt/jsbeeb/b ... d?raw=true which is a simple timer test. The expected output (as measured on a real BBC B) is at https://github.com/mattgodbolt/jsbeeb/b ... ngsResults

Good luck!

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tricky
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Re: jsbeeb - a Javascript emulator

Postby tricky » Tue May 06, 2014 11:07 pm

My code may be wrong (well, it is) but the Crtc R3 Sync Pulse Widths "hack" doesn't seem to work correctly - well, it is different to B-Em.
Sorry, I don't have a beeb that I can currently try this on.
Use crsr keys:
RallyX.zip
demo, use crsr keys
(2 KiB) Downloaded 74 times

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Matt Godbolt
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Re: jsbeeb - a Javascript emulator

Postby Matt Godbolt » Tue May 13, 2014 5:38 pm

Thanks tricky; I'll take a look and see if I can work out what's going on. What's it "supposed" to do? :)

ptheta
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Re: jsbeeb - a Javascript emulator

Postby ptheta » Thu May 15, 2014 12:09 pm

I see this has been reported on the Register now.
http://www.theregister.co.uk/2014/05/15 ... avascript/

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Re: jsbeeb - a Javascript emulator

Postby ghbearman » Sun Sep 14, 2014 9:26 am

Slightly off topic, I have a theory about cracking Nightshade on tape in software, but I haven't tried it yet.

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leenew
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Re: jsbeeb - a Javascript emulator

Postby leenew » Sun Sep 14, 2014 12:38 pm

Hi GHB,
(Assuming it works :D )
Would your theory have been possible back in the 80s?
Also, do you reckon it would have been possible without the knowledge that we now know about nightshade?
Lastly, Will this be a universal "copy everything" piece of software? Or will it only work (hopefully) for Nightshade?
Cheers,
Lee.
p.s. May be better in its own thread?

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Re: jsbeeb - a Javascript emulator

Postby ghbearman » Sun Sep 14, 2014 5:01 pm

new thread, ok.

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tricky
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Re: jsbeeb - a Javascript emulator

Postby tricky » Sun Sep 14, 2014 5:19 pm

Would it be possible to add an off/on button to jsbeeb so that I can leave the jsbeeb page open with out draining my battery please?

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Matt Godbolt
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Re: jsbeeb - a Javascript emulator

Postby Matt Godbolt » Mon Sep 15, 2014 12:46 pm

Thanks for the idea; I have the same problem when developing on the train on my laptop! I work around it by pressing 'HOME' to bring up the debugger which effectively pauses the emulator, and stops draining the battery. (hit G to resume)

I'll look in to using the browser notifications that tell me when you tab away to auto-pause, and also having an on/off switch isn't a bad idea anyway!

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Re: jsbeeb - a Javascript emulator

Postby richardtoohey » Tue Sep 16, 2014 12:17 am

Anyone had a chance to try this on the latest Raspian with Epiphany ("hardware-accelerated video support and better standards compliance")?

I'm assuming it will be altogether too much for the Pi but wondering if anyone tried it yet.

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Rich Talbot-Watkins
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Re: jsbeeb - a Javascript emulator

Postby Rich Talbot-Watkins » Thu Nov 06, 2014 9:09 am

Is there anyone out there with a real Beeb (and, even better, a Cub monitor!) who could post a photo of their monitor after entering the following:

Code: Select all

*TV 0,1
MODE 1
VDU 19,0,4;0;


We want to adjust the visible borders in jsbeeb so it matches better with what a real Beeb/monitor outputs. At the moment, I think the top/bottom borders are too big (going by my memory of what it looked like on a TV anyway).

Cheers!

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sydney
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Re: jsbeeb - a Javascript emulator

Postby sydney » Thu Nov 06, 2014 9:52 am

vdu.jpg


On a standard beeb connected via rgb scart to an lcd screen.

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Rich Talbot-Watkins
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Re: jsbeeb - a Javascript emulator

Postby Rich Talbot-Watkins » Thu Nov 06, 2014 10:18 am

Thanks for that Sydney Simon! :) It's kinda hard to tell where the sides of the VDU are there to get a feeling for how much border is visible at the sides. Any chance you can give us another one from a bit further back, so we can see the entire physical screen?

As it happens, this is more or less what I remember from a TV as well: hardly any top/bottom border and plenty at the sides. Also *TV 0 was so close to the top of the screen, there was barely any top border at all.

Thanks again!

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sydney
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Re: jsbeeb - a Javascript emulator

Postby sydney » Thu Nov 06, 2014 10:38 am

It's a widescreen tv set to 4:3 mode so I'm not sure how much use that would be. I can grab my daughters 14" crt tv if that would be any better?

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Rich Talbot-Watkins
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Re: jsbeeb - a Javascript emulator

Postby Rich Talbot-Watkins » Thu Nov 06, 2014 10:53 am

Ah I see, don't worry then - we're mostly after seeing how the Beeb's display is framed inside a typical (for the time) monitor screen. That's already helpful to confirm that the top/bottom borders are virtually non-existent!

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sydney
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Re: jsbeeb - a Javascript emulator

Postby sydney » Thu Nov 06, 2014 10:58 am

14" crt via rf cable! She's lost the remote so I can't select the scart socket.

tv.jpg


EDIT: Just saw your post! I'd already took the photo so no harm in uploading it.

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Re: jsbeeb - a Javascript emulator

Postby Rich Talbot-Watkins » Thu Nov 06, 2014 11:02 am

Ah brill! Thanks a lot! It's exactly like I remember it too, with the top row even disappearing a bit beyond the top of the screen. We'll do some measurements (with a ruler!) and adjust the emulated screen so it looks more like that.

Cheers!

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Matt Godbolt
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Re: jsbeeb - a Javascript emulator

Postby Matt Godbolt » Thu Nov 06, 2014 1:32 pm

Fantastic - thanks :) I'll have a hack about tonight (unless Rich gets there first) and see what we can do!

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Re: jsbeeb - a Javascript emulator

Postby Matt Godbolt » Fri Nov 07, 2014 3:01 am

I just updated the jsbeeb beta site with a new version: http://bbc.godbolt.org/beta

Comments welcome! I have a small laptop screen so maybe there's improvements in terms of the size I can choose

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Pernod
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Re: jsbeeb - a Javascript emulator

Postby Pernod » Wed Apr 01, 2015 9:04 am

Hi Matt,

Your SAA5050 character definitions have a few minor inaccuracies. All the separated graphics should be right aligned (B-em is wrong too), just shift the bits to the right. Also separated graphics for m and * are top heavy. They are formed of rows of 322 whereas they should be 232.

sepgraph.PNG
- Nigel

BBC Model B, ATPL Sidewise, Acorn Speech, 2xWatford Floppy Drives, AMX Mouse, Viglen case, etc.

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Matt Godbolt
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Re: jsbeeb - a Javascript emulator

Postby Matt Godbolt » Wed Apr 01, 2015 11:44 am

Thanks Nigel; I'll try and get them fixed up. I saw the other thread on the teletext engineering test screen too; I should use it as a test base. As you've probably realised the majority of the teletext emulation in jsbeeb is cribbed from b-em :)

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Re: jsbeeb - a Javascript emulator

Postby Pernod » Wed Apr 01, 2015 11:50 am

I'm currently fixing up MESS so have been referring to the other emus for tips. The graphics should be generated rather than read from a lookup table (they weren't stored in ROM). BeebEm actually implements the graphics generator.

The test screen from the other thread is perfect in jsbeeb, apart from the separated issue.
- Nigel

BBC Model B, ATPL Sidewise, Acorn Speech, 2xWatford Floppy Drives, AMX Mouse, Viglen case, etc.

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Matt Godbolt
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Re: jsbeeb - a Javascript emulator

Postby Matt Godbolt » Wed Apr 01, 2015 11:57 am

Oh sweet - thanks. Maybe I'll replace that horrendous hardcoded file of the graphics with a generated one: cheers for the tip.

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Re: jsbeeb - a Javascript emulator

Postby richardtoohey » Wed Apr 01, 2015 6:06 pm

Pernod wrote:BeebEm actually implements the graphics generator.
As per the other thread, it's not 100% right - I started looking but as I fixed one thing I broke another ...

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Pernod
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Re: jsbeeb - a Javascript emulator

Postby Pernod » Wed Apr 01, 2015 9:32 pm

richardtoohey wrote:As per the other thread, it's not 100% right - I started looking but as I fixed one thing I broke another ...

The actual graphics generator is good, but agree there are still issues with some control codes.
- Nigel

BBC Model B, ATPL Sidewise, Acorn Speech, 2xWatford Floppy Drives, AMX Mouse, Viglen case, etc.

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Re: jsbeeb - a Javascript emulator

Postby davidb » Thu Apr 30, 2015 9:41 pm

Browsing the Retro Software site, I noticed the Applet Games page. Since I've almost completely removed Java from my online life :D, it would be great to be able to replace this with jsbeeb and perhaps add something similar for the Electron using elkjs. What do people think?

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tricky
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Re: jsbeeb - a Javascript emulator

Postby tricky » Thu Apr 30, 2015 11:30 pm

I was looking at that earlier and wondering the same thing about the been emulator.


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