• Sign in
  • Sign up
Elektrine
EN
  • EN English
  • 中 中文
Log in Register
Modes
Overview Search Chat Timeline Communities Gallery Lists Friends Email Vault VPN
Back to Timeline
  • Open on universeodon.com

Mark Moxon

@markmoxon@universeodon.com
mastodon 4.5.6

Writer, walker, software archaeologist. Back in the day: Editor of Acorn User, Editor of h2g2.

I love analysing old code, and my aim is to create the best code disassemblies you have ever seen.

Purveyor of Elite/Lander/Revs hacks.

0 Followers
0 Following
Joined November 19, 2022
Personal website:
https://www.markmoxon.com
GitHub:
https://github.com/markmoxon
Software archaeology website:
https://www.bbcelite.com
RSS feed of my posts on Mastodon:
https://universeodon.com/@markmoxon.rss

Posts

Thread context 2 posts in path
Parent @thomasadam@bsd.network Open
on bsd.network
Open ancestor post
Current reply
markmoxon
Mark Moxon
@markmoxon@universeodon.com

Writer, walker, software archaeologist. Back in the day: Editor of Acorn User, Editor of h2g2. I love analysing old code, and my aim is to create the best code disassemblies you have ever seen. Purveyor of Elite/Lander/Revs hacks.

universeodon.com
Mark Moxon
Mark Moxon
@markmoxon@universeodon.com

Writer, walker, software archaeologist. Back in the day: Editor of Acorn User, Editor of h2g2. I love analysing old code, and my aim is to create the best code disassemblies you have ever seen. Purveyor of Elite/Lander/Revs hacks.

universeodon.com
@markmoxon@universeodon.com · 3d ago
@thomasadam@bsd.network Lots of disc games switch to the tape filing system after loading from floppy, so they can reuse the memory that would otherwise be used by the disc filing system. That would mean any *LOAD commands would then try loading from tape, which would appear to break if you were expecting it to load something from disc - not sure if that’s what you mean? Glad you like the writing!
View full thread on universeodon.com
1
1
1
0
markmoxon
Mark Moxon
@markmoxon@universeodon.com

Writer, walker, software archaeologist. Back in the day: Editor of Acorn User, Editor of h2g2. I love analysing old code, and my aim is to create the best code disassemblies you have ever seen. Purveyor of Elite/Lander/Revs hacks.

universeodon.com
Mark Moxon
Mark Moxon
@markmoxon@universeodon.com

Writer, walker, software archaeologist. Back in the day: Editor of Acorn User, Editor of h2g2. I love analysing old code, and my aim is to create the best code disassemblies you have ever seen. Purveyor of Elite/Lander/Revs hacks.

universeodon.com
@markmoxon@universeodon.com · Feb 27, 2026
This is pretty cool. It's a visualisation of the internals of The Sentinel on the #BBCMicro. This is it generating the game landscape for the first level from 1024 pseudo-random numbers. Next week I'll be releasing a deep dive into exactly how this works. *** A big thanks to Simon Owen, whose excellent repository I forked and enhanced in order to build this visualisation. It's well worth a visit. https://github.com/simonowen/sentland/ #bbcmicro #retrocomputing #retrogaming #c64 #8bit
View on universeodon.com
0
0
1
0
Thread context 2 posts in path
Parent @marksemczyszyn@mastodon.social Open
on mastodon.social
Open ancestor post
Current reply
markmoxon
Mark Moxon
@markmoxon@universeodon.com

Writer, walker, software archaeologist. Back in the day: Editor of Acorn User, Editor of h2g2. I love analysing old code, and my aim is to create the best code disassemblies you have ever seen. Purveyor of Elite/Lander/Revs hacks.

universeodon.com
Mark Moxon
Mark Moxon
@markmoxon@universeodon.com

Writer, walker, software archaeologist. Back in the day: Editor of Acorn User, Editor of h2g2. I love analysing old code, and my aim is to create the best code disassemblies you have ever seen. Purveyor of Elite/Lander/Revs hacks.

universeodon.com
@markmoxon@universeodon.com · Feb 25, 2026
@marksemczyszyn@mastodon.social That’s definitely the plan - I’d like to add the C64 versions of both The Sentinel and Revs to my site, as I did with Elite, and add deep dives on their unique aspects. It’s a bit of a long-term plan as I’ve got to finish the BBC Micro site first, but I bought a lovely original C64 last year and I’d like to celebrate it with a bit more coverage in my projects. Such a great machine!
View full thread on universeodon.com
0
0
0
0
markmoxon
Mark Moxon
@markmoxon@universeodon.com

Writer, walker, software archaeologist. Back in the day: Editor of Acorn User, Editor of h2g2. I love analysing old code, and my aim is to create the best code disassemblies you have ever seen. Purveyor of Elite/Lander/Revs hacks.

universeodon.com
Mark Moxon
Mark Moxon
@markmoxon@universeodon.com

Writer, walker, software archaeologist. Back in the day: Editor of Acorn User, Editor of h2g2. I love analysing old code, and my aim is to create the best code disassemblies you have ever seen. Purveyor of Elite/Lander/Revs hacks.

universeodon.com
@markmoxon@universeodon.com · Feb 25, 2026
I'm (slowly!) releasing 50+ deep dives into The Sentinel, Geoff Crammond's epic #BBCMicro game. Batch #2 is now ready: 7 new articles about maths, geometry, trigonometry… and Revs. https://thesentinel.bbcelite.com/deep_dives Batch #3 (landscape) coming soon. Enjoy! #retrocomputing #retrogaming #c64 #8bit
View on universeodon.com
0
0
0
0
markmoxon
Mark Moxon
@markmoxon@universeodon.com

Writer, walker, software archaeologist. Back in the day: Editor of Acorn User, Editor of h2g2. I love analysing old code, and my aim is to create the best code disassemblies you have ever seen. Purveyor of Elite/Lander/Revs hacks.

universeodon.com
Mark Moxon
Mark Moxon
@markmoxon@universeodon.com

Writer, walker, software archaeologist. Back in the day: Editor of Acorn User, Editor of h2g2. I love analysing old code, and my aim is to create the best code disassemblies you have ever seen. Purveyor of Elite/Lander/Revs hacks.

universeodon.com
@markmoxon@universeodon.com · Feb 19, 2026
I'm releasing over 50 deep dives into The Sentinel, Geoff Crammond's epic #BBCMicro game. Batch #1 is now ready: 6 new articles about memory maps, program flow and interrupts, all at: https://thesentinel.bbcelite.com/deep_dives Batch #2 (maths, lots of!) coming soon. Enjoy! #retrocomputing #retrogaming #c64 #8bit
View on universeodon.com
0
0
0
0
markmoxon
Mark Moxon
@markmoxon@universeodon.com

Writer, walker, software archaeologist. Back in the day: Editor of Acorn User, Editor of h2g2. I love analysing old code, and my aim is to create the best code disassemblies you have ever seen. Purveyor of Elite/Lander/Revs hacks.

universeodon.com
Mark Moxon
Mark Moxon
@markmoxon@universeodon.com

Writer, walker, software archaeologist. Back in the day: Editor of Acorn User, Editor of h2g2. I love analysing old code, and my aim is to create the best code disassemblies you have ever seen. Purveyor of Elite/Lander/Revs hacks.

universeodon.com
@markmoxon@universeodon.com · Jan 31, 2026

@scattershot@merveilles.town Well, there's a lot to say! And I'll be taking my time to say it... 🙂

View on universeodon.com
1
0
0
0
markmoxon
Mark Moxon
@markmoxon@universeodon.com

Writer, walker, software archaeologist. Back in the day: Editor of Acorn User, Editor of h2g2. I love analysing old code, and my aim is to create the best code disassemblies you have ever seen. Purveyor of Elite/Lander/Revs hacks.

universeodon.com
Mark Moxon
Mark Moxon
@markmoxon@universeodon.com

Writer, walker, software archaeologist. Back in the day: Editor of Acorn User, Editor of h2g2. I love analysing old code, and my aim is to create the best code disassemblies you have ever seen. Purveyor of Elite/Lander/Revs hacks.

universeodon.com
@markmoxon@universeodon.com · Jan 31, 2026
I've started writing a series of deep dives into Geoff Crammond's epic #BBCMicro game The Sentinel. Here's the to-do list. I will post a link here whenever I add a new one to https://thesentinel.bbcelite.com/ It's going to take a while! But it should be worth it... #retrocomputing #retrogaming #c64 #8bit
View on universeodon.com
0
0
0
0
markmoxon
Mark Moxon
@markmoxon@universeodon.com

Writer, walker, software archaeologist. Back in the day: Editor of Acorn User, Editor of h2g2. I love analysing old code, and my aim is to create the best code disassemblies you have ever seen. Purveyor of Elite/Lander/Revs hacks.

universeodon.com
Mark Moxon
Mark Moxon
@markmoxon@universeodon.com

Writer, walker, software archaeologist. Back in the day: Editor of Acorn User, Editor of h2g2. I love analysing old code, and my aim is to create the best code disassemblies you have ever seen. Purveyor of Elite/Lander/Revs hacks.

universeodon.com
@markmoxon@universeodon.com · Jan 13, 2026

You didn't know you needed this in your life, but you do.

Marine Beaufils is a French artist who creates beautiful embroideries of... The Sentinel (amongst others).

It's inspired and quite beautiful. Enjoy!

https://www.marine.st/en/pages/sentinel

#bbcmicro #zxspectrum #c64 #retrogaming #retrocomputing

View on universeodon.com
47
0
15
0
markmoxon
Mark Moxon
@markmoxon@universeodon.com

Writer, walker, software archaeologist. Back in the day: Editor of Acorn User, Editor of h2g2. I love analysing old code, and my aim is to create the best code disassemblies you have ever seen. Purveyor of Elite/Lander/Revs hacks.

universeodon.com
Mark Moxon
Mark Moxon
@markmoxon@universeodon.com

Writer, walker, software archaeologist. Back in the day: Editor of Acorn User, Editor of h2g2. I love analysing old code, and my aim is to create the best code disassemblies you have ever seen. Purveyor of Elite/Lander/Revs hacks.

universeodon.com
@markmoxon@universeodon.com · Jan 10, 2026

Have you ever wondered how big the full landscape is in The Sentinel?

It's 1856 pixels high and 2048 pixels wide.

Here's the first level. The initial 192x160 screen is in red. Panning jumps the view to different grid points.

It's a big old world!

So the game screen shows shows 1/9.7 of the full height and 1/12.8 of the full width of the landscape.

The weird figures are because the screen is a different shape to the full view.

Also visible is the point carée equirectangular projection used in the game. This is taken straight from Revs.

For those who don't know, The Sentinel is a classic game from 1986, written by Geoff Crammond and published by Firebird.

It was originally released on the BBC Micro, and was converted to lots of other home computers, including the Commodore 64, ZX Spectrum.

See https://thesentinel.bbcelite.com/ for more.

#retrocomputing #retrogaming #bbcmicro #c64 #8bit

View on universeodon.com
17
0
5
0
markmoxon
Mark Moxon
@markmoxon@universeodon.com

Writer, walker, software archaeologist. Back in the day: Editor of Acorn User, Editor of h2g2. I love analysing old code, and my aim is to create the best code disassemblies you have ever seen. Purveyor of Elite/Lander/Revs hacks.

universeodon.com
Mark Moxon
Mark Moxon
@markmoxon@universeodon.com

Writer, walker, software archaeologist. Back in the day: Editor of Acorn User, Editor of h2g2. I love analysing old code, and my aim is to create the best code disassemblies you have ever seen. Purveyor of Elite/Lander/Revs hacks.

universeodon.com
@markmoxon@universeodon.com · Jan 07, 2026

I've just released the fully documented source code for The Sentinel as an easy-to-browse website.

It's a lot more fun to explore than the GitHub repository, with cross-references, popups, indexes, statistics and more. I hope you like it!

The next step is to add a whole load of deep dives explaining how Geoff Crammond's proto-VR masterpiece works under the hood, with links into the code itself.

This part will take some weeks as there's a lot to explain, but I'll try to publish them as I go.

Watch this space...

https://thesentinel.bbcelite.com/

#retrocomputing #retrogaming #bbcmicro #c64 #8bit

View on universeodon.com
29
0
21
0
markmoxon
Mark Moxon
@markmoxon@universeodon.com

Writer, walker, software archaeologist. Back in the day: Editor of Acorn User, Editor of h2g2. I love analysing old code, and my aim is to create the best code disassemblies you have ever seen. Purveyor of Elite/Lander/Revs hacks.

universeodon.com
Mark Moxon
Mark Moxon
@markmoxon@universeodon.com

Writer, walker, software archaeologist. Back in the day: Editor of Acorn User, Editor of h2g2. I love analysing old code, and my aim is to create the best code disassemblies you have ever seen. Purveyor of Elite/Lander/Revs hacks.

universeodon.com
@markmoxon@universeodon.com · Jan 02, 2026

@tehstu@hachyderm.io Indeed, there are no multiply instructions on the 6502, so Elite, Aviator, Revs and The Sentinel all do their matrix maths using nothing more than 8-bit integers. It's amazing.

Then again, the ARM1 didn't have a multiply instruction either, so Lander - the first game ever for the ARM platform - had to roll its own multiplication routines. Everybody had to do it back then!

Here's a rabbit-hole for you 🙂

https://lander.bbcelite.com/deep_dives/landers_origins_on_the_arm1.html

View on universeodon.com
2
0
1
0

Media

313k7r1n3

Company

  • About
  • Contact
  • FAQ

Legal

  • Terms of Service
  • Privacy Policy
  • VPN Policy

Email Settings

IMAP: imap.elektrine.com:993

POP3: pop.elektrine.com:995

SMTP: smtp.elektrine.com:465

SSL/TLS required

Support

  • support@elektrine.com
  • Report Security Issue

Connect

Tor Hidden Service

khav7sdajxu6om3arvglevskg2vwuy7luyjcwfwg6xnkd7qtskr2vhad.onion
© 2026 Elektrine. All rights reserved. • Server: 09:09:21 UTC