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Fully documented source code for Lander on the Acorn Archimedes

74 points| Kye | 2 years ago |github.com | reply

26 comments

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[+] adulau|2 years ago|reply
That's great for analyzing or reviewing the code. However, beyond that, there's not much else you can do with this code.

   This repository is not provided with a licence, and there is intentionally no LICENSE file provided.

   According to GitHub's licensing documentation, this means that "the default copyright laws apply, meaning that you retain all rights to your source code and no one may reproduce, distribute, or create derivative works from your work".
[+] MarkMoxon|2 years ago|reply
Yeah, I’ve had to add the same disclaimer to all my analyses of old code (e.g. Elite, Revs, Aviator). I’m not sure there’s any other solution - the original copyright owners still hold the copyright, and that’s just how it is. You can’t grant a license if you don’t own the rights…
[+] Smoosh|2 years ago|reply
It seems that the software can be run in-browser here: https://archi.medes.live/
[+] Kim_Bruning|2 years ago|reply
An Archimedes in the browser, Nostalgia overload!

I'm a little rusty, but I can still use it. Seems like things you learn when you're young stick with you, even if you haven't done it in over a decade.

Thank you for linking this, Smoosh!

[+] qingcharles|2 years ago|reply
The Archimedes had a mouse, so it is mouse-controlled in case anyone was wondering!
[+] readthenotes1|2 years ago|reply
Fresh out of school I started a job that involved updating some assembly code.

I came across:

#transfer the value from address 0x600 into R0

Mov &0x600, R0

... several lines later ...

#transfer the value in R0 to R1

Mov R1, R0

I puzzled over this while reading the rest of the program which had been similarly commented line for line and then eventually, there being no manuals, asked an older coworker to explain what was going on.

He looked at me with incredulity and said "what makes you think the comments have anything to do with the code?"

He explained "about 10 years ago the mechanical engineer finally got this program to work and his boss told him to explain what every line did, so he added the comments. The code has been updated for 10 years and no one's bothered to update the comments."

I have noticed that this is a truth throughout the rest of my career, although I have heard that NASA has someone whose job it is during code reviews specifically to make sure that the comments are kept up to date.

In just about every code base I have come across, 3/4 of the comments are wrong or unnecessary, and there is at least 1/4 of comments entirely missing to explain the inexplicable.

[+] tudorw|2 years ago|reply
Managing comments is one thing I really appreciate AI helping me with in cursor.so, I can ask it to strip all the comments to get a dense code view, make some changes, then re-comment it, with the verbosity aligned with my level of understanding.
[+] twic|2 years ago|reply
I remember playing this for the first time and being absolutely stunned. I think it would have been on an A3000, and up to then, the only machines I'd used were BBC micros and a Mac 512, neither of which were capable of anything like this. It was like science fiction.
[+] Symbiote|2 years ago|reply
This is written in Arm assembly language, for (I think) the ARM 2 CPU.

Se the history section: https://en.wikipedia.org/wiki/ARM_architecture_family

[+] MarkMoxon|2 years ago|reply
Technically, Lander was written for the ARM1, as it originated on an Acorn ARM Evaluation System. As a result there are no MUL instructions in Lander, as they only got added in the ARM2.

That makes Lander first ever ARM game, and probably the only game ever written for the ARM1.

[+] KingOfCoders|2 years ago|reply
Back in the days I wanted to get an Archimedes, moving away from my Amiga A4k40 but it was hard to get in Germany. I did get a Bebox instead. Sadly, both were killed by PCs with GPUs.
[+] qingcharles|2 years ago|reply
OK, I need to see how the ship shadow was done.
[+] MarkMoxon|2 years ago|reply
The coordinates of the shadow are calculated here:

https://lander.bbcelite.com/source/main/subroutine/drawobjec...

and they are drawn here:

https://lander.bbcelite.com/source/main/subroutine/drawobjec...

The shadow is a very simple projection straight down onto the landscape, which isn’t totally accurate, but it’s quick and easy and looks good enough. The shadow doesn’t drape over the shape of the landscape, and the ship shadow appears on the ground beneath objects rather than on top of them, but you don’t really notice.

Lovely, simple, effective code. Much like the rest of Lander, really!

[+] dynjo|2 years ago|reply
Amazing work!
[+] Tempest1981|2 years ago|reply
Indeed. Although I was hoping to see units on variables for altitude, velocity. (Maybe that's documented elsewhere?)