[stella] entropy & randomness

Subject: [stella] entropy & randomness
From: urchlay@xxxxxxxxxxxxxxxx
Date: Wed, 10 Oct 2001 13:10:35 -0400 (EDT)
> > The Suicide Mission routine doesn't repeat the first time the start value comes
> > around again... I got a sequence like this (using $AA as seed):
> 
> Sure, it's a TWO byte random generator, so you have to check both bytes.
> 

d'oh!

> I doubt that a bit, look at your sequence: 55, 2a, 15 is repeated within
> only 69 bytes.

yes... but the next byte after that, isn't the next byte in the sequence from the
beginning.. not sure how you'd describe that, there are recurring patterns, but
overall the sequence doesn't repeat for something like 4096 bytes.

> Maybe you could test some other (one or two byte) LFSRs.
> Try Starmaster (could be worse), Pitfall! (should be better) and River
> Raid (looks promising).

Is there anything actually random in Pitfall? The game seems the same
every time... Pitfall II had what, some sorta hardware random number
generator? I've got the disassembly of River Raid that was posted here,
will look when I get home.

> But everything is random, as long as nobody notices it isn't.

That's the best advice you could have given me :)

B.


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