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   mcc (mcc@mastodon.social)'s status on Wednesday, 28-Jun-2023 05:35:17 JST mcc

   Speedrunning is kinda cursed https://www.youtube.com/watch?v=CEQWT9rSkfM

   Did you know this? Apparently if you bought a copy of Super Mario Bros. 3 in the US, depending on when you bought it the "bros" in the logo is either aligned left on the label or right.

   *If the logo on your cart is aligned right, you can't get a world record under current strategies.*

   And until *last year*, nobody realized this was a problem. It was believed the versions were functionally identical.

   (image source reddit user stang189)

   • Embed this notice
     feld (feld@bikeshed.party)'s status on Wednesday, 28-Jun-2023 05:35:17 JST feld

     in reply to
     > And until *last year*, nobody realized this was a problem. It was believed the versions were functionally identical.
     
     how is it possible nobody has diffed the dumped ROMs? very strange
   • Embed this notice
     mcc (mcc@mastodon.social)'s status on Wednesday, 28-Jun-2023 05:37:25 JST mcc

     in reply to

     Infosec-minded people watching this video will have a slow-dawning realization that what this speedrunner is haltingly describing is a timing attack performed on the video game. The version difference would not have been a problem if Nintendo had used constant-time algorithms in their end-of-level score check arithmetic. There's some DJB shit going on here.

   • Embed this notice
     feld (feld@bikeshed.party)'s status on Wednesday, 28-Jun-2023 05:37:25 JST feld

     in reply to
     > There's some DJB shit going on here.
     
     nah, DJB is usually right. He's a prick and a misogynist, but he's right about cryptography.
   • Embed this notice
     mcc (mcc@mastodon.social)'s status on Wednesday, 28-Jun-2023 05:37:26 JST mcc

     in reply to

     If this video confuses/bores you: Read this post then jump to 10:19.

     In warpless SMB3 runs, there's an early (second world) instance of randomness where a hammer brother can run either right or left, and if it runs left you can skip three entire levels and save an entire minute:

     https://smb3.bf0.org/smb3mechanics/2018-08-22-early-hammer/

     Getting this randomness is important, so players use a "manipulation"– they play in a very precise way (in Mitch's case, literally miming along to a video of a TAS) to get exact random numbers.

   • Embed this notice
     mcc (mcc@mastodon.social)'s status on Wednesday, 28-Jun-2023 05:40:12 JST mcc

     in reply to

     • feld

     @feld Not sure I understand this response. What I mean is that the video hinges on the kind of analysis DJB performs.

   • Embed this notice
     feld (feld@bikeshed.party)'s status on Wednesday, 28-Jun-2023 05:40:12 JST feld

     in reply to
     ahh I read it as "this was designed like something DJB would have done" :laugh:
   • Embed this notice
     feld (feld@bikeshed.party)'s status on Wednesday, 28-Jun-2023 05:41:20 JST feld

     in reply to
     💯
     
     
     but yeah this stuff is crazy, they're figuring out how to influence random number generators and all kinds of stuff to optimize their runs... blows my mind.
   • Embed this notice
     mcc (mcc@mastodon.social)'s status on Wednesday, 28-Jun-2023 05:41:21 JST mcc

     in reply to

     • feld

     @feld No the opposite. This is a mistake DJB would have caught

   • Embed this notice
     feld (feld@bikeshed.party)'s status on Wednesday, 28-Jun-2023 08:49:22 JST feld

     in reply to

     • ShadSterling
     Society is a massively complex opaque problem with tons of externalities and secondary effects. It's hard to test your policies in a sandbox and you need years of data to measure success
   • Embed this notice
     ShadSterling (shadsterling@mastodon.social)'s status on Wednesday, 28-Jun-2023 08:49:23 JST ShadSterling

     in reply to

     • feld

     @feld @mcc every time I see this sort of thing I wonder, what if we could spend more of that time and attention on feeding the hungry, healing the sick, housing the homeless…. Not that other pursuits aren’t worthy, just that if we can solve such tiny obscure technical things, why can’t we also solve the big obvious social things?

   • Embed this notice
     feld (feld@bikeshed.party)'s status on Wednesday, 28-Jun-2023 22:15:53 JST feld

     in reply to

     • ShadSterling
     • GabeMoralesVR
     • John-Mark Gurney
     @encthenet may be able to give you links to useful information about pRNGs
   • Embed this notice
     GabeMoralesVR (gabemoralesvr@mastodon.gamedev.place)'s status on Wednesday, 28-Jun-2023 22:15:54 JST GabeMoralesVR

     in reply to

     • feld
     • ShadSterling

     @mcc @ShadSterling @feld obligatory: https://www.youtube.com/watch?v=q15yNrJHOak

     an aside MCC, but in this video, they talk about how they mapped out the distribution of the randomness of Mario World's pRNG. Would you have any reading on A) how to calculate such a distribution (and more specifically how long it'd take to loop) and B) how to create a pRNG with a specifically wide distribution? As in, I want to read more about how to better design a pRNG.

   • Embed this notice
     mcc (mcc@mastodon.social)'s status on Wednesday, 28-Jun-2023 22:15:55 JST mcc

     in reply to

     • feld
     • ShadSterling

     @ShadSterling @feld You can reverse engineer the Super Mario 3 random number generator without leaving a room. Any solution to poverty would require the cooperation of more than one person, probably many people. Social problems are always more difficult than technical ones (even if your goal is writing a piece of software, the hard part will be the social work of relating to and promoting yourself to your user) and few problems are so polite as to admit purely technical solutions.