from Hacker News

From ASCII to ASIC: Porting donut.c to a tiny slice of silicon

by a1k0n on 1/12/25, 5:36 PM with 25 comments

• by swores on 1/12/25, 9:22 PM

  Going slightly off topic, I was interested to learn from this blog about Tiny Tapeout, the service they've used to order their custom chip design. The concept for anyone as unfamiliar with it as me is that lots of people pay a few hundred dollars each to get a small part of a chip being made, and once it's made they receive the chip ready to use with their section everyone else's, too, with a way to choose which bit gets run.

  I know basically nothing about chip design, and I'm wondering if anyone could tell me: is this only useful for education purposes, for example learning how to make a chip that creates a donut on a screen, or are there people using Tiny Tapeout for useful projects, too?

  For each of their chip runs, they publish a list of the different people's projects that got included - https://tinytapeout.com/runs/ - but it's not easy to spot which ones might be more than somebody just learning how to play with chip design.

  Essentially, if someone were to pick this up as a hobby, what is the most interesting thing they could make using this?

• by malux85 on 1/12/25, 7:21 PM

  The thing about donut.c is that its source code is shaped like a donut, that’s a huge part of its charm.

  While altering it to use shifts and adds is a fun exercise, since its source code is no longer shaped like the donut it renders, I would argue that a large part of its charm has disappeared and it’s no longer a donut.c

• by refulgentis on 1/12/25, 9:23 PM

  I've been deeply curious about the sort of speedup you get from doing what was in software, on hardware:

  I know the chips hasn't been delivered yet, but, the statements at the beginning re: we can expect a new frame every N nanoseconds, give me hope there's a rough heuristic for what speedup we'd expect in this particular case.

  Do we have a rough* understanding of what the speedup will be?

  * Within 2 OOMs

• by anthk on 1/13/25, 6:02 PM

  I suggest you all to compile the C examples with -O3 -ffast-math on legacy systems.

• by binarymax on 1/12/25, 6:31 PM

  So great to see this excellent explanation. Have been a fan of donut.c since it first came out. Also I'm way better at golfing js than c so it kinda feels like you wrote this just for me :)

• by amstan on 1/13/25, 6:26 AM

  Yay, a1k0n!

  Long time since AI Challenge, I see you're dabbling into hardware too!

• by still_waiting on 1/12/25, 11:45 PM

  When are you going to post part 3 of your Hacker Challenge?

  It's been fifteen years and we're still waiting. Thanks.