You ever notice how when you're a rando it's a "harebrained scheme" but if you're a Fortune 500 CEO it's a "bold plan"

New blog post: "Memory ordering in CPUs" https://fgiesen.wordpress.com/2026/08/25/memory-ordering-in-cpus/ I've written about this before, but this is really _just_ about memory ordering so I have something I can point people at when the topic comes up again. :)

I have been reliably informed I shall soon be boarding a flight to HEL.

Oh well. Can't say I don't know what I did.

Lou Wall: "Where is Bed" https://www.youtube.com/watch?v=8HXFurHCkP8

Every time. I swear CDG is Airport Concentrate. It's "yo dawg I heard you like airports so we put multiple airports inside an airport so you can get lost while you get lost."

Travel PROTIP: I took to (hand-)writing a checklist before I leave for trips in the early 2010s. On this checklist I write all kinds of things I have never once forgotten to do, but most importantly, I write "throw used coffee filter in the trash", which I had previously forgotten more than once and which is the exact kind of thing whose consequences you don't want to deal with when you arrive tired and jetlagged back home after a 10h+ flight

Saw a comment of someone mentioning building multiplication on a Z80 using log/exp tables.

Don't! You can do better. Make a 510-entry table of squares (actually, squares divided by 4).

t[x] = (x * x) >> 2

then for 8-bit unsigned a, b, a >= b,

a * b = t[a + b] - t[a - b]

16-bit entries (or, usually, two tables, one for low, one for high bytes) if you want a full 16-bit result, but you can skip the high byte table if you only want low 8b.

boring regular way:
// Count <= 4
uint MyIndex = WavePrefixSum(Count);

uint MyOutputIndex = OutputPos + MyIndex;
// Write items to [MyOutputIndex, MyOutputIndex + Count) in a list

OutputPos += WaveActiveSum(Count);

sicko mode:
uint MyIndex =
WavePrefixCountBits(Count >= 4) * 4 +
WavePrefixCountBits((Count & 2) != 0) * 2 +
WavePrefixCountBits((Count & 1) != 0);

OutputPos +=
WaveActiveCountBits(Count >= 4) * 4 +
... +
WaveActiveCountBits((Count & 1) != 0);