Hacker News: aqrit

New comment by aqrit in "Unearthing a 31 year old Easter egg in Ecco the Dolphin"

aqrit — Sat, 15 Aug 2026 12:02:39 +0000

Not the author but:

`GetKeyState` and `LoadMenuA` are going to stand out in the disassembly.

Backtracking from `GetKeyState` is how I found a devmode in "warhammer: shadow of the horned rat". Though it is activated by a boring commandline argument.

https://www.gog.com/forum/warhammer_shadow_of_the_horned_rat...

New comment by aqrit in "Firewood Splitting Simulator"

aqrit — Sun, 14 Jun 2026 17:17:24 +0000

>Is it really that difficult?

Fiberglass handles are now standard on splitting mauls (for this reason). Rotten hearts, or driving wedges. It is easy to miss a swing by an inch or two when fatigued.

Edit: I also broke my first axe handle. The sibling comments here are wild.

New comment by aqrit in "An AI agent published a hit piece on me – more things have happened"

aqrit — Sat, 14 Feb 2026 14:57:11 +0000

_Daily_ hit pieces on Elon Musk (or Musk companies), going for something like a decade. These have petered out somewhat since he left DOGE. But they started way back before he should have had that much notoriety.

New comment by aqrit in "Rubio stages font coup: Times New Roman ousts Calibri"

aqrit — Thu, 11 Dec 2025 16:42:30 +0000

MS makes "Times New Roman" available (at no cost), but not "Calibri".

New comment by aqrit in "Faster substring search with SIMD in Zig"

aqrit — Mon, 11 Aug 2025 20:09:57 +0000

`_mm_alignr_epi8` is a compile-time known shuffle that gets optimized well by LLVM [1].

If you need the exact behavior of `pshufb` you can use asm or the llvm intrinsic [2]. iirc, I once got the compiler to emit a `pshufb` for a runtime shuffle... that always guaranteed indices in the 0..15 range?

Ironically, I also wanted to try zig by doing a StreamVByte implementation, but got derailed by the lack of SSE/AVX intrinsics support.

[1] https://github.com/aqrit/sse2zig/blob/444ed8d129625ab5deec34... [2] https://github.com/aqrit/sse2zig/blob/444ed8d129625ab5deec34...

New comment by aqrit in "How to live on $432 a month in America"

aqrit — Sat, 24 May 2025 15:23:53 +0000

> health services in the area

Massena Hospital is a 25-bed hospital. Might have to go to Canton or Ogdensburg for a family doctor (45 minutes by car). Most things serious get referred to Syracuse or Burlington (3 hours away by car).

AFAIK, Cost[1] is "theoretically" nothing if annual income is less than the federal poverty line ($15,650 for an individuality). And might as well be free for an income up to $39,125.

[1] https://info.nystateofhealth.ny.gov/EssentialPlan

New comment by aqrit in "How to live on $432 a month in America"

aqrit — Sat, 24 May 2025 11:33:04 +0000

Alcoa (Aluminum Smelter, *cheap electricity*) was the major industry in the area. Massena plant now produces 85% less aluminum compared to ~15 years ago (AFAICT), leading to something of a ghost town (and cheap housing).

New comment by aqrit in "YouTube DRM added on ALL videos with TV (TVHTML5) clients"

aqrit — Mon, 10 Mar 2025 20:16:12 +0000

Limited internet connections (speed and/or data-caps). Something like Hughesnet (satellite ISP) couldn't stream more than 240p from youtube during peek times. The data-cap coerced users to do downloads between 2am to 6am.

New comment by aqrit in "Constantly Divisionless Random Numbers"

aqrit — Sun, 09 Mar 2025 19:45:52 +0000

> “regular” rejection sampling

I was thinking naive: mask off unwanted bits then reject any value above the limit.

It would seem like https://c-faq.com/lib/randrange.html would also move the multiply --or divide by constant-- out of the loop.

New comment by aqrit in "Improving on std:count_if()'s auto-vectorization"

aqrit — Sun, 09 Mar 2025 15:58:47 +0000

A optimized version would use 64-bit accumulators (`psadbw` on SSE2, or some sort of horizontal adds on NEON). The `255` max constraint is pointless.

Many programming languages/frameworks expose this operation as `reduce()`.

New comment by aqrit in "Constantly Divisionless Random Numbers"

aqrit — Sun, 09 Mar 2025 15:32:29 +0000

Why not use regular rejection sampling when `limit` is known at compile-time. Does fastrange[1] have fewer rejections due to any excess random bits[2]?

[1] https://github.com/lemire/fastrange

[2] https://github.com/swiftlang/swift/pull/39143

New comment by aqrit in "Parsing time stamps faster with SIMD instructions"

aqrit — Mon, 03 Jul 2023 11:09:50 +0000

That snippet would not reject bad chars, are non-digits rejected somewhere else? A simple scalar loop that multiplies an accumulator by 10, itoa() style, would be faster.

New comment by aqrit in "Parsing time stamps faster with SIMD instructions"

aqrit — Mon, 03 Jul 2023 02:24:31 +0000

The methods in those articles could be slightly improved by picking better multipliers. https://stackoverflow.com/a/71594769

New comment by aqrit in "Parsing time stamps faster with SIMD instructions"

aqrit — Mon, 03 Jul 2023 01:57:52 +0000

There are two digits for months. A check is required per-character to prevent bad chars (e.g 0x3A) from being laundered by the multiply. The '19' comes from fact that the first digit may be only 0 or 1, while the 2nd digit maybe any value 0..9 (e.g September '0'9' October '1'0'). The second check catches bad month values between 13..19 which were not caught by looking at individual digits. Realistically, the first check may be overbuilt, it only needs to check is_digit or not, but it still has to ignore the padding bytes at the end, somehow. Now... I believe there would be a problem with the month value of '00'... because it unconditionally subtracts 1 from that field then uses it as a table index.

New comment by aqrit in "Basic SAT model of x86 instructions using Z3, autogenerated from Intel docs"

aqrit — Mon, 15 May 2023 20:06:17 +0000

This was for a super optimizer.

New comment by aqrit in "High speed Unicode routines using SIMD"

aqrit — Mon, 05 Sep 2022 17:46:57 +0000

One of the authors/contributors was looking into it: https://old.reddit.com/r/mainframe/comments/wevyvg/whats_the... I don't think this project was ready for a public announcement, yet.

New comment by aqrit in "Filtering a vector with SIMD instructions (AVX-2 and AVX-512)"

aqrit — Thu, 01 Sep 2022 19:43:13 +0000

The AVX2 version is using a 8 KiB table...? Even the range check is inefficient. I'd bet that the AVX2 version could be 50% faster.

New comment by aqrit in "Converting integers to decimal strings faster with AVX-512"

aqrit — Tue, 29 Mar 2022 20:41:35 +0000

related to IEEE 754 double-precision floating-point round-trips?

New comment by aqrit in "Walmart has stopped fighting the $7k fine for a worker's death in 2008 (2015)"

aqrit — Sat, 06 Nov 2021 22:18:15 +0000

Any fine shows Walmart as liable. A free win for any $100mm civil lawsuit.

New comment by aqrit in "No sane compiler would optimize atomics (2015)"

aqrit — Sun, 11 Jul 2021 22:40:57 +0000

https://media.ccc.de/v/35c3-9788-memsad