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Comment by acqq | Hacker News Reader

It's a good and common practice to keep the constants in the sanest form and not obfuscate them, see the collections of such functions, like the already quoted

http://aggregate.org/MAGIC/

or like

https://graphics.stanford.edu/~seander/bithacks.html

By keeping the decimal constants he diminishes the chance to be attributed.

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Sure, sure, in most contexts code as communication medium is laudable. Here, the game is to make people accustomed to understanding go "the hell just happened?" when it works. I like it.

Yeah but that does not apply to jokes.

You mean the whole article is a joke just because the article ends with "the last thing I did was changing the constants to decimal - they look way more scary this way"?

I see it as a presentation of an efficient specialized function, just like the other bit hacks are (some already linked, one more, a whole book, here: http://www.hackersdelight.org/ ).

If it's is to impress the uninitiated, such are more probable to not know the hex codes too. For them is the decimal number the one less scary than the hex one. For others, converting back to hex is just a tiny annoyance, nothing more.

But it's not efficient. The author even explicitly says so at the beginning:

> (Disclaimer: It's not faster. It's not better. It's not production-quality code. It's just is and it was fun to make ;>)

It's a joke, a joke with some context, that you tell other people who know the context. Would you accuse people of intentionally obfuscating things when they riff on "the door is ajar" joke?

No, on modern 64-bit processors it's definitely more efficient and faster than the loop variant. It's measurable. The author's disclaimer that it isn't faster is actually valid only for old or small processors.

See cnvogel's attempt to measure it:

https://news.ycombinator.com/item?id=10513767

I also haven't accused anybody anything here.

You just won't give up will you?

Do you post similar rants to mechanical engineers building rube goldberg machines and electrical engineers building impractical extremely high voltage transformers?

Can you imagine that there are people who actually program on such a low level that they actually care about that kind of functions, constants and the number of T states that the resulting assembly code takes? I'm one of those. If these aspects aren't relevant to you please allow me to address them.

The article author actually engineered an effective function for spreading out bits to bytes. I invite you to read the comments here that are actually mine and what's in them.

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