Re: [RFC] div64_64 support

From: Roland Kuhn
Date: Tue Mar 06 2007 - 10:10:45 EST


Hi Andi!

On 6 Mar 2007, at 15:45, Andi Kleen wrote:

<rant>
Let me see... You throw code like that and expect someone to actually
understand it in one year, and be able to correct a bug ?

To be honest I don't expect any bugs in this function.

</rant>

Please add something, an URL or even better a nice explanation, per favor...

It's straight out of Hacker's delight which is referenced in the commit
log.

And it's pretty neat, too. Hint: (y+1)**3 = y**3 + 3*y**2 + 3*y + 1. The algorithm is exactly the same as for calculating the cubic root on paper, digit by digit. I found that algo in the school notebook of my grandpa (late 1920ies), a pity that it's not taught anymore... pocket calculators _do_ have downsides ;-)

Ciao,
Roland

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-----BEGIN GEEK CODE BLOCK-----
Version: 3.12
GS/CS/M/MU d-(++) s:+ a-> C+++ UL++++ P+++ L+++ E(+) W+ !N K- w--- M + !V Y+
PGP++ t+(++) 5 R+ tv-- b+ DI++ e+++>++++ h---- y+++
------END GEEK CODE BLOCK------


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