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Ruud H.G. van Tol on Thu, 30 Mar 2023 19:44:32 +0200
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- To: pari-dev@pari.math.u-bordeaux.fr
- Subject: Re: bit_ffs
- From: "Ruud H.G. van Tol" <rvtol@isolution.nl>
- Date: Thu, 30 Mar 2023 19:43:16 +0200
- Delivery-date: Thu, 30 Mar 2023 19:44:32 +0200
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On 2023-03-30 19:02, Ruud H.G. van Tol wrote:
Might be interesting to add:
https://en.wikipedia.org/wiki/Find_first_set
https://www.man7.org/linux/man-pages/man3/ffs.3.html
https://www.go4expert.com/articles/builtin-gcc-functions-builtinclz-t29238/
Or are those too low-level?
bit_ffs, bit_ctz
Count trailing set bits:
bit_cts(n) = logint( 1 + bitand(n, bitneg(n) - 1), 2 )
(no idea yet if that is a good implementation)
Would also be nice to have a turbo version of that.
-- Ruud
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- From: "Ruud H.G. van Tol" <rvtol@isolution.nl>