Messages in this thread | | | From | Crt Mori <> | Date | Wed, 20 Dec 2017 16:41:46 +0100 | Subject | Re: [PATCH v10 1/3] lib: Add strongly typed 64bit int_sqrt |
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On 20 December 2017 at 15:39, David Laight <David.Laight@aculab.com> wrote: > From: Crt Mori >> Sent: 20 December 2017 14:20 >> >> There is no option to perform 64bit integer sqrt on 32bit platform. >> Added stronger typed int_sqrt64 enables the 64bit calculations to >> be performed on 32bit platforms. Although int_sqrt() is a rough >> approximation, the same algorithm is used in int_sqrt64() as good >> enough on 32bit platform. > > The algorithm used gives an exact (rounded down) square root, > not an approximation. >
OK, noted. This is from new changed function indeed - will change in v11.
> With minor changes it ought to be possible to remove most of the > 64bit arithmetic and shifts. > > If you care about performance then using 32 bit maths will be much faster. >
I need precision not the performance. That is why I would like to leave int_sqrt as one for good performance while my will be used when you require a precision.
> David >
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