Messages in this thread | | | Date | 24 Sep 2012 10:18:05 -0400 | From | "George Spelvin" <> | Subject | Re: [PATCH 1/4] lib: vsprintf: Optimize division by 10 for small integers. |
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Michal Nazarewicz <mpn@google.com> wrote: > On Fri, Aug 03 2012, George Spelvin <linux@horizon.com> wrote: >> Shrink the reciprocal approximations used in put_dec_full4 >> based on the comments in put_dec_full9. > > Have you verified that the comment is correct?
I rechecked all the validity limits myself.
>> r = (q * 0xcd) >> 11;
> If you are changing everything, this could also be changed to: > > r = (q * 0x67) >> 10; > > no?
Also in those comments is a statement I did *not* recheck, as it didn't affect correctness, saying that 0xcd produces shorter code than 0x67 on x86 (if the code is generated using shifts and adds).
That's why I left it that way.
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