Messages in this thread | | | From | Max Filippov <> | Date | Tue, 10 May 2022 10:57:25 -0700 | Subject | Re: [PATCH 08/22] bitops: introduce MANY_BITS() macro |
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Hi Yury,
On Tue, May 10, 2022 at 8:48 AM Yury Norov <yury.norov@gmail.com> wrote: > arch/xtensa/kernel/traps.c and include/linux/log2.h define very similar > functions with different behaviour. XTENSA defines IS_POW2(), and > log2.h defines is_power_of_2(). The difference is that IS_POW2() > considers 0 as power of 2, while is_power_of_2() - does not.
IS_POW2 is constructed this way because we know that there is at least one non-zero bit in the value that it tests.
> This discrepancy may confuse reader. From mathematical point of view, > 0 is not a power of 2.
If it would reduce the confusion we can add a check that the value is non-zero in the IS_POW2 macro.
I'd really like to not introduce the local macro and just use something standard, but I can't use is_power_of_2 in a preprocessor condition, can I?
-- Thanks. -- Max
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