Messages in this thread | | | From | Max Filippov <> | Date | Tue, 10 May 2022 21:55:23 -0700 | Subject | Re: [PATCH 08/22] bitops: introduce MANY_BITS() macro |
| |
On Tue, May 10, 2022 at 12:16 PM Yury Norov <yury.norov@gmail.com> wrote: > > Hi Max, > > On Tue, May 10, 2022 at 10:57:25AM -0700, Max Filippov wrote: > > 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, > > This patch introduces a macro MANY_BITS() in include/linux/bitops.h, which > is a full analogue of IS_POW2(). Would it work for you to switch to > MANY_BITS()?
It would, I guess. It would also work if is_power_of_2 was a macro.
-- Thanks. -- Max
| |