Re: [PATCH 2/3] linux/bits.h: Add fixed-width GENMASK and BIT macros

Andy Shevchenko
2023-06-15T15:55:39Z

On Fri, May 12, 2023 at 02:45:19PM +0300, Jani Nikula wrote:
> On Fri, 12 May 2023, Andy Shevchenko <andriy.shevchenko@linux.intel.com> wrote:
> > On Fri, May 12, 2023 at 02:25:18PM +0300, Jani Nikula wrote:
> >> On Fri, 12 May 2023, Andy Shevchenko <andriy.shevchenko@linux.intel.com> wrote:
> >> > On Mon, May 08, 2023 at 10:14:02PM -0700, Lucas De Marchi wrote:
> >> >> Add GENMASK_U32(), GENMASK_U16() and GENMASK_U8() macros to create
> >> >> masks for fixed-width types and also the corresponding BIT_U32(),
> >> >> BIT_U16() and BIT_U8().
> >> >
> >> > Why?
> >>
> >> The main reason is that GENMASK() and BIT() size varies for 32/64 bit
> >> builds.
> >
> > When needed GENMASK_ULL() can be used (with respective castings perhaps)
> > and BIT_ULL(), no?
>
> How does that help with making them the same 32-bit size on both 32 and
> 64 bit builds?

u32 x = GENMASK();
u64 y = GENMASK_ULL();

No? Then use in your code either x or y. Note that I assume that the parameters
to GENMASK*() are built-time constants. Is it the case for you?

--
With Best Regards,
Andy Shevchenko