I will admit that I am a big fan of the `BIT` macro as well, but that seems to not be as well-received, so if that's not an option, I would second `1u << 31`
On Thu, Jan 7, 2021 at 3:25 PM Furquan Shaikh <[email protected]> wrote: > Would it make sense to use BIT(31)? > > On Thu, Jan 7, 2021 at 2:20 PM Matt DeVillier <[email protected]> > wrote: > > > > `1u << 31` is correct, clear, and easy to read/understand quickly. It > > has my vote. > > > > On Thu, Jan 7, 2021 at 3:42 PM Nico Huber <[email protected]> wrote: > > > > > > Hi coreboot fellows, > > > > > > another patch that fixes a `1 << 31` to `1UL << 31` [1] reminded me > that > > > some people objected to such changes. I'm not sure if we ever draw a > > > conclusion on the matter. > > > > > > `1 << 31` is undefined behavior because the `1` can (and thus will) be > > > represented as a (signed) `int` which is limited by 2^31-1 for all our > > > targets. But we know very well that GCC (and I assume Clang too) do the > > > right thing: Produce a value that when casted to an `unsigned int` is > > > converted to 2^31. > > > > > > So, it's wrong but not broken ;) and any suffix to the `1` makes it a > > > bit harder to read. > > > > > > What do you think? Should we allow such changes? Should we normalize > > > on any style? > > > > > > If we want to make it defined behavior, my personal preference would be > > > `1u << 31`. Lower case because it's more distinct from the number part, > > > and we actually don't need a long (that might even hide actual errors > > > if we want a 32-bit limited value). > > > > > > Cheers, > > > Nico > > > > > > PS. Happy new year btw. :D > > > > > > [1] https://review.coreboot.org/c/coreboot/+/49076 > > > _______________________________________________ > > > coreboot mailing list -- [email protected] > > > To unsubscribe send an email to [email protected] > > _______________________________________________ > > coreboot mailing list -- [email protected] > > To unsubscribe send an email to [email protected] > _______________________________________________ > coreboot mailing list -- [email protected] > To unsubscribe send an email to [email protected] >
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