Would it make sense to use BIT(31)?
On Thu, Jan 7, 2021 at 2:20 PM Matt DeVillier <matt.devill...@gmail.com> 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 <nic...@gmx.de> 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 -- coreboot@coreboot.org > > To unsubscribe send an email to coreboot-le...@coreboot.org > _______________________________________________ > coreboot mailing list -- coreboot@coreboot.org > To unsubscribe send an email to coreboot-le...@coreboot.org _______________________________________________ coreboot mailing list -- coreboot@coreboot.org To unsubscribe send an email to coreboot-le...@coreboot.org
