On Wed, Dec 22, 2021 at 08:56:12PM +0200, Andy Shevchenko wrote: > On Wed, Dec 22, 2021 at 8:38 PM Liam Beguin <liambeguin@xxxxxxxxx> wrote: > > On Wed, Dec 22, 2021 at 02:29:04PM +0200, Andy Shevchenko wrote: > > > On Wed, Dec 22, 2021 at 5:47 AM Liam Beguin <liambeguin@xxxxxxxxx> wrote: > > ... > > > > > - tmp = 1 << *val2; > > > > > > At some point this should be BIT() > > Forgot to add, If it's 64-bit, then BIT_ULL(). > > > I'm not against changing this, but (to me at least) 1 << *val2 seems > > more explicit as we're not working with bitfields. No? > > You may add a comment. You may use int_pow(), but it will be suboptimal. > > > > Rule of thumb (in accordance with C standard), always use unsigned > > > value as left operand of the _left_ shift. > > > > Right, that makes sense! In practice though, since we'll most likely > > never use higher bits of *val2 with IIO_VAL_FRACTIONAL_LOG2, would it be > > enough to simply typecast? > > > > tmp = 1 << (unsigned int)*val2; > > No, it's about the _left_ operand. > I haven't checked if tmp is 64-bit, then even that would be still wrong. Okay so your recommendation is to not use a left shift? I can look into that but given how unlikely it is to fall into those bad cases, I'd rather keep things as they are. Would that be okay? Also, I don't think using BIT() or BIT_ULL() would address this as they both do the same shift, with no extra checks. Cheers, Liam > -- > With Best Regards, > Andy Shevchenko
