[U-Boot] [PATCH v5] bitops: introduce BIT() definition

[Scott Wood]

On Tue, 2015-09-08 at 21:01 +0300, ivan.khoronzhuk wrote:
> Hi, Andreas
> 
> On 07.09.15 14:43, Andreas Bießmann wrote:
> > From: Heiko Schocher <hs at denx.de>
> > 
> > introduce BIT() definition, used in at91_udc gadget
> > driver.
> > 
> > Signed-off-by: Heiko Schocher <hs at denx.de>
> > [remove all other occurrences of BIT(x) definition]
> > Signed-off-by: Andreas Bießmann <andreas.devel at googlemail.com>
> > ---
> > Full buildman is running
> > 
> 
> ....
> 
> > 
> > +#define BIT(nr)            (1UL << (nr))
> 
> Why UL? Why not simply 1 << (nr)?

That would give the wrong result for nr == 31 if used as a 64-bit number, and 
would produce undefined behavior for nr >= 32 (though even with 1UL that 
would be undefined on 32-bit builds).

> What if I need set ULL bit on 32-bit system?
> Thanks for explanation.

Yes, ULL would be better.

-Scott