Re: [LinuxBIOS] Another dumb C question

[Corey Osgood]

Joseph Smith wrote:
> Quoting Peter Stuge :
> > > value = 9
> > >
> > > (2 << (value - 1))
> > Bit shift is fine methinks but I would suggest:
> >
> > (1 << value)
> >
> > instead of
> >
> > (2 << (value - 1))
> >
> > //Peter
>
> Not sure I understand. I am trying to get 2 "to the power of" value.
>
> if value = 9
> (1 << value)
> This equals 18???? Not 2^9 = 512
> where
> (2 << (value - 1))
> (2 << (9 - 1))
> 2 << 8 = 512
>
> Thanks - Joe

remember that 2 = (1 << 1). so 2 << (value - 1) = 1 << value. I'm not
sure where you're getting an 18 from, that makes no sense at all (since
18 in either hex or dec has two non-zero bits, so it's impossible to get
that result with just that binary shift).

-Corey