[LinuxBIOS] Another dumb C question

Peter Stuge peter at stuge.se
Thu Jul 12 11:16:52 CEST 2007


On Thu, Jul 12, 2007 at 05:00:23AM -0400, Joseph Smith wrote:
> Hello,
> I have another newbie C question.
> Is this the same as 2^9 ??

Note that ^ means XOR in C. Exclusive or. Output 1 when only one
input bit is 1, but not both.

  00100011
^ 10101010
----------
  10001001



> value = 9
> 
> (2 << (value - 1))
> 
> This will give me 512, but will it work no matter what "value" is?

Yep.


> Or does linuxbios already have a "to the power of" global function?

No pow() in LB and the pow() in libm uses doubles so it's bad for the
task.


Bit shift is fine methinks but I would suggest:

(1 << value)

instead of

(2 << (value - 1))


//Peter




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