[LinuxBIOS] Silly Question

This is a silly question but, when I see something like this (2<<20)  
in raminit.c it is saying to change bit 20 to a value of 2?? Is that  
correct?? That would have to be a binary value than right? Than what  
would that look like?? Just trying to understand the whole registry  
setting thing better.

Thanks - Joe

[Alan Carvalho de Assis]

Hi Joe

2007/3/26, [e-mail] :
> This is a silly question but, when I see something like this (2<<20)
> in raminit.c it is saying to change bit 20 to a value of 2?? Is that
> correct?? That would have to be a binary value than right? Than what
> would that look like?? Just trying to understand the whole registry
> setting thing better.

This is a shift operation, then you need think it in binary:

2 = 10 (binary)

10 << 20 = 1000000000000000000000

This operation is just to set the 22th bit.
This is equivalent to 1 << 21.

More info read about shift operation:

http://en.wikipedia.org/wiki/Arithmetic_shift
> Thanks - Joe

Cheers,

Alan

Quoting Alan Carvalho de Assis :
> Hi Joe
>
> 2007/3/26, [e-mail] :
> > This is a silly question but, when I see something like this (2<<20)
> > in raminit.c it is saying to change bit 20 to a value of 2?? Is that
> > correct?? That would have to be a binary value than right? Than what
> > would that look like?? Just trying to understand the whole registry
> > setting thing better.
>
> This is a shift operation, then you need think it in binary:
>
> 2 = 10 (binary)
>
> 10 << 20 = 1000000000000000000000
>
> This operation is just to set the 22th bit.
> This is equivalent to 1 << 21.
>
> More info read about shift operation:
>
> http://en.wikipedia.org/wiki/Arithmetic_shift
> > Thanks - Joe
>
> Cheers,
>
> Alan

Thanks Alan. That makes perfect sense, I thought it was something like that.

Thanks - Joe