Re: Need for SHIFT and MASK

From: Fawad Lateef
Date: Mon Oct 10 2005 - 11:50:14 EST

On 10/10/05, Vivek Kutal <vivek.kutal@xxxxxxxxx> wrote:
> > And as far as SHIFT, MASK, SIZE macros are concerned they are used in
> > creating Page Translation Tables and also used to get the translation
> > from linear to physical
> how are these macros used to create page translation tables (functions
> like pgd_alloc(), pmd_alloc() & pte_alloc() are used for this
> purpose)and the translation (virtual/linear to physical)is done by
> the processor and not by the OS.

Actually I don't mean by mentioning "SHIFT, MASK, SZIE macros are used
in creating Page Translation Table" that you will see them in
pgd_alloc() etc but they are used in many memory initialization
fucntions at the boot time ...... and for example look !!!!!! These
Macros are might be there for the compatibility reasons tooo as you
can see the PAGE_SIZE can be changed but if you use PAGE_SIZE in every
module/place you won't be concerned about the actual size of the page
at that moment or in Architecture ...........

Fawad Lateef
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