Re: Need for SHIFT and MASK

[Fawad Lateef <fawadlateef@gmail.com>]

On 10/10/05, Vivek Kutal <vivek.kutal@gmail.com> 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
http://lxr.linux.no/source/arch/i386/mm/init.c#L207  !!!!!! 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