[ros-kernel] memory manager

[Gunnar Dalsnes]

> I don't think we should be making changes just for the sake 
> of it - especially
> since we might want to run ROS on systems where the size of a 
> physical address
> and the size of an int are different.

I don't see the problem. If we typedef a PHYSICAL_PAGE as ULONG, we can
change this at any time to a ULONGLONG for example.

You are correct that my proposed changes are just cosmetics. It will
simplify stuff thou, avoiding stupid castings everywhere. We won't need to
multiply/divide with the page size everywhere just to get to the page number
either. And finally/hopefully we can get rid of the stupid Microsoft
invented LARGE_INTEGER most places, except for the exported function of
course.

The reason I began to think about this cleanup is that Microsoft use page
numbers everywhere. Mdl's i Windows keep page numbers while we keep page
addresses for example. They also use page numbers in
MmHighest/LowestPhysicalPage etc. It's strange that ROS don't use page
numbers also, since the only use of a physical address is to get to the page
entry in the physical page table/array, indexed by the page number.

-Gunnar