That makes sense...
Thanks,
Jason
-----Original Message-----
From: Dr. David Gilbert [mailto:[EMAIL PROTECTED]]
Sent: Friday, August 20, 1999 11:40 AM
To: Chagas, Jason
Subject: RE: pgd_offset
On Fri, 20 Aug 1999, Chagas, Jason wrote:
> Kong,
>
> That's right, 'pgd' is a pointer to the translation table
(TB) and 'address'
> contains the virtual address being mapped. Shifting the
virtual address
> [right] by 18 (the most significant 11 bits - 31-20) yield
the address of
> first-level descriptor in the translation table with the
first two least
> significant bits (1-0) set to zero. Oddly enough, the
function below is
> shifts by 20. I just wondering if anyone could explain it
to me...
I wonder if it is something like the fact that this is
shifting bits 1-0
off the bottom and then I wonder if the pointer its
modifying is actually
a word pointer and thus each value causes a 4 byte offset in
the language
- the effect being to do the clear of bits 1-0 for you.
Dave
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