Subject: pmap
To: None <>
From: None <newsham@uhunix.uhcc.Hawaii.Edu>
List: amiga-dev
Date: 03/20/1994 09:33:06
I'm a bit confused about one detail in the pmap and vm system.  There
are two page sizes defined,  PAGE_SIZE = 4096 and AMIGA_PAGE_SIZE = 8192.
When the kernel steals pages for its own use it seems to be grabbing
AMIGA_PAGE_SIZE sized chunks.  atop() which should convert an address
into pages does a >> page_size, page_size is initialized to 12 by the
vm system (2^12 = 4096). 

One of the things I have to do to use MACHINE_NONCONTIG is to make routines
reporting how many pages left and another routine to pass the address
of the next page.   Should I be using PAGE_SIZE and atop() or should
I be handing out AMIGA_PAGE_SIZE pages and using >> 13 to get the number
of pages?

What is the purpose of the two different page sizes?

                                     Tim N.