On Mar 20,  9:33am, newsham@uhunix.uhcc.Hawaii.Edu wrote:
> 
> 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?

  PAGE_SIZE is 8192 on the Amiga.

  If you look deep enough, you will find:
  - PAGE_SIZE is defined to be page_size.
  - page_size is initialized to 4096.
  - start_c sets page_size to 8192.

Michael

-- 
Michael L. Hitch			INTERNET:  osymh@montana.edu
Computer Consultant			BITNET:  OSYMH@MTSUNIX1.BITNET
Office of Systems and Computing Services
Montana State University	Bozeman, MT	USA

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