pte entries for the 440

Gabriel Paubert paubert at
Wed Apr 25 02:19:15 EST 2001

On Tue, 24 Apr 2001, Ralph Blach wrote:

> I am starting a port of linux to the IBM440 processor.  The 440 has an
> 36 bit address space.  Reading the kernel sources, I see two options for
> the page tables.
> 1)One, make it a structure with the permissions being in the second
> word.
> 2)Make it a long long.

Make it a structure, gcc is (or at least was) not very good at
manipulating 64 bit integers on 32 bit machines. I suspect that you need
to shift/mask the physical address to put the bits in the correct place,
in this case gcc prefers a stucture for sure.

It is much easier on the compiler and the register allocation routines to
consider single register quantities.


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