On Fri, Apr 27, 2018 at 07:33:55AM +0200, Vincent Siles wrote:
> I get the 10 bits part, but then why is PPN 10 bits and PPN 12 bits
> when both VPN and VPN are 10 bits ?
> I think it is like ARM's LPAE idea, to allow accessing more RAM even with
> only 32 bit of virtual addresses, but I don't understand why this situation
> (physaddr > virtaddr) remains in the two other modes.
Exactly. Same as x86 PAE or arm LPAE or whatever the mips version is
called. 4GB is very low in terms of physical memory even for a 32-bit
CPU these days, while you can probably do with 4G virtual, although
it would be a lot less painful if we had a full supervisor/user
address space split (shameless plug :))