Re: [f-cpu] virtually or physically-addressed cache ?

[Cedric BAIL <cedric.bail@free.fr>]

Hi,

> > Concerning the cost of physical addressing from the CPU point of view,
> > i think i have found a way to reduce the cost to this of flat addressing
> > (ie in "kernel mode" when there is no TLB access). This also simplifies
> > the pipeline scheduler because there is no need to modify the timing :
> > kernel mode and vritual-addessed mode take the same time.
> > The big disadvantage is that it works better with only one page
> > granularity :-/
> Kernel mode is only no-paging !? oh bad !!!!! how can I transfer data to
> user memory (virtual addresses) when i'm in kernel mode !? Must I use a
> function to translate a virtual address to a physical address !? hey !!! if
> I have 16 pages to copy I must translate 16 times !?! whereas if kernel
> mode can handle virtual address space (so it should be able to use TLB), I
> would just need to do a memcpy (or user_memcpy for Linux hacker).
And what about a SR that active/unactivate the TLB when you are in kernel mode ?
That should be enough and not to difficult to implement, no ?

Cedric
*************************************************************
To unsubscribe, send an e-mail to majordomo@seul.org with
unsubscribe f-cpu       in the body. http://f-cpu.seul.org/