Re: [MiNT] virtual memory

[Frank Naumann <fnaumann@freemint.de>]

Hello!

> This gives us
>  - a virtual address space of a bit less than 4GB *per process* (actually

And on the Milan there are 3 (three!!!) GB reserved I/O area.

And you forgot completly the kernel address space. For speed reasons the
kernel address space is best permantly mapped as supervisor into very
application, otherwise it make to much trouble and expensive dramatically
copyin/copyout actions.

> For system processes that need to access IO (or for processes that need to
> write to PCI memory in Milan, which starts at $40000000, we would need to
> decrease the top, but we would still have 1GB *per process* in the case a
> dirty program needs to write to video memory on a Milan).

So on Milan we doesn't have 1 GB per process. Kernel address space is not
so small as you may think (it includes first a mapping of all available
RAM).


Tschuess
   ...Frank

--
ATARI FALCON 040 // MILAN 060
-----------------------------------------
http://www.cs.uni-magdeburg.de/~fnaumann/
e-Mail: fnaumann@freemint.de