Re: [hatari-devel] MMU address translation for TT-RAM?

[Nicolas Pomarède <npomarede@xxxxxxxxxxxx>]

Le 02/10/2024 à 08:13, Christian Zietz a écrit :
> Eero Tamminen schrieb:
>
> > Looking further, I noticed that there's no MMU memory bank declared for
> > TT-RAM, like there's e.g. for ST-RAM:
> > https://git.tuxfamily.org/hatari/hatari.git/tree/src/cpu/memory.c#n1143
> >
> > Does this mean there's no MMU address translation done for TT-RAM?
>
> I think two concepts are mixed up here. The code that you are referring
> to here (i.e., STmem_lget_MMU, etc.) handles the potential address
> translation by the ST's and STE's MCUs, which only manage ST RAM anyway.
>
> But you are probably interested in address translation by the 68030's
> MMU, which is handled inside the CPU emulation.

exactly, Atari unfortunately chose MMU at the time of the ST/STF, which 
got a different meaning (or at least much more "management" abilities) 
when included later in more advanced CPU like the 68030.

So, no bank need to be declared for 68030-MMU, this is declared as 
normal RAM that the MMU can map between a logical and a physical address