Re: [hatari-devel] add support for TT ram ?

[Nicolas Pomarède <npomarede@xxxxxxxxxxxx>]

Le 17/12/2014 21:15, Eero Tamminen a écrit :

> I've changed TOS memory setup code to automatically disable 24-bit
> addressing and fastboot if TT-RAM is used under TT emulation.  It
> will notify user about about this.
>
> As there's no point in using 32-addressing unless there's TT-RAM,
> and it makes things less compatible, I'm forcing 24-bit addressing
> when TT-RAM is not in use.  Should I remove 24-bit selection from
> SDL GUI, options and config file too?

Hi

I think your changes are a little too restrictive at the moment, because 
basically it prevents me from working on TT RAM for falcon :)

The following lines should be removed :

 +		} else {
    1.22 +			Log_Printf(LOG_WARN, "Disabling TT-RAM, it would need TT / 
32-bit addressing!");
    1.23 +			ConfigureParams.Memory.nTTRamSize = 0;
    1.24 +		}
    1.25 +	} else {
    1.26 +		/* enable 24-bit for better compatibility, only TT-RAM 
needs 32-bit addressing */
    1.27 +		ConfigureParams.System.bAddressSpace24 = true;
    1.28 +	}

-> don't force nTTRamSize=0 if machine is not a TT, the code in memory.c 
will not allocate RAM anyway.
-> don't force 24 bit addressing if not TT

Both cases should be removed, let's just force 32 bit and normal boot at 
the moment only for TT.

As for forcing 24 bit addressing, I think it should be forced only when 
CPU is a 68000, but in all others cases, even if no extra ram is added, 
it should be left as selected by the user.

32 bits adressing are required when Falcon will have extra RAM, and it 
can be needed to for better compatibility with a real Falcon where it's 
the PMMU that does the translation.

And even if 32 bit is less stable (HD gemdos emulation at the moment for 
example), I'd rather have people test it anyway and report bugs, as it 
should work with recent TOS (this allowed to see the cartdridge bug at 
$FA0000 in EmuTOS and the DTA bug in HD gemdos)

> No need to wait, Vincent did EmuTOS CVS snapshot including the fix:
> http://sourceforge.net/projects/emutos/files/snapshots/CVS-20141215/

Yes, but I meant wait for next official release, I don't think users 
want to look for the latest cvs devel version which might not be ready 
for "production".

> > So, only solution for now to have extra TT RAM and HD is to use
> > a direct HD image, not the HD gemdos emulation.
>
> Just use EmuTOS, only TOS v3 has that problem.

If we limit ourselves to stable release, EmuTOS is not ready yet.

> After these are done, the forcing part can be updated.

Yes, some changes will be needed

Nicolas