[hatari-devel] 6301 emulation : work in progress

[Thomas Huth]

On Wed, 19 Aug 2009 09:19:07 +0200
LAURENT SALLAFRANQUE <LAURENT.SALLAFRANQUE at ARKEA.COM> wrote:

> Hello,
> 
> > AFAIK the 6301 firmware is _not_ uploaded by TOS on a real ST.
> > And no, as long as you don't have the written permission by Atari
> > that we're allowed to use it, we can't provide it with Hatari.
> 
> OK, so I have a few more questions :
> 
> - Should I continue to code the 6301 ?
> ( I've already coded half the cpu main core).

That's up to you. Thanks to Nicolas' fake 6301 emulation, there is
currently no need for it, since all known demos that use the 6301
directly already work. But if you have fun writing a full 6301
emulation, I certainly won't stop you ;-)

> - Can we imagine to have a new entrance in the parameters to select a
> 6301 ROM ? If the file is selected, hatari runs with the emulated
> cpu, else, it runs with Nicolas' fake emulation ?

Sure, there's plenty of space left in the ROM or keyboard setup dialog,
so this shouldn't be a problem.

> - Is the 6301 ROM the same for every atari computer ? 
> ( I mean 520 Stf, 1040 Ste, TT, Falcon, Hades, Milan, ...)

I think there are at least two different versions available. When you
sent the IKBD RESET command (0x80, 0x01) to the IKBD, it returns one
byte where the lowest nibble is the version number of the IKBD ROM.
There seem to have been two different versions, one that returns 0xf0
and one that returns 0xf1.

> - Is the 6301 ROM the same for every country ?
> ( does a french and a german falcon have the same 6301 ROM) ?

I'm not sure, but I think so, yes. The IKBD just returns scan codes,
the mapping two the keyboard layout is then done by TOS.

> - I think Saint includes a real 6301 emulation. 
> Do you think they include the ROM directly in the binary ?

I don't know, I never really used Saint (since it's Windows only).

> Is this allowed ? 

Legally certainly not.

 Thomas