Aram Iskenderian wrote:
> 
> On Wed, 02 Sep 1998 10:14:11 -0700
>  in article <35ED7CE3.E6C@htlchur.ch>
>  sam jordan  wrote:
> 
> >The current emulator emulates the whole AMIGA-OS in a 'black box',
> 
> The whole Amiga OS?
> You guys did a complete "classic" Amiga emulation then?

No. The emulator doesn't emulate the AMIGA hardware.

> I thought it was a 68K emulation and the OS runs on top of it, on a
> PPC Amiga.

It *is* a 68K emulation, just like the Mac emulator.

OK, I will shortly explain this. There are two emulator scenarios:

- blackbox emulation, this means, the 68K-AMIGA-OS is emulated
completely, inclusive interrupts, exceptions, scheduling, really
everything. The emulator starts its work at $f80002, all exec tasks
are running in the same emulator context/task. This emulator task
is a WarpOS task and is running on a modified version of WarpOS,
which is completely 68K- and AMIGA-OS-independent. It cares
for multitasking between PPC-native applications and the emulator
task. Or in other words: The high-level OS AMIGA-OS-68K is running
on the low-level OS WarpOS.

This solution already exists as image file and can easily
be put into a flash ROM, so that new PPC-hardware can directly
boot with the PPC instead of booting with a low-end 68K and then
starting the PPC software.

Due to the 'black box' nature of this concept, the compatibility
to existing 68K software is very high, so that it will be possible
even in 5 years to run old software on a Power-AMIGA, even hardware-
hacking games starting from the bootblock. And it will be even possible
to make software running, which doesn't run on the original 68040,
because the emulator can be patched with command emulations, which
are not 040-compatible, if desired. Or a busy loop can be activated,
if software is running too fast (remember all those games accessing
the disk motor too fast on faster processors?)

- emulator integrated into a PPC-AMIGA-OS (Mac-style solution). Every
task can run either native-code or use the emulator for 68K code.
That's the solution for the future, but now we can't use it, because
there is no PPC-AMIGA-OS. But the H&P emulator will be adapted to
such a solution, as soon as AMIGA-OS gets ported to PPC.

Using this type of emulation, you probably can't use the really
'dirty' software, like hardware-hack games etc. and many other
programs (for example applications, which use supervisor resources,
MMU etc.) probably also will have problems, since the supervisor
stuff will be handled by the PPC-AMIGA-OS in a different way,
because of many differences between 68K-supervisor handling and
PPC-supervisor handling.


By providing the blackbox emulation, we allow hardware manufacturers
to start *now* producing PPC-only hardware. If we only had developed
the emulator with the integration solution in mind, all HW
manufacturers would have to wait, until the AMIGA-OS-PPC would be
ready, and again, much time would be lost and we would be stuck with
the dual-processor boards (and we could never use L2 caches because
of the context switch problem).

So we see the future in the development of a ported AMIGA-OS, in 
the integration of the emulator into this new OS. Additionally
the blackbox-solution will also be available, so that owners
of a PowerAMIGA can decide to use the modern PPC-AMIGA-OS
with integrated emulator or use the 'blackbox emulation' to
launch the old 68K-based AMIGA-OS, to achieve even higher
compatility to old software than with the integration solution.
And even with the blackbox-solution, PPC software can be used,
which is available today. I could image a kind of 'boot menu'
where the type of emulation could be selected.

bye
-- 
Sam Jordan              
Member of Haage&Partner PowerPC Development Team

s.jordan@haage-partner.com (business related)
sam_jordan@bluewin.ch (private related)

----------------------------------------------------------------------

Hi!

>>The current emulator emulates the whole AMIGA-OS in a 'black box',

ar> The whole Amiga OS?
ar> You guys did a complete "classic" Amiga emulation then?

Well, if you emulate the 68k, naturally the 68k OS "AmigaOS" will run on
it 
(as it is a 68k application). This emulator is NOT a
"Custom-Chip-Emulator" or 
such like UAE. It emulates the 68k of the Amiga. And the AmigaOS runs
then in 
Emulation. Of course this is only the first step which has to be done...
for 
the future the market needs a PPC Port of the OS... with the Emulation
running 
- so that the system works already - this could be done even "Step by
Step".

Steffen Haeuser