Re: [Qemu-ppc] Status of mac99?

[Alexander Graf]

On 07.03.15 10:56, ardi wrote:
> On 3/7/15, Alexander Graf <address@hidden> wrote:
>>
>>
>> On 06.03.15 23:05, ardi wrote:
>>> On 3/6/15, Alexander Graf <address@hidden> wrote:
>>>>
>>>> No :). For G5 support we really should implement a U3 or U4 chipset.
>>>
>>> Can you point me towards how is this planned to be done, so that I can
>>> tell if I can help advancing this? Reading the uninorth source code
>>> from mac99 I see definitions for U3 and/or U4, so I don't know if the
>>> plan is to integrate it with uninorth or to write new source files.
>>
>> Phew, those were mostly messups on my side so far. I think the cleanest
>> way to go with this would be to just start from scratch.
>>
>>> Also, what's already done for U3/U4, and what's still to be done?
>>
>> Uh, pretty much nothing has been done so far :). Only enough to make
>> Linux happy enough to boot a VM with a semi-broken U1-that-exposes-as-U3.
> 
> Alex, I'm afraid starting a U3 implementation from scratch is well
> beyond my chipset knowledge :-(  

I think U4 is the better choice, because U3 is mostly undocumented,
while there is public documentation on U4 which is just a normal IBM chip.

> But, however, I just had an idea that
> (I believe) would work for my purposes of debugging G5 code on an
> emulated Tiger machine: would it be possible to boot mac99 with a G4
> CPU that identifies itself as G4 but that can execute (32 bit)
> specific G5 instructions?

Which instructions do you have in mind? But yes, you can modify the code
generator whichever way you like.


Alex