Re: [Qemu-devel] Mac OS X PPC host support (was: [4932] Preliminary PPC64/Linux host support)

[Andreas Färber]

Am 27.07.2008 um 20:14 schrieb malc:

> On Sat, 26 Jul 2008, Andreas F?rber wrote:
>
> > Am 26.07.2008 um 20:54 schrieb malc:
> >
> > > > there are currently numbers hardcoded for Linux.
> > > It's not just about numbers, last time i looked (cursory) the ABIs  
> > > where
> > > a lot different (PPC32 case) just changing the numbers wont get  
> > > one very
> > > far i think.
> >
> > Of course not only, but it's one step that could be applied. The  
> > stack alignment is 16 Bytes for both, and the prolog in my ppc(32)  
> > branch seems to match the referenced Apple pseudocode now.
> >
> > Where else do you have differences in mind? Which additional  
> > functions may need to be adjusted?
>
> I'd have to check Darwins ABI to be sure, but here's the short list:

http://developer.apple.com/documentation/DeveloperTools/Conceptual/LowLevelABI/Articles/32bitPowerPC.html

> a. Alignement of 64 bit arguments (in the register file)
>    (This was the thing that confused Sparcs ASI helpers when i first
>     tried to boot Sparc on, then new, PPC32 tcg)

What register file? Please be more detailed, I'm not intimate with TCG.

> b. List of reserved registers

According to the Apple ppc ABI document, r2 is not system-reserved  
compared to SVR4 ppc ABI. The other general-purpose registers look  
similar (assuming we don't have nested functions), although Apple  
seems to have less strict prescriptions what to store where.

> c. The approach to TOC (or however Apple calls the substitute)

Not sure what you mean. Pointers to concrete files and functions might  
help.


> In any case, PPC32 + MacOS X i can help with. PPC64 + MacOS X not so  
> much.

Restoring Mac OS X ppc(32) to work again would be just great.
PPC64 didn't work pre-TCG. We'll probably know where to poke ourselves  
once ppc is running.

Andreas