Re: [PATCH] [RESEND] Re: [Qemu-devel] [6443] Enabled building of x86_64 code on Mac OS X (Alexander Graf)

[Alexander Graf]

On 22.02.2009, at 19:48, Andreas Färber wrote:

> Am 22.02.2009 um 16:50 schrieb Natalia Portillo:
>
> > Why not to just simply compile a multiarchitecture fat?
> > It is possible in 10.4 and 10.5 SDKs to compile at the same time  
> > ppc, ppc64, ia32 and x86_64 fully independent of what cpu is running.
> > On execute time the OS will choose the most adequate.
>
> Often due to autoconf et al. it is necessary to postprocess using  
> the `lipo` tool instead of directly passing multiple architectures  
> to GCC. QEMU's configure detects the endianness for instance, so  
> building a classical Universal Binary (ppc+i386) seems destined to  
> fail...

Creating a universal binary is more hassle than it's worth IMHO. But  
if anyone wants to take on the challenge, I won't keep him.

> Anyway, having a ppc64 binary in the bundle would on a G5  
> unconditionally run the 64-bit version, independent of whether that  
> makes sense (e.g., 32-bit guest w/ <4GB RAM). Loading a 64-bit  
> address consumes 5 instructions compared to 2 in 32-bit userland; on  
> amd64 it probably makes more sense.

I agree here. 64-bit makes a _lot_ more sense on x86_64. You get more  
registers and other neat features (like direct read of rip).

> > 64 bit WILL NOT COMPILE COCOA, this is not implemented until 10.6  
> > SDK.
>
> I thought it was a feature of v10.5?
> Cf. http://www.apple.com/macosx/technology/64bit.html

It worked fine last time I checked. For me cocoa compilation is broken  
right now (x86 and x86_64 alike), but there was an unbreaking fix on  
the list somewhere :)

Alex