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

[Andreas Färber]

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...

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.


> 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

Andreas