Re: [Qemu-devel] Re: strange crash on FreeBSD-current/amd64 (pointertruncation?)

[Rob Landley]

On Friday 02 February 2007 2:03 pm, Gwenole Beauchesne wrote:
> On Fri, 2 Feb 2007, Gwenole Beauchesne wrote:
> 
> > The proper fix would be to not globally allocate registers for the whole
> > program but only for the micro-ops. Then, make the necessary
> > save/restore around the gen_func call.
> 
> Hmm, I realized in the train that this wouldn't work for QEMU.
> 
> > +    /* Preserve callee-saved registers */
> > +#ifdef AREG0
> > +    register unsigned long reg_AREG0 asm(AREG0);
> > +    volatile unsigned long saved_AREG0;
> > +#endif
> 
> BTW, better read (unsigned long) as (void *) or uintptr_t in case you ever
> want to port QEMU to Win64 or other strange LLP64 platform.

Is there an LLP64 platform other than Windows-64?  I know there can't be a 
standards compliant Unix platform (including MacOS X) that isn't LP64:

The LP64 standard is here:
http://www.unix.org/whitepapers/64bit.html>the LP64 standard

The rationale for that standard is here:
http://www.unix.org/version2/whatsnew/lp64_wp.html

And the insane legacy reasons Windows decided on a broken approach are 
explained here:
http://blogs.msdn.com/oldnewthing/archive/2005/01/31/363790.aspx

Considering that Windows 64 currently has less of a userbase than Itanium, I'd 
personally wait and see Microsoft's first attempt at a 64 bit solution turns 
out any better than Intel's before putting much effort into supporting it.  
So far it _sounds_ like the software equivalent of Itanic...

Rob
-- 
"Perfection is reached, not when there is no longer anything to add, but
when there is no longer anything to take away." - Antoine de Saint-Exupery