[Openmcl-devel] Apple to switch to Intel - what does this portend?

Gary Byers gb at clozure.com
Tue Jun 7 02:49:25 UTC 2005



On Mon, 6 Jun 2005, John Wiseman wrote:

> Well, it's official.
>
> "Select" Apple developers can get an x86-based Mac for $999.
> Membership in the Select developer program is $500/year.  I bet if we
> donated $1500 to Gary it would speed up development of the x86 backend
> for OpenMCL.
>
>
> John

That's the kind of thinking we like to see!

(Not to discourage anyone from following John's suggestion, but I am
a "Select" developer already, and tend to impulse-buy computer hardware
on a regular basis.)

Before following this particular impulse, it'd be nice to know whether
Apple's switching to x86-32 or x86-64 (or both); the P4 CPU in the
development system they're offering seems to support Intel's EM64T
extensions, which are roughly equivalent to AMD64 (though it may
or may not be a "true" 64-bit implementation, currently.  Or I may
have been looking at out-of-date information ...)

The little bit of actual concrete information that I've seen so far
just mentions "Intel architecture", which strongly suggests x86-32
(but that isn't really definitive.)  Even if it's true that current
porting tools only support x86-32 (and only support ppc32-based fat/
universal binaries ?), it's not clear that this will be the case a
year or two down the road.  (All other things being equal, C programs
compiled for x86-64 tend to run faster than their x86-32 equivaents:
C compilers like to have a few more registers, too.)

The emphasis on x86-32 in the current porting tools -may- have more to
do with the fat/universal binary issue (having something that's
ppc32/x86-64 or vice versa -sounds- like a hard problem ...) than with
the future direction of Intel-base Macs.  It'd be somewhat interesting
to know whether the Mac Intel-based hardware that's available in the
next year or two will be capable of running x86-64 code and whether
the OS supports it.  (If not, it seems likely that the Mac would be
the only Intel-based platform that -doesn't- do so in that time frame,
giving "industry analysts" a whole new set of things to complain about.)

It's possible that the answers to some of these questions are out there
(my reaction to today's announcement was to have a few phone meetings,
then take a nap).  It's also possible that some of those answers may
take a while to materialize.





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