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Intel's Itanium Will Get x86 Emulation
pissoncutler writes "Intel has announced that they will be releasing a software emulation product to allow 32-bit x86 apps to run on Itanium Processors.
According to these stories (story 1, story 2), the emulator is capable of the x86 performance of a 1.5Ghz Xeon (when run on a similar speed Itanium.) Who said that no one cared about x86 anymore?"
http://www.macslash.org/comments.pl?sid=03/04/23/1 82250&cid=3
First off, the disclaimer: this is my pet theory, i.e., a total, wild, pulled-of-out-my-*ss speculation, okay. I have no inside info or contact with people who might know this, but here is my speculation of why this AMD thing keeps coming up despite the fact that the use of the IBM 970 is almost a certainty.
Put this AMD thing into a bigger context of recent events.
We've heard that 10.3 will include a more integrated Classic environment where Classic Mac OS apps will be given many of the benefits of Aqua.
Apple quietly releases their implementation of XWindows system, X11. Despite the fact that this news set Slashdot buzzing for days on end and probably should have had some mention from Steve Jobs in the keynote he'd given a few days prior, it was released very quietly. Interesting.
Next, the somewhat unexpected news that Microsoft was buying Virtual PC. What on earth could Microsoft want with VPC? We can speculate that they want greater control over emulation of Windows on the Mac, but that sounds weak. They still control the operating system that gets installed on VPC so from that perspective they've gained nothing by buying out VPC.
And then these weird, peristent, inexplicable rumors that Apple is in talks with AMD about something or other. Who knows what. It's very doubtful that it's about a chip that would replace the PPC since we've read many, many well-informed examinations of such a move and the technical hurdles would likely ruin Apple.
So what could all this possibly point to? Apple has given us a system that can basically run software from three different operating systems: the classic Mac OS, Mas OS X (the Next OS), and Unix. They recently brought the Unix world closer with the release of X11. Wouldn't it be amazing if hardware in the near-future included an "add-on" chip (something like Altivec that works in conjuction with the PPC processor) that emulated the x86 hardware? Maybe it would give Mac users the ability to run Windows and PC software, not via software emulation, but with hardware assistance. Imagine the interest Apple could draw if they presented the world with a machine that runs the Classic, OS X, Unix and Windows applications... all in one environment and almost seamlessly.
Now does Microsoft buying VPC make sense? Maybe? Maybe not. Maybe MS Mac Business Unit caught wind of this and wants to one-up Apple somehow. Any thoughts?
AMD would be a likely partner is such a move since one could imagine the problems with Intel assisting Apple with this. If it was popular, Intel would be killing their own business. AMD, on the other hand, wouldn't, if I understand the situation correctly.
Anyway... like I said... wild speculation, but that's what all this says to me.
Remember, Motorola didn't even release the PowerPC 7400 (G4), much less any information about it, until apple introduced the Power Mac G4. Does that mean it didn't exist?
Apple probably can't play those same kind of "keep it secret until we announce our product" games with IBM, but keep in mind the only thing IBM has really done was introduce the concept for the processor at MPF. Judging from how Apple has rolled out new processors in the past, it wouldn't be surprising to find if further information about the 970 is being withheld at Apple's request (Apple being a potentially huge customer for this chip).
Also, remember that before CeBIT, IBM posted press releases on its German site talking about 970, the fact that it featured AltiVec, and how IBM was going to be demoing several 970-based blade servers at CeBIT. The press release suddenly got pulled and there was no further information about the 970 from IBM.
One way this could be interpreted is that the 970 is vaporware.
The more likely scenario, however, based on how apple has done releases of new processors in the past, including several iterations of the 7400 family, is that more information is being withheld until Apple releases a system featuring this processor. Then the floodgates will open.
The only reason we may know anything of it at all is that IBM felt it fundamentally important enough to present at MPF - we haven't heard a peep since.
Actually I believe that the complete opposite is true. Apples market share could go up 10x overnight if they released Mac OSX for x86. Hardware is a tough place to make money, the hardware COSTS money. Lost of it, profit margins are slim.
And even if Apple made the OS free-standing for any x86 machine, that would not stop Apple from being able to build ultra-stylish, high-priced, boutique x86 machines and put their own OS on it now would it? They'd probably sell exactly the same # of machines that way as the die hard Apple aficinados would probably still prefer to buy apple branded machines, AND it would grow their OS market share tremendously, maybe even driving their branded machine sales higher in the future.
Frankly I think not porting OSX to x86 was a huge blunder that will hold the company back another 5 years till the next actual achetecture change is forced upon them.
Contrary to popular belief, coding is not all free blow-jobs and beer. Those things cost MONEY!
I have a better reason: AMD can fab those CPUS easily and IBM has better things to do than fab chips for Macs. Apple needs to make sure it doesn't have to stop the assembly line for IBM to fab more CPUs. My guess is that Apple will have AMD produce IBM 970 chips alongside IBM. IBM probably doesn't want to be the first in line for Macintosh CPUs, there's not enough money in it for a multi-faceted operation like IBM. AMD can produce ample chips and they might be able to make a profit doing it.
This has nothing to do with Macs and x86, AMD produces a LOT more than just athlon chips, they'll be pumping out AMD-970s with their extra capacity.
"Sometimes, I think Trent just needs a cup of hot chocolate and a blankie." -Tori Amos on Nine Inch Nails
Well, no.
Actually, it was a painful transition. Horrible hacks were required to make it work, and Apple lost considerable market share.
From the user perspective, all the applications that used the FPU stopped working. Worse, the PPC only had (has?) a 64-bit FPU, while the 68K and x86 have 80-bit FPUs. So a simple recompile often wasn't enough. Most of the engineering applications (CAD, EDA) were never ported to the PPC at all. There were unsupported 3rd party FPU emulators for the 68K FPU, but they were really slow, since they had to emulate a wider FPU.
Most of the OS ran in 68K emulation mode for years after the "transition". The PPC interrupt model was mainframe-like, assuming that you didn't do much in an interrupt routine except activate some process. The 68K interrupt model was minicomputer-like, with multiple interrupt levels used as the main locking primitive. Hammering those two together was painful. There were some things you just couldn't do in PPC mode; you had to drop into 68K emulation to prevent interrupts.
The old MacOS had what was euphemistically called "cooperative multiprogramming". That didn't mean you had threads without time-slicing, like a real-time OS. It meant you didn't have real context switching at all. You plugged your code into callbacks at different levels of processing, like "system tasks", "VBI tasks", "timer tasks", "interrupt tasks", etc., none of which could block. No mutexes. No locking. Only interrupt prevention. Trying to do anything in the background was very tough. (I know; I wrote a PPP protocol module for the 68K Mac. I had the only one that could dial the phone in the background without locking up the whole machine, and it wasn't easy.)
Worse, the 68K emulator depended on a jump table with 65536 entries, one for each of the first 16 bits an instruction could have. Early PPCs didn't have enough cache to keep that entire table in the cache all the time. But if it wasn't all in the cache, 68K emulation performance was terrible.
Amusingly, much of the perceived performance advantage of the early PPC machines came from the miserable 68K code generators used on the Mac. The Apple and Zortech compilers were clueless about 68K register allocation, preferring to do all arithmetic in register A0. The PPC code generators were much better. Some high-end apps used to be cross-compiled on Sun 68K machines because the Mac code generators were so bad.
Most of these problems were papered over using the Jobs Reality Distortion Field. But this was the period when Apple started losing market share big-time. Arguably, the PPC transition cost Apple its preeminence.
What Apple really needed was faster 68K CPUs, not a new architecture. Technically, that was quite possible. The Motorola 68060, (never used by Apple, but in the last 68K Amiga), was faster than the PPC of the same vintage. But Jobs had cut a deal with IBM under which IBM was supposed to make MacOS compatible machines (!), and that was the motivation for the PPC.