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Inside the PowerPC 970
daveschroeder writes "Jon "Hannibal" Stokes has posted a long-awaited, very detailed analysis of the IBM PowerPC 970 at Ars Technica. Notable quote: 'The 970 was made for Apple'."
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PAGERANK++ Robsell.com
altivec units are special 128bit registers that can be used for many different optimizations.
||| I still can't believe Parkay's not butter.
Floating point ops, optimized for graphics processing and things like compression (jpeg, mpeg, mp3). If you read the Ars article he waxes on about it's superiority over MMX/SSE/SSE2.
Also: "Water is special stuff that makes stuff float."
"The CPU does important stuff."
For all of your "What is AltiVec?" needs, check this out instead:
http://www.motorola.com/SPS/PowerPC/AltiVec/
Mikey-San
Karma: +Eleventy billion (mostly affected by watching Celebrity Jeopardy)
Apple'd be putting DDR400 on the G4 right now if they could. None of this (well, except the decision to go Moto) was their fault.
My real problem with the current G4e situation, aside from the 167 SDR FSB, is the fact that it's a shared bus topology, which is just ridiculous. To my knowledge, there's nothing stopping Apple from putting out a chipset that gives each G4e a dedicated FSB (even if it's still 167MHz SDR) to the chipset.
As far as the low MHz and SDR situation, I've also never been totally convinced that Apple wasn't partially to blame for this either, unless they just have zero clout with Moto SPS.
I understand that a while ago there was some competition between IBM and Motorola about whose chip would be the G5. Was Motorola ever a serious contender, and if so, has Apple decided on IBM? I haven't heard much about Motorola for some time.
Mot actually had a G5 on the roadmap. They apparently got all the way to samples, but then ditched the effort. There never was a competition per se wrt the G5 name. There was a bit of friction over AltiVec, as IBM wanted to focus on clock speed and didn't think AV was worth the complexity (and hence why Mot came out with the G4 while IBM stuck with the G3). Motorola hasn't been serious about the mainstream cpu market for a while as they've been losing money on it. They'd rather focus on things like embedded proccies and cell phones (and related chips).
I don't know which came first, Mot ditching G5 so Apple pleads with IBM to come out with 970. Or Mot gets whiff of 970, so sees a way out of doing G5. Perhaps others more "in the know" can chime in?
It's a really fast verctor processing unit. It can do floating point manipulations blazingly quickly.
Officially, the PowerPC G5 is the Motorola PowerPC 8500 chip. So this would not be it. Apple may or may not call a computer that features IBM's PowerPC 970 the PowerMac G5 or PowerBook G5, but it wouldn't be the actual G5 chip. Although I don't think this chip officially has a G* name, I'd be more inclined to designate it the G6, since the G5 was actually a 32-bit chip.
Karma: Ran over your dogma.
http://wwws.sun.com/software/star/gnome/. Also, you take a shot at CDE rather than Solaris? Wow.
Earth-to-poster: Linux runs in 64-bit. Thank you.
AltiVec is important for Apple marketing because it lets them claim impressive performance figures without actually needing to push the state of the art in terms of processor design further than Intel.
No, AltiVec is important for Apple full stop - in the short term to make up for the anemic bus speeds allowed by the G4, and in the longer term because a SIMD unit is now as expected a component of modern desktop CPUs as an FPU is.
And even something like a hand-coded vectorized BLAS library doesn't help because most scientific software still doesn't use such libraries
The only thing you can really sure about "most" scientific software is that it needs an FPU. Scientists and engineers do a huge variety of simulations, some of which are vectorizable and some of which aren't.
If AltiVec has a weakness in the scientific field, it's the lack of support for double precision. And there's nothing in the instruction set which precludes this, so I wouldn't be surprised to see it appear in some future CPU.
Imagine how much better it would be if Apple could ship systems based on the 970 today, rather than after a few months additional delay due to AltiVec.
If it didn't have AltiVec, it wouldn't be what Apple needs in a desktop CPU - not much point in getting what you don't need a few months early (not like that would happen anyway: this isn't lego: you can't unplug "the AltiVec bits" without any impact on the rest of the design).
And every dollar and watt that is shaved off the AltiVec price makes it a much more viable processor for servers and blades, which would get volume up and prices down.
Except that Apple aren't currently in the blade market at all, and have a fairly small presence in the more general server market. If they can sell a few boxes there, fine, but getting the volume up means targetting consumers - not server farms.
Nae bother
They had a Mac with a DSP built-in back in the day. The Quadra A/V! It blasted the shit out of most any other computer when it came to Photoshop - rivaling modern computers for some tasks.
Altivec is Motorola's name for the vector processing unit. The unit handles SIMD commands. SIMD stands for Single Instruction, Multiple Data. Basically, intead of looping through a list of 50,000 values one by one and multiplying each value by PI for instance, you simply tell the CPU where the list is, and to multiply it by PI.
In a much simplified analogy, it's like lighting 200 candles with a flame thrower instead of one by one with a match.
Article X: The powers not delegated... by the Constitution...are reserved...to the people
Actually every single application that is actually pushing the PC at this point benifits from vector units. Lets look at what is somewhat strenuous for a modern PC, 3D rendering:yep, media encoding and transcoding:yep, audio processing and creation:yep, 3D gaming:yep, etc. Basically all of the applications that will push a PC are things that process large chunks of data that can be worked on efficiently by a vector processing unit. This isn;t a server processor, it's a PC processor. If you want a server processor get a Power4 or Power5 with the huge cache and multicore chips that are designed for that market.
There are 4 boxes to use in the defense of liberty: soap, ballot, jury, ammo. Use in that order. Starting now.
"Currently AMD has the fastest commodity SIMD implementation"
You've not been looking at the distributed.net results, have you? The Altivec/VMX technology currently used by Moto and soon to be used by IBM is LEAGUES ahead.
That was classic intercourse!
"AMD is delivering fast SIMD today, not next year"
What ARE you blathering about? Pentium 4 has SSE2, PowerPC has Altivec - here's a clue for you, when people code for x86 SIMD, they choose MMX, SSE and SSE2, they don't choose 3D Now!, when people code for SIMD under PowerPc ISA, they choose Altivec. Both SSE2 and Altivec are available to day, both are used in "commodity" CPU families. I think you'll find that it's "x87" FPu strength that typically marks out AMD's current CPUs, not their patchy implementation of SSE2.
That was classic intercourse!
Well, not really, but you're close. You can't just pass the Altivec unit an array of numbers and tell it to do some operation on them. Altivec (and MMX, etc) simply allows you to process the data in bigger chunks that normal.
Altivec can process 128 bits of data at a time. For example, it can add 16 8-bit integers to another 16 8-bit integers, resulting in yet another vector of 16 8-bit integers with a single instruction, rather than doing them one at a time.
Just raise the taxes on crack.