Linux Running On Intel XScale CPU

Erik Mouw writes: "Just want to let you know that Nicolas Pitre (nico@cam.org) and I got Linux running on the Intel 80200 XScale CPU. Nico did the largest part of the work during the past couple of weeks, and we did the final bug fixes in a hotel room in New York. The official announce of the patch is available at the linux-arm-announce mailing list archive." The board was on display at the MontaVista booth at Linux World Expo, one of the several tiny Linux set-ups on tantalizing display around the show floor for everything from vending machines to cheap PDAs. (No Yopy in sight, though, despite the fact that development models are available for sale.) Congratulations to Erik and Nicolas.

Comments

80200 is a nice CPU..

[toastyman]

I've got one of the Intel 80200 evaluation boards on my desk at work. They're reallllly nice CPU's..

They run existing ARM code. Intel has a "porting guide" that's only a few pages long, mentioning hardly used features of the original chips. The only big difference is that the don't support thumb mode anymore, which isn't a huge loss.

They change their clock speed depending on the input voltage. Yes, you heard me right. Wanna slow the system down? Don't bother with changing clock generators and the such, just bring Vcc lower. It's very cool. Even at full speed, it only draws a few watts. And of course, no heatsink needed.

It's faaaaaaaaaaast. As long as you don't need floating point, it's actually a very competitive chip. You can check intel's site for actual benchmarks, but I was very surprised.

It's small. It's in a BGA package less than an inch square. The PCI-PCI bridge they used on the sample board is several times larger than the CPU itself, I had to look several times to find it.

It's cheap. I don't think my NDA with Intel allows me to discuss the pricing we have, but.... They're cheap enough to put in a PDA for sure.

I hope this chip really takes off, because there are so many cool things I'd love to do with it. :)

-- Kevin

Linux on a calculator

[whydna]

How much longer until I can get linux on my TI-92?? I can imagine that compile times might be a little high, but hey... at least it'd look like you're doing work in class... =)

-Andy

Pentium and StrongARM are NOT comparable!

[BitMan]

Please, please, stop any comparison, debate or otherwise general ignorant commentary on Intel's StrongARM microcontrollers versus their Pentium microprocessors. They are two very different breeds of products!

Here's some major design differences:

• Speed v. Power: Pentium is sold at its top speed, irrespective of power usage (which varies little between speeds) -- plus Intel sells a separate, redesigned "mobile" line for when power becomes an issue. In contrast, the single StrongARM product series's speed is "scaled" up and down and power usage depends on its speed -- plus a 733MHz part uses 1.3W (an order of magnitude lower than even the mobile Pentium), and the 333MHz model only disapates around 0.5W (and there is an older StrongARM design that vary from 40-600MHz, which makes power usage fluctuate from as low as 0.04W to 450mW).
• Superscalar v. Superpipelined: The Pentium is superscalar, with multiple pipelines (5-6 in most Pentium products, 8-20 stages each, depending on model) and uses advanced concepts like out-of-order execution and branch prediction to keeps its pipes full and executing. The StrongARM has but a single, 7-stage pipe that is kept full by a optimized compiler tuned for applications with fewer branchs and less interactive code.
  [ Side note: the AMD Athlon uses 9 pipes. Which goes a long way to describing why a 9 pipe x 20 stage Athlon kicks the living crap out of a 6 pipe x 20 stage Pentium IV, MHz for MHz -- especially when combined with the fact that the Athlon only loses an average of 10 stages on a branch mis-predict, whereas all Pentiums have to flush all pipes -- a loss of all 20 stages on a Pentium IV. Even the 6 pipe x 10 stage Pentium III can handle itself against a Pentium IV -- more stages is usually less efficient and more troublesome (especially on branch mis-predicts), although required for OO, timing and other scalability issues. ]
• Applications: Again, the applications the Pentium is used for is radically different than the StrongARM. In the case of the Pentium, most apps will require floating-point, whereas applications on the later usually do not. And the former can do 64/80-bit math, whereas the later can only do 32-bit. As far as multitasking, the later is great at multiple tasks and instruction rescheduling (again, micro"processor"), whereas the later is more akin to less random operations and control of data flow (again, micro"controller"). The StrongARM does NOT make an ideal, general-purpose CPU for heavy, multi-tasking workstations, but it does make a great, low-power CPU for support as well as standalone devices that only do a couple of things (or run only a couple of user apps simultaneously).

-- Bryan "TheBS" Smith