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

Support for XScale's Thumb instructions?

[Morgaine]

Are the Thumb and ARM instruction sets on the XScale mutually exclusive, or is there some way for Linux to use Thumb instructions --- for example in user-mode processes only?

And an even more fundamental question: does gcc support the Thumb instruction set at all?

Finally, what is the relationship between the XScale and Atmel's 91AT series, which also features a combination of ARM and Thumb instruction sets?

Re:leaving out floating point is stupid

[q000921]

It's funny how when DEC had it, everybody thought the StrongARM was the best thing since sliced bread.

Until recently, handhelds like the Palm and its WinCE clones didn't need much smarts. That's rapidly changing.

What boards did you use? What's available?

[billstewart]

Sounds cool - for the vast majority of us who do very little high-speed floating point, and would much rather have DSP features like a fast MAC (:-), this would be a really good machine. What kind of hardware did you use - the Intel 80310 evaluation board? How much hardware did you have to add around it? Looks like there are a few PCI slots, ether and RAM, so it shouldn't be too hard to add a video an d a disk controller of some sort.

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

Stan

[deran9ed]

Slashdot's gone cold I'm wondering why I got out of bed at all
The morning rain clouds up my window and I can't see at all
And even if I could it'll all be gray but your picture on my wall
It reminds me, that it's not so bad -- it's not so bad

Dear Rob, I wrote but you still ain't callin
I left my email, my ICQ, and my yahoo chat at the bottom
I sent two emails back in autumn, you must not-a got 'em
There probably was a problem with your sendmail or somethin
Sometimes I scribble email addees too sloppy when I jot 'em
but anyways; fsck it, what's been up? Man how's your boxes?
My boxes is linux too, I'm bout to be a compiler
once I learn gcc,
I'ma compile for miles ah
I read about your Palm Pilot too I'm sorry
I had a friend lose his Palm over at the airport in Maradonna
I know you probably hear this everyday, but I'm your biggest fan
I even read all your bullshit Linux news and BSD scams
I got a room full of your posters and your pictures man
I like the way you sold your ass too that shit was fat
Anyways, I hope you get this man, hit me back,
just to chat, truly yours, your biggest fan
This is Stan

Dear Rob, you still ain't called or wrote, I hope you have a chance
I ain't mad - I just think it's FUCKED UP you don't answer fans
If you didn't wanna talk to me outside your Linux World
you didn't have to, but you coulda signed an autograph for Matthew
That's my Senior sys admin he's only 26 years old
We waited on a 9600 baud for you,
four hours and you just said, "No."
That's pretty shitty man - you're like his fsckin idol
He wants to be just like you man, he likes you more than I do
I ain't that mad though, I just don't like bein lied to
Remember when we met in Boston - you said if I'd write you
you would write back - see I'm just like you in a way
I never had a clue about shit either
I gcc'd shit with my wife then beat her
I can relate to what you're saying in your page
so when I feel like rmusering I read Slashdot to being the rage
cause I don't really got shit else so that shit helps when I'm depressed
I even got a tattoo of slashdot across the chest
Sometimes I even packet myself to see how much it floods
It's like adrenaline, the DDoS is such a sudden rush of blood
See everything you say is real, and I respect you cause you tell it
My girlfriend's jealous cause I talk about you 24/7
But she don't know you like I know you Rob, no one does
She don't know what it was like for people like us growin up
You gotta call me man, I'll be the biggest fan you'll ever lose
Sincerely yours, Stan -- P.S.
We should be together too
Dear Mister-I'm-Too-Good-To-Call-Or-Write-My-Fans,
this'll be the last packet I ever send your ass
It's been six months and still no word - I don't deserve it?
I know you got my last two emails
I wrote the @ signs on 'em perfect
So this is my payload I'm sending you, I hope you hear it
I'm on my modem now, I'm doing 9600 on the infohiway
Hey Rob, I drank a fifth of vodka, you dare me to code?
You know the song by Deep Purple by Depache Mode
its irrelevant by playing on my linux player
while I write some php scripts and play some Dragonslayer
That's kinda how shit is, you coulda rescued me from drowning
Now it's too late - I'm on a 1000 downloads now, I'm drowsy
and all I wanted was a lousy letter or a call
I hope you know I ripped +ALL+ of your pictures off the wall
I love you Rob, we coulda been together, think about it
You ruined it now, I hope you can't sleep and you dream about it
And when you dream I hope you can't sleep and you SCREAM about it
I hope your conscience EATS AT YOU and you can't BREATHE without me
See Rob {*screaming*} Shut up bitch! I'm tryin to page
Hey Rob, that's my senior admin screamin in the cage
but I didn't cut the power off, I just rebooted, see I ain't like you
cause if he works some harder he'll suffer more, and then the boxes die too
Well, gotta go, I'm almost BGP bridged
Oh shit, I forgot, how'm I supposed to send this packet out?

Dear Stan, I meant to write you sooner but I just been busy
You said your box is running now, how'd you like your gcc?
Look, I'm really flattered you would install 7.0 Redhat
and here's an autograph for your senior admin
I wrote it on the Starter cap
I'm sorry I didn't see you at the show, I musta missed you
Don't think I did that shit intentionally just to diss you
But what's this shit you said about you like to DDoS lamers too?
I say that shit just clownin dogg,
c'mon - how fucked up is you?
You got some issues Stan, I think you need some counseling
so heres some more Linux stories to keep your as busy when you get down some
And what's this shit about us meant to be together?
I already have a boyfriend Timothy he gets me wetter
I really think you and your boxes need each other
or maybe you just need to treat them better
I hope you get to read this letter, I just hope it reaches you in time
before you hurt yourself, I think that you'll be doin just fine
if you relax a little, I'm glad I inspire you but Stan
why are you so mad? Try to understand, that Linux and MS is just grand
I just don't want you to do some crazy shit
I seen this one shit on the news a couple weeks ago that made me sick
Some dude was drunk and switched his router for a bridge
and his packets were blackholed, and his DNS couldn't get digged
and in the colo they found a tape, but they didn't say who it was to
Come to think about, his name was.. it was you
Damn!

Don't be a moron

[crisco]

This isn't a processor for those kind of applications.

This processor is for RAID controllers and similar I/O processing situations. Its not 'crippled', it is designed for a certain task, just as the x86 processors are designed for backwards compatibility.

The real moron is the moderators who marked this insightful, it is neither insightful nor particularly relevant.

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

Re:what's the use?

[Wesley Felter]

XScale isn't just an embedded CPU; its predecessor StrongARM was used in the NetWinder desktop machine a few years back. Now that XScale is up to ~700 MHz we might see an ARM comeback in non-embedded systems.