ARM Assembly Language Programming

http://www.arm.com/miscPDFs/9658.pdf

by chipsy • 17 years ago

46 39 17 years ago

arm.com

chipsy• 17 years ago

A nicely documented overview and introduction.

TheEarlyShow• 17 years ago

[pdf]

obvioustroll• 17 years ago

Isn't that true of everything that comes from scribd?

RiderOfGiraffes5• 17 years ago

It doesn't come from scribd. scribd automatically scrape every PDF they find and put it on their site. They do this without considering that many of the PDFs have copyright notices, and require the copyright holder to pay a lawyer to issue a formal C&D before they do anything about it.

I think what they do is reprehensible and I think they're scum. I don't know why the powers that be at HN automatically add the link to scribd.

ZeroGravitas2• 17 years ago

Why does it say [scribd] in the Hacker News title?

daeken4• 17 years ago

PDF links automatically give a scribd link after the original.

ZeroGravitas2• 17 years ago

Okay, then there's two issues here:

1. Adding something in square brackets after a title looks like a format hint (e.g. [pdf]) and not a seperate, clickable link

2. With Safari (Mac and iPhone) the second link just gives me the PDF file on the arm.com site. Is scridb unsupported on these platforms? Is its purpose purely adding a redirect? What value does this add?

yason• 17 years ago

Thanks, this seems like a nice book.

As it happens, I've been learning ARM assembly in the recent weeks; just for fun so far. I've mostly used some instruction set references or ARM cheatsheets I found on the web.

Having written mostly m68k assembly before (well, 6502 too...) I knew a bit how to read ARM assembly but I wanted to learn it throughoutly and gain such insight into the instruction set that can only be achieved by writing non-trivial programs with it. Before that I wanted to learn x86 assembly but I soon gathered I'll have better use for my time than that.

I like ARM instruction set quite a lot: it's nicely coherent, has nicely orthogonal features (such as conditional instructions), and doesn't seem to be ridden with despicable backwards-compatibility hacks like x86 assembly.

I like that for once something as good as this has significant marketshare in mobile cpus. Just wondering if they could gradually creep into the market for desktop cpus as well.

daeken4• 17 years ago

A word of warning. Get in the habit of thoroughly commenting your assembly early on, or you likely never will. If you start by commenting too much, you can gradually bring it down. If you start commenting sparsely (or like me, not at all), it's considerably more difficult to increase it.

That said, you picked a good first ISA to learn seriously. ARM has some very cool features, even if it does have its serious faults (poor floating point/vector support, even where it's available). Learning x86 will be trivial from there; the only difficult thing is knowing what the side-effects of functions are, as x86 is horribly inconsistent in that regard.

Good luck!

mru4• 17 years ago

ARMv7 has a SIMD unit (NEON) that easily outshines SSE and Altivec. Floating point support is also good nowadays.

nchong• 17 years ago

In that case I fully recommend that you also check out Steve Furber's "ARM System-on-Chip Architecture" as a very readable introduction to ARM assembler and an easy way to learn about the microarchitecture and design philosphy of early ARM processors (ARM7 and ARM9) [Furber was one of the original engineers that worked on the first ARM design].

The architecture has come along quite a bit since those days so if you'd like the most up to date release you need to look for the ARM v7AR Architecture Reference Manual which you can get (with a click-through) here: http://infocenter.arm.com/help/topic/com.arm.doc.ddi0406b/in...

This will cover you up to the latest cores like Cortex-A8 inside the Beagleboard and Cortex-A9. Enjoy!

gvb• 17 years ago

"I like that for once something as good as this has significant marketshare in mobile cpus. Just wondering if they could gradually creep into the market for desktop cpus as well."

It is going to be hard to displace x86 desktops, but I'm looking forward to ARM-based "netbooks" and pocket-sized computers like the Nokia N900. See Ubuntu job postings and Google's ChromeOS - I believe this presages ARM-based small and tiny mobile computers.

The big question is whether the Atom (and whatever AMD is working on) will be able to reduce their chipSET power to compete with the ARM SOC power numbers before ARM grows up into that market (growing up is always easier than growing down).

yuvi• 17 years ago

>it's nicely coherent, has nicely orthogonal features

Obviously with exceptions, especially with the instructions added after armv4.

For instance, the allowed addressing modes vary depending on instruction: ldr allows a 12 bit offset, ldrd only an 8 bit, ldm and vld allow none, though vld allows a strided increment. Only ldr* non-exclusive allow a register offset.

Thumb-1/2 and exclusive load/store change things a bit more, but they aren't generally stuff to care about unless you're doing kernel or compiler programming. Also, none of the neon instructions can be conditionally encoded, but there isn't much reason to do that.

As for desktop arm, a massively multicore machine would be nice, but the average user doesn't care much about desktop CPU power consumption nor make good use of more than two cores. Netbooks have to watch out though.

prodigal_erik• 17 years ago

> Just wondering if they could gradually creep into the market for desktop cpus as well.

Much like I was hoping that PPC would dethrone IA-32 back in the day (I think Linux, OS/2, and NT were all just about ready to support it) but it seems economies of scale are everything.

I'd buy an ARM and a desktop motherboard just to mess around with, but I've literally never seen a local screwdriver shop that carried them even for smoke tests. I guess they're doing fine without hobbyists.

Tuna-Fish• 17 years ago

Arm is creeping toward bigger market share trough netbooks -- if if can succeed there, it will become more available as a desktop choice.

Lacking that, just go buy a Nokia n900 (or an used n810 or something), and code for it.

Avshalom• 17 years ago

The Beagle Board is probably the closest thing there is to a desktop MB that uses the Cortex chips.

bensummers• 17 years ago

I have a particular fondness for ARM assembly. It's a beautiful instruction set, with a minimal elegance and internal consistency.

My only experience of a "normal job" was between school and university, writing import/export filters for a DTP application written entirely in ARM assembly. It was quite a year.

If you want to get into ARM assembly, this is the original and best:

http://www.peter-cockerell.net/aalp/

I still have one of the original paper copies. 1987 was a long time ago, but the legacy of those heady years is still strong.

RiderOfGiraffes5• 17 years ago

I've been using ARM assembly language since the early 1990s. It's a beautiful instruction set, far nicer than the 8080 and Z80 I started with (and which can still be seen in the x86 line) and the m68k line I contracted for.

I've built robots with and compilers for Z80s, and programmed embedded m68k for food, but it was the ARM family that I remember with particular fondness. Every instruction being conditional, clean registers, orthogonal instructions. Simply fun to program.

petewarden• 17 years ago

Since other people are reminiscing about ARM:

- It was the first language I wrote real programs in, back in the late 80's on the Acorn Archimedes desktop machines it was originally built for. The A in ARM originally stood for Acorn, not Advanced.

- Writing ARM demos I was always jealous of the Amiga's blitter, but then I discovered STMIA could store multiple registers pretty darn fast.

- I chose to go to Manchester University purely because Steve Furber, one of the chip's designers, would be a lecturer on my course.

- He spent weeks taking us through diagrams of the x86's instruction decode hardware. I was convinced that any processor that had to expend so much of its silicon just decoding instructions was doomed, not my best insight.

- The instructions' simplicity did make it easy to build low-power versions however, hence its ubiquity in mobile devices. Steve seemed as surprised by this as anyone, it definitely didn't seem like a design goal at the start.

- His main research project was a clockless version of the ARM chip, with asynchronous logic, called Amulet, really interesting technology that never caught on: http://en.wikipedia.org/wiki/AMULET_microprocessor

- ARM is the only British-born computer technology company I can think of that achieved lasting international success. I'd welcome any other examples.

bumblebird• 17 years ago

>> "He spent weeks taking us through diagrams of the x86's instruction decode hardware. I was convinced that any processor that had to expend so much of its silicon just decoding instructions was doomed, not my best insight."

I haven't found figures, but I'd be willing to bet there's far more ARM devices in the world than x86. x86 didn't die, but it's not in the same league as ARM in terms of success.

Agreed though, the x86 is an absolute dog mainly because of the backward compatibility. Tacking on 32 bit instructions with prefixes, It's a mess.

mru4• 17 years ago

ARM core sales are measured in billions per year.

miles3• 17 years ago

The PDF is password protected, restricting copy/paste and print functions.

The old ColorSync trick ( http://www.macosxhints.com/article.php?story=200512231728165 ) has long been disabled by Apple, but the link offers some other ideas for OS X (including GhostScript).

Freeware PDF Unlocker for Windows (which includes and uses GhostScript) proved effective at removing the restrictions (though bookmarks are broken in the process): http://hotshare.net/file/106490-50163782f0.html

eworoshow2• 17 years ago

I became interested in ARM assembly after reading the x86 assembly Forth tutorial that was recently posted on HN. Lacking an ARM processor, though, I'm wondering what emulation options are available? I'm looking for a dead-simple setup that will let me test and run whatever toy ARM assembly programs I write.

miles3• 17 years ago

Free ARM Emulators http://www.thefreecountry.com/emulators/arm.shtml

eworoshow2• 17 years ago

Any specific recommendations from that set? I was looking at Qemu earlier but I'm curious to hear from HN folks who have had experience with these emulators.

ARM Assembly Language Programming

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