ARM Assembly Language Programming • Hacker News Board

Re: ARM Assembly Language Programming

#21

Post by mru » Sat, Nov 21, 2009, 7:43 PM UTC

daeken wrote: post #7

yason wrote: post #5

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 ach…

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…

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

Re: ARM Assembly Language Programming

#22

Post by miles » Sat, Nov 21, 2009, 7:50 PM UTC

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

Re: ARM Assembly Language Programming

#23

Post by eworoshow » Sat, Nov 21, 2009, 8:38 PM UTC

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.

Re: ARM Assembly Language Programming

#24

Post by miles » Sat, Nov 21, 2009, 8:43 PM UTC

eworoshow wrote: post #23

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.

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

Re: ARM Assembly Language Programming

#25

Post by eworoshow » Sat, Nov 21, 2009, 8:46 PM UTC

miles wrote: post #24

eworoshow wrote: post #23

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.

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

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.

Re: ARM Assembly Language Programming

#26

Post by miles » Sat, Nov 21, 2009, 8:59 PM UTC

eworoshow wrote: post #25

miles wrote: post #24

Earlier quoted context omitted.

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

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.

Check out the Amiga emulator UAE - it's been ported to virtually everything (Linux, OS X, Windows, DOS, BeOS, Palm OS, and much more, including AmigaOS!) and is under active development (WINUAE, anyway):

http://www.thefreecountry.com/emulators/amiga.shtml http://en.wikipedia.org/wiki/UAE_(emulator)

Re: ARM Assembly Language Programming

#27

Post by pkaler » Sat, Nov 21, 2009, 9:22 PM UTC

RiderOfGiraffes wrote: post #10

obvioustroll wrote: post #9

Earlier quoted context omitted.

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

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…

Scribd was seed funded by Y Combinator.

http://www.crunchbase.com/company/scribd

Re: ARM Assembly Language Programming

#28

Post by RiderOfGiraffes » Sat, Nov 21, 2009, 10:55 PM UTC

pkaler wrote: post #27

RiderOfGiraffes wrote: post #10

Earlier quoted context omitted.

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…

Scribd was seed funded by Y Combinator. http://www.crunchbase.com/company/scribd

Which explains why HN puts the link on every PDF. Thank you.

It won't make any difference, and probably no one cares, but I still think what scribd does is ethically and morally wrong.

I'll shut up about it now.

Re: ARM Assembly Language Programming

#29

Post by DarkShikari » Sat, Nov 21, 2009, 11:01 PM UTC

mru wrote: post #21

daeken wrote: post #7

Earlier quoted context omitted.

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…

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

Or, better said, the instruction set NEON outshines SSE and Altivec. The actual vector unit is a bit lacking performance-wise by comparison, which shouldn't be particularly surprising given that it runs on 100 times less power.

Re: ARM Assembly Language Programming

#30

Post by yuvi » Sun, Nov 22, 2009, 12:10 AM UTC

yason wrote: post #5

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 ach…

>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.