I need to learn ARM assembly, and I use Linux.

http://ubuntuforums.org/archive/index.php/t-2010979.html

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chuchi

June 26th, 2012, 04:53 PM

Hi there!!

I need to learn ARM assembly, and I use Linux. Please, could you give
me any starting point about how to install it?? I do not pretend that
you teach me ARM assembly. Just a link.

thank you very much!!!

youknowme

June 27th, 2012, 05:03 AM

Hi there!!

I need to learn ARM assembly, and I use Linux. Please, could you give
me any starting point about how to install it?? I do not pretend that
you teach me ARM assembly. Just a link.

thank you very much!!!

This might be useful to start you off
http://www.coranac.com/tonc/text/asm.htm
SevenMachines

June 27th, 2012, 08:11 AM

Been
a year or so, but i think this works? Although personally I recommend
setting up a chroot or pbuilder arm environment, its less hassle with
more complicated programs, or at least was in my previous experience.

$ apt-get install gcc-4.6-arm-linux-gnueabi libc6-dev-armel-cross

$ cat hello.s

.data

msg:

.ascii "Hello, ARM World!\n"

len = . - msg

.text

.globl _start

_start:

/* write syscall */

mov %r0, $1

ldr %r1, =msg

ldr %r2, =len

mov %r7, $4

swi $0

/* exit syscall */

mov %r0, $0

mov %r7, $1

swi $0

$ arm-linux-gnueabi-as -o hello.o hello.s

$ arm-linux-gnueabi-ld -o hello hello.o

$ file hello

hello: ELF 32-bit LSB executable, ARM, version 1 (SYSV), statically linked, not stripped

$ ./hello

Hello, ARM World!

chuchi

June 27th, 2012, 06:35 PM

Hi!!
thank you very much for reply. But that type of instructions is of the
form: Mov source,dest. The syntax instructions on ARM is : Mov
dest,source. This is what I need

Thank you very much!

chuchi

June 27th, 2012, 06:49 PM

Ok I was wrong, your code is right!! I am very sorry!!

Everything is ok, except when I type ./hello I get

bash: ./hello: cannot execute binary file

Why??

Thank you very much!

SevenMachines

June 27th, 2012, 07:17 PM

Yes. its just at&t syntax versus intel.

Sorry, obviously the binary is arm and not x86 so wont run, I just forgot I had qemu emulation enabled. Try,

$ ./hello

bash: ./hello: cannot execute binary file

# Set up qemu arm emulation

$ sudo apt-get install qemu-user-static

$ ./hello

Hello, ARM World!

chuchi

June 27th, 2012, 07:25 PM

HI!! now it works!! thank you very very much!!

chuchi

June 28th, 2012, 09:48 AM

Hi again!!

Do you know any way of debugging in qemu?

Surfing the net they say you have to install and configure a new kernel. Is there any other way??

thank you very much!!

SevenMachines

June 28th, 2012, 11:21 PM

You can set qemu to wait on a gdb connection

# In a terminal

$ qemu-arm-static -g 10101 ./hello

# In a new terminal

$ sudo apt-get install gdb-multiarch

Then start gdb-multiarch, load symbols, and connect gdb to qemu, eg

$gdb-multiarch

(gdb) list _start

8 .text

9

10 .globl _start

11 _start:

12 /* write syscall */

13 mov %r0, $1

14 ldr %r1, =msg

15 ldr %r2, =len

16 mov %r7, $4

17 swi $0

(gdb) b 16

Breakpoint 1 at 0x8080: file hello.s, line 16.

(gdb) target remote :10101

Remote debugging using :10101

[New Remote target]

[Switching to Remote target]

_start () at hello.s:13

13 mov %r0, $1

(gdb) c

Continuing.

Breakpoint 1, _start () at hello.s:16

16 mov %r7, $4

(gdb) n

17 swi $0

(gdb) n

20 mov %r0, $0

(gdb) c

Continuing.

[Inferior 1 (Remote target) exited normally]

[EDIT] You'll want debugging information ie

$ arm-linux-gnueabi-as -gstabs -o hello.o hello.s