GCC compiling- help needed

Hi guys !

I am a rookie in gcc.So please help me out.

I have arm-elf-gcc 4.1.1 installed on Ubuntu and I have to cross
compile for ARM7TDMI-S core based LPC2368 processor.

I have the C runtime file crt0.S, the startup.S,processor's header
file and I have also modified the ROM.ld.

So, what I remember , the process will be :
1. Convert C source code to object file.
2. Link all the object files to create an executable.
3. Convert the executable to intel hex format.

But I am unable to link as I have a few doubts.
Question 1 : crt0.S is not getting converted to crt0.o and startup.s
to startup.o. How to do it ?
Question 2 : How to link ROM.ld  with other files ?


Thanks a lot.

"nik" <nitinkothari@gmail.com> wrote in message 
news:69f0ba14-b977-4aad-a672-6b406df5e3eb@a29g2000pra.googlegroups.com...
> Hi guys !
>
> I am a rookie in gcc.So please help me out.
>
> I have arm-elf-gcc 4.1.1 installed on Ubuntu and I have to cross
> compile for ARM7TDMI-S core based LPC2368 processor.
>
> I have the C runtime file crt0.S, the startup.S,processor's header
> file and I have also modified the ROM.ld.
>
> So, what I remember , the process will be :
> 1. Convert C source code to object file.
> 2. Link all the object files to create an executable.
> 3. Convert the executable to intel hex format.
>
> But I am unable to link as I have a few doubts.
> Question 1 : crt0.S is not getting converted to crt0.o and startup.s
> to startup.o. How to do it ?
> Question 2 : How to link ROM.ld  with other files ?

Best bet is just to start with a project that is already working.  You could 
start with the LPC2368/Eclipse demo in the FreeRTOS.org download which has a 
standard makefile (although I have only tested on Windoze so you may find 
some case problems in the include paths).  Alternatively look in the files 
section of the LPC2000 Yahoo group.

-- 
Regards,
Richard.

+ http://www.FreeRTOS.org & http://www.FreeRTOS.org/shop
17 official architecture ports, more than 6000 downloads per month.

+ http://www.SafeRTOS.com
Certified by T&#4294967295;V as meeting the requirements for safety related systems. 

In article <69f0ba14-b977-4aad-a672-6b406df5e3eb@a29g2000pra.googlegroups.com>,
nik  <nitinkothari@gmail.com> wrote:
>So, what I remember , the process will be :
>1. Convert C source code to object file.
>2. Link all the object files to create an executable.
>3. Convert the executable to intel hex format.
>
>But I am unable to link as I have a few doubts.
>Question 1 : crt0.S is not getting converted to crt0.o and startup.s
>to startup.o. How to do it ?

The GNU assembler, 'gas', is part of the gcc setup and will convert assembly
sources to object files. However, the main 'gcc' command knows how to
invoke all of the compiler components and I usually find it easier to use
gcc to invoke gas rather than invoke gas directly. So just pretend that those
files are C source files and compile them using "gcc -c -o crt0.o crt0.S"
(along with any other compiler flags you need, etc.).

>Question 2 : How to link ROM.ld  with other files ?

I assume that's a linker script ("put the code starting at address 0x800000,
followed by the constant strings, and put the readwrite data at 0xC000000",
that kind of thing). Take a look at the man and info pages for the GNU linker
for details, but basically, you use the linker's -T flag to tell it to
use that linker script:
  arm-elf-ld -m blahblah -T ROM.ld obj1.o obj2.o obj3.o -o result.elf
or, if you're invoking the linker via the 'gcc' command,
  arm-elf-gcc ... -Wl,-T,ROM.ld  ...
(the -W... flag is a way to tell gcc to pass extra flags to one of the
phases it runs, even if the 'gcc' command itself doesn't understand about
linker scripts).

Hope this helps.

-- 
   Wim Lewis <wiml@hhhh.org>, Seattle, WA, USA. PGP keyID 27F772C1
  "We learn from history that we do not learn from history." -Hegel