Re: [ECOS] Stand-alone program

[Hugo Villeneuve <hvilleneuve at softacoustik dot com>]

Hi,

	If my understanding is correct, the only purpose of adding a 
'.global __gccmain' line to a file is to make that label '__gccmain' 
available to the linker. Normally, when running the "arm-elf-gcc -c 
main.c" command, main.c is first compiled and then assembled and the 
'__gccmain' variable should be exported to the linker with the 
'.global' assembly directive. Why I still have any errors there?


By the way, my startup assembly file looks like this:

     .text
     .code 32
     .globl _start
_start:
     # Do initialization stuff here
     BAL   __gccmain
     BAL   _start


With which assembly directive can I specify that the label 
'__gccmain' is defined externally to this file?


	Thanks, Hugo Villeneuve.




10-26-2001 11:03:25, Grant Edwards <grante@visi.com> wrote:

>On Fri, Oct 26, 2001 at 09:08:28AM -0400, Hugo Villeneuve wrote:
>
>> 	I have successfully installed ecos and all the binutils, gcc and 
>> gdb stuff for the arm-elf target. How strange it may sounds, I just 
>> want to know how I can compile a simple application, not using any 
>> built-in libraries of gcc. I mean, I want to create my own crt.s (C 
>> runtime startup) assembly file, and then call my main function from 
>> this crt.s file.
>> 
>> 	My crt.s assembly file assembles great with arm-elf-as, but I 
>> have a small error when compiling my main.c file (the main function 
of 
>> which do nothing but return a success exit code):
>> 
>> command used:
>> 	arm-elf-gcc -c -Wa,-marm7tdmi,-mapcs-32 main.c -o main.o
>> output:
>> 	main.o: In function `main':
>> 	main.o(.text+0xc): undefined reference to `__gccmain'
>
>Add a __gccmain to your startup file.  It doesn't need to do
>anything, just return. Mine looks like this:
>
>        .global __gccmain
>__gccmain:
>        mov     pc,lr   
>        
>
>-- 
>Grant Edwards
>grante@visi.com
>

--------------------------------------
  Hugo Villeneuve
  Hardware/Firmware Developer
  SoftAcoustik Inc.

  (418) 521-1515
  hvilleneuve@softacoustik.com
  http://www.softacoustik.com
--------------------------------------