Re: need help

[Nick Clifton]

Hi Kiran,

>         i wanted to run a small program on MPC8560 processor  
> i wrote a small application and i cross compile with PPC_82xx-gcc
> i got a obj file as a.out

I hope that you mean that you obtained an executable called "a.out".  An 
object file is just the output of the assembler.  It has not been linked 
with the necessary libraries and so cannot be executed on its own.

>         even if i changed the code in my application the final "a.out"is 
> showing the same size

Small changes in your application's code will probably not change the 
size of the a.out executable.  This is because the linker will pad it 
out so that it fits into a whole number of pages of memory.  Large 
changes to your application most certainly will change the size of the 
executable however.

> * will the out put file(a.out) work only if there is a OS  on the target?

In general yes.  Applications need some kind of operating system support 
in order to be able to run.  It is possible to build a completely self 
contained executable however which needs no outside OS support.  This is 
usually quite a complex task however, and requires intimate knowledge of 
the hardware upon which the application is going to run.

> should i need to do linking manualy or it is don automaticaly with gcc

As long as you are not using the -c, -S or -E command line switches to 
gcc it will try to perform the linking step for you.

Cheers
  Nick