Stephane REY wrote:
-------------------------------
I'm using the Keil C compiler.
When I'm writting a software with many functions, how could I specify that the software should jump to the 'main ()' function ?

The C runtime startup code is what jumps to main() for you. Take a look at startup.a51 and init.a51 in the ..c51lib directory where you installed the compiler. startup.a51 has the code that executes first. You can follow it from there.