what does system does before start executing main()

vkmgeek · 06-19-2006, 03:10 AM

.o file of .c file having single function say main, contains so many functions like _init, _start , _fini etc..

what r they 4?

what exactly system does b4 executing first instruction of main..

I had started executing instructions from _init , before reaching to first instruction of main.., it had set pc to 0x00.
why it had done so ??

generally 0x00 is for reset, so it will now reset the system
so how program is reaching to main then ??

jlliagre · 06-19-2006, 06:36 AM

Please try using plain english in your postings.

Before calling main, the system is preparing the environment for the program to work properly. This is usually done by something called crt0 (for C run time).

Concerning the pc address, don't confuse virtual adresses the application is living in, and physical adresses with which adress 0 may or may not trigger a system reset.