CCS4 call stack window has no main() function

Hi, 

I am using CCS4 with XDS510USB JTAG to debug an OMAP35x board. The target is connected. but in the call stack window there is no main() function, thus I cannot access to my main program.

In my Debug call stack window, there is something like:

Device

  Thread[main](Running)

    0 _c_int00() at boot.asm:185 0x40208358

Can anybody help me on this? 

Thanks,