The default cyg_prestart() function does not do anything; it is meant to be overwritten if the programmer needs to do any initialization before other system level initialization.
You can override the default cyg_prestart() routine by providing your own function by the same name with the following prototype:
void cyg_prestart
(void);Note: If you are supplying your own definition of this function from a C++ file, make sure it has "C" linkage.