The __initialize_hardware() function is called from the _startup function after an initialization of the stack pointer. This function is defined in the cpu module, usually Cpu.c, and provides necessary system initialization such as PLL, and external bus.
Sometimes it is necessary to do some special user initialization immediately after the cpu reset. Processor Expert provides a possibility to insert user code into the __initialize_hardware() function. There is a User Initialization property in the build options tab of a processor component inspector defined for this purpose. See Component Inspector topic for details.