Dear Mr.Neil

Thanks for your answer but my actual problem is now i am working in a project where a 16 bit AMD188 microcontroller is induced and so i am asking all about a general microcontroller doubt. where a boot code is normally placed in boot code area which is in the internal memory of the micro controller where it is one time programmable.so to avoid the hassle of one time programming the boot code is placed in external memory and probably in the 0x00000th memory location so that it gets boot up since it is the first memory location,my doubt is when the microcontroller reaches to fffffth memory location it rolls over to 00000th memory location obviously rebooting the system what can be done in this situation? are i am somewhere going wrong in explaining the microcontroller action.
Waiting for your reply...