I am curious as to what measurement (input to the '51) that can be that precise as to needing 8 digit precision. A microCONTROLLER will always lose to a microPROCESSOR on high precision arithmetic. My GUESS is that you have a measurement precise to say 3 digits that some salesman want displayed in 8 digits. In that case calculate the first 3 digits and set a randomly generated number in the remaining 5.

Have fun,

Erik