Random Number Generator for range 0 to 7999, all operations mod 8000 !?!

Hello,

I need a random number generator for integer range 0 to 7999.

It should generate random numbers between range 0 to 7999.

All operations are mod 8000.

Math operations allowed:
addition, subtraction, div, mod

And some logic operations:
if, while, for, compare, jump, whatever.

Anybody have an idea ?

Bye,
  Skybuck.