Registers (synchronous designs)

In previous posts I showed, how to build OR gate. This was an example of combinational logic. If you look at the code, you will see, that output depends only on present inputs and changes as fast as possible after modifying them. Though you have to know how to build combinational logic and how it works,  you won’t create any bigger design only with that. To store data or pipeline the calculations, you have to create synchronous logic, dependent on a clock.