In some processors, all data registers act in the same manner, while in other processors different operations are performed are specific registers. This allows for the hardware implementation of dynamic memory pages, virtual memory, and protected memory. A 16-bit address register can address 64K of physical memory. A 24-bit address register can address address 16 MB of physical memory. A 32-bit address register can address 4 GB of physical memory.
Addresses are always unsigned binary numbers.
See number of bits . Attempts to write to a constant register are illegal or ignored. Constant registers are also often used in floating point units to provide such value as pi or e with additional hidden bits for greater accuracy in computations. Effective addresses are computed by adding the contents of the base or segment register to the rest of the effective address computation. In some processors, any register can serve as a base register.