Design of a Goldschmidt iterative divider for quantum-dot cellular automata

A Goldschmidt iterative divider for quantum-dot cellular automata (QCA) is designed using a new architecture that solves a problem that arises in implementing conventional state machines in QCA. State machines for QCA often have synchronization problems due to the long delays between the state machines and the units (i.e., the computational circuits) to be controlled. To resolve this problem, a data tag method is used. The data tags are associated with the data and local tag decoders generate control signals. Since each datum has a tag, it is possible to issue a new division command at any iteration stage of a previous issued operation. Thus the throughput is significantly increased since multiple division computations can be performed in a time skewed manner using one iterative divider due to the large number of inherent pipeline stages in QCA circuits (unlike CMOS circuits). Using the new architecture, a fixed-point Goldschmidt divider is implemented using a 12-bit multiplier.