Register-to-Register Communications

• Point-to-point

• Single shared bus

• Multiple special purpose busses

Tradeoffs between datapath/control complexity and

amount of parallelism supported by the hardware

Case study:

Four general purpose registers that must be able to exchange

their contents

Swap instruction must be supported:

SWAP(Ri, Rj)

Ri ? Rj;

Rj ? Ri;