Dynamic barrel shifter

Claim 1

A dynamic barrel shifter for shifting input data with binary codes transmitted through a plurality of N channel transistors connected by first-data-transmission routes, comprising: first pre-charging means for pre-charging the first-data-transmission routes to a preset high level with a first electric potential of less than a supply electric potential, through an N channel transistor before shifting the input data; second pre-charging means for pre-charging second-data-transmission routes which follow the first-data-transmission routes to the supply electric potential, through a P channel transistor before shifting the input data, the second-data-transmission routes thereby being preset at the high level; input data shifting means for shifting the input data by a shift count in response to shift control signals by discharging the first-data-transmission routes and the second-data-transmission routes in cases where the input data is at a low level and by maintaining the charges of both the first-data-transmission routes and the second-data-transmission routes in cases where the input data is at the high level; and input data output means with sense inverters for outputting the input data shifted by the input data shifting means after inverting the shifted input data at the high level in the sense inverters when the supply electric potential of the second-data-transmission routes is decreased to a value lower than that of a threshold voltage of the sense inverter, the threshold voltage being higher than half of the supply electric potential, and after inverting the shifted input data at the low level in the sense inverters when the second-data-transmission routes are maintained at the supply electric potential.