US Patent 7949697 Bit field operation circuit

A bit field operation circuit has a first shift unit, a mask shift amount control circuit, a second shift unit, a logic operation unit, and a selection unit. The first shift unit outputs a first intermediate data based on a first control signal. The mask shift amount control circuit outputs a mask shift control signal in accordance with a mask shift amount. The second shift unit outputs a second intermediate data based on a mask shift control signal. The third shift unit outputs a third intermediate data based on the first control signal. The logic operation unit performs logical operation of the second intermediate data and the third intermediate data, and outputs a mask selection data. The selection unit selects either one of the first intermediate data or the second input data based on the mask selection data to output as output data.