Arithmetic shifter with sign extend facility

摘要

A shifter for shifting a first data word by a bit width which is specified by a second data word. The shifter provides a sign extension so that the shifter can be used for arithmetic shifts. The shifter includes a first inverter for inverting the bits of the first data word only when the most significant bit of the data word is a predetermined datum. The output from the inverter is shifted, using a shifter array, by a bit width specified by the second data word. The output from the shifter array is provided to a second inverter. The second inverter inverts the output from the shifter array only if the most significant bit of the first data word is a predetermined datum.