Barrel shifter
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A barrel shifter is a hardware device that can shift a data word by any number of bits in a single operation. It is implemented like a multiplexer, each output can be connected to any input depending on the shift distance.
Take for example a 4-bit barrel shifter, with inputs A, B, C and D. The shifter can cyclicly alter the order of the outputs. i.e. it can 'shift' all of the outputs up to 3 units to the right (and thus make any cyclic combination of A, B, C and D). Barrel shifters have a variety of implementations, including being a vital component in digital filtering (alongside the ALU).
References
- This article was originally based on material from the Free On-line Dictionary of Computing, which is licensed under the GFDL.