Variable barrel shifter

A method of shifting data in a variable barrel shifter, comprising:

• when a mode selector in the variable barrel shifter is in a first state, switching a data word to a shifter and then to a pivot circuit, and when the mode selector in the variable barrel shifter is in a second state, switching the data word to the pivot circuit and then to the shifter;
• applying a cyclic shift on the data word in the shifter;
• and
• performing a pivot operation on the data word in the pivot circuit.

A storage system comprising:

• a storage medium maintaining a data set;
• a write head configured to magnetically record the data set to the storage medium;
• and
• a low density parity check decoder with a variable barrel shifter comprising:
• a shifter configured to apply a cyclic shift to each of a plurality of portions of a data word in the data set;
• a pivot circuit configured to swap sections of the data word around at least one pivot point in the data word;
• a first multiplexer configured to select between an input of the variable barrel shifter or an output of the pivot circuit as an input to the shifter;
• a second multiplexer configured to select between the input of the variable barrel shifter or an output of the shifter as an input to the pivot circuit;
• and
• a third multiplexer configured to select between the output of the shifter or the output of the pivot circuit as an output to the variable barrel shifter.