Barrel shifter for combining pieces of data into a piece of combined data and shifting the combined data

A barrel shifter comprising:

• a first data selector configured to hold first input data of at most N bits;
• a second data selector configured to hold second input data of at most N bits;
• and
• a plurality of shifters connected in a series arrangement and configured to carry out a shift operation of one of a plurality of shift amounts, said plurality of shifters including a top shifter of 3N/2 bits being directly connected to said first and second data selectors and configured to receive said first and second input data, each of remaining said plurality of shifters performing a necessary shift operation by selecting bit positions of a preceding one of said plurality of shifters in said series arrangement from which data is received in accordance with a respective shift control signal corresponding to said one of a plurality of shift amounts;
• said top shifter operating in one of a first, second and third mode in accordance with said respective shift control signal for said top shifter, said top shifter outputting first output data of 3N/2 bits such that, in the first mode, the least significant N/2 bits of said first input data is output as the most significant N/2 bits of said first output data and said N bits of said second input data is output as the least significant N bits of said first output data, in the second mode, the N bits of said first input data is output as the most significant N bits of said first output data and the most significant N/2 bits of said second input data is output as the least significant N/2 bits of said first output data, and in the third mode, the least significant N/2 bits of said first input data is output as the intermediate N/2 bits located between the most significant N/2 bits and the least significant N/2 bits of said first output data and the least significant N/2 bits of said second input data is output as the least significant N/2 bits of said first output data,
• wherein said plurality of shifters further comprise:
• a first shifter directly connected to said top shifter and configured to provide a first shift amount greater than or equal to 0 bits and less than or equal to N/4 bits to said first output data, said first shifter outputting second output data as a result thereof, wherein an amount of said first shift amount provided by said first shifter is based on said respective shift control signal received by said first shifter;
• a second shifter directly connected to said first shifter and configured to provide a second shift amount greater than or equal to 0 bits and less than or equal to N/8 bits to said second output data, said second shifter outputting third output data as a result thereof, wherein an amount of said second shift amount provided by said second shifter is based on said respective shift control signal received by said second shifter;
• a third shifter directly connected to said second shifter and configured to provide a third shift amount greater than or equal to 0 bits and less than or equal to N/16 bits to said third output data, said third shifter outputting fourth output data as a result thereof, wherein an amount of said third shift amount provided by said third shifter is based on said respective shift control signal received by said third shifter;
• a fourth shifter directly connected to said third shifter and configured to provide a fourth shift amount greater than or equal to 0 bits and less than or equal to N/32 bits to said fourth output data, said fourth shifter outputting fifth output data as a result thereof, wherein an amount of said fourth shift amount provided by said fourth shifter is based on said respective shift control signal received by said fourth shifter;
• and
• a fifth shifter directly connected to said fourth shifter and configured to provide a fifth shift amount greater than or equal to 0 bits and less than or equal to N/32 bits to said fifth output data, said fifth shifter outputting sixth output data as a result thereof, wherein an amount of said fifth shift amount provided by said fifth shifter is based on said respective shift control signal received by said fifth shifter,
• wherein each of said respective shift control signals for said top shifter and said first through fifth shifters include a right shift control signal and a left shift control signal, each of which can be ON of OFF, and
• wherein said first shifter operates in one of a first, second and third mode in accordance with said respective shift control signal for said first shifter, said first shifter outputting said second output data of 5N/4 bits such that, in the first mode, the least significant N bits of said first output data received from said top shifter is output as the least significant N bits of said second output data, in the second mode, the most significant 5N/4 bits of said first output data received from said top shifter is output as the 5N/4 bits of said second output data in said second mode, and in the third mode, the least significant N/4 bits of said first output data received from said top shifter is output as the least significant N/4 bits of said second output data and the third least significant group of N/4 bits of said first output data received from said top shifter is output as the second least significant group of N/4 bits of said second output data.