16-bit barrel shifter A Mini Project Report   Mini Project Report Submitted in the partial fulfillment of the requirements for the award of the Degree of Bachelor of Technology ELECTRONICS AND COMMUNICATION ENGINEERING Under the guidance of ( MR S.V.S.PRASAD ) Submitted by G.SHYAMKUMAR (08E31A0458) G.RAMESH (08R21A0499) P. PARDTHASARADHI (08R21A0487)

Abstract A barrel shifter is a digital circuit that can shift a data word by a specified number of bits in one clock cycle. The number of multiplexers required for an n-bit word is n X log2(n) The shifter works by shifting the bits left. Inputs: Data bits D0-D7 & encoded Select lines S2, S1, S0. Outputs: Shifted Data bits Q0 – Q7. Implementation Technology : 0.6 micron process. A barrel shifter, comprising: an n-bit by n-bit transistor array arranged into n rows and n columns

8 Bit Barrel Shifter Block Diagram data(16- bits) clk rst dataout(16bits load_shift no. of bits to be shifted(16-bit

FUNCTION OF BARREL SHIFTER Each shifter will be designed as a 16-bit shifter that receives a 16-bit input data value along with a two’s compliment encoded shift value, and will produce a 16- bit shifted result. This section will describe the internal design characteristics for each shifter.

Introduction to barrel shifter A hardware device that can shift or rotate 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 Four common word sizes and the number of multiplexers needed are listed below: 64-bit — 64 * log2(64) = 64 * 6 = 384 32-bit — 32 * log2(32) = 32 * 5 = 160 16-bit — 16 * log2(16) = 16 * 4 = 64 8-bit — 8 * log2(8) = 8 * 3 = 24

Simulations

Project Summary We designed a 16bit Barrel Shifter that shifts data from an input to an output depending on the combination of three select lines. Our design of the Barrel shifter allows for an increase in the number of input bits without having to modify the existing design. Our design met the specifications for the project.

Applications of barrel shifter Digital Signal Processing Array Processing Graphics Database Addressing High Speed Arithmetic Processors

Summary Our project was a worthwhile endeavor as not many people know what a barrel shifter is and what it is used for. As such, doing it and presenting it to the class has helped to enlighten our classmates. Most importantly we got our circuit design to work and meet specification as we have ably shown in our presentation. We believe that our circuit can become a stepping stone to improving computer organization and memory.

  CONCLUSION Hence we have designed the IP Core for Barrel Shifter using VHDL. The simulation has been done using ISE Simulator. The synthesis has been done using XILINX ISE 9.1i. The bit file has been generated and the output is dumped on the FPGA Device (Spartan3E).

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