barrelshifter.bsv

import Multiplexer::*;

interface BarrelShifterRight;
  method ActionValue#(Bit#(64)) rightShift(Bit#(64) val, Bit#(6) shiftAmt, Bit#(1) shiftValue);
endinterface

module mkBarrelShifterRight(BarrelShifterRight);
  method ActionValue#(Bit#(64)) rightShift(Bit#(64) val, Bit#(6) shiftAmt, Bit#(1) shiftValue);
    /* TODO: Implement right barrel shifter using six multiplexer */
    Bit#(64) shiftedVal;
    for(Integer i = 0; i < 6; i = i + 1)
      begin
      for(Integer j = 0; j < 64 - 2 ** i; j = j + 1)
        begin
        shiftedVal[j] =  val[j + 2 ** i];
        end
      for(Integer j = 0; j < 2 ** i; j = j + 1)
        begin
        shiftedVal[63 - j] = shiftValue;
        end
      val = multiplexer_n(shiftAmt[i], val, shiftedVal);
      end
    return val;
  endmethod
endmodule

interface BarrelShifterRightLogical;
  method ActionValue#(Bit#(64)) rightShift(Bit#(64) val, Bit#(6) shiftAmt);
endinterface

module mkBarrelShifterRightLogical(BarrelShifterRightLogical);
  let bsr <- mkBarrelShifterRight;
  method ActionValue#(Bit#(64)) rightShift(Bit#(64) val, Bit#(6) shiftAmt);
    /* TODO: Implement logical right shifter using the right shifter */
    let ans = bsr.rightShift(val, shiftAmt, 0);
    let result <- ans;
    return result;
  endmethod
endmodule

typedef BarrelShifterRightLogical BarrelShifterRightArithmetic;

module mkBarrelShifterRightArithmetic(BarrelShifterRightArithmetic);
  let bsr <- mkBarrelShifterRight;
  method ActionValue#(Bit#(64)) rightShift(Bit#(64) val, Bit#(6) shiftAmt);
    /* TODO: Implement arithmetic right shifter using the right shifter */
    let ans = bsr.rightShift(val, shiftAmt, val[63]);

    let result <- ans;
    return result;
  endmethod
endmodule