UInt_t RanBit(UInt_t hRead)
{

// 
// 

  UInt_t bit7    = (fgShreg & 0x00000040) != 0;
  UInt_t bit28   = (fgShreg & 0x08000000) != 0;
  UInt_t bit29   = (fgShreg & 0x10000000) != 0;
  UInt_t bit30   = (fgShreg & 0x20000000) != 0;

  UInt_t newbit = (bit30 ^ bit29 ^ bit28 ^ bit7) & 0x1;
  fgShreg = ( (hRead == 2 ? newbit : hRead) | (fgShreg << 1 )) & 0x3FFFFFFF;
  return newbit; 

}

//

UInt_t fgShreg = 416864460; // Initial value of 11000110110001101100011001100, 0x18D8D8CC

void NewPseudoRanBitGenR(){

  // define style here 
  // general parameters
  gStyle->SetOptDate(0);     gStyle->SetOptTitle(0);
  gStyle->SetStatColor(10);  gStyle->SetStatH(0.2);
  gStyle->SetStatW(0.3);     gStyle->SetOptStat(0); 
  
  // canvas parameters
  gStyle->SetFrameBorderMode(0);
  gStyle->SetFrameBorderSize(0);
  gStyle->SetFrameFillColor(10);
  // pads parameters
  //  gStyle->SetPadColor(39); 
  gStyle->SetPadColor(0); 
  gStyle->SetPadBorderMode(0);
  gStyle->SetPadBorderSize(0);
  gStyle->SetPadBottomMargin(0.18);
  gStyle->SetPadRightMargin(0.05);
  gStyle->SetPadLeftMargin(0.14);
  gStyle->SetLabelSize(0.04,"x");
  gStyle->SetLabelSize(0.04,"y");
  gStyle->SetTitleXSize(0.08);
  gStyle->SetPaperSize(10,12);

  gStyle->SetTitleYOffset(0.8);
  gStyle->SetTitleYSize(0.10);
  gROOT->ForceStyle();  

  //
  
  TString pstit;

 ofstream outfile;
 char ofile[200];
 sprintf(ofile,"NewPseudoRanBitGenR.dat");
 outfile.open(ofile);

 //
  b1 = new TCanvas("b1","Helicity Sequence",40,40,700,1000);
  b1->Divide(1,2);
  
  //
  
  h1 = new TH1F("h1","Helicity Pattern",6,-1,2);
  h1->SetFillColor(46);
  
  h2 = new TH2F("h2","Helicity Pattern",100,0,100,6,-1,2);
  h2->SetFillColor(38);
  
  // Predict the helicity pattern
  
  cout << "  -> Predict the helicity pattern:" << endl;
  
  // The Shift Registor repeats every 2^(30) - 1 = 1,073,741,823 pairs, 25 days (500 Hz).

  for(Int_t j=0; j<100; j++){
    cout << "LFSR = " << fgShreg << endl; 
    Printf("fgShreg = 0x%0x",fgShreg);

    UInt_t eb = RanBit(2);

    outfile << eb << "    " << fgShreg <<endl; 
    cout << "Predicted Helicity Pair = " << eb << " " << (~eb & 0x1) << endl;
    
    //   
    h1->Fill(eb);
    h2->Fill(j,eb);
  }
  
  b1->cd(1);
  h1->GetXaxis()->CenterTitle();
  h1->GetXaxis()->SetTitleOffset(1.0);
  h1->GetXaxis()->SetTitleSize(0.06);
  TString tit = "Helicity Pattern";
  h1->GetXaxis()->SetTitle(tit.Data());

  h1->Draw();
  
  b1->cd(2);
  
  h2->GetXaxis()->CenterTitle();
  h2->GetXaxis()->SetTitleOffset(1.0);
  h2->GetXaxis()->SetTitleSize(0.06);
  TString tit = "Helicity Sequence, first window";
  h2->GetXaxis()->SetTitle(tit.Data());
  
  h2->Draw("BOX");
  
  b1->cd();   
  b1->Update();   
  pstit = "NewPseudoRanBitGenR.gif";
  b1->Print(pstit.Data());

}