Fit code results meaning:
========================

0        all good
+1000    it was refit and suceeded with either a non-lin or lin fit
0x1      pedestal out of range (-200 to 400)
0x2      gain out of range (1 to 50)
0x4      center out of range (0 to 128)
0x8      sqrlow out of range (-5 to 5)
0x10     sqrhigh out of range (-5 to 5)
0x20     linsat out of range (-50 to 50)
-999     didn't even bother trying to fit. Lack of valid calibration
         data for this channel (showed no increase of ADC values with
         varying DAC settings)

Fitting function:
================
is in getAdc method of online/calibration/Run3/subsystems/mutr/MutCalib.C
in CVS:

getAdc(int x, Double_t *par, int Saturation)
{
  Double_t fitval;
  int dac = x;

  fitval = par[0] + par[1]*x; // default is just a straight line

  double distCenter, center = par[2];
  double sumdev = 0.0;
  double distSat, olddiff = 0;

  int nsteps = dac/FITSTEP;

  for (int i = 0; i<nsteps; i++) 
    {
      dac = i*FITSTEP;
      distCenter = dac - center; 
      //      cout << " distCenter = " << distCenter << endl;
      if (distCenter<0) // low side
	{
	  sumdev = sumdev + par[3]*distCenter*distCenter;
	}
      else
	{	      
	  if ( (dac - Saturation) < 0) 
	    { // not yet saturated: normal
	      olddiff = par[4]*distCenter*distCenter;
	      sumdev += olddiff;
	    }
	  else 
	    {// we have passed saturation point, new rules apply here
	      // olddiff is kept from previous step
	      distSat = dac - Saturation; 
	      sumdev = sumdev + olddiff + par[5]*distSat;
	    }
	}
    }  

  fitval -= sumdev;
  return fitval;
}