function [res] = CHIP(rnd,r,x)
% This program is used by Iterative Refinement (Algorithm 7.4)
% to round or chop to a specific number of digits.
if x == 0
  w = 0;
else
  ee = fix(log10(abs(x)));
  if abs(x) > 1
     ee = ee + 1;
  end;   
  if rnd == 1
     w = round(x*10^(r-ee))*10^(ee-r);
  else
     w = fix(x*10^(r-ee))*10^(ee-r);
  end;
end;
res = w ;