Two tricks of making integer computation faster in Delphi.
  
  1. Two integers a and b, to compute a mod b, where b is power of two (two, four, eight ... etc)...
  
  in delphi, you write
      result := a mod b;
  in this case, to make it faster,
  you can write
      result := a and (b - 1); // b >= 2, and power of 2.
  
  2. Two integers a (a >= 0) and b, to compute a div b, where b is power of two (two, four, eight ... etc)...
  
  in delphi, you write
      result := a div b;
  in this case, to make it faster,
  you can write
      c := fun(b);       // fun returns the integer(log2(b))        
      result := a shr c; // where b >= 2, and power of 2    
  
  // returns the left-most significant digit.
  function fun(b: integer): integer; assembler; register;
  asm
    bsr eax, eax
  end; 
  
  if (a < 0), it can be reworked as result = -((-a) shr c)