my $z = 0x0FED_CBA9_8765_4321 ;
  my $d = 9 ;

  printf " a = %20s * %d + i, for i = 0..%d\n", "$z", $d, $d ;
         # 12: 12345678901234567890 : +2345
  print  "  i:                a / $d : Error\n" ;
 
  foreach my $i (0..$d) {
    my $a = ($z * $d) + $i ;
    my $q = $a / $d ;

    printf " %2d: %20s : %+5d\n", $i, "$q", $q - ($z + int($i/$d)) ;
  } ;