FOR x, -2147483648, 1610612736, 1073741824
  80000000 = -2147483648
  c0000000 = -1073741824
  00000000 = 0
  40000000 = 1073741824
  done 80000000 = -2147483648
FOR x, -2147483648, 1879048192, 1140850688
  80000000 = -2147483648
  c4000000 = -1006632960
  08000000 = 134217728
  4c000000 = 1275068416
  done 90000000 = -1879048192
FOR x, 2147483647, -2147483648, -2147483648
  7fffffff = 2147483647
  ffffffff = -1
  done 7fffffff = 2147483647
FOR x, -2147483648, -1, -2147483648
  done 80000000 = -2147483648