The behavior of the FOR command depends on the value of the
    expression3 parameter, as detailed in the following table:

    expression3Action of the FOR Command

    Positive   name parameter is incremented from the value of
               expression1 by the value of expression3 until it is
               greater than the value of expression2
    Negative   name is decremented from the value of expression1 by
               the value of expression3 until it is less than the
               value of expression2
    0          The debugger returns an error message
    Omitted    The debugger assumes it to have the value +1

    Related commands:

       EXITLOOP
       REPEAT
       WHILE