INT 33h,  0Bh (11)       Read Mouse Motion Counters

    Returns the Horizontal and Vertical Mickey Count.

       On entry:      AX         11h

       Returns:       CX         Horizontal Count
                      DX         Vertical Count

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    Function 0Bh returns the Horizontal and Vertical Mickey Count since last
    call to this function. The Mickey count is the distance the mouse has
    moved, in 1/200-of-an-inch increments.

    The Mickey count is always within the range -32768 to 32767.

    ■ A positive horizontal count specifies a motion to the right. A
      negative horizontal count specifies a motion to the left.

    ■ A positive vertical count specifies a motion downwards. A
      negative vertical count specifies a motion upwards.

    Overflow is ignored. The mickey count is set to 0 after the call is
    completed.