INT 31H 0003H: Query Selector Increment Value

                                                    Compatibility: DPMI 0.9+ 
 Expects: AX    0003H
 Returns: CF    NC (clear) always successful
          AX    selector increment value
    Info: When the host allocates a consecutive block of descriptors via
          INT 31H 0000H (allocate LDT descriptors) or INT 31H 0100H
          (allocate DOS memory block), it returns only a single, base

          The value returned in AX can be added to that base selector (or
          others in the series) in order to obtain the valid value of the
          next selector in the series.

See Also: DPMI API
          INT 2fH: Multiplex Interrupt
          DOS Functions