Get Next Selector Increment Value


                 Some functions  such as  allocate LDT  descriptors  and
                 allocate  DOS   memory  can   return  more   than   one
                 descriptor.   You must  call this function to determine
                 the value  that must  be added  to a selector to access
                 the next descriptor in the array.

            To Call

                 AX = 0003h

            Returns

                 Carry flag clear (this function always succeeds)
                 AX = Value to add to get to next selector

            Programmer's Notes

                 o    Do not  make any  assumptions about the value this
                      function will return.
                 o    The increment  value returned  will be  a power of
                      two.