Int 2F Fn 4300  - Extended Memory Specification (xms) V2+ - Installation   [m]

   AX = 4300h

Return: AL = 80h XMS driver installed
   AL <> 80h no driver

Notes: XMS gives access to extended memory and noncontiguous/nonEMS memory
     above 640K
   this installation check DOES NOT follow the format used by other
     software

See Also: AX=4310h,AX=1687h,INT 67/AH=40h,@xxxxh:xxxxh"PMM"
Index: installation check;XMS version 2+