INT 67H 4700H: Save Mapping Context

                                                     Compatibility: EMS 3.2+ 
 Expects: AX    4700H
          DX    EMM handle owned by caller
          ──────────────────────────────────────────────────────────────────
 Returns: AH    EMM status (0=successful)
          ──────────────────────────────────────────────────────────────────
    Info: EMM will save the current mapping of physical to logical EMS
          pages, so that a TSR program or device driver may page-in its own
          memory transparently to the interrupted program.

          Use INT 67H 4800H restores the original mapping.

See Also: INT 67H: EMM Services
          Extended Memory Specification (XMS)
          Interrupts and BIOS Services
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