INT 67H 4800H: Restore Mapping Context

                                                     Compatibility: EMS 3.2+ 
 Expects: AX    4800H
          DX    EMM handle owned by caller
          ──────────────────────────────────────────────────────────────────
 Returns: AH    EMM status (0=successful)
          ──────────────────────────────────────────────────────────────────
    Info: EMM will restore the page mapping to what it was upon a previous
          INT 67H 4700H call with the same handle.  Device drivers and TSRs
          should use this before exiting to the application.

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