Compatibility: EMS 4.0+
Expects: AH    52H
AL    subfn: 00H=Query handle attribute
01H=Set handle attribute
12H-Query capability
DX    EMM Handle (as obtained via INT 67H 4300H)
                                                                  
Returns: AH    EMM status (0=successful)
AL    (fn 5200H) attribute: 00H = volatile
01H = non-volatile (lives thru reboot)
(fn 5202H)   support: 00H = NO support for non-volatile pgs
01H = OK to tag as non-volatile
                                                                  
Info: EMS 4.0 describes this system in which you can mark the pages of
a handle as "volatile" and "non-volatile".  Pages of a
non-volatile handle will be intact after a warm boot.

Most EMS cards and EMM emulators do not support this capability,
so don't waste your time or mine.

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INT 67H 52xxH: Get/Set Handle Attribute