Compatibility: XMS 2.0+
Expects: AH    0aH
DX    XMS handle (as obtained via XMS 09H)
Returns: AX    status: 0000H = successful
0001H = error and BL=XMS error code (if BL >= 80H)
Info: This fn frees a block of extended memory that was previously
allocated via XMS 09H (allocate XMB).

When an XMB is freed, its handle and all data in it become
invalid and should not be accessed.

See Also: XMS Functions
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XMS 0aH: Free Extended Memory Block