XMS 0dH: Unlock Extended Memory Block

                                                     Compatibility: XMS 2.0+ 
 Expects: AH    0dH
          DX    XMS handle (as obtained via XMS 09H)
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 Returns: AX    status: 0000H = successful
                        0001H = error and BL=XMS error code (if BL >= 80H)
          DX:BX 32-bit linear address of base of block
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    Info: This unlocks an extended memory block that has been locked via
          XMS 0cH.  After unlocking, any 32-bit pointers to the data become
          invalid.

          XMBs should be unlocked as soon as possible to avoid memory
          fragmentation.

          The XMM maintains a "lock-count" and only allows the block to
          move when the lock count is decremented to 0.  XMS 0eH obtains
          the current lock count.

See Also: XMS Functions
          Extended Memory Specification (XMS)
          DOS Functions
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