DOS Fn 5802H: Query Upper-Memory Link State

                                                         Compatibility: 5.0+ 
 Expects: AX    5802H
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 Returns: AL    01H = upper▲ memory is currently linked
                00H = not linked (all allocations go to conventional▲ mem)
          CF    always clear (CF=NC=0)
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    Info: Obtains a code indicating whether programs can allocate memory
          from UMBs▲.

          See Accessing Upper Memory for info on allocating from UMBs.

See Also: Fn 48H (allocate memory)
          Memory Control Functions
          DOS Functions
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