Int 81 Fn 2011  - Gravis Ultrasound - Mega_em V3.0+ - Nmi Redirect         [s]

   AX = 2011h
   ???

Return: ???

Note:  MegaEm calls this function from its NMI (INT 02) handler, and then
     immediately returns; this permits it to operate while hooking only
     one interrupt through the memory manager in protected mode

See Also: AX=2010h,AX=2012h