INT 2F - DOS Protected-Mode InterfaceAn API which provides basic services for protected-mode programs to allocate memory, invoke real-mode software, etc.  See also Virtual Control Program Interface. - INSTALLATION CHECK
	AX = 1687h
Return: AX = 0000h if installed
	    BX = flags
		bit 0: 32-bit programs supported
	    CL = processor type (02h=80286, 03h=80386, 04h=80486)
	    DH = DPMIsee DOS Protected-Mode Interface major version
	    DL = two-digit DPMIsee DOS Protected-Mode Interface minor version (binary)
	    SI = number of paragraphs of DOS extender private data
	    ES:DI -> DPMIsee DOS Protected-Mode Interface mode-switch entry point (see #02718)
	AX nonzero if not installed
SeeAlso: AX=1686h,AX=43E0h,AX=DE01h/BX=4450h,AX=FB42h/BX=0001h
SeeAlso: INT 31/AX=0400h,INT 31/AX=5702h,INT D4/AH=10h


(Table 02718)
Call DPMIsee DOS Protected-Mode Interface mode switch entry point with:
	AX = flags
	    bit 0: set if 32-bit program
	ES = real mode segment of buffer for DPMIsee DOS Protected-Mode Interface private data (ignored if
		SI was zero)
Return: CF set on error
	    program still in real mode
	    AX = error code (DPMIsee DOS Protected-Mode Interface 1.0+)
	       8011h unable to allocate all necessary descriptors
	       8021h 32-bit program specified, but 16-bit DPMIsee DOS Protected-Mode Interface host
	CF clear if successful
	    CS = 16-bit selector corresponding to real-mode CS
	    SS = selector corresponding to real-mode SS (64K limit)
	    DS = selector corresponding to real-mode DS (64K limit)
	    ES = selector to program's PSPsee Program Segment Prefix (100h byte limit)
	    FS = GS = 0
	    high word of ESP = 0 if 32-bit program
	    program now in protected mode
Note:	this entry point is only called for the initial switch to protected
	  mode