INT EF - GEM - VDI INTERFACE                                                    
	CX = 0473h
	DS:DX -> GEM VDI parameter block (see #04066)
Note:	if installed, one of the following ASCII signatures will appear two
	  bytes after the INT EF entry point:
	    "GEMVDI"	GEM VDI (but not AES) is present
	    "GEMAES"	GEM/ViewMAX VDI and AES are both present
	    "ViewMAX"	ViewMAX VDI (only) is present
	  each of the above is followed by an ASCIZA NUL-terminated ASCII string.	The ASCIZ string "ABC" consists of the four bytes 41h, 42h, 43h, and 00h.  Unless otherwise specified, maximum lengths given in the interrupt list do not include the terminating NUL. number indicating the
	  version ("10" for GEM/1 AES and VDI; "20" for GEM/2,GEM/3,ViewMAX
	  AES and GEM/2 VDI; "23" for GEM/3 VDI; and "1" for ViewMAX VDIs)
SeeAlso: INT EF/CX=00C8h,INT EF/CX=00C9h
Index:	installation check;GEM


Format of VDI parameter block:
Offset	Size	Description	(Table 04066)
 00h	DWORDDoubleword; four bytes.	 Commonly used to hold a 32-bit segment:offset or selector:offset address.	-> control array (see #04067)
 08h	DWORDDoubleword; four bytes.	 Commonly used to hold a 32-bit segment:offset or selector:offset address.	-> integer parameters
 0Ch	DWORDDoubleword; four bytes.	 Commonly used to hold a 32-bit segment:offset or selector:offset address.	-> (x,y) pair parameters
 10h	DWORDDoubleword; four bytes.	 Commonly used to hold a 32-bit segment:offset or selector:offset address.	-> integer results
 14h	DWORDDoubleword; four bytes.	 Commonly used to hold a 32-bit segment:offset or selector:offset address.	-> (x,y) pair results
SeeAlso: #04064


Format of VDI control array:
Offset	Size	Description	(Table 04067)
 00h	WORD	(call) function number (0001h-0084h)
 02h	WORD	(call) number of words of pair parameters
 04h	WORD	(ret) number of words of pair results
 06h	WORD	(call) number of words of integer parameters
 08h	WORD	(ret) number of words of integer results
 0Ah	WORD	subfunction number
 0Ch	WORD	graphics handle
 0Eh	DWORDDoubleword; four bytes.	 Commonly used to hold a 32-bit segment:offset or selector:offset address.	(call) -> pointer parameter
 12h	DWORDDoubleword; four bytes.	 Commonly used to hold a 32-bit segment:offset or selector:offset address.	(ret) -> pointer result
SeeAlso: #04066