INT 21 - DOS 3.2+ - IOCTL - GENERIC CHARACTER DEVICE REQUEST                    
	AX = 440Ch
	BX = device handle
	CH = category code (see #01545)
	CL = function number (see #01546)
	DS:DX -> parameter block (see #01547,#01548,#01549,#01550,#01551,#01552)
	SI = parameter to pass to driver (European MS-DOS 4.0, OS/2 comp box)
	DI = parameter to pass to driver (European MS-DOS 4.0, OS/2 comp box)
Return: CF set on error
	    AX = error code (see #01680 at AH=59h/BX=0000h)
	CF clear if successful
	    DS:DX -> iteration count if CL=65h
	    SI = returned value (European MS-DOS 4.0, OS/2 comp box)
	    DI = returned value (European MS-DOS 4.0, OS/2 comp box)
Note:	DR DOS 3.41 and 5.0 return error code 16h on CL=45h,65h if the device
	  does not support a retry counter
SeeAlso: AX=440Dh"DOS 3.2+",INT 2F/AX=0802h,INT 2F/AX=122Bh,INT 2F/AX=14FFh
SeeAlso: INT 2F/AX=1A01h


(Table 01545)
Values for IOCTL category code:
 00h	unknown (DOS 3.3+)
 01h	COMn: (DOS 3.3+)
 02h	reserved for terminal control
 03h	CON (DOS 3.3+)
 04h	reserved for keyboard control
 05h	LPTn:
 07h	mouse control (European MS-DOS 4.0)
 08h	reserved for disk control -- same as for block devices
	(see INT 21/AX=440Dh)
 9Eh	Media Access Control driver (STARLITE)
 00h-7Fh reserved for Microsoft
 80h-FFh reserved for OEM(Original Equipment Manufacturer) a company which purchases components that are resold as part of its own products under the company's own brand name, e.g. a Gateway 2000-branded monitor may actually be a Mag or NEC monitor./user-defined
SeeAlso: #01558


(Table 01546)
Values for generic character IOCTL function:
 00h	MAC driver Bind (STARLITE) (see #01547)
 40h	DOS 3??? only: was reserved for set screen mode (see #04116)
 45h	set iteration (retry) count (see #01548)
 4Ah	select code page (see #01549)
 4Ch	start code-page preparation (see #01550)
 4Dh	end code-page preparation (see #01551)
 5Fh	set display information (DOS 4.0+) (see #01552)
 60h	DOS 3??? only: was reserved for get screen mode (see #04116)
 65h	get iteration (retry) count
 6Ah	query selected code page (see #01549)
 6Bh	query codepage prepare list (DOS 4.0+) (see #01553)
 7Fh	get display information (DOS 4.0+) (see #01552)
Note:	bit assignments for function code:
	    bit 7: set to ignore if unsupported, clear to return error
	    bit 6: set if passed to driver, clear if intercepted by DOS
	    bit 5: set if queries data from device, clear if sends command
		(by convention, if a function both queries and sends data,
		  bit 5 should be clear)
	    bits 4-0: subfunction


Format of parameter block for function 00h:
Offset	Size	Description	(Table 01547)
 00h  8 BYTEs	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. signature "STARMAC"
 08h	WORD	version
 0Ah	WORD	flags
		bit 0: media requires connect or listen request before use
		bit 1: network is a LAN (broadcast/multicast supported)
		bit 2: point-to-point network
 0Ch	WORD	handle for use with MAC driver's private interface (filled in
		by MAC driver)
 0Eh	WORD	context
 10h	WORD	approximate speed in KB/sec (filled in by MAC driver)
 12h	WORD	approximate cost in cents per hour (filled in by MAC driver)
 14h	WORD	maximum packet size in bytes (filled in by MAC driver)
 16h	WORD	addressing format (filled in by MAC driver)
		0000h general addressing
		0001h Ethernet addressing
		0002h Token Ring addressing
		0003h Token Bus addressing
 18h	DWORDDoubleword; four bytes.	 Commonly used to hold a 32-bit segment:offset or selector:offset address.	Send entry point (filled in by MAC driver)
 1Ch	DWORDDoubleword; four bytes.	 Commonly used to hold a 32-bit segment:offset or selector:offset address.	RegisterEventHandler entry point (filled in by MAC driver)
 20h	DWORDDoubleword; four bytes.	 Commonly used to hold a 32-bit segment:offset or selector:offset address.	SetPacketFilter entry point (filled in by MAC driver)
 24h	DWORDDoubleword; four bytes.	 Commonly used to hold a 32-bit segment:offset or selector:offset address.	UnBind entry point (filled in by MAC driver)


Format of parameter block for DOS 3??? screen mode functions 40h and 60h:
Offset	Size	Description	(Table 04116)
 00h	WORD	length of folowing data (0009h)
 02h	BYTE	mode type
 03h	WORD	number of colors
 05h	WORD	width
 07h	WORD	height
Note:	these functions appear never to have been released to the public
SeeAlso: #01546


Format of parameter block for function 45h:
Offset	Size	Description	(Table 01548)
 00h	WORD	number of times output is attempted before driver assumes
		  device is busy


Format of parameter block for functions 4Ah and 6Ah:
Offset	Size	Description	(Table 01549)
 00h	WORD	length of data
 02h	WORD	code page ID (see #01757 at INT 21/AX=6602h)
 04h 2N BYTEs	DCBS (double byte character set) lead byte range
		  start/end for each of N ranges (DOS 4.0)
	WORD	0000h  end of data (DOS 4.0)


Format of parameter block for function 4Ch:
Offset	Size	Description	(Table 01550)
 00h	WORD	flags
		DISPLAY.SYS = 0000h
		PRINTER.SYS bit 0 clear to prepare downloaded font, set to
			prepare cartridge selection
 02h	WORD	length of remainder of parameter block
 04h	WORD	number of code pages following
 06h  N WORDs	code page 1,...,N


Format of parameter block for function 4Dh:
Offset	Size	Description	(Table 01551)
 00h	WORD	length of data
 02h	WORD	code page ID (see #01757 at INT 21/AX=6602h)


Format of parameter block for functions 5Fh and 7Fh:
Offset	Size	Description	(Table 01552)
 00h	BYTE	level (0 for DOS 4.x-6.0)
 01h	BYTE	reserved (0)
 02h	WORD	length of following data (14)
 04h	WORD	control flags
		bit 0 set for blink, clear for intensity
		bits 1-15 reserved
 06h	BYTE	mode type (1=text, 2=graphics)
 07h	BYTE	reserved (0)
 08h	WORD	colors
		0000h = monochrome
		else N bits per pixel
 0Ah	WORD	pixel columns
 0Ch	WORD	pixel rows
 0Eh	WORD	character columns
 10h	WORD	character rows


Format of parameter block for function 6Bh:
Offset	Size	Description	(Table 01553)
 00h	WORD	length of following data
 02h	WORD	number of hardware code pages
 04h  N WORDs	hardware code pages 1,...,N
	WORD	number of prepared code pages
      N WORDs	prepared code pages 1,...,N