Int 21/AX=440Ch

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

See Also: 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/user-defined

See Also: #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   ASCIZ 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    DWORD   Send entry point (filled in by MAC driver)
1Ch    DWORD   RegisterEventHandler entry point (filled in by MAC driver)
20h    DWORD   SetPacketFilter entry point (filled in by MAC driver)
24h    DWORD   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

See Also: #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

Category: DOS Kernel - Int 21h - D

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