Int 10/AH=12h/BH=55h

VIDEO - ALTERNATE FUNC SELECT (ATI,Tatung,Taxan) - ENHANCED FEATURES

AH = 12h
BH = 55h
BL = subfunction
00h disable enhanced features
01h enable enhanced features
02h get status
Return:
AL = status flags (see #00027)
03h disable register trapping (CGA emulation)
04h enable register trapping
05h program video mode
ES:BP -> video mode table (see #00028)
06h get mode table
AL = video mode
Return:
ES:BP -> table suitable for mode AL
(and subfunc BL=05h) (see #00028)
BP = FFFFh on error
SI = 0000h (ATI Mach32)

Note: The ATI Mouse driver (MOUSE.COM/MOUSE.SYS) uses subfunction 06h to get the mode table for mode 03h, and then looks for a signature string beginning within 32 bytes of the offset specified by the word at ES:000Ch

See Also: AH=FFh"Oak"

Index:
Installation check;ATI video adapters

Bitfields for status flags:

Bit(s)  Description     (Table 00027)
3      set if enhanced features enabled
7-5    monitor type.
000 PS/2 mono.
001 PS/2 color.
010 multi-sync.
011 Taxan 650 25kHz.
100 RGB.
101 mono.
110 EGA.
111 Compaq internal

Format of ATI VGA Wonder video mode table:

Offset  Size    Description     (Table 00028)
00h    BYTE    number of columns
01h    BYTE    maximum row (number of rows - 1)
02h    BYTE    scan lines per row
03h    WORD    video buffer size in bytes
05h  4 BYTEs   values for Sequencer registers 1-4
09h    BYTE    value for Miscellaneous Output register
0Ah 25 BYTEs   values for CRTC registers 00h-18h
00h horizontal total size (chars)
01h horizontal displayed (chars)
02h horizontal sync position (chars)
03h horizontal sync width (chars)
04h vertical total size (char rows)
05h vertical total adjust (scan lines)
06h vertical displayed (char rows)
07h vertical sync position (char rows)
08h interlace mode
09h max scan line in row
0Ah cursor start scan line
0Bh cursor end scan line
0Ch screen memory start (high)
0Dh screen memory start (low)
0Eh cursor address (high)
0Fh cursor address (low)
10h light pen (high)
11h light pen (low)
23h 20 BYTEs   default palette (values for Attribute Controller regs 00h-13h)
37h  9 BYTEs   values for Graphics Controller registers 00h-08h

Category: Video - Int 10h - V

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