Int 10 Fn 12  - Video - Alternate Func Select (ati,tatung,taxan) - Enhanc  [V]

   AH = 12h
   BH = 55h
   BL = subfunction
       00h disable enhanced features
       01h enable enhanced features
       02h get status

       Return: AL = status flags (see #0026)
       03h disable register trapping (CGA emulation)
       04h enable register trapping
       05h program video mode
       ES:BP -> video mode table (see #0027)
       06h get mode table
       AL = video mode

       Return: ES:BP -> table suitable for mode AL
                 (and subfunc BL=05h) (see #0027)
           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 0026)
 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 0027)
 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