----------1000-------------------------------
INT 10 - VIDEO - SET VIDEO MODE
        AH = 00h
        AL = mode (see below)
Return: AL = video mode flag (Phoenix BIOS)
             20h mode > 7
             30h modes <= 7 except mode 6
             3Fh mode 6
        AL = CRT controller mode byte (Phoenix 386 BIOS v1.10)
Note: IBM standard modes do not clear the screen if the high bit of AL is set
      (EGA or higher only)

Values for video mode:
     text/ text   pixel pixel    colors  display  scrn system
     grph  resol  box   resoltn          pages   addr
 00h = T   40x25  8x14           16gray     8    B800 EGA
     = T   40x25  8x16             16       8    B800 MCGA
     = T   40x25  9x16             16       8    B800 VGA
 01h = T   40x25  8x14             16       8    B800 EGA
     = T   40x25  8x16             16       8    B800 MCGA
     = T   40x25  9x16             16       8    B800 VGA
 02h = T   80x25  8x14           16gray     4    B800 EGA
     = T   80x25  8x16             16       4    B800 MCGA
     = T   80x25  9x16             16       4    B800 VGA
 03h = T   80x25  8x14             16       4    B800 EGA
     = T   80x25  8x16             16       4    B800 MCGA
     = T   80x25  9x16             16       4    B800 VGA
 04h = G   40x25  8x8     320x200           4    B800 CGA,PCjr,EGA,MCGA,VGA
 05h = G   40x25  8x8     320x200 4gray          B800 CGA,PCjr,EGA
     = G   40x25  8x8     320x200   4            B800 MCGA,VGA
 06h = G   80x25  8x8     640x200   2            B800 CGA,PCjr,EGA,MCGA,VGA
 07h = T   80x25  9x14            mono     var   B000 MDA,Hercules,EGA
     = T   80x25  9x16            mono           B000 VGA
 0Bh =                 reserved (used internally by EGA BIOS)
 0Ch =                 reserved (used internally by EGA BIOS)
 0Dh = G   40x25  8x8     320x200  16       8    A000 EGA,VGA
 0Eh = G   80x25  8x8     640x200  16       4    A000 EGA,VGA
 0Fh = G   80x25  8x14    640x350 mono      2    A000 EGA,VGA
 10h = G   80x25  8x14    640x350   4       2    A000 64k EGA
     = G                  640x350  16            A000 256k EGA,VGA
 11h = G   80x30  8x16    640x480 mono           A000 VGA,MCGA,ATI EGA,ATI VIP
 12h = G   80x30  8x16    640x480 16/256k        A000 VGA,ATI VIP
     = G   80x30  8x16    640x480 16/64          A000 ATI EGA Wonder
 13h = G   40x25  8x8     320x200 256/256k       A000 VGA,MCGA,ATI VIP
----------1001-------------------------------
INT 10 - VIDEO - SET TEXT-MODE CURSOR SHAPE
        AH = 01h
        CH = bit 7    should be zero
             bits 6,5 cursor blink
                (00=normal, 01=invisible, 10=erratic, 11=slow)
                (00=normal, other=invisible on EGA/VGA)
             bits 4-0 top scan line containing cursor
        CL = bottom scan line containing cursor (bits 0-4)
Notes: buggy on EGA systems--BIOS remaps cursor shape in 43 line modes, but
       returns unmapped cursor shape
       applications which wish to change the cursor by programming the
       hardware directly on EGA or above should call INT 10/AX=1130h or
       read 0040h:0085h first to determine the current font height
BUG:   AMI 386 BIOS and AST Premier 386 BIOS will lock up the system if AL
       is not equal to the current video mode
----------1002-------------------------------
INT 10 - VIDEO - SET CURSOR POSITION
        AH = 02h
        BH = page number
              0-3 in modes 2&3
              0-7 in modes 0&1
                0 in graphics modes
        DH = row (00h is top)
        DL = column (00h is left)
----------1003-------------------------------
INT 10 - VIDEO - GET CURSOR POSITION AND SIZE
        AH = 03h
        BH = page number
              0-3 in modes 2&3
              0-7 in modes 0&1
                0 in graphics modes
Return: AX = 0000h (Phoenix BIOS)
        CH = start scan line
        CL = end scan line
        DH = row (00h is top)
        DL = column (00h is left)
Notes: a separate cursor is maintained for each of up to 8 display pages
       many ROM BIOSes incorrectly return the default size for a color display
       (start 06h, end 07h) when a monochrome display is attached
----------1004-------------------------------
INT 10 - VIDEO - READ LIGHT PEN POSITION (EGA Only)
        AH = 04h
Return: AH = light pen trigger flag
             00h not down/triggered
             01h down/triggered
        DH,DL = row,column of character light pen is on
        CH = pixel row (graphics modes 04h-06h)
        CX = pixel row (graphics modes with >200 rows)
        BX = pixel column
Notes: on a CGA, returned column numbers are always multiples of 2 (320-
       column modes) or 4 (640-column modes)
       returned row numbers are only accurate to two lines
----------1005-------------------------------
INT 10 - VIDEO -  SELECT ACTIVE DISPLAY PAGE
        AH = 05h
        AL = new page number (00h to number of pages - 1) (see AH=00h)
----------1006-------------------------------
INT 10 - VIDEO - SCROLL UP WINDOW
        AH = 06h
        AL = number of lines by which to scroll up (00h = clear entire window)
        BH = attribute used to write blank lines at bottom of window
     CH,CL = row,column of window's upper left corner
     DH,DL = row,column of window's lower right corner
Note:  affects only the currently active page (see AH=05h)
Warning: some implementations have a bug which destroys BP
----------1007-------------------------------
INT 10 - VIDEO - SCROLL DOWN WINDOW
        AH = 07h
        AL = number of lines by which to scroll down (00h=clear entire window)
        BH = attribute used to write blank lines at top of window
     CH,CL = row,column of window's upper left corner
     DH,DL = row,column of window's lower right corner
Note:  affects only the currently active page (see AH=05h)
Warning: some implementations have a bug which destroys BP
----------1008-------------------------------
INT 10 - VIDEO - READ CHARACTER AND ATTRIBUTE AT CURSOR POSITION
        AH = 08h
        BH = page number (00h to number of pages - 1) (see AH=00h)
Return: AH = attribute
             bit    7: blink
             bits 6-4: background color
                       000 black
                       001 blue
                       010 green
                       011 cyan
                       100 red
                       101 magenta
                       110 brown
                       111 white
             bits 3-0: foreground color
                       0000 black       1000 dark grey
                       0001 blue        1001 light blue
                       0010 green       1010 light green
                       0011 cyan        1011 light cyan
                       0100 red         1100 light red
                       0101 magenta     1101 light magenta
                       0110 brown       1110 yellow
                       0111 light grey  1111 white
        AL = character
Notes: for monochrome displays, a foreground of 1 with background 0 is
       underlined the blink bit may be reprogrammed to enable intense
       background colors using AX=1003h or by programming the CRT controller
----------1009-------------------------------
INT 10 - VIDEO - WRITE CHARACTER AND ATTRIBUTE AT CURSOR POSITION
        AH = 09h
        AL = character to display
        BH = page number (00h to number of pages - 1) (see AH=00h)
        BL = attribute (text mode) or color (graphics mode)
             if bit 7 set in graphics mode, character is xor'ed onto screen
        CX = number of times to write character
Notes: all characters are displayed, including CR, LF, and BS
       replication count in CX may produce an unpredictable result in graphics
       modes if it is greater than the number of positions remaining in the
       current row
----------100A-------------------------------
INT 10 - VIDEO - WRITE CHARACTER ONLY AT CURSOR POSITION
        AH = 0Ah
        AL = character to display
        BH = page number (00h to number of pages - 1) (see AH=00h)
        BL = attribute (PCjr only) or color (graphics mode)
             if bit 7 set in graphics mode, character is xor'ed onto screen
        CX = number of times to write character
Notes: all characters are displayed, including CR, LF, and BS
       replication count in CX may produce an unpredictable result in graphics
       modes if it is greater than the number of positions remaining in the
       current row
----------100B--BH00-------------------------
INT 10 - VIDEO - SET BACKGROUND/BORDER COLOR
        AH = 0Bh
        BH = 00h
        BL = background/border color (border only in text modes)
----------100B--BH01-------------------------
INT 10 - VIDEO - SET PALETTE
        AH = 0BH
        BH = 01h
        BL = palette ID
             00h background, green, red, and brown/yellow
             01h background, cyan, magenta, and white
----------100C-------------------------------
INT 10 - VIDEO - WRITE GRAPHICS PIXEL
        AH = 0Ch
        BH = page number
        AL = pixel color (if bit 7 set, value is xor'ed onto screen)
        CX = column
        DX = row
Notes: valid only in graphics modes
       BH is ignored if the current video mode supports only one page
----------100D-------------------------------
INT 10 - VIDEO - READ GRAPHICS PIXEL
        AH = 0Dh
        BH = page number
        CX = column
        DX = row
Return: AL = pixel color
Notes: valid only in graphics modes
       BH is ignored if the current video mode supports only one page
----------100E-------------------------------
INT 10 - VIDEO - TELETYPE OUTPUT
        AH = 0Eh
        AL = character to write
        BH = page number
        BL = foreground color (graphics modes only)
Notes: characters 07h (BEL), 08h (BS), 0Ah (LF), and 0Dh (CR) are interpreted
       and do the expected things
       IBM PC ROMs dated 4/24/81 and 10/19/81 require that BH be the same as
       the current active page
----------100F-------------------------------
INT 10 - VIDEO - GET CURRENT VIDEO MODE
        AH = 0Fh
Return: AH = number of character columns
        AL = display mode (see AH=00h)
        BH = active page (see AH=05h)
Notes: if mode was set with bit 7 set ("no blanking"), the returned mode will
       also have bit 7 set
       EGA and VGA return either AL=03h (color) or AL=07h (monochrome) in all
       extended-row text modes
----------101000----------------------------
INT 10 - VIDEO - SET SINGLE PALETTE REGISTER (PCjr,EGA,MCGA,VGA)
        AX = 1000h
        BL = palette register number (00h-0Fh)
           = attribute register number (undocumented)
             10h attribute mode control register (should let BIOS control
                 this)
             11h overscan color register (see also AX=1001h)
             12h color plane enable register (bits 3-0 enable corresponding
                 text attribute bit)
             13h horizontal PEL panning register
             14h color select register
        BH = color or attribute register value
Notes: on MCGA, only BX = 0712h is supported
----------101001-----------------------------
INT 10 - VIDEO - SET BORDER (OVERSCAN) COLOR (PCjr,EGA,VGA)
        AX = 1001h
        BH = border color (00h-3Fh)
BUG: the original IBM VGA BIOS incorrectly updates the parameter save area
     and places the border color at offset 11h of the palette table
     rather than offset 10h
----------101002-----------------------------
INT 10 - VIDEO - SET ALL PALETTE REGISTERS (PCjr,EGA,VGA)
        AX = 1002h
        ES:DX -> palette register list

Format of palette register list:
Offset  Size     Description
 00h   16 BYTEs  colors for palette registers 00h through 0Fh
 10h      BYTE   border color
----------101003-----------------------------
INT 10 - VIDEO - TOGGLE INTENSITY/BLINKING BIT (Jr, PS, TANDY 1000, EGA, VGA)
        AX = 1003h
        BL = new state
             00h background intensity enabled
             01h blink enabled
Note: although there is no function to get the current status, bit 5 of
      0040h:0065h indicates the state
----------101007-----------------------------
INT 10 - VIDEO - GET INDIVIDUAL PALETTE REGISTER  (VGA)
        AX = 1007h
        BL = palette or attribute (undoc) register number (see AX=1000h)
Return: BH = palette or attribute register value
----------101008-----------------------------
INT 10 - VIDEO - READ OVERSCAN (BORDER COLOR) REGISTER  (VGA)
        AX = 1008h
Return: BH = border color (00h-3Fh)
----------101009-----------------------------
INT 10 - VIDEO - READ ALL PALETTE REGISTERS AND OVERSCAN REGISTER (VGA)
        AX = 1009h
        ES:DX -> 17-byte buffer (see AX=1002h)
----------101010-----------------------------
INT 10 - VIDEO - SET INDIVIDUAL DAC REGISTER (VGA/MCGA)
        AX = 1010h
        BX = register number
        CH = new value for green (0-63)
        CL = new value for blue (0-63)
        DH = new value for red (0-63)
----------101012-----------------------------
INT 10 - VIDEO - SET BLOCK OF DAC REGISTERS (VGA/MCGA)
        AX = 1012h
        BX = starting color register
        CX = number of registers to set
        ES:DX -> table of 3*CX bytes where each 3 byte group represents one
                 byte each of red, green and blue (0-63)
----------101013-----------------------------
INT 10 - VIDEO - SELECT VIDEO DAC COLOR PAGE (VGA)
        AX = 1013h
        BL = subfunction
             00h select paging mode
                 BH = 00h select 4 blocks of 64
                 BH = 01h select 16 blocks of 16
             01h select page
                 BH = page number (00h to 03h) or (00h to 0Fh)
Note: not valid in mode 13h
----------101015-----------------------------
INT 10 - VIDEO - READ INDIVIDUAL DAC REGISTER (VGA/MCGA)
        AX = 1015h
        BL = palette register number
Return: DH = red value
        CH = green value
        CL = blue value
----------101017-----------------------------
INT 10 - VIDEO - READ BLOCK OF DAC REGISTERS (VGA/MCGA)
        AX = 1017h
        BX = starting palette register
        CX = number of palette registers to read
        ES:DX -> buffer (3 * CX bytes in size) (see also AX=1012h)
Return: buffer filled with CX red, green and blue triples
----------101018-----------------------------
INT 10 - VIDEO - undocumented - SET PEL MASK (VGA/MCGA)
        AX = 1018h
        BL = new PEL value
----------101019-----------------------------
INT 10 - VIDEO - undocumented - READ PEL MASK (VGA/MCGA)
        AX = 1019h
Return: BL = value read
----------10101A-----------------------------
INT 10 - VIDEO - GET VIDEO DAC COLOR-PAGE STATE (VGA)
        AX = 101Ah
Return: BL = paging mode
             00h four pages of 64
             01h sixteen pages of 16
        BH = current page
----------10101B-----------------------------
INT 10 - VIDEO - PERFORM GRAY-SCALE SUMMING (VGA/MCGA)
        AX = 101Bh
        BX = starting palette register
        CX = number of registers to convert
----------1011-------------------------------
INT 10 - VIDEO - TEXT-MODE CHARACTER GENERATOR FUNCTIONS (PS, EGA, VGA)
        AH = 11h
The following functions will cause a mode set, completely resetting
the video environment, but without clearing the video buffer
        AL = 00h, 10h: load user-specified patterns
             ES:BP -> user table
             CX  = count of patterns to store
             DX  = character offset into map 2 block
             BL  = block to load in map 2
             BH  = number of bytes per character pattern
        AL = 01h, 11h: load ROM monochrome patterns (8 by 14)
             BL  = block to load
        AL = 02h, 12h: load ROM 8 by 8 double-dot patterns
             BL  = block to load
        AL = 03h: set block specifier
             BL  = block specifier
               (EGA/MCGA) bits 0,1 = block selected by chars with attribute
                                     bit 3=0
                          bits 2,3 = block selected by chars with attribute
                                     bit 3=1
                    (VGA) bits 0,1,4 = block selected by attribute bit 3 = 0
                          bits 2,3,5 = block selected by attribute bit 3 = 1
        AL = 04h, 14h: load ROM 8x16 character set (VGA)
             BL  = block to load
The routines called with AL=1xh are designed to be called only immediately
after a mode set and are similar to the routines called with AL=0xh,
except that:
      Page 0 must be active.
      Bytes/character is recalculated.
      Max character rows is recalculated.
      CRT buffer length is recalculated.
      CRTC registers are reprogrammed as follows:
           R09 = bytes/char-1 ; max scan line (mode 7 only)
           R0A = bytes/char-2 ; cursor start
           R0B = 0            ; cursor end
           R12 = ((rows+1)*(bytes/char))-1 ; vertical display end
           R14 = bytes/char; underline loc
                  (*** BUG: should be 1 less ***)
----------1011-------------------------------
INT 10 - VIDEO - GRAPHICS-MODE CHARACTER GENERATOR FUNCTIONS (PS, EGA, VGA)
        AH = 11h
        AL = 20h: set user 8 by 8 graphics characters (INT 1F)
                  ES:BP -> user table
        AL = 21h: set user graphics characters
                  ES:BP -> user table
                  CX  = bytes per character
                  BL  = row specifier
                        00h user set
                            DL = number of rows
                        01h 14 rows
                        02h 25 rows
                        03h 43 rows
        AL = 22h: ROM 8 by 14 set
                  BL = row specifier (see above)
        AL = 23h: ROM 8 by 8 double dot
                  BL = row specifier (see above)
        AL = 24h: load 8x16 graphics characters (VGA/MCGA)
                  BL = row specifier (see above)
        AL = 29h: load 8x16 graphics characters (Compaq Systempro)
                  BL = row specifier (see above)
Notes: these functions are meant to be called only after a mode set
----------101130-----------------------------
INT 10 - VIDEO - GET FONT INFORMATION (EGA, MCGA, VGA)
        AX = 1130h
        BH = pointer specifier
             00h INT 1Fh pointer
             01h INT 43h pointer
             02h ROM 8x14 character font pointer
             03h ROM 8x8 double dot font pointer
             04h ROM 8x8 double dot font (high 128 characters)
             05h ROM alpha alternate (9 by 14) pointer (EGA,VGA)
             06h ROM 8x16 font (MCGA, VGA)
             07h ROM alternate 9x16 font (VGA only)
Return: ES:BP = specified pointer
        CX    = bytes/character
        DL    = character rows on screen - 1
----------1012--BL10-------------------------
INT 10 - VIDEO - ALTERNATE FUNCTION SELECT (PS, EGA, VGA, MCGA) - GET EGA INFO
        AH = 12h
        BL = 10h
Return: BH = 00h color mode in effect (I/O port 3Dxh)
             01h mono mode in effect (I/O port 3Bxh)
        BL = 00h  64k bytes memory installed
             01h 128k bytes memory installed
             02h 192k bytes memory installed
             03h 256k bytes memory installed
        CH = feature bits
        CL = switch settings
----------1012--BL20-------------------------
INT 10 - VIDEO - ALTERNATE FUNCTION SELECT (PS,EGA,VGA,MCGA) - ALTERNATE PRTSC
        AH = 12h
        BL = 20h  select alternate print screen routine
Notes: installs a PrtSc routine from the video card's BIOS to replace the
       default PrtSc handler from the ROM BIOS, which usually does not
       understand screen heights other than 25 lines
       some adapters disable print-screen instead of enhancing it
----------1012--BL30-------------------------
INT 10 - VIDEO - ALTERNATE FUNCTION SELECT (VGA) - SELECT VERTICAL RESOLUTION
        AH = 12h
        BL = 30h
        AL = vertical resolution
             00h 200 scan lines
             01h 350 scan lines
             02h 400 scan lines
Return: AL = 12h if function supported
----------1012--BL31-------------------------
INT 10 - VIDEO - ALTERNATE FUNCTION SELECT (VGA, MCGA) - PALETTE LOADING
        AH = 12h
        BL = 31h
        AL = 00h enable default palette loading
             01h disable default palette loading
Return: AL = 12h if function supported
----------1012--BL32-------------------------
INT 10 - VIDEO - ALTERNATE FUNCTION SELECT (VGA, MCGA) - VIDEO ADDRESSING
        AH = 12h
        BL = 32h
        AL = 00h enable video addressing
             01h disable video addressing
Return: AL = 12h if function supported
Desc:   Specifies whether the CPU should have access to video memory and the
        display adapter's I/O registers
----------1012--BL33-------------------------
INT 10 - VIDEO - ALTERNATE FUNCTION SELECT (VGA, MCGA) - GRAY-SCALE SUMMING
        AH = 12h
        BL = 33h
        AL = 00h enable grey scale summing
             01h disable grey scale summing
Return: AL = 12h if function supported
----------1012--BL34-------------------------
INT 10 - VIDEO - ALTERNATE FUNCTION SELECT (VGA) - CURSOR EMULATION
        AH = 12h
        BL = 34h
        AL = 00h enable alphanumeric cursor emulation
             01h disable alphanumeric cursor emulation
Return: AL = 12h if function supported
----------1012--BL35-------------------------
INT 10 - VIDEO - ALTERNATE FUNCTION SELECT (PS) - DISPLAY-SWITCH INTERFACE
        AH = 12h
        BL = 35h
        AL = 00h initial adapter video off
             01h initial planar video on
             02h switch active video off
             03h switch inactive video on
             80h *UNDOCUMENTED* set system board video active flag
        ES:DX -> buffer (128 byte save area if AL = 0, 2 or 3)
Return: AL = 12h if function supported
----------1012--BL36-------------------------
INT 10 - VIDEO - ALTERNATE FUNCTION SELECT (PS, VGA) - VIDEO REFRESH CONTROL
        AH = 12h
        BL = 36h
        AL = 00h enable refresh
             01h disable refresh
Return: AL = 12h if function supported
----------1013-------------------------------
INT 10 - VIDEO - WRITE STRING (AT and later,EGA)
        AH = 13h
        AL = write mode
             bit 0: update cursor after writing
                 1: string contains alternating characters and attributes
        BH = page number
        BL = attribute if string contains only characters
        CX = number of characters in string
        DH,DL = row,column at which to start writing
        ES:BP -> string to write
Notes: recognises CR, LF, BS, and bell
       also available PC or XT with EGA or higher
       HP 95LX only supports write mode 00h
BUG: on the IBM VGA Adapter, any scrolling which may occur is performed on
     the active page rather than the requested page
----------101A-------------------------------
INT 10 - VIDEO - DISPLAY COMBINATION (PS,VGA/MCGA)
        AH = 1Ah
        AL = 00h read display combination code
Return:          BL = active display code (see below)
                 BH = alternate display code
             01h set display combination code
                 BL = active display code (see below)
                 BH = alternate display code
Return: AL = 1Ah if function was supported

Values for display combination code:
  00h no display
  01h monochrome adapter w/ monochrome display
  02h CGA w/ color display
  03h reserved
  04h EGA w/ color display
  05h EGA w/ monochrome display
  06h PGA w/ color display
  07h VGA w/ monochrome analog display
  08h VGA w/ color analog display
  09h reserved
  0Ah MCGA w/ digital color display
  0Bh MCGA w/ monochrome analog display
  0Ch MCGA w/ color analog display
  FFh unknown display type
----------101B-------------------------------
INT 10 - VIDEO - FUNCTIONALITY/STATE INFORMATION (PS,VGA/MCGA)
        AH = 1Bh
        BX = implementation type
             0000h return functionality/state information
        ES:DI -> 64 byte buffer for state information (see below)
Return: AL = 1Bh if function supported
        ES:DI buffer filled with state information

Format of state information:
Offset Size   Description
 00h   DWORD  address of static functionality table (see below)
 04h   BYTE   video mode in effect
 05h   WORD   number of columns
 07h   WORD   length of regen buffer in bytes
 09h   WORD   starting address of regen buffer
 0Bh   WORD   cursor position for page 0
 0Dh   WORD   cursor position for page 1
 0Fh   WORD   cursor position for page 2
 11h   WORD   cursor position for page 3
 13h   WORD   cursor position for page 4
 15h   WORD   cursor position for page 5
 17h   WORD   cursor position for page 6
 19h   WORD   cursor position for page 7
 1Bh   WORD   cursor type
 1Dh   BYTE   active display page
 1Eh   WORD   CRTC port address
 20h   BYTE   current setting of register (3?8)
 21h   BYTE   current setting of register (3?9)
 22h   BYTE   number of rows
 23h   WORD   bytes/character
 25h   BYTE   display combination code of active display
 26h   BYTE   DCC of alternate display
 27h   WORD   number of colors supported in current mode
 29h   BYTE   number of pages supported in current mode
 2Ah   BYTE   number of scan lines active
              (0,1,2,3) = (200,350,400,480)
 2Bh   BYTE   primary character block
 2Ch   BYTE   secondary character block
 2Dh   BYTE   miscellaneous flags
              bit 0 all modes on all displays on
                  1 grey summing on
                  2 monochrome display attached
                  3 default palette loading disabled
                  4 cursor emulation enabled
                  5 0 = intensity; 1 = blinking
                  6 PS/2 P70 plasma display (without 9-dot wide font) active
                  7 reserved
 2Eh  3 BYTEs reserved (00h)
 31h   BYTE   video memory available
              00h = 64K, 01h = 128K, 02h = 192K, 03h = 256K
 32h   BYTE   save pointer state flags
              bit 0 512 character set active
                  1 dynamic save area present
                  2 alpha font override active
                  3 graphics font override active
                  4 palette override active
                  5 DCC override active
                  6 reserved
                  7 reserved
 33h 13 BYTEs reserved (00h)

Format of Static Functionality Table:
Offset Size    Description
 00h   BYTE    modes supported #1
               bit 0 to bit 7 = 1 modes 0,1,2,3,4,5,6 supported
 01h   BYTE    modes supported #2
               bit 0 to bit 7 = 1 modes 8,9,0Ah,0Bh,0Ch,0Dh,0Eh,0Fh supported
 02h   BYTE    modes supported #3
               bit 0 to bit 3 = 1 modes 10h,11h,12h,13h supported
               bit 4 to bit 7 reserved
 03h  4 BYTEs  reserved
 07h   BYTE    scan lines supported
               bit 0 to bit 2 = 1 if scan lines 200,350,400 supported
 08h   BYTE    total number of character blocks available in text modes
 09h   BYTE    maximum number of active character blocks in text modes
 0Ah   BYTE    miscellaneous function flags #1
               bit 0 all modes on all displays function supported
                   1 grey summing function supported
                   2 character font loading function supported
                   3 default palette loading enable/disable supported
                   4 cursor emulation function supported
                   5 EGA palette present
                   6 color palette present
                   7 color paging function supported
 0Bh   BYTE    miscellaneous function flags #2
               bit 0 light pen supported
                   1 save/restore state function 1Ch supported
                   2 intensity blinking function supported
                   3 Display Combination Code supported
                 4-7 reserved
 0Ch   WORD    reserved
 0Eh   BYTE    save pointer function flags
               bit 0 512 character set supported
                   1 dynamic save area supported
                   2 alpha font override supported
                   3 graphics font override supported
                   4 palette override supported
                   5 DCC extension supported
                   6 reserved
                   7 reserved
 0Fh   BYTE    reserved
----------101C-------------------------------
INT 10 - VIDEO - SAVE/RESTORE VIDEO STATE (PS50+,VGA)
        AH = 1Ch
        AL = 00h return state buffer size
Return: BX = number of 64-byte blocks needed
             01h save video state
                 ES:BX -> buffer
             02h restore video state
                 ES:BX -> buffer containing previously saved state
        CX = requested states
             bit 0 video hardware
                 1 BIOS data areas
                 2 color registers and DAC state
              3-15 reserved
Return: AL = 1Ch if function supported

Format of video hardware state:
Offset  Size    Description
 00h    BYTE    sequencer index register
 01h    BYTE    CRTC index register
 02h    BYTE    graphics controller index register
 03h    BYTE    attribute controller index register
 04h    BYTE    feature controller register
 05h  4 BYTEs   sequencer registers
 09h    BYTE    sequencer register 0
 0Ah 25 BYTEs   CRTC registers 0-8
 23h 16 BYTEs   palette registers 00h-0Fh
 33h  4 BYTEs   attribute registers 10h-13h
 37h  9 BYTEs   graphics controller registers 0-8
 40h    BYTE    CRTC base address (low)
 41h    BYTE    CRTC base address (high)
 42h    BYTE    plane 0 latch
 43h    BYTE    plane 1 latch
 44h    BYTE    plane 2 latch
 45h    BYTE    plane 3 latch

Format of DAC state:
Offset  Size    Description
 00h    BYTE    read/write mode DAC
 01h    BYTE    pixel address
 02h    BYTE    pixel mask
 03h 768 BYTEs  color data (256 triples)
303h    BYTE    color select register



Memory:
0:410h    WORD    Bit 4-5:  Initial video mode
                              0: EGA,VGA,PGA  1:40x25 color, 2: 80x25 color,
                              3: 80x25 monochrome
0:449h    BYTE    Video current mode
0:44Ah    WORD    Video columns on screen
0:44Ch    WORD    Video page (regen buffer) size in bytes
0:44Eh    WORD    Video current page start address in regen buffer
0:450h  16 BYTEs  Video cursor position (col, row) for eight pages, 0 based
0:460h    WORD    Video cursor type, 6845 compatible, hi=startline, lo=endline
0:462h    BYTE    Video current page number
0:463h    WORD    Video CRT controller base address: color=03D4h, mono=03B4h
0:465h    BYTE    Video current setting of mode select register 03D8h/03B8h
0:466h    BYTE    Video current setting of CGA palette register 03D9h
0:484h    BYTE    Video EGA/MCGA/VGA rows on screen minus one
0:485h    WORD    Video EGA/MCGA/VGA character height in scan-lines
0:487h    BYTE    Video EGA/VGA control: [MCGA: =00h]
                  bit  0:  =0 alphanumeric cursor emulation enabled, =1 not.
                              When enabled the text mode cursor size (INT 10h,
                              AH=01h) are translated to EGA/VGA size.
                       1:  =0 for color or ECD monitor, =1 for mono monitor
                       2:  =1 if to wait for display enable (what means this?)
                       3:  =0 if EGA/VGA video system active, =1 if inactive
                       4:  reserved
                     6-5:  RAM on adapter = (this field + 1) * 64K
                       7:  =1 if not to clear RAM (see INT 10h, AH=00h)
0:488h    BYTE    Video EGA/VGA switches: [MCGA: reserved]
                  bits 0-3: configuration switches 4-1 (=0 on, =1 off)
                            Values as read:
                              0h Pri MDA,    Sec EGA+old color display 40 x 25
                              1h Pri MDA,    Sec EGA+old color display 80 x 25
                              2h Pri MDA,    Sec EGA+ECD normal mode (CGA
                                             emulation)
                              3h Pri MDA,    Sec EGA+ECD enhanced mode
                              4h Pri CGA 40 x 25, Sec EGA mono display
                              5h Pri CGA 80 x 25, Sec EGA mono display
                              6h Pri EGA+old color display 40 x 25,  Sec MDA
                              7h Pri EGA+old color display 80 x 25,  Sec MDA
                              8h Pri EGA+ECD normal mode (CGA emul), Sec MDA
                              9h Pri EGA+ECD enhanced mode,       Sec MDA
                              Ah Pri EGA mono display,       Sec CGA 40 x 25
                              Bh Pri EGA mono display,       Sec CGA 80 x 25
                  bits 7-4: power-on state of feature connector bits 3-0
   Note:  When bit4 of 40h:89h is 0, VGA emulates 350-line EGA if
          this byte is x3h or x9h, otherwise emulates 200-line CGA in
          400-line double scan. VGA resets this byte to x9h after the
          mode set.
0:489h    BYTE    Video MCGA/VGA mode-set option control:
                  bit 0:  [VGA] =1 if VGA active, =0 if not
                          [MCGA] reserved, zero
                      1:  =1 if grey scale summing enabled, =0 if disabled
                      2:  =1 if mono display, =0 if color display
                      3:  =0 if default palette loading enabled at mode set
                      4:  [VGA]  =1 if to use 400-line mode at next mode set
                                 =0 if to emulate EGA at next mode set
                                    This bit set to 1 after the mode set.
                          [MCGA] =1 use 400-line mode at next mode set
                                 =0 emulate CGA, digital monitor, 200 lines,
                                    8 x 8 text font at next mode set
                                    Bit unchanged by mode set.
                      5:  reserved
                      6:  =1 if display switching enabled, =0 if disabled
                  bits 7 and 4:
                           0 0  350-line mode requested
                           0 1  400-line mode at next mode set
                           1 0  200-line mode requested
                           1 1  reserved
   Note:  Apparently VGA BIOS mode set disregards bit 7 and uses
          byte 40h:88h to determine 200/350 selection when bit 4
          is zero . Presumably bit 7 is a convenience for other
          purposes. Bit 7 is reset to zero after the mode set.
0:48Ah    BYTE    Video [MCGA/VGA]: index into Display Combination Code table
0:4A8h    DWORD   Pointer to the Video Save Pointer Table (see below)


Format of Video Save Pointer Table [EGA/VGA/MCGA only]:
Offset  Size    Description
  00h   DWORD   ptr to Video Parameter Table
  04h   DWORD   ptr to Parameter Dynamic Save Area, else 0 [EGA/VGA only]
  08h   DWORD   ptr to Alphanumeric Character Set Override, else 0
  0Ch   DWORD   ptr to Graphics Character Set Override, else 0
  10h   DWORD   [VGA only] ptr to Secondary Save Pointer Table, must be valid
  14h   DWORD   reserved, zero
  18h   DWORD   reserved, zero
Note: table initially in ROM, copy to RAM to alter, then update 40h:A8h.

Format of Secondary Video Save Pointer Table [VGA only]:
Offset  Size    Description
  00h   WORD    Length of this table in bytes, including this word (1Ah)
  02h   DWORD   ptr to Display Combination Code Table, must be valid
  06h   DWORD   ptr to second Alphanumeric Character Set Override, else 0
  0Ah   DWORD   ptr to User Palette Profile Table, else 0
  0Eh   DWORD   reserved, zero
  12h   DWORD   reserved, zero
  16h   DWORD   reserved, zero
Note: table initially in ROM, copy to RAM to alter, then alter Save Ptr Table.

Format of Video Parameter Table [EGA, VGA only]:
An array of 23 [EGA] or 29 [VGA] elements, each element being 64 bytes long.
Elements appear in the order:
  00h-03h  Modes 00h-03h in 200-line CGA emulation mode
  04h-0Eh  Modes 04h-0Eh
  0Fh-10h  Modes 0Fh-10h when only 64kB RAM on adapter
  11h-12h  Modes 0Fh-10h when >64kB RAM on adapter
  13h-16h  Modes 00h-03h in 350-line mode
  17h      VGA Modes 00h or 01h in 400-line mode
  18h      VGA Modes 02h or 03h in 400-line mode
  19h      VGA Mode  07h in 400-line mode
  1Ah-1Ch  VGA Modes 11h-13h

Format of Video Parameter Table element [EGA, VGA only]:
Offset  Size    Description
  00h   BYTE    Columns on screen   (see 0:44Ah)
  01h   BYTE    Rows on screen minus one  (see 0:484h)
  02h   BYTE    Height of character in scan lines (see 0:485h)
  03h   WORD    Size of video buffer   (see 0:44Ch)
  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
  23h 20 BYTEs  Values for Attribute Controller Registers 00h-13h
  37h  9 BYTEs  Values for Graphics Controller Registers 00h-08h

Format of Video Parameter Table [MCGA only] {guesswork from inspection}:
      16 triplet BYTEs of R,G,B DAC info for 16 colors;
      An array of 11 elements, each element being 32 bytes long.
      Elements appear in the order:
        Modes 00h,01h in 200-line mode for digital displays
        Modes 00h,01h in 400-line mode for analog displays
        Modes 02h,03h in 200-line mode for digital displays
        Modes 02h,03h in 400-line mode for analog displays
        Modes 04h,05h in 200-line mode for digital displays
        Modes 04h,05h in 400-line mode for analog displays
        Mode  06h in 200-line mode for digital displays
        Mode  06h in 400-line mode for analog displays
        Mode  11h
        Mode  13h in 200-line mode for digital displays
        Mode  13h in 400-line mode for analog displays

Format of Video Parameter Table element [MCGA only]:
Offset  Size    Description
  00h   BYTE    Columns on screen         (see 0:44Ah)
  01h   BYTE    Rows on screen minus one  (see 0:484h)
  02h   BYTE    Height of character in scan lines (see 0:485h)
  03h   WORD    Size of video buffer      (see 0:44Ch)
  05h   WORD    ??? always zero
  07h 21 BYTEs  Video data registers 00h-14h to port 3D5h indexed by 3D4h
  1Ch   BYTE    PEL Mask to port 3C6h
  1Dh   BYTE    CGA Mode Control to port 3D8h
  1Eh   BYTE    CGA Border Control to port 3D9h
  1Fh   BYTE    Extended Mode Control to port 3DDh

Format of Video Parameter Dynamic Save Area [EGA, VGA only]:
Offset  Size    Description
  00h 16 BYTEs  Last data written to Attribute Contr. Palette Registers 0-15
  10h   BYTE    Last data written to Attribute Controller Overscan Register
  11h-FFh       Reserved
Note: Need for table was that EGA registers were write-only.
Note: If default values (from the Video Parameter Table) are
      over-ridden at a mode set by the VGA User Palette Profile
      Table, then the Dynamic Save Area is updated with the
      default values, not the User Profile ones.

