Assembly Language Help (alang.hlp) (Table of Contents; Topic list)
Important Notice
The pages on this site contain documentation for very old MS-DOS software, purely for historical purposes. If you're looking for up-to-date documentation, particularly for programming, you should not rely on the information found here, as it will be woefully out of date.
Int 10h Function 1Bh
 Summary                                   Up Contents Index Back
────────────────────────────────────────────────────────────────────────────
 
     The caller's buffer is filled in with information that depends on
     the current video display mode:
 
     Bytes       Contents
 
     00h-03h     Pointer to functionality information
     04h         Current video mode
     05h-06h     Number of character columns
     07h-08h     Length of video refresh buffer (bytes)
     09h-0Ah     Starting address in buffer of upper left corner of
                 display
     0Bh-1Ah     Cursor position for video pages 0-7 as eight 2-byte
                 entries; first byte of each pair is y coordinate,
                 second byte is x coordinate
     1Bh         Cursor starting line
     1Ch         Cursor ending line
     1Dh         Active display page
     1Eh-1Fh     Adapter base port address (3BXH monochrome,
                 3DXH color)
     20h         Current setting of register 3B8h or 3D8h
     21h         Current setting of register 3B9h or 3D9h
     22h         Number of character rows
     23h-24h     Character height in scan lines
     25h         Active display code
                 See: Int 10h Function 1Ah
     26h         Inactive display code
                 See: Int 10h Function 1Ah
     27h-28h     Number of displayable colors (0 for monochrome)
     29h         Number of display pages
     2Ah         Number of scan lines
                 00h = 200 scan lines
                 01h = 350 scan lines
                 02h = 400 scan lines
                 03h = 480 scan lines
                 04h-FFh = Reserved
     2Bh         Primary character block
                 See: Int 10h Function 11h Subfunction 03h
     2Ch         Secondary character block
     2Dh         Miscellaneous state information
 
                 Bits          Significance
 
                 0             = 1 if all modes on all displays active
                                 (always 0 on MCGA)
                 1             = 1 if gray-scale summing active
                 2             = 1 if monochrome display attached
                 3             = 1 if mode set default palette
                                 loading disabled
                 4             = 1 if cursor emulation active
                                 (always 0 on MCGA)
                 5             = State of I/B toggle (0 = intensity,
                                 1 = blink)
                 6-7           = Reserved
     2Eh-30h     Reserved
     31h         Video memory available
                 00h = 64K
                 01h = 128K
                 02h = 192K
                 03h = 256K
     32h         Save pointer state information
 
                 Bits     Significance
 
                 0        = 1 if 512-character set active
                 1        = 1 if dynamic save area active
                 2        = 1 if alpha font override active
                 3        = 1 if graphics font override active
                 4        = 1 if palette override active
                 5        = 1 if display combination code (DCC)
                            extension active
                 6-7      = Reserved
 
     33h-3Fh     Reserved
 
     Bytes 0-3 of the caller's buffer contain a DWORD pointer (offset
     in lower word, segment in upper word) to the following information
     about the display adapter and monitor:
 
     Bytes       Contents
 
     00h         Video modes supported
 
                 Bits     Significance
 
                 0        = 1 if mode 00h supported
                 1        = 1 if mode 01h supported
                 2        = 1 if mode 02h supported
                 3        = 1 if mode 03h supported
                 4        = 1 if mode 04h supported
                 5        = 1 if mode 05h supported
                 6        = 1 if mode 06h supported
                 7        = 1 if mode 07h supported
 
     01h         Video modes supported
 
                 Bits     Significance
 
                 0        = 1 if mode 08h supported
                 1        = 1 if mode 09h supported
                 2        = 1 if mode 0Ah supported
                 3        = 1 if mode 0Bh supported
                 4        = 1 if mode 0Ch supported
                 5        = 1 if mode 0Dh supported
                 6        = 1 if mode 0Eh supported
                 7        = 1 if mode 0Fh supported
 
     02h         Video modes supported
 
                 Bits     Significance
 
                 0        = 1 if mode 10h supported
                 1        = 1 if mode 11h supported
                 2        = 1 if mode 12h supported
                 3        = 1 if mode 13h supported
                 4-7      = Reserved
 
     03h-06h     Reserved
     07h         Scan lines available in text modes
 
                 Bits     Significance
 
                 0        = 1 if 200 scan lines
                 1        = 1 if 350 scan lines
                 2        = 1 if 400 scan lines
                 3-7      = Reserved
 
     08h         Character blocks available in text modes
                 See: Int 10h Function 11h
     09h         Maximum number of active character blocks in text modes
     0Ah         Miscellaneous BIOS capabilities
 
                 Bits     Significance
 
                 0        = 1 if all modes active on all displays
                            (always 0 for MCGA)
                 1        = 1 if gray-scale summing available
                 2        = 1 if character font loading available
                 3        = 1 if mode set default palette
                            loading available
                 4        = 1 if cursor emulation available
                 5        = 1 if EGA (64-color) palette available
                 6        = 1 if color register loading available
                 7        = 1 if color register paging mode
                            select available
 
     0Bh         Miscellaneous BIOS capabilities
 
                 Bits     Significance
 
                 0        = 1 if light pen available
                 1        = 1 if save/restore video state available
                            (always 0 on MCGA)
                 2        = 1 if background intensity/blinking
                            control available
                 3        = 1 if get/set display combination
                            code available
                 4-7      = Reserved
 
     0Ch-0Dh     Reserved
     0Eh         Save area capabilities
 
                 Bits     Significance
 
                 0        = 1 if supports 512-character sets
                 1        = 1 if dynamic save area available
                 2        = 1 if alpha font override available
                 3        = 1 if graphics font override available
                 4        = 1 if palette override available
                 5        = 1 if display combination code
                            extension available
                 6-7      = Reserved
 
     0Fh         Reserved
                                    -♦-