INT 10H 1121H: Setup User-Defined Font for Graphics Mode
Compatibility: EGA VGA
Expects: AX 1121H
BL screen rows code: 00H = user-specified (in DL)
01H = 14 rows
02H = 25 rows
03H = 43 rows
CX bytes per character definition
DL (when BL=0) custom number of character rows on screen
ES:BP address of font-definition information
Info: Sets up a custom character set to be used by the BIOS when
displaying text while in graphics modes. This sets the INT 43H
vector and sets BIOS variables so it can use the custom font.
ES:BP points to a table containing the character-definition codes. It
should be CX*256 bytes long (if you are defining all 256 ASCII
characters). The table is laid out as a series of groups with
CX bytes in each group.
See Video Font Definition for byte layout.
Note: This fn requires that you modify BP. When calling from high-
level languages such as C, be very careful to save and restore
BP, since it is used to keep track of the "stack frame".
See Also: INT 10H 11H: EGA/VGA Character Generator Functions
INT 10H: Video Services
EGA/VGA Data Areas