Changing hardware font
Posted: Thu Aug 02, 2001 11:00 pm
I want to change the hardware font for my OS. Does anyone know where
I can get some information on doing this? Thanks.
I can get some information on doing this? Thanks.
>On 2001-08-03 02:16:41, Hillbillie wrote:
>I want to change the hardware font for my OS. Does anyone know where
>I can get some information on doing this? Thanks.
VGA has four "planes". Call them plane 1,
plane 2, plane 4, and plane 8.
In text mode, plane 1 = text,
plane 2 = attribute bytes,
plane 4 = font,
plane 8 = ???
To change the font:
- turn off planes 1 and 2,
and turn on plane 4
- turn off Even-Odd mode
- write the font to framebuffer
memory (B800:0000)
- turn on Even-Odd
- turn off plane 4,
and turn on planes 1 and 2
Font characters can be up to 32 pixels high.
Characters are always 1 byte wide (8 pixels).
Each font character is 32 bytes exactly.
http://www.execpc.com/~geezer/temp/90x60.c