setting powerup EGA/VGA text mode without BIOS

setting powerup EGA/VGA text mode without BIOS

Post by Mark Scot » Fri, 21 Mar 1997 04:00:00

I wonder if someone can help me. I'd *really* like to find some code
that could show me the minimal registers & font loading stuff to get
any off the shelf EGA/VGA card (without BIOS) up and running in
text mode after power-up. I've worked with the Linux for PowerPC
boot loader a little bit & am tired of hard coding things per card.
I assume there has got to be some bare bones algorithm & register
settings that would work on *ANY* EGA/VGA card, right? So far, I've
found this task much harder than it seems it needs to be. Any ideas?

PS: A C-code implementation would be preferred
| Mark Scott                    | Don't interrupt me while I'm       |



1. Help needed on BIOS VGA mode programming


My company is develloping a SVGA board for use with a 680xx system. Because
of the limited size of the board, ROM BIOS is not included. Hence, I have
to write a driver that takes over the BIOS function. I do have some examples
of programming a VGA controller, but they all contain INT10 calls.
The main problem is how to emulate these.

Could someone tell me for instance what the following lines do? (and don't
tell it puts the mode 13 on)

        mov     ah,$13
        int     $10

What I would like to know is:   what happens in the BIOS?
                                does it initialize the CRT Control Registers?

I'm greatful for any answers on these!!

                                        .... have a nice day.
Jan Ekkel               PO Box 627, NL 5340 AP  OSS     +-----+

Inducom Systems BV      Fax:    (31)4120-22640          |  INDUCOM SYSTEMS BV
****** Specialists in OS-9, VMEbus and G-64

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