[LispM-Hackers] Keyboard problem

[Nyef]

On Mon, 25 Mar 2002, John Morrison wrote:

> Hi;

Hello.

> (*) I stumbled across some weird mechanism for calling BIOS routines
> from a "Virtual 8086" task running under protected mode, so I could use
> BIOS calls to do lots of stuff like mucking about with video modes
> (switching back and forth from a microcode console to the E3 window,
> much like Linux does), or peripheral devices like disks, etc.  It's only
> a few hundred lines of assembler, and it's already in NASM syntax (the
> assembler I use), so I'm kind of tempted.  Does anybody know anything
> about this?

I'm given to believe that many free OSes out there use this method or a
full realmode switch to access the VESA graphics mode controls. There are
likely just as many that switch graphics mode before hitting protected
mode and don't change it afterwards. These are certainly approaches I
would consider for my next standalone system.

It's quite possible to get code to switch between various VGA modes, but
once you get into SVGA territory it's a heck of a lot easier just to use
the VESA BIOS any way you can.

I don't recommend using the BIOS for anything that you can reasonably do
yourself. It's just too easy to write more suitable floppy and IDE drivers
than the BIOS ones (the BIOS drivers block the entire system until they
complete, for example).

Stuff you can't reasonably do without BIOS assistance include APM support,
SVGA mode switching and initial startup.

> -jm

---------------------------
All programming can be viewed as an exercise.
---------------------------
Alastair Bridgewater
e-mail: nyef@softhome.net