We don't write anything in C++ for this project. Only C. See the
archives for more info.
Jeroen Janssen wrote:
>
> Willow Schlanger wrote:
> >
> > Instead of hooking INT 10 via INT 80 do this:
> > Put your ROM at C000:8000. Make C000:8003 just contain a RETF.
> > Read 3 bytes from C000:3.
> > Patch C000:3 with a JUMP to C000:c004.
> > Make C000:c004 do a far call to the target of the old C000:3
> > instruction. Then _replace_ interrupt 10h with your handler, _without_
> > worrying about backing it up.
>
> Hmm.. I don't quite understand what you mean here: what actions do you want to do
> *outside* the plex guest os and what do you want to do inside the guest environment?
>(+
> can I "patch" the guest rom bios in my extension rom initialization? - "normally"
>rom can
> not be written to)
>
> > Now make your handler generate INT 6Dh to call the "old" handler.
> >
> > Why will this work? Because all 100^ VGA-compatible BIOSes must hook INT
> > 10 and INT 6D and make them _both_ go to the same place. Since INT 10 is
> > what gets called by programs, we can simply hook that. Elpin's BIOS
> > isn't 100% compatible and instead of making INT 10 and INT 6D go to the
> > same handler, they made INT 10 go to code that does INT 6Dh and then
> > IRETs.
>
> Yes, I figured this out after posting my message (and reading back in the mailinglist
> archive). I now hook up to int 10h and just call int 6d when I should call the
>normal VGA
> bios.
>
> > I guess I can through some code together. Lemme know... if I must...
>
> ok, I was wondering if it would be better to (as suggested on the mailinglist a while
> back) output AX to a specific port when calling a VBE function. That way we can have
>a
> plex plugin (written in C++) to handle things for a while (at least while
>"prototyping" -
> I'm a "little" better at writing C++ then I'm with asm :).. then when we have
>"enough"
> functionality we can start thinking about moving things the extension rom again (we
> probably need a plex plugin too, because we need to have a LFB + some way of being
>able to
> "detect" available video modi).
>
> --
> Best regards,
>
> Jeroen Janssen
> ---
> "It's got three keyboards and a hundred extra knobs, including twelve with
> '?' on them."
> -- The Unseen University Organ, as designed by B. S. Johnson
> (Terry Pratchett, Men at Arms)
--
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