>> I need info on the Expanded BIOS (also known as H.BEXT, EXTBIO or
#FFCA)!!!
>
>Don't worry brave man! Konami Man goes to rescue you! (-v-)v
Ah....
>Expanded BIOS hook was designed to expand BIOS (then why it has a so
>strange name?? X-D) in order to manage new devices. So it is used for
>example by RS-232 and DOS 2 mapper support routines. Nowadays, also TSR
>programs (MemmMan, NestorAcentos...) use it, because it provides a fixed
>memory location to CALL in page 3.
>
>How it works? You put a device ID number in register D, a function
>number in register E, and registers AF, BC, HL depending of the calling
>routine (you can't use alternative registers, nor indexed ones). DE is
>always preserved when returning; AF, BC, DE depends on the calling
>routine; alternative and indexed are corrupted.
I already knew that, it is described this way in a lot of docs, for example
in the Dos2 documentation. What I actually would like to have is a complete
list of all devide IDs and their corresponding functions, complete with
explanation and input/output per function.
>How to patch it for your own use? First, you must select your own device
>ID number. Of course it must be a number not used by anyone before, for
>avoid computer crash when other TSR sre installed. Here is a list if ID
>numbers which I know:
>
>#00 y #01, used by RS-232 BIOS.
>#04, used by DOS 2 mapper support routines.
>#22, used by me! (NestorAcentos, NestorCDPlayer and all TSRs which name
>is Nestor*.*) 8-)
>#34, used by MWMPLAY by Ramones.
>#4D, used by MemMan.
>#F0, used by MGSDRV.
I can add 1 to this list: #10 Kanji Driver
>It is recommended that once selected, you use always this number in your
>programs, modifying register E for every program. For example I use
>DE=#2200 for NestorAcentos, and DE=#2201 for NestorCDPlayer.
Ofcourse.
>Now you must patch hook #FFCA, of course saving previous value. The
>new jump routine must do this:
>
>- Check D. If it does not match with your ID number, jump to the old
>hook without any register modified.
>- If it matches, check register E for required function, do anything and
>return preserving DE.
>
>This jump routine should be placed in page 3 if the program is a TSR.
>How to reserve memory on page 3 is another question.
Well it's a hook so that's the way it should be done, yes.
>> Can't anybody help me???
>
>I hope I helped you! 8-) If you want I can send some source code about
>this (for example, source of NestorAcentos).
No, I don't need to know how to hook it.
What would be perfect is a textfile including the explanation of as many
Extended Bios-calls as possible. But I guess it isn't there yet. So I
suggest we make it.
I will go on holidays tomorrow, but I can look up the Expanded BIOS function
calls of Dos2 and the Kanji Driver. Maybe other people know about other
devices and can email about it to this list (If not at hand, don't be lazy
and look it up!!!)...
~Grauw
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