DOS ain't dead

Hello ! Apologies if this quest is not exactly on-topic on this board. Using boards with SiS chipsets - several, but let's say the SiS 741 for definiteness, the video subsystem of which is has PCI device id : SiS 6330 - I wish to add more text video modes than provided by the cr@ppy video BIOS provides.

I mean, especially, wide text modes, 132 char or so per line. Unfortunately though I have some SiS chipset docs, I couldn't find anything about locating & programming the extra video clocks beyond basic EGA/VGA frequencies

Someone has a pointer to docs for the SiS PCI video systems including non standard registers ? Or some ready made TSRs ? I thought of looking at Linux kernel sources, but I'm unsure Linux uses any exotic text modes even in the booting stages (not talking of text in graphics modes).

Don't you people find irritating that the video BIOSes will care less and less about providing useful text modes ?

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Ninho

Did you try SVGATextMode?
Perhaps nothing beyond basic VGA register tweaking for SiS chipsets, but at least you could have more text modes than BIOS provides.

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Glory to God for all things

> Did you try SVGATextMode?
> Perhaps nothing beyond basic VGA register tweaking for SiS chipsets, but
> at least you could have more text modes than BIOS provides.

Thanks for your kind answer! Yes I was aware of and tried STM for DOs, unfortunately that excellent program doesn't know how to program the SiS chips any more than I do. I even tried to contact the author by email a few weeks ago, but got no answer - either he was not interested/ had nothing to add, or the email address I used was not up to date ...

I know how to tweak VGA registers provided either I have the docs for the non standard ones, or a program which knows how to access the chipset ;=)
In this case I can't guess how the VClocks are accessed.

When posting here I was thinking, maybe someone has a physical SiS based "deluxe" video adapter (not the integrated, shared memory thing) and then if the BIOS for that provides a larger choice of modes, VESA or otherwise, I could study how it is programmed. Just a possibility.

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Ninho

> When posting here I was thinking, maybe someone has a physical SiS based
> "deluxe" video adapter (not the integrated, shared memory thing) and then

I avoid SiS chips at all, because these are slow and crappy.

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Forum admin

Maybe svgalib's source code could be of help. It contains a SiS driver, but I don't know in what degree it concerns text modes.

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Glory to God for all things

I simply forgot that Vidix has also SiS support, perhaps it is a better choice to look upon it. Again, I don't know how useful re: text modes though. Anyway, I don't think you could find more detailed information freely available.

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Glory to God for all things

> I avoid SiS chips at all, because these are slow and crappy.

I agree. I have one SIS 6xxx PCI VGA that I bought because I need TV-out on a PCI. It was cheap but it is crap.

I cannot tell you anything to SIS but just idea how it works on nVidia BIOS. nVidia has defined some internal gfx and txt mode numbers that are supported by chip. Then there is a table that assigns VESA mode numbers to specific nVidia mode numbers. I you have a luck that chip supports the resolution you need but it is not in VESA mode table then it is possible to replace some unused VESA mode by mode that you need. But it is not simply task.

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DOS gives me freedom to unlimited HW access.

> I avoid SiS chips at all, because these are slow and crappy.

Why, such statements need qualifying. SiS chipsets aim at the "value" market, they are well engineered and give you bang for the buck. I've had SiS powered machines starting with a SiS471+i486DX2 which is still working and humming alond on the table next to this one. I also have a SiS530+AMD K6-2+ system (IBM Aptiva.)

I used to like SiS because they provided almost unlimited access to their docs, but alas! this has now changed under the pressure of the idiot marketoons, I believe. Oh, well my next system won't be SiS - but I have no more money left anyway so I'm keeping with what I have, and besides I dislike the X-64 trend and the multicore approach which are both a waste of silicium real estate.

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Ninho

> > I avoid SiS chips at all, because these are slow and crappy.
>
> I agree. I have one SIS 6xxx PCI VGA that I bought because I need TV-out
> on a PCI. It was cheap but it is crap.
>
> I cannot tell you anything to SIS but just idea how it works on nVidia
> BIOS.

It won't tell me anything about the SiS registers : programming any 'superVGA' chipset requires a knowlege of the purpose of every bit in every register (and access to features which were not part of IBM's original VGA is generally protected by 'password'!) Failing an authoritative documentation, the next best thing would be to look at video BIOS or other code made by ppl who had access to the docs. Unfortunately their is nothing in the video BIOS for my Asrock board that tells me how to program the divisors for and activate extra frequency generators. But of course it has to be possible in principle, just that SiS (and others) have lost any interest in text modes because their customers don't care about DOS nor compatibility any more.

I've had some experience in playing with video chipsets : back in the 80s, I managed to enhance a Goupil AT clone having a Paradise EGA system on the mainboard (and a good, 13"! EGA multisync monitor, possibly of Sony design, not your basic crappy EGA) and in particular I forged 126 characters wide text modes; it was fun (not) because if you'll remember, with EGA you couldn't read back the registers at all...and I almost became blind in the process ;=) I had to define a set of six-bit-wide characters, but the real difficulty was finding the hidden registers, password, and how to tweak the whole stuff.

> nVidia has defined some internal gfx and txt mode numbers that are
> supported by chip. Then there is a table that assigns VESA mode numbers to
> specific nVidia mode numbers.

That step is really the last piece of icing, we need to fabricate the modes, and only then optionaly give them BIOS and/or VESA 'int 10' numbers. I prefer to keep the BIOS mode as 03 for tesxt color modes of any width, and of course update the mode's params in BIOS data segment 40h. They are for use in DOS anyway, not Windows.

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Ninho

Maybe VGA enchancer helps?

http://www.laaca.borec.cz/ve.zip

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DOS-u-akbar!

> Maybe VGA enchancer helps?
>
> http://www.laaca.borec.cz/ve.zip

I'll have a look later when I'm running DOS on the bare metal (most of the time nowadays I run Win/DOS only in VMWare player under Linux). From the 'readme' it looks like that product deals with changing the # of screen /lines/ not /columns/; lines is easy and does not require special clocking, contrary to columns. thank you in any case; are you related to the authors of that package ?

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Ninho

> I simply forgot that Vidix has
> also SiS support, perhaps it is a better choice to look upon it. Again, I
> don't know how useful re: text modes though. Anyway, I don't think you
> could find more detailed information freely available.

I checked the old SiS 530 docs, gotten in ancient times when serious SiS docs were freely available from their site, before the idiotic marketoïd types decided otherwise : it has full description of the (super)VGA registers and preliminary investigation shows much of that is might be still working on the 741, so there is some hope I can make something useful out of it...

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Ninho

> Maybe VGA enchancer helps?

Hi again, Laaca ! I did try the VGA 'enchancer' (sic)... It turns out that programming the Vclocks is an option only for registered users, there isn't a way to even try it for limited time; and since the accompanying program, test.com, just hangs the 'puter I'm not too tempted to fork out a fee until I'm satisfied VE does work on the SiS 741.

Please tell, did VE work for you ? Are you connected to the author ?

Cheers -

Ninho

> > Did you try SVGATextMode?
...
> I can't guess how the VClocks are accessed.

For the record, I found the "bits" I needed - pun intended - in the C-language sources of the Linux kernel driver for SiS chipsets (by Thomas Winischhofer : http://www.winischhofer.net/sis/)

With the knowledge, it was a piece of cake to setup a 40 MHz Vclock and get
at modes with 132 chars per line as well as many others. The program you pointed to, SVGATextMode helped much in trying and testing the modes. Now I can write own tiny programs that shall set up only the modes I want

Thanks !

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Ninho