vanfanel wrote on Yesterday, 14:26:

But I didn't know that I would use the SeaBIOS VGA BIOS on the Vortex! I thought BIOS ROMs were tailored to the low-level registers of each card in order to work at all...

VGA registers are pretty standardized, otherwise DOS games that use low-level VGA access wouldn't work across different cards.

I suspect the biggest differences would be in init code

rasteri wrote on Yesterday, 14:48:

vanfanel wrote on Yesterday, 14:26:

But I didn't know that I would use the SeaBIOS VGA BIOS on the Vortex! I thought BIOS ROMs were tailored to the low-level registers of each card in order to work at all...

VGA registers are pretty standardized, otherwise DOS games that use low-level VGA access wouldn't work across different cards.

I suspect the biggest differences would be in init code

That's VERY interesting, beause looking at the compatibility results in:
https://gona.mactar.hu/DOS_TESTS/
...it seems like, for example, a Trio32/64 should work with every "picky" DOS fine-scrolling game.
Are you telling me I could inject the Trio32/64 Video ROM (it's dumped and can be currently used on the MAME project for the ct486 driver) onto the Vortex86 DX BIOS (using AMI MMTOOL) and it's graphics chip would work as a Trio32/64? I *believe* scroll routines are part of the VIDEO ROM.

vanfanel wrote on Yesterday, 15:03:

*believe* scroll routines are part of the VIDEO ROM.

There are scroll routines in the BIOS, but I expect the vast majority of games don't use them.

vanfanel wrote on Yesterday, 15:03:

Are you telling me I could inject the Trio32/64 Video ROM (it's dumped and can be currently used on the MAME project for the ct486 driver) onto the Vortex86 DX BIOS (using AMI MMTOOL) and it's graphics chip would work as a Trio32/64? I *believe* scroll routines are part of the VIDEO ROM.

That would be very unlikely to work. It would probably hang on those init routines that rasteri mentioned above. Even if the BIOS would miraculously initialize without hanging in the init code, you would, at best, get only the legacy VGA modes to work. If any of those scrolling routines in the BIOS use any hardware-specific stuff beyond the standard legacy VGA registers, those won't work on a different GPU either.

At least the generic SeaBIOS VGA BIOS ROM was tailored carefully to be the "lowest common denominator" in terms of generic legacy VGA compatibility. Or at least that's how I understand it.