[CDG5] Getting old world ROM boot on QEMU g3beige

[Max Poliakovski]

>
> Hello guys,


> The firmware ROM seems to expect the GPU to be at PCI address 0x12 and
> does not seem to touch other devices. I wonder how does a plug-in PCI
> graphics card wotks on real hardware because that's probably a different
> PCI address?


The Mac ROM does indeed expect the soldered onboard ATI card to be at
address 0x12. That card doesn't come with an expansion ROM required for
pluggable cards - the FCode driver is supplied with the OpenFirmware/MacOS
instead.

Another PCI video card would need an expansion ROM to be recognizable by
the Apple OpenFirmware implementation. Pluggable ATI Rage 128 cards do
include such an expansion ROM. It can be flushed to contain either a PC x86
bios code or FCode.

I have the original ATI dumps for Mac on my HD. They contain a FCODE
program, very similar to that found in the Beige ROM, that will initialize
the video chip as well as the MacOS driver encoded as Forth strings.

An attempt to emulate the expansion ROM with the corresponding FCODE
program might work.

Best regards
Max
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