Re: Emulated PCI devices?

[Mouse <mouse@Rodents-Montreal.ORG>]

>> I'm working with dosemu and would like to add an emulated PCI device
>> to the emulated DOS machine.  [...]

>> Is this something that's already got hooks supporting it, or am I
>> breaking new ground here?

> There was never any need to emulate the PCI device for DOS.  There
> are hardly too many DOS drivers for the PCI devices.

In general, perhaps not. :-)

> Maybe you can instead emulate the ISA version of that device,

As far as I know, no ISA version has ever existed - and, indeed, the
particular device in question has just recently been EOLed by its
maker.

> Or maybe you simply want to use qemu

It may come to that; I'm working with dosemu because that was the first
DOS emulator we tried that we could make the software run in.  And, in
some respects, I prefer the way dosemu emulates DOS in much the same
sense that wine emulates Windows, instead of emulating hardware proper
and not caring what software is running on it.

> because I can't think of the real use-cases where you want to emulate
> some modern device under dosemu or dosbox.

Well, I daresay they are not common, but I've got one. :-)

I can't go into too much detail (NDAs and such), but it involves a
legacy application, running under DOS, which depends on a particular
(relatively rare and expensive) piece of hardware.  I got involved in
an effort to port/rewrite to make it run under something more modern -
but then the hardware was EOLed and the full port/rewrite is likely to
take longer than the company can keep going on their EOL-buy hardware
quantity.  Thus, we are looking at adding a little glue logic and
running the legacy code (unchanged or with minor tweaks) under
emulation, as a bridge until the full move to something more modern is
completed.

We'd rather keep the application basically unchanged (so that the same
binary can run on real machines with the special hardware, or on the
emulator), or I'd just rip out all the special hardware interfacing and
replace it with traps to the emulator.  I may have to do that with a
run-time switch based on a test for emulation anyway, but I figured
emulating the device was an approach worth at least looking at.

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