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32-bit MSDOS (Announce)

posted by kerravon E-mail, Ligao, Free World North, 30.06.2021, 23:14

> > > I do not know where you get the idea that DPMI applications demand
> "that
> > a
> > > segment register be set a certain way",
> >
> > http://dos32a.narechk.net/manual/index.html
> >
> > ES = 32-bit data selector with base=PSP and limit=256 bytes
> >
> >
> > That's what DOS32A executables require. The
> > caller needs the privilege requires to set the
> > ES register. In some environments I am interested
> > in, that is not possible.
>
> And how is that related to DPMI ? E.g. DJGPP go32v2 programs afaik assume
> es to be simply equal to ds. (so that rep movsb can be used to copy)
>
> We also map the first 1MB of memory to the FS selector for easy dos access,
> but that is also not related to DPMI, and since your OS would be an
> independent target/OS anyway, that is not relevant.
Then maybe I can support go32v2 programs!
I'm not familiar with them. I'm only a little
bit familiar with DOS32A.

For go32v2 programs can I just redirect INT 31H
calls over to my 32-bit INT 21H instead of a
16-bit INT 21H that was requested?

Basically what does a "hello world" go32v2
executable look like as far as environmental
requirements are concerned?

> > > or that they cannot run unprivileged.
> >
> > It is the caller who needs to be privileged in
> > order to set segment registers and interrupt
> > vectors. In an environment I am interested in
> > (interested in running Win32 executables), I
> > will not be privileged.
>
> You can work around entry requirements in the privileged program loader.
I want to have an unprivileged program loader
(see "bios" directory).

That's for "generic PDOS" rather than PDOS/386
where the loader is indeed privileged. So are
all applications for that matter (same as
MSDOS).

> Doesn't have to mean that the binary itself must run privileged.
I didn't say that.

BFN. Paul.

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