Most DOS games from the 1990s were in 32-bit protected mode, and few games from the late 1980s as well (though 286s were still very common, so developers tended to keep it safe with 16-bit programs). DOSBox emulates the 80486 because there are many games that use the features of that processor 😀

Most games after 1993 are protected mode games and almost all use the DOS4GW extender with a couple using CSDPMI or their own custom extender.

But with dpmi, doesn't it mean that the program doesn't actually use any protected mode features of the cpu, but only makes calls to the dpmi spec to change segment descriptors etc. So in effect one would only need to emulate a real mode, with some very limited segment related stuff, and add all dpmi functionality.
Or am I missing something?

anton

The extenders (dos4gw, cwsdpmi, pmodew etc.) need protected mode to
provide dpmi services. Also not all games/app can utilize dpmi.

Besides that the application code runs in protected mode anyways so "just"
emulating dpmi is somewhat braindead.

Real mode is the normal 16-bit mode, and protected mode is the 32-bit mode. A game using DPMI functions perhaps provided by a DOS extender has to be running in protected mode. The DOS extender is there to allow the protected mode program to easily interface with DOS/BIOS functions that only work in real mode (The extender either switches back to real mode to call the functions or just implements them itself in protected mode code)

A bit of generalization there; there is also a 16-bit protected mode introduced with the 80286, I believe Wolfenstein 3-D is one game that uses it.

MikeRS wrote:

A bit of generalization there; there is also a 16-bit protected mode introduced with the 80286, I believe Wolfenstein 3-D is one game that uses it.

Yes there is, but it had a lot of restrictions and wasn't widely used. I'm not aware of any game that uses it, although I guess there must be a few. Wolf3D just used real mode with XMS/EMS like many games until around 1993 when 386 protected mode and dos extenders took over.

wolf3d is realmode, yes.
16bit pmode is not that unusual, think the borland (rtm) used it a lot before
the rtm32 stuff (?), and many extenders use 16bit pmode during mode
transitions and for some handlers. But 32bit pmode is far more common
simply due to the amount of dos4gw games.

Im seeing that realmode games like wolf3d run very slow on dosbox. Ive tried many combinations in the dosbox.conf file and same results. It's just too slow to play. The funny thing is the game starts ok, then as it plays, it starts slowing down, to being unplayable.

What is your cycles settings? What hardware and operating system do you have?

Wolf3D is a light game by today's standards, even on emulators; it plays full speed with DOSBox on the Wii (729MHz single-core PowerPC) at 3000 cycles (default cycles).

Im seeing that realmode games like wolf3d run very slow on dosbox.

set cycles=max

Wolf3D is a light game by today's standards, even on emulators; it plays full speed with DOSBox on the Wii (729MHz single-core PowerPC) at 3000 cycles (default cycles).

Dosbox for the Wii? Must look now...

There's a port of Debian to the Wii, don't remember the name, but it should be easy to find. It's nothing special really beyond the fact that the drivers in Linux and X.Org were ported to the Wii's hardware, you can install any Debian/powerpc package 😀

Hehe cute 😀

Wolf3D just used real mode with XMS/EMS like many games until around 1993 when 386 protected mode and dos extenders took over.

So it is true that there are many real mode games out there, that only rely on protected mode to emulate xms/ems (i.e. map high mem into the first 1mb)?
...I wonder whether there's a list of those games, i.e. what can be accomplished with that sort of emulation (real mode+api's).

that only rely on protected mode to emulate xms/ems (i.e. map high mem into the first 1mb)?

ems has nothing to do with protected mode, real ems cards have hardware
mechanisms to map memory (on the ems card) into the pageframe.
emm386 requires v86 mode (so 386+) to emulate those cards, parts of it
also utilize protected mode.

xms doesn't need protected mode either, though himem may use it as one
way of copying/moving memory blocks.

I do maintain a list of REAL/PROTECTED mode games in my PC Game Compatibility list but sadly I haven't updated it in like 3 or 4 years. I went through all of the DOS games I had at the time for when we were implementing support for protected mode games in DOSBox.

Very few of my games were protected mode games. I think it was like 100+ protected mode games out of 500 to 600+ real mode games.

They were all tested in a build of DOSBox that didn't have protected mode support. (I couldn't be sure if I did a scan if I would miss a custom extender so I executed each and every game in DOSBox)

There's a port of Debian to the Wii, don't remember the name, but it should be easy to find. It's nothing special really beyond the fact that the drivers in Linux and X.Org were ported to the Wii's hardware, you can install any Debian/powerpc package

yeah, found that out earlier today 😀
There was a native port for the Wii called DosWii but it never got off the first stage. It compiled but gave a blank screen and then the porter left the scene...

This pretty much answers my original question, thx! Can that list be found somewhere?
...The only question remains is whether any of these old games that run in real mode, but might use an extender (xms, ems, whatever) are all 16bit, or whether there are 32 bit real mode games out there.
thx

anton