RealDOOM: A port of DOOM to Real Mode (2025)

1ST1 said:

I know, RealDoom is different, but it only runs on XT with VGA card, originally allmost no XT used to have VGA, even for 286 PC EGA would be more typical, only late 286 used already to have VGA, when 386 PC already were there.

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Real doom is a real mode port of doom, not an XT port of doom. Doom is a VGA game. That said, it does run on a 5155 as recorded here:

1ST1 said:

Please don't go too high with soundcard support. It's called Doom8088. 8088 is xt class, there is not a big choice for soundcards on 8 bit ISA. SB-16 on a 80286 is already "fat". Only a 486 and faster is happy with GUS and AWE32, but then I can start the original DOOM from 1993. What your versions makes special is that it runs on XT class PC with graphics cards less than VGA and it makes matching noise on the speaker, even on MS-DOS based typewriters like my ETV 260.

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I am looking to eventually support the sound cards supported by the vanilla doom. Anyway, you seem to have the wrong thread.

1ST1 said:

Timedemo 3 is a very long one, on an XT less than 10 Mhz it runs about half an hour... , there used to be much shorter benchmarks, as far as I remember it was 1 which was just a 360 degree turn which took just a few seconds. But that one was already good enough to see a trend if a PC is fast enough. But yes, that is long time ago and I don't remember well.

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No, timedemo 3 is the shortest by 2-3x the other ones in the shareware wad. If you are remembering such a timedemo then maybe it was a buggy playback which did not play inputs back accurately, or a buggy time demo.

1ST1 said:

By the way, would Doom8088 profit of the presence of the 8087 FPU ? That would be interesting, it maybe would help to speed up the game. Here we have a neighbour thread where where it accelerates 3D calculation by factor 10. And now see my Olivetti M21/24 8086 8 MHz at 1 to 3.7 fps, if it could accelerate it by a factor where it could get playable (only the calculation would profit but text/mda/cga graphics would not get faster).

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See Also

Timeless Classics: 13 Must-Have PC Games that Withstand the Test of Time | HP® Tech TakesHow Doom: The Dark Ages Is Changing the Way You Slay DemonsThe Doom of Icewind dale is the start of a “love letter to Neverwinter Nights”PC Digital Downloads: Doom Eternal $8.20

Doom would generally not benefit from an FPU because it does not use floating point calculations, it uses fixed point calculations.

sqpat said:

No, timedemo 3 is the shortest by 2-3x the other ones in the shareware wad. If you are remembering such a timedemo then maybe it was a buggy playback which did not play inputs back accurately, or a buggy time demo.

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No it was something official. All my friends used it. It was inside the game, there is a command shell and you typed a command and it did that 360 degree turn and displaying the fps.

1ST1 said:

No it was something official. All my friends used it. It was inside the game, there is a command shell and you typed a command and it did that 360 degree turn and displaying the fps.

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I think you might be getting confused with a another game here

1ST1 said:

An original 5155 has no VGA card.

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Sorry, I meant 5150.

1ST1 said:

I know, RealDoom is different, but it only runs on XT with VGA card, originally allmost no XT used to have VGA, even for 286 PC EGA would be more typical, only late 286 used already to have VGA, when 386 PC already were there.

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This thread is about RealDoom, requires peculiar hardware to run.

1ST1 said:

Please don't go too high with soundcard support. It's called Doom8088.

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Doom8088 is discussed in this [other thread]. It does support CGA and PC speaker.

Here is a little gameplay recording from my 286 running at 33.3 mhz today.

MAZter said:

Don't understand complete system requirements, but I'm unable to make it work on Zeos 386 notebook. Every build just freeze machine in the middle of loading process without any errors.

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Start with the latest release, not an older one

You will need a line in your config sys similar to:
DEVICE=C:\DOS\EMM386.EXE RAM /FRAME=D000 /I=E000-EFFF

And load dos high, and possible emm386 high or with UMBs if you enable some other region such as c800-cfff.
You should also probably have 3-4 MB minimum system memory.

(You will need a build with the useD000 flag if your system bios is in the e000 region.)

EDIT: Also keep in mind this is still pre-alpha and heavily under development, so there aren't a lot of easy-to-follow directions on the github page yet.