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Multicore suppport for DOS is real – partly

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Re: Multicore suppport for DOS is real – partly

#11

Post by mikestorrent »

Stevvo wrote: post #10
toast0 wrote: post #7

Earlier quoted context omitted.

> In this setup, how would cross-core communication work, including cross-thread? Communication via shared memory. DOS and friends run on core 0 more or less normally; core 1 runs your alternate programming. Allocate a shared ring buffer for messages in each direction, core 0 writes messages and updates the written index on one, reads messages and updates the read index on the other; vice version for core 1. Core 1 p…

Pretty much how its done in TempleOS

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Re: Multicore suppport for DOS is real – partly

#12

Post by fao_ »

People who are interested in DOS software might take note of "Pits", a DOS assembler demo from 2024 which features, quote:

    - Multithreading (using all hyper-threads / CPU cores)
    - Video mode up to Full HD (1920x1080 / 16 bpp)
    - 64-iterative ray-casting
    - Pure DOS with Protected Mode (no drivers, no DPMI)
https://www.pouet.net/prod.php?which=96532

It is a seriously technically impressive demo, if not being the most visually impressive.

Re: Multicore suppport for DOS is real – partly

#14

Post by userbinator »

I wouldn't necessarily call this "support" because DOS itself does nothing for or against; and "all" you need to do conceptually is tickle the APIC to get the other cores running, something that can be done easily even in flat real mode (but this sample appears to use DPMI, so protected mode --- and DPMI itself begins to contain the elements of an OS.)

Not surprised to see the German comments; a lot of low-level PC stuff came from there in the 80s and 90s.

Re: Multicore suppport for DOS is real – partly

#15

Post by vkaku »

Pastebin links here in case someone's getting Vogons issues.

https://pastebin.com/9sgW9dVu https://pastebin.com/3rG2eiWD

I seriously wonder how many APICs are exposed in the DOSBOX code even... Would be a fun exercise to do this and wake up real mode on all cores. I know it's easy to get to long mode after that:

https://github.com/guilt/KOS/blob/master/os/src/x86/realprot...

Re: Multicore suppport for DOS is real – partly

#18

Post by HellMood »

fao_ wrote: post #12

People who are interested in DOS software might take note of "Pits", a DOS assembler demo from 2024 which features, quote: - Multithreading (using all hyper-threads / CPU cores) - Video mode up to Full HD (1920x1080 / 16 bpp) - 64-iterative ray-casting - Pure DOS with Protected Mode (no drivers, no DPMI) https://www.pouet.net/prod.php?which=96532 It is a seriously technically impressive demo, if not being the most vi…

Those people should also definitely check out "Mariana" (2024), a 256 byte demo from the same author, using the same techniques, which was even nominated for the Meteoriks Award for that year.

https://www.pouet.net/prod.php?which=96105

https://2025.meteoriks.org/laureates/#nominees-ota

  Features:
  - Multithreading (using all CPU cores & hyper-threads)
  - Full HD / HiColor (1920x1080 / 16 bpp)
  - 128-iterative fractal on FPU
  - Pure DOS (no drivers, no DPMI)
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