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  • gloriouscowgloriouscow@oldbytes.space
    Nov 10, 2026, 9:34 PM

    I had both the 286 and 386 boards plugged in today to debug the protocol changes, and I got an especially stupid idea

    I added support in the GUI to connect to two CPUs at the same time.

    And then we can wire IO ports together, via mail slot ports. Two pairs of IO addresses indicate data and data-ready in both directions - like a virtual serial link.

    So now the 386 can talk to the 286 and vice versa. What is the point of that? I don't know.

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Replies

  • gloriouscowgloriouscow@oldbytes.space
    Nov 10, 2026, 9:36 PM

    The multi-cpu support itself is useful since I want to implement support for a 'consensus' mode where I can execute the same code on say, two different steppings of 8088, and see how they may differ.

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  • gloriouscowgloriouscow@oldbytes.space
    Nov 10, 2026, 9:36 PM

    Differences in registers, flags, or cycle execution can be highlighted.

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  • gloriouscowgloriouscow@oldbytes.space
    Nov 10, 2026, 10:01 PM

    it still blows my mind that a i soldered a 138-pin 386EX to a PCB I slapped together in KiCad without any sort of engineering degree and it actually functions

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  • gloriouscowgloriouscow@oldbytes.space
    Nov 10, 2026, 10:03 PM

    actually I wonder if @MuseumJoe would be interested in carrying #ArduinoX86 boards.

    The 8088/8086 board is completely passive and the software GUI is becoming quite mature. It has huge potential for use by educational institutions

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  • gloriouscowgloriouscow@oldbytes.space
    Nov 10, 2026, 10:14 PM

    The best thing about ditching the serial UART though - I get two 5v tolerant GPIO pins back.

    This lets me hook up the PEREQ and /PEACK pins that implement the CPU<->FPU handshake. Capturing those pins in future FPU instruction tests isn't strictly necessary for emulation, but they will make the tests that much useful as an oracle of hardware behavior

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  • Joe's Computer MuseumMuseumJoe@oldbytes.space
    Nov 10, 2026, 11:27 PM

    @gloriouscow I mean, certainly. I can make them available for less than folks can get them in small batches on their own.

    Not sure what the demand is, but I'm always amenable to a conversation.

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  • Henning Paul DC4HPhennichodernich@radiosocial.de
    Nov 11, 2026, 7:17 AM

    @gloriouscow I know enough people with an engineering degree who completely unable to design a PCB.
    You can get very far without an engineering degree by just following best practices. The engineering degree however might help you understand where they come from.

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  • The ghost of internet pastjpm@aus.social
    Nov 10, 2026, 10:32 PM

    @gloriouscow I’m sure Intel had a point when they glued two completely different CPU cores with different instruction set capabilities into a single socket *stares in Alder Lake*

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