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  • gloriouscowgloriouscow@oldbytes.space
    Oct 14, 2026, 6:57 PM

    8080EXR is an 8080 CPU exerciser that runs under CP/M. On real hardware at around 2 MHz or so it takes about 4 hours to complete - a V20 maybe half that. It's still a long process.

    The version I have somehow has lost its internal hashes, or maybe that's a separate data file, I don't know.

    This is a frame capture from the test running on a real V20, so we can use the 'found' hashes as truth.

    #retrocomputing #emulation

    A screenshot of the output of the 8080 instruction exerciser 8080EXER.COM A number of instruction families are printed, and a message showing the expected and computed hashes
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  • gloriouscowgloriouscow@oldbytes.space
    Oct 14, 2026, 6:59 PM

    We can execute this on our V20 using an 8080 emulator such as Sydex's 22NICE, which supports the V20's 8080 emulation mode.

    The V20's emulation mode requires software support - it's not as simple as just running your favorite CP/M program. The program must be located in memory and some strategy for handling interrupts employed.

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  • gloriouscowgloriouscow@oldbytes.space
    Oct 14, 2026, 7:01 PM

    Happily, our new microcode V20 core matches every hash, so 8080 emulation mode seems to be working well.

    For all 3 people who will ever use it, rejoice.

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