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Thread: Trixter's latest magic... Holy how-in-the-hell!!!???

  1. #1

    Default Trixter's latest magic... Holy how-in-the-hell!!!???

    I don't have too many words to use right now... how in the????

    Here are the videos:

    https://www.youtube.com/watch?v=yHXx3orN35Y

    Audience reaction:

    https://www.youtube.com/watch?v=gdb3AQ14iVc

  2. #2
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    So Trixter, is the reason this demo breaks all emulators due to the fact that none of them emulate the 8088 prefetch queue bus cycle behavior properly? If so, I didn't know it was possible to so finely-tune number of clock cycles elapsed except in a tight loop where the queue is kept between empty/full.

    Cross reference: http://www.vintage-computer.com/vcfo...eal-8088/page3
    Looking for: Needham's Electronics PB-10 Microcontroller Adapter (yes, still looking after 2 years :P).

  3. #3
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    Very nicely done! Speaking of Doc Brown and Calvin Klein, a time machine back to 1982 to run this on a 5150 in front of a middle aged wool blend suited IBM exec would be a priceless reaction to behold.

    Anyone going to Assembly later in the year? Sadly my 2600 demo won't be ready in time. Demo compos have faded in popularity over the past 2 decades in favor of LAN gaming. But many like Revision are still a nice spectacle to witness in-person. i highly recommend it; even if just once.
    "Good engineers keep thick authoritative books on their shelf. Not for their own reference, but to throw at people who ask stupid questions; hoping a small fragment of knowledge will osmotically transfer with each cranial impact." - Me

  4. #4
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    Quote Originally Posted by cr1901 View Post
    So Trixter, is the reason this demo breaks all emulators due to the fact that none of them emulate the 8088 prefetch queue bus cycle behavior properly?
    That is the reason why the demo will probably crash on emulators.
    But even if it doesn't crash, some effects will not look/sound right, because they rely on cycle-exactness of the CPU, the CRTC and video memory wait states.
    And then there is probably no emulator out there that will correctly simulate the high-colour tweakmodes with NTSC artifacting.

    This demo will also not work entirely correctly on most clones, because just having a 4.77 MHz 8088 and a CGA-compatible adapter is no guarantee for cycle-exactness with the real IBM PC/XT and CGA. We have also found that the artifact colours on clone CGA (ATi Small Wonder/Paradise PVC4) tend to be different from real CGA.

  5. #5

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    So this in fact does what any C64-demo (or other fixed platform) does: it uses/abuses the HW that is available, and will not work correctly if the HW is not 100% correct. Nice!
    I really like the demo. Too bad I don't have a proper IBM...

  6. #6

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    Quote Originally Posted by cr1901 View Post
    So Trixter, is the reason this demo breaks all emulators due to the fact that none of them emulate the 8088 prefetch queue bus cycle behavior properly?
    Yes, specifically the end credits part (with the 4 channel music) does not work on DOSBox for exactly this reason. In the source code for this part (which I will be releasing soon) there is a build flag to make a version that does work with DOSBox (which was useful for debugging) by moving the "to be patched" instruction above the instruction that does the patching. Unfortunately on real hardware the routine takes a couple of cycles longer to execute with this change, preventing the PC speaker update from happening at the right time.

  7. #7
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    As pointed out in another thread, there's a variant of the LEA instruction that will also break just about every 8088 emulator as well.

  8. #8

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    Quote Originally Posted by Chuck(G) View Post
    As pointed out in another thread, there's a variant of the LEA instruction that will also break just about every 8088 emulator as well.
    Unfortunately we couldn't come with an excuse to use an "LEA r" instruction in 8088mph!

  9. #9
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    I would love to be a fly on the wall of that wool suited ibm execs office. I agree, How in the holy hell did you achieve that. If IBM had you 30 years ago in their graphics department. Commodore, Amiga, Atari, all of them would be out of business....
    JOZXYQK[/B][/B]

  10. #10
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    The better demo video, just the demo.
    8088 MPH by Hornet + CRTC + DESiRE
    https://fedgeno.com/apps/global-para...desire-2817554

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