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ZeroByte

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Everything posted by ZeroByte

  1. Stand up a Linux VM in Virtual box? Or build it on a RPi? If you have trouble, Ill PM one to ya.
  2. Pretty sure this arrangement exists because at the time it was designed, the 65c816 was still being considered.
  3. Ahh! That was the correct answer! (or at least I'm 99.9999% sure it is - obviously Strider may say I'm wrong too - lol)
  4. I just looked up a video of the Amiga version, and omg it's awful.
  5. The busy delay is incurred after each and every write to the YM data port, not just KeyON/OFF. I worked with @StephenHorn on the box16 emulator project while he was refactoring that emulator to use the new BSD-licensed YMFM core library. I've learned quite a bit about how this chip works. R38 has several inaccuracies in the YM implementation - the core it uses does not emulate the busy behavior at all. You can bang away on it all day long and it won't skip a beat. The library just handles it. Furthermore, I don't think the IRQ functionality is emulated, and I also think the timer behavior might not be implemented either - I'll go re-test this and let y'all know... Box16 has extended the YM support in several ways - it supports YM IRQs as well as busy flag behavior. Some of this has been a matter of the group's interpretation of other example code and/or the official YM2151 application manual. In other words, the current behavior in Box16 is our best guess as to the real behavior. Stephen has done an excellent job integrating this code and dealing with a colossal time synchronization nightmare, by the way. Kudos to his hard work! One of his decisions was to make these "enhancements" be disabled by default to maintain functional parity with the official emulator. They are activated by command-line arguments. Interestingly, when testing the accuracy improvements, one of my VGM playback routines went nuts and played an entire song back in less than 1.5 seconds. It turns out that the original VGM data stream contains commands that enable YM IRQs. My player just used WAI as a poor man's IRQ handler to wait for VSYNC. Thus it mistook these YM IRQs as VBLANK IRQs. The player was built to read the busy flag though, and even with strict enforcement of the busy state, the player doesn't drop any updates, so that seems to work properly. After removing the IRQ enable messages from the VGM, it plays back perfectly on Box16 even when it enforces busy flags. Real Hardware? The big question is how will this work on the real thing? As I said above, the behavior is currently our best guess based on other sources, none of which being real hardware. One thing I can say is that @SlithyMatt's Chase Vault game works on real HW, and the game's YM routine uses busy flag reads to ensure that it does not write to the chip when it's busy - so that's a good sign. Beyond that, I've sent a basic read test program to Kevin, as the YM reading functionality has never been subjected to testing on X16 hardware the way writing has been. So far, the "hello world" results are interesting. Kevin's only been able to test at 2 and 4MHz which the math says should work just fine on YM. 8MHz is the really important one, but as the system is currently experiencing other 8MHz-related problems, Kevin wasn't able to test at 8MHz. In short - the test program successfully read IRQ status flags w/o any errors at 2 and 4 MHz. Interestingly, the busy flag read test never observed the flag's having been set, but I think there might've been a bug in my code. I'm personally convinced that the write delay specification is actually a little bit different in reality than you might expect from reading the application manual. That is, I strongly suspect that the "64 YM clock delay" is not a minimum but a maximum. The data sheet definitely has other errata, and I'm convinced this is just another example. I have a real YM to test with, but don't have everything lined up enough to be able to put it on a breadboard and do real testing just yet. If I can get that done, I'm definitely going to poke around with the real chip's busy state flag to see what makes it tick. YM and write performance / overhead: As for writing performance with the YM, I'd like to point out that in my experience with generating byte streams of PCM writes and FM writes, the FM music data streams are much smaller than the PSG streams. This is completely to be expected. That's because the FM chip does so much of the modulation in hardware that you don't need to update it nearly as often to get decent-sounding music. PSGs must be constantly modified for every little thing, be it pulse width modulation, vibrato, etc - all of which is done in hardware on the FM chips. Consequently, you end up performing SIGNIFICANTLY fewer writes to an FM chip than you do a PSG over the course of a tune. Still, sitting around for ~144 clock cycles waiting on the chip to finish chewing the last bite is not ideal. I believe one way to handle YM writes may be to queue up the writes into a ring buffer, and have an IRQ that empties the ring buffer. You can set the YM's timers to run a little slower than the actual rate the YM could drain the buffer in order to cut down on the IRQ overhead. This would have the effect of spreading the load evenly throughout a frame if that's what you'd like to do. Kevin has confirmed that the YM2151's IRQ line is indeed connected to the system, so this should be doable on the real system.
  6. To me the #1 reason I like the YM chip is that it sounds like it does. I like the fact that both the FM and PSG sounds can work together could make for some truly great stuff.
  7. They've started a Super Metroid playlist, and wow - the first track is the mysterious statue that blocks the way to the final area - that track sounds mind-blowing on the original synths with uncompressed samples. The Mother Brain fight is pretty amazing too.
  8. The arcade version uses a YM2151. I bet the Commander X16 could do a near-perfect port.
  9. What's funny is that in a way, they made the revelations from the gigaleak just that much more special by virtue of their own secretive nature. If they just put all that stuff in "bonus features" sections like an assets gallery and had commentary nodes like Valve does - then people would've thought it was cool, but when it's been a mystery for years and years, with people slobbering gleefully whenver so much as a single unused asset gets mined from a ROM image.... well, the gigaleak makes people feel like they're holding a winning lottery ticket during a total eclipse on Christmas day.
  10. Apparently, the Zelda tracks were made using some pretty awesome detective work. They looked at a photo of Koji Kondo in his studio and identified the hardware in his equipment rack - then went through sample libraries for the devices until they found the original samples used, and reconstructed that way. Pretty awesome.
  11. I was browsing around and decided to revisit the Nintendo Gigaleak from last year. I had stopped following when a later release had come out including archives of Koji Kondo's original uncompressed samples used to make the music for classics Super Mario World, Zelda A Link To The Past, etc. Well, fast forward from there, and a guy "The Brickster" has released 'remastered' soundtracks of several games, made using the original uncompressed samples. Here's a link to the Zelda playlist - it's amazing to hear this Note, these videos have been posted for a little while, so it's not that this is "breaking news" but I thought that this would be interesting for anyone here who wasn't aware of such things' existence (like me)
  12. Hey, you got tiles converted and loaded and a nice per-scanline routine running. Nice work so far.
  13. Money laundering makes sense, but to me, simple greed is sufficiently explanatory. This is just pump-n-dump with an industrial-scale pump. People like this don't care that the bubble bursts. They'll have made enough money by the time it bursts that whatever they had left in the market was already made from pure profit to begin with. Hopefully, the fact that this story is gaining as much traction as it seems to be gaining will cause it to go ahead and burst right now before these dudes have a chance to pull their money out of it.
  14. ZeroByte

    My X16 Case

    Looks more like 3u to me....
  15. I made that very point in another thread. I suspect the main hesitancy along this line is the fact that there's a major design decision in flux right now regarding the PS/2 interface. Personally, as long as the board is flashable without special hardware/cables, then I don't see any reason why it couldn't get "firmware updates" to go along with emulator updates. Anyway, I also suspect that the particulars of the "phase 3" design aren't as close to being done as the X8 which is probably why Dave's leaning towards releasing the X8.
  16. This was a cool post. While watching, I actually kinda got which game the middle title is. Never even heard of the other two.
  17. I'd say make sure that the one and only time you put .org $80D is in the file which is intended to assemble there. Don't put any .org statements into the other files so the assembler will just find places to plop them down into memory. Don't know if this applies to your situation (i.e. don't know if you're putting .org into all of the files or not) but it might be helpful.
  18. This is my number-1 "whoopsie" in assembly coding. That, or putting one in when it didn't belong.
  19. The game’s title in Japan: Top Secret , Hitler’s Resurrection.
  20. I think Reddit has shown us all what happens when downvotes are available. Like my grandma used to say "If you can't say something nice, don't say anything at all."
  21. I plan to post a GIF of that soccer hooligan kid giving the middle finger in place of a downvote.
  22. ZeroByte

    1980's Memes

    Don't worry, they'll soon upgrade that to ZIPdisk.
  23. Okay here's one: This is another run-n-gun style action game which began as an arcade title but is much more well-known for its NES version. Like many NES titles, the home version saw many changes from the original arcade format which take into account the fact that this is a home game for enjoyment, rather than an experience designed to gobble quarters. The core gameplay mechanic was kept but expanded upon with "rpg-like" elements done via permanent upgrades obtainable through the course of gameplay. The NES title has you rescue the arcade version's player character. The game is noteworthy among platforming / run-and-gun games in that jumping is not a gameplay mechanic. The Japanese version of the game contains a story line and imagery that was deemed too controversial for western markets, so this content was mostly removed from the western releases, being replaced by thinly-veiled fictional names and imagery which stronly evoked the original subject without naming it explicitly. The game's final sequence contains a gory cinematic sequence which was relatively shocking at the time, especially for a Nintendo platform.
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