bsnes v0.033
This release adds SPC7110 emulation, without the need for graphics packs!!, and a rewritten S-RTC (real-time clock) emulator.
SPC7110 support means that Far East of Eden Zero, FEoEZ: Shounen Jump Edition, Momotarou Dentetsu Happy and Super Power League 4 are now all fully playable. I will warn you, the emulation is very slow in this version -- while most areas of each game will run at the same speed as other games, there are a few peak moments where speed will drop by up to ~50%. The reason for the slow-down is that I am currently uncertain how to determine the amount of data to decompress in advance, so I default to the maximum amount possible. The reason I am releasing now anyway, is because I beleive in the "release early, release often" paradigm. It will likely take me a few weeks to finish researching this chip, and I didn't want to keep the work I had private during that time. But rest assured, bsnes v034 should feature much faster SPC7110 emulation.
neviksti, Andreas Naive and jolly_codger worked non-stop on the SPC7110 decompression algorithm for the past two weeks. caitsith2 provided valuable data to the effort. I only wish that I could've been of some use, but alas, I had no role in this. In the end, it was neviksti who managed to crack all three(!!) compression modes of this chip, which turned out to be a customized 8-bit QM-coder with a prediction model. You can read more about this here. I would also like to thank Dark Force and John Weidman (aka The Dumper) for their research notes on the SPC7110 register interface.
For those who don't understand the hoopla about figuring out this compression algorithm when we already had graphics pack simulation, I should note that we have since found a few errors in these packs. Not to mention, you no longer need ~4-16MB packs for each game you wish to run. They work like any other game now. Better still, the chip can now be used to compress new graphics, eg for any future translation efforts on these titles.
The real-time clocks in both Far East of Eden Zero and Dai Kaijuu Monogatari 2 will now save a ".rtc" file in your save folder, which contains the clock as set by the video game, as well as a timestamp from your computer when the time was last updated. It uses the difference between the saved timestamp and current time to update the time. This allows you to specify any time you like, whereas previously bsnes would just use your computer's current time, ignoring the time you set in-game. It also allows the "round clock by 30 seconds" option in both games to work. I avoided this before because this method makes supporting daylight savings time and such impractical, although I should note that the original hardware did not support DST, either. This method was required to pass the SPC7110 tests, and is overall much more faithful to how the original chips worked.
Once again, I'd really like to personally thank neviksti for his tireless efforts. Eliminating graphics packs from SNES emulation was one of my primary reasons for getting involved in the SNES emulation scene. That neviksti managed to crack this algorithm means a lot to me. Thank you so much, neviksti. This release is dedicated to you, now go get some sleep ;)
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發表於 2007-1-31 20:48
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