Wrong timings in Dragon's Lair 2

MathewWi / fbzx-wii

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Wrong timings in Dragon's Lair 2 #25

Open GoogleCodeExporter opened 9 years ago

GoogleCodeExporter commented 9 years ago

What steps will reproduce the problem?
1. Load Dragon's Lair 2 in 128K mode
2. Start the game

What is the expected output? What do you see instead?
The game should have some slowdown that's specially noticeable in the music 
department. In the emu, music doesn't slow down like it does on real hardware 
(which is actually neat, but incorrect).

What version of the product are you using? On what operating system?
Latest public release.

Please provide any additional information below.
This "no slowdown" thing could be made optional once the emu's behavior is 
corrected, as it might benefit other games, as well.

Original issue reported on code.google.com by iceknigh...@gmail.com on 4 Jan 2013 at 7:38

GoogleCodeExporter commented 9 years ago

Have you tried the precise emulation?
can you send me a snapshot of the game in the instant the issue occours?

Original comment by olimpier...@gmail.com on 5 Jan 2013 at 3:29

GoogleCodeExporter commented 9 years ago

Yeah, I've tried but the music still has no slowdown.

Here's a snapshot I've just made, you just need to start the game and the lack 
of slowdown is immediately noticeable if you've ever tried this game in some 
other emulator or the real thing.

Original comment by iceknigh...@gmail.com on 5 Jan 2013 at 9:14

Attachments:

[Dragon's Lair Part II - Escape from Singe's Castle.z80](https://storage.googleapis.com/google-code-attachments/fbzx-wii/issue-25/comment-2/Dragon's Lair Part II - Escape from Singe's Castle.z80)

GoogleCodeExporter commented 9 years ago

It seems an issue related to the AY-3-8912 chip emulation. 
I though I had conclusively fixed the AY-3-8912 chip emulation.

Original comment by olimpier...@gmail.com on 6 Jan 2013 at 8:11

GoogleCodeExporter commented 9 years ago

Perhaps your emulation is actually too accurate to the official documentation?

I know that the official documentation in certain Mega Drive chips actually 
differs sligthly from how the real ones inside the actual systems work, so this 
might be a similar case.

Original comment by iceknigh...@gmail.com on 6 Jan 2013 at 10:55

GoogleCodeExporter commented 9 years ago

Unfortunatly the documentation on AY-3-8912 is scarse.

I made a list of AY-3-8912 techical charateristics collecting information from 
several sources and peeking other emulators code: 

http://www.worldofspectrum.org/forums/showthread.php?t=39644&highlight=AY-3-8912
&page=3

Original comment by olimpier...@gmail.com on 7 Jan 2013 at 5:41