ParaJVE Bugtracker

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ID Category Severity Reproducibility Date Submitted Last Update
0000025 [ParaJVE] Emulation > Timings minor always 2009-11-03 14:34 2009-11-04 20:39
Reporter parabellum View Status public  
Assigned To parabellum
Priority normal Resolution fixed  
Status resolved   Product Version
Summary 0000025: Bedlam runs way too fast
Description ParaJVE has some speed timing issues, nonetheless, the games usually remain playable.
An exception is Bedlam, that runs much too fast to be played correctly.
Additional Information
Tags No tags attached.
Cartridge Bedlam, Cosmic Chasm, Hyperchase, Rip Off, Star Trek, Tour de France, Polar Rescue
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parabellum (administrator)
2009-11-03 14:42
edited on: 2009-11-04 10:05

The emulator detects end of frames using the 6522 T2 timer. After each end of frame, it waits for a specified delay, in order to achieve a constant framerate.

So far, we made the assumption that the T2 counter was always set to 30.000 (which is the default for most of the existing games), but Bedlam does set this counter to 49407 ($C0FF). Hence, ParaJVE was running the game at 160% of its original speed.

Now that it has been fixed, the emulator computes the ratio (T2 value / 30000), and use this as a factor to multiply the initial delay to wait for the next frame.

parabellum (administrator)
2009-11-03 21:22
edited on: 2009-11-04 10:04

After testing the patch against the whole set of ROMs, it appears that no less than 7 games were impacted by this bug. So the correction fixes all the 7 games.

Following is a list of these "non-standard" games, with the delay value they're using.

45000 ($AFC8) :
  • Cosmic Chasm
  • Hyperchase
  • Rip Off
  • Star Trek
45056 ($B000) :
  • Tour de France
49152 ($C000) :
  • Polar Rescue
49407 ($C0FF) :
  • Bedlam

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