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Name Yotam Barnoy
Team Member since 2009-09-22
Working on PSP platform
PSP Optimization
Personal webpage/BLOG -
Email -

Worked On

  • PSP
    • Suspend/resume support
    • Plugin support (ELF loader)
    • Console-oriented virtual keyboard
    • D-pad directional support
    • Eliminating the evil undead flickering bug (it was a tough one)
    • Refactoring, redesign and cleanup

Working On

  • PSP Optimization
    • Rendering speedup: done and makes vsync super accurate (better than PC)
    • MP3 using Media Engine: done
      • Turn into thread for better efficiency (allowing music more processing time without slowdown)
      • But will threading really help? It's pretty complicated. What about syncing?
      • Correct small bug with seeking (already corrected in mainstream mp3 decoder). Clean up messy code.
    • Video Speedup
      • Actually harder than expected: it's hard to find codecs that do the kind of work that the VFPU will improve
      • Check other codecs for possible speedups using VFPU/alignment
    • Tests: done
      • how much reading is done by MP3 rendering/movie playback? How much will we need to cache? done. Reads chunks of 15-25KB preceded by small 4KB reads. Whole MP3 loads are a problem (200KB+).
      • How often do we read from the memory stick when we're going fast (movies)? Can we use a thread to do async reading? Is there enough time between reads?
    • Improve memcpy: alignment, rotation
      • Memcpy is done. Not sure how to improve it with VFPU.
      • Memmove can also be improved -- needs reverse memcpy.
    • No More SDL: done.
    • Threads for audio: consumer and producer
      • Again, is this really helpful? It may allow lowering of priority, but only temporarily? What about syncing?
  • Aspect Ratio: done
  • Replace stdio with PSP functions: done.
    • Turns out it's a huge speed boost!
  • Timidity
    • A lot of work. May improve speed over midi and sound better.

To Do

  • PSP
    • Groovie video is slow
      • Seems like problem is in Groovie engine. Sounds start out fine and then get crackly.
    • Use libTimidity for music
  • Generic virtual keyboard: take my keyboard and make it available to all. Involves switching from bitmaps to vectors.
  • Generic ELF loader
    • Already done in GSOC. Solve issue with loading one plugin at a time.
  • MP3 header processing for faster seeking and getting the file length.
  • Image Viewer


  • PSP may some day be unable to load ScummVM plugins as they are, because it's shifting towards accepting only PRX files (ie. PIC code). Some solution will be needed to adapt the current plugin code for PIC in the main executable.
    • Idea: dump the symbol table of the main executable into another file. When loading plugins, load this into memory. Create a symbol in memory using ld script that will indicate where in memory the main executable was loaded. Finally, relocating the plugins will obviously be more work since we don't have ld to do some of the job for us. We might need 2 MipsPlugins: MipsComplete and MipsIncomplete.
    • Alternatively instead of dumping the table, just copy the executable into the plugin directory and rename it base.plg.