Jpcsp is the most advanced PlayStation Portable emulator, allowing you to play your PSP games on a PC. Even though Jpcsp is written in Java, it can already reach 100% PSP speed on a lot of commercial games... and the emulator performance is constantly increasing.
Here's the changelog from 3 latest SVN builds:
r2552 - Improvement in ELF Loader: support program sections of length 0
r2551 - Improved compilation of SB and SH instructions: compilerPerf.pbp is showing a small performance improvement.
r2550 - No SVN build. Improved performance of UmdBrowser on slow computers. The param.sfo and ICON0.PNG are now cached under tmp/UmdBrowserCache and not read from the ISO/CSO at each restart of Jpcsp.
Visit official homepage for further information and grab the latest build from automated SVN repository.