Picodrive is a Megadrive/Genesis emulator for the GP2x by notaz.

Changes:

* Fixed DMA timing emulation (caused lock-ups for some genesis games).
* Idle loop detection was picking up wrong code and causing glitches, fixed.
* The ym2612 code on 940 now can handle multiple updates per frame (fixes Thunger Force III “seiren” level drums for example).
* Memory handlers were ignoring some writes to PSG chip, fixed (missing sounds in Popful Mail, Silpheed).
* Improved z80 timing, should fix some sound problems.
* Fixed a bug with sram register (fixes Phantasy Star 4).
* ROM loader was incorrectly identifying some ROMs as invalid. Fixed.
* Added code for PRG ram write protection register (Dungeon Explorer).
* The memory mode register change in 1.31 was unsafe and caused some glitches in AH-3 Thunderstrike. Fixed.
* Fixed a file descriptor leak.
* Updated documentation, added Gmenu2x manual.

http://notaz.gp2x.de/releases/PicoDrive/PicoDrive_132.zip