TTYman has updated his MAME port.

Release notes:

Specific Features:
– Based on latest GP2X MAME4All releases v4.7;
– 480×272 full PSP Hires Support, now games with >320 orizz. and >240 vert. pixels are fully playable (Loderun, Galaga etc.);
– Overclock support, from 133 to 333 MHz;
– Fixed, Fixed Divided by 2, Software Scaled and Software Full Screen Stretched resolutions (all maximum 480×272);
– Frameskip as GP2X version (fixed 0-5, auto 1-5);
– Vsync on/off;
– Save configuration support, default and per game;
– 22KHz with 16 voices predefined sounds, 33KHz and 44KHz frequencies with 4, 8 and 16 voices combinations added;
– Preliminary analog support;
– Autocentering fix for all resolutions;
– Optimized compiled code as derived from GP2X version, but for PSP cpu (fastest graphics core!);
– Stripped & Packed executable, only 2.1MB;
– Original graphics theme from Gold edition;
– Music in menu (filename music.psp in data folder), in these supported formats: .MOD, .S3M, .IT, .XM and .OGG;
– Added, as bonus, 1st classified OldSkool at Assembly 2007 Music Competition (Commodore 64 based), in .OGG format;
– Graphic theme 480×272 BMP skins support, both pspmenu480.bmp and pspsplash480.bmp in folder skins;

Specific Controls:
– Button SELECT: Insert credits.
– Button START: Play.
– Button HOME: after Pause exit game and return to menu.
– Buttons L+R: Activate/deactivate screen fixed/fixed div2/scale/stretch.
– Buttons L+R pressed during one second: Pause.
– Buttons L+HOME simultaneously: Reset emulation.

Fixed from 4.7r2:
– Sounds now are near arcade perfect, with minor gliches in some sound chips emulations;
– Gold (CPS1, System16 and Neogeo) specific emulations are now stand-alone, as require different z80 cpu implementation;
– Improved performance with sounds, oldies with 0 frame skip and vsync on, others with auto-1 and auto-2;