gameplaySP (gpSP for short) is a GBA emulator written completely from scratch. It is still pretty young (only having started a 3 months ago)
and thus rather immature, but it does a decent job of playing a number of games. It is currently very minimalistic, in the sourcecode, presentation, and features. Its number one focus is to deliver a GBA
gaming experience in the most playable way that PSP can manage, with frills being secondary.

Having said that, optimization was the important way in achieving this goal, with overall compatability being a near second. Because of this
some games may not run at the favor of running more games significantly better. Of course, the compatability will improve with time.

Many games will run at their best out of the box, but some games will run very slowly unless idle loops are taken care of. There is a supplied
ROM database, game_config.txt, that gives idle loop targets and other settings that may help a game to run better (or at all) on a per-game basis. Currently (as of the first release) only a very small number of
games are entered. This number should improve dramatically over time.

gpSP currently requires an authentic GBA BIOS image file to run. It will make no effort to run without one present; this file is 16kb and should
be called gba_bios.bin and present in the same location as the EBOOT.PBP file. Please do not ask me where to obtain this, you'll have to look
online or grab it from a GBA. Note that it is not legal to have this file unless you own a GBA, and even then it's rather gray area.

-- Features --

gpSP mostly emulates the core Gameboy Advance system. As of right now it does not emulate any special hardware present on various GBA cartridges.

What it emulates:

GBA CPU: All ARM7TDMI ARM and Thumb mode opcodes except block memory w/ s-bit (probably aren't used in GBA games) Video: Modes 0, 1, 2 almost completely, basic 3-5 support, sprites,
windows/OBJ windows Interrupts: HBlank, VBlank, all timers, all DMA channels, keypad DMA: Immediate, HBlank, VBlank, sound timer triggered
Sound: Both DirectSound channels and all 4 GBC audio channels Input: Basic GBA input delivered through PSP controls Cartridges: Currently supports up to 16MB large ROMs (32MB will not load)
Backup: 32/64kb SRAM, 64kb flash, 512bit/8kb EEPROM

What it lacks:

Video: No mosaic, bitmap modes lack color effects (alpha, fades), there might be some minor inaccuracies in blending...Cycle accuracy: Very cycle innacurate; CPU is effectively very overclocked, meaning games with rampant idle loops will probably run very poorly. DMA transfers effectively happen for free (0 cycle). Please do NOT use gpSP as a first source for developing GBA homebrew,
try No$GBA instead.Backup: 128kb flash is not currently supported.

-- Controls --

The control scheme is very simple and currently can not be changed.

At the ROM selection screen:

Up/down: navigate current selection window.
Left/right: switch between file window and directory window. Circle/start: select current entry.
Square: go one directory up.