sdlBasic is a small, efficient multiplatform basic interpreter originally created by Roberto Viola in 2002.

Its core is based on wxBasic and syntax, inspired by AMOS, is easy to learn by beginners http://www.sdlbasic.altervista.org contains the reference guides language overview, comand syntax, examples and additional tools and resources, required for development.

Using the interpreter
sdlBasic program(s) should be saved in [program_name].sdlbas file and placed in sdlBasic folder, together with EBOOT.PBP file and fonts directory. Of course, sdlBasic folder can be renamed, and EBOOT icon/background can be replaced with a number of tools. If only one .sdlbas file is detected in the folder, the interpreter immediately runs it. Over wise the program selection screen is displayed.

PSP-specific features & limitations
– setdisplay() dimensions are limited to 640×480, 320×240, 480×272 (and some derivatives)
– only some keyboard keys are mapped (arrows, enter, space, escape) and available through key() / inkey commands.
– all psp buttons can be queried with getButtonJoystick() call with button indexes from 0 to 13
– mouse calls are partially implemented via the analog pad and buttons mapped to [x],[o],[triangle],[square]
– isPSP=1 and os=PSP variables are added for platform detection.
– network, mpeg and cd-control calls as well as shell() are not implemented yet.
– mp3 playbeack is not supported. Ogg, wav and tracker formats should be used instead.

http://deniska.dcemu.co.uk/sdlbasic-for-psp-version-0-5-114787.html