AFAIK the PSPSDK was not leaked. It was made from scratch using information gathered from PSP, and specially (IIRC) the Bubble Bobble game with debug info on the retail version helped a lot to make a working SDK and figuring out the functions names used by the official SDK.
Quaeton wrote:Is it just a case of decrypting the firmware and seeing how the different functions are defined?
You actually don't need anything from the firmware. If you are able to RE the executables (e.g. PRXs on PSP) then you can create tools to make your own.
Quaeton wrote:For example if the native programming language for Vita is C
Common mistake: programming languages are not native to anything. ALL
devices have only ONE
native language: machine code. Anything else (.e.g assembly, C, C#, Java, whatever) is for us humans. Machines do not understand a thing about that.