You need to have your PSP games as .CSO or .ISO files. I do not have the right to distribute those with the app, so you'll have to provide them on your own. To convert your real PSP games for use with PPSSPP, you need to install a "Custom Firmware" on your PSP. Google for that. Then follow these steps:
There are tools to turn ISO files into CSO (compressed ISO) files to save space, such as maxcso by [Unknown].
If you have digital downloads on your real PSP, they can be used directly on PPSSPP. Just copy the EBOOT.PBP over. Note that this has not been tested as much as ISO loading so there may still be issues with some games.
It may be that you switched the graphics backend to Vulkan, and there might be some devices out there with broken support for this brand new graphics API. If you're stuck in this situation, delete the file /PSP/SYSTEM/ppsspp.ini, or open it in a text editor and change GPUBackend to 0.
PPSSPP can run on iOS up to 12.x. On some versions, the JIT works. See the Downloads page for more info.
Install it exactly the same way as you would on a PSP, that is, copy the files to PSP/GAME or PSP/SAVEDATA (depending on the DLC) on the memory stick. In the Android version of PPSSPP, the memory stick is simply the SD card or USB storage of your phone, PPSSPP will create a PSP folder in the root of that. On Windows without installer, the memory stick is the "memstick" subdirectory in the PPSSPP folder. On iOS, it's in /User/Documents/PSP/ . On Mac and Linux, it's in ~/.config/PPSSPP.
No. PSP Vita is a completely different machine, far more powerful than the PSP and with different security technologies. I don't have neither the information needed nor the time.
No. PPSSPP simulates the BIOS and the internal OS. It does not currently emulate enough of the hardware for the actual PSP operating system to run, so even if you have a copy of it, PPSSPP can't run it.
You probably run PPSSPP on a mobile device. Some of these devices, especially older ones, often have poor OpenGL ES or Vulkan drivers, although the situation is improving.
Why not? The domain name ppsspp.org was available, unlike the corresponding domains for many other alternatives I considered. Today I probably would have named it something different and more memorable.
Unfortunately there is no way to get information about Android app purchases, so I can't pre-approve email addresses or something like that. But feel free to use the free PC version indefinitely.
Yes, PPSSPP has built-in XInput and DirectInput support on Windows so it will "just work" with any Xbox 360 pad and most other pads that you plug into your PC.
On Android, many gamepads like Ouya's pad or Moga work just fine, sometimes with a few limitations. One remaining problem is that the Xperia Play buttons will work but not the touch sticks, for technical reasons.
Any reasonably modern CPU will be just fine, and any GPU that can handle OpenGL 2.0 should have no issues. You should make sure to install the latest graphics drivers available though. Windows XP or later is required, Windows 7 or 8 is recommended. Vulkan will help performance where available, also try D3D9 or D3D11 if OpenGL is slow by changing the backend in settings. On some older computers, you may need to use the D3D9 backend.
CSO are compressed ISO files that can be played directly, decompressing on the fly. Very useful to save space on your Android device, for example. MaxCSO is a great program to create CSO files. Of course, there are others around the web, too.
You can either help out with fixing it, or wait until someone does.
To emulate advanced systems like the PSP fast, the emulator needs to translate the machine code language of the PSP to the machine code language of your PC or mobile device at runtime. This is done with a "Just-In-Time recompiler" or JIT, also known as a Dynarec. PPSSPP has JITs for x86 and ARM, 32-bit and 64-bit.
For a JIT to function, an app needs to have the ability to generate machine code at runtime. This is allowed on Windows, Mac, Linux and Android, while it is completely disallowed on non-jailbroken iOS and on App Store Mac apps, and on Windows Phone 8. It's almost possible on Windows Phone 10 but the OS has a deficiency making it very unstable on ARM (missing support for FlushInstructionCache()).
Shoot me an e-mail (hrydgard at gmail dot com) and I'll remove it.