Emulation method like PPSSPP?

[Blackbird]

So do you use the same method PPSSPP uses to emulate PSP? As far as I know it emulates the firmware rather than the hardware directly thus there isn't that much of a speed hit. From my layman perspective it looks like it emulates the OS much more than the HW itself. Correct me if I'm wrong. I'm no expert
Juts interested in this stuff.
You guys really need dev blog sometime in the future. I really enjoyed reading PCSX2's.