I agree with Exophase. The Playstation 1 has a lot of guesswork involved as well. Those root counters are fun! Interrupt's are terrible to figure out at first.
But if you use plugin's where the majority of code is already written, writing that "core" is very easy, which I think what Tinnus was trying to say.
So Exophase, let's write a DOSBox MIPS/ARM Dynarec? What do you say? :)