missing opcodes

[xor32dotcom]

opcodes need careful examination.

tempAR already allows for easy opcode reversal, but I did notice some of them were missing,
(ones that default to ????). I compared some of these missing opcodes on the PPSSPP
emulator to instructions that decoded as ???? on tempAR, and where still being executed on the PSP in some occasions.

I'm willing to try and implement this myself, although there doesn't to be any readily available documentation pertaining the PSP custom MIPS IV (?) - Allegrex