@MiniBobF In regards to the 16bit instruction + 16bit data.
The G4/G3 processors aligns all instructions on 32bit boundries so even if an instruction takes 8 bit, it will still be padded with 0's till it's 32bit long. Thats part of the MSB/LSB thing. PPC has MSB where bit 31 is 1 bit in instruction, optionaly padding till bit 0.