Addressing modes: pseudo-direct
PC <-- PC31-28 :: IR25-0 :: 00
direct addressing: complete 32-bit address
26 bits in instruction are concatenated with PC
        4 high-order PC bits
        00 for low-order bits
can access 1/16 of all possible MIPS addresses
note that figure is not clear on which bits are actually used from PC
J-type instructions