Show the MIPS instructions that implement the following pseudo instructions. You may use the assembler register, $at, but you may not corrupt (overwrite) any other registers. 

(a) addi $t0, $s2, imm31:0
(b) lw $t5, imm31:0($s0)
(c) rol $t0, $t1, 5 (rotate $t1 left by 5 and put the result in $t0)
(d) ror $s4, $t6, 31 (rotate $t6 right by 31 and put the result in $s4)