Answer from cs61c-cl (Hiroki Terashima 16032281) for Question 4
Memory-mapped I/O is a a way to address and give commands to an I/O device.  Portions of the address space are assigned to I/O devices, and reads and writes to those addresses get interpreted as commands to the I/O device.


($t0 = interrupt enable, $t1 = currentindex , $t2 = current value) 
Loop:
   beq $t0, $t2, exit
   add $v0, $v0, $t2
   addi $t1, $t1, 1
   lw $t2, 0 ($t1)  
j Loop
exit: