Question

Write the MIPS assembly instructions corresponding to the following high level instruction. The used base register is $s2 for Al] and $s1 for F[]. and s 1 for F[6]A[4] +5

Answer 1

li $t2, 4 # put the index into $t2

add $t2, $t2, $t2 # double the index

add $t2, $t2, $t2 # double the index again (now 4x)

add $t1, $t2, $s2 # combine the two components of the address

lw $t3, 0($t1) # get the value from the array cell

add $t4, t4, 5 # add 5 to the value of the array cell

li $x2, 4 # put the index into $x2

add $x2, $x2, $x2 # double the index

add $x2, $x2, $x2 # double the index again (now 4x)

add $x1, $x2, $s1 # combine the two components of the address

sw $t4, 0($x1) # store the value into the array cell F[4]

NOTE: To access the data in the array requires that we know the address of the data and then use the load word (lw) or store word (sw) instructions. Words (which is how integers are stored) in MIPS take up 32 bits or 4 bytes. This is the reason I am doing 4x.