Assume the following register contents:
$t0 = 0x, $t1 = 0x12345678.
(a) What is the value of $t2 for the following sequence of instructions?
sll $t2, $t0, 4 or
$t2, $t2, $t1
(b) What is the value of $t2 for the following sequence of instructions?
sll $t2, $t0, 4 and
$t2, $t2, -1

Explanation:

1. Write the binary representation of $t0:

1010 1010 1010 1010 1010 1010 1010 1010

After shifting left 44 times, we get

0000 0000 0000 0000 0000 0000 0000 0000

Therefore, after the first instruction we get $t2 = 0;

clearly after the second instruction; we have $t2 = $t1 = 0x12345678

2.after shifting $t0 4 times we get

1010 1010 1010 1010 1010 1010 1010 0000

therefore after first instruction we get $t2 = 0x0

Also notice that

-1₁₀ = 1111 1111 1111 1111 1111 1111 1111 1111₂

therefore the second operation does not have any effect we get $t2 =

0x0

3. after shifting $t0 3 times we get;

0001 0101 0101 0101 0101 0101 0101 0101

therefore after the first instruction we get $t2 = 0x15555555

Also

0xFFEF = 0001 0101 0101 0101 0101 0101 0101 0101

Now apply the logical and

result $t2 = 0x00005545