32 bits.
And the result is 32 bits.
Here is an addition problem using 4-bit operands:
1111 0111 1001 0000 Overflow happened
Two four-bit numbers are added, but the sum does not fit in four bits. Overflow happened. The carry-out from the leftmost column is "1".
If we were using five bits the sum would be
1 0000.
But with four bits there is no room
for the leftmost 1.
Because the carry out from the most significant
column of the sum is 1,
the 4-bit result is not valid.
The leftmost column is called the most significant column
because it corresponds to the highest power of two.
The bits in the leftmost columns are called the most significant bits
or the high-order bits.
The electronic circuits of a processor can detect overflow by checking the carry-out of the leftmost column. A program might branch to an error handling routine when overflow is detected.
Add these unsigned numbers, represented in eight bits. Determine if overflow occurs.
0010 1100 0101 0101