4. Overflow
ď‚´In any circumstances, the results of operations can be
greater than that can accommodate the size of the word in
use.
ď‚´When an overflow occurs, the ALU must clear the signal
about this state so there is no attempt to use the results of
the operation
ď‚´When two numbers are added, and both are positive or
both negative, the overflow will occur if and only when it
has the opposite sign
5. Adder
Half Adder
ď‚´The function : to add two
binary digits with the result
of an increase and a carry
of.
ď‚´Input : 2 kinds of A and B
ď‚´Output : Sum and Cout
ď‚´The carry of results is not
added to the next
calculation
Full Adder
ď‚´The function : to add two
binary digits and carry of the
previous calculation with the
result of the increment and a
carry of.
ď‚´Input : A, B and Cin
ď‚´Output : Sum and Cout
ď‚´Result of carry of also added
at next calculation
8. Addition and Subtraction
ď‚´Normal binary addition
ď‚´Monitor sign bit for overflow
ď‚´Take twos compliment of subtrahend and add to
minuend
ď‚´i.e. a - b = a + (-b)
ď‚´So we only need addition and complement circuits
9. Exercise
Gunakan perhitungan biner untuk mencari hasil
perhitungan desimal dari :
a. 5 + 2 =
b. (-3) + (-6) =
c. 7 – 7 =
d. (-6) + 3 =
e. 6 – 3 =
10. Refference
Stalling, William, Computer Organization
and Architecture, 10th Edition, Pearson,
2015
Abdurohman, Maman, Organisasi dan
Arsitektur Komputer revisi ke-4, Penerbit
Informatika, 2017