4-BIT ADD/SUB CIRCUIT DIAGRAM
Visual Representation with Automatic 2's Complement
A3:
A2:
A1:
A0:
B3:
B2:
B1:
B0:
SA:
SB:
OPERATION: 0 + 0 = 0
CIRCUIT STAGES
STAGE 1: CONDITIONAL INVERSION
A3
A2
A1
A0
B3
B2
B1
B0
SA
SB
⊕
⊕
⊕
⊕
⊕
⊕
⊕
⊕
∨
Cin
STAGE 2: FIRST ADDITION
4-BIT ADDER
(First Stage)
A'[3:0]
B'[3:0]
Cin
Sum1[3:0]
Cout1
0000
∧
SA∧SB
STAGE 3: CONDITIONAL INCREMENT
INCREMENTER
(+1)
In[3:0]
Out[3:0]
0000
MUX
2:1
0
1
SEL
FINAL OUTPUT
S3
S2
S1
S0
Cout
RESULT
0000
Dec: 0
Active Signal (1)
Inactive Signal (0)
Processing Block
Output
TEST CASES - CLICK TO LOAD
3 + 5 = 8
5 - 3 = 2
-3 + 5 = 2
-3 - 5 = -8
7 + 1 = 8
7 - 7 = 0
-4 + 4 = 0
-7 - 6 = -13