MA 240 2-bit ADDER TRUTH TABLE Name: __SOLUTION____________________
Fill out the truth table (meaning the columns for the three sum bits: s2, s1, and s0, where s0 is the low order bit, and in general si is the column for 2i).
(See below for example of 2-bit binary addition, with carries.) Just
the truth table! (No need to include boolean
expressions or circuits.)
|
a |
b |
|
a+b = s |
a1a0
+ b1b0
----------
s2s1s0 |
DECIMAL ANSWER |
||||
|
a1 |
a0 |
b1 |
b0 |
|
s2 |
s1 |
s0 |
sum10 |
|
|
0 |
0 |
0 |
0 |
|
0 |
0 |
0 |
0 |
|
|
0 |
0 |
0 |
1 |
|
0 |
0 |
1 |
1 |
|
|
0 |
0 |
1 |
0 |
|
0 |
1 |
0 |
2 |
|
|
0 |
0 |
1 |
1 |
|
0 |
1 |
1 |
3 |
|
|
0 |
1 |
0 |
0 |
|
0 |
0 |
1 |
1 |
|
|
0 |
1 |
0 |
1 |
|
0 |
1 |
0 |
2 |
|
|
0 |
1 |
1 |
0 |
|
0 |
1 |
1 |
3 |
|
|
0 |
1 |
1 |
1 |
|
1 |
0 |
0 |
4 |
|
|
1 |
0 |
0 |
0 |
|
0 |
1 |
0 |
2 |
|
|
1 |
0 |
0 |
1 |
|
0 |
1 |
1 |
3 |
|
|
1 |
0 |
1 |
0 |
|
1 |
0 |
0 |
4 |
|
|
1 |
0 |
1 |
1 |
|
1 |
0 |
1 |
5 |
|
|
1 |
1 |
0 |
0 |
|
0 |
1 |
1 |
3 |
|
|
1 |
1 |
0 |
1 |
|
1 |
0 |
0 |
4 |
|
|
1 |
1 |
1 |
0 |
|
1 |
0 |
1 |
5 |
|
|
1 |
1 |
1 |
1 |
|
1 |
1 |
0 |
6 |
|
Example of two-bit binary addition, with two carries:
|
0
1
|
00
1 0 |
1 0 1 |
0 1 |
(superscripted numerals are carry bits from column to the left)