Computers
posted by Sara .
I have project i need your help.
this is the Project Description
In this project, you will design a complete arithmetic unit of a microprocessor which can
do addition, subtraction, multiplication, and division of two 2bit binary numbers (A1A0
and B1B0). Using a 2x4 decoder whose inputs X1X0 will act as control inputs, you will
select the circuits within the arithmetic unit as following:
Decoder inputs
X1X0
Arithmetic
Circuit
Activated
00 Adder
01 Subtractor
10 Multiplier
11 Divider
Depending on the circuit activated and the A1A0 and B1B0 inputs of that circuit,
corresponding results will be produced by the arithmetic unit. For example,
¡ú if X1X0 = 00, adder circuit will be activated. Then if we supply A1A0 = 102 and B1B0 =
102, the adder circuit will output 1002 = 410 as the result.
(Hint: A1A0 + B1B0 = CS1S0 where C is the carryout and S1, S0 represent sums)
¡ú if X1X0 = 01, subtractor circuit will be activated. Then if we supply A1A0 = 102 and B1B0
= 112, the subtractor output will be 1112s complement = ¨C110.
(Hint: A1A0 ¨C B1B0 = BD1D0 where B represents borrow and D1,D0 represent differences)
¡ú if X1X0 = 10, multiplier circuit will be activated. Then if we supply A1A0 = 102 and B1B0 =
112, the multiplier output will be 01102 = 610.
(Hint: A1A0 x B1B0 = P3P2P1P0 where P3,P2,P1,P0 represent product bits)
¡ú if X1X0 = 11, divider circuit will be activated. Then if we supply A1A0 = 102 and B1B0 =
112, the divider output will be 10002. The first twobit in the result show that the
remainder is 102 and the last twobits show that the quotient is 002.
(Hint: A1A0 ¡ B1B0 = R1R0Q1Q0 where R1,R0 represent remainder bits and Q1Q0 represent
quotient bits. For division 00/00, result will be displayed as 0000. For division 01/00 or
10/00 or 11/00, result ¡Þ (infinity) will be displayed as 1111)

There are many computer architecture references available that may help you.
However good the books are, you'll need a good background of digital logic, which I assume you are in the process of pursuing.