In computing, an arithmetic logic unit (ALU) is a digital circuit that performs arithmetic and logical operations. The ALU is a fundamental building block of the central processing unit (CPU) of a computer, and even the simplest microprocessors contain one for purposes such as maintaining timers. The processors found inside modern CPUs and graphics processing units (GPUs) accommodate very powerful and very complex ALUs; a single component may contain a number of ALUs.
4. In computing, an arithmetic logic unit (ALU) is a digital circuit that
performs arithmetic and logical operations. The ALU is a fundamental
building block of the central processing unit (CPU) of a computer, and
even the simplest microprocessors contain one for purposes such as
maintaining timers. The processors found inside modern CPUs and
graphics processing units (GPUs) accommodate very powerful and very
complex ALUs; a single component may contain a number of ALUs.
Mathematician John von Neumann proposed the ALU concept in 1945,
when he wrote a report on the foundations for a new computer called
the EDVAC. Research into ALUs remains an important part of computer
science, falling under Arithmetic and logic structures in the ACM
Computing Classification System.
12. The shifting :
S1 S0 Operation
0 0 No change
0 1 Parallel input
1 0 Shift right
1 1 Shift left
13. V1
5 V
A3
A2
A1
A0
B3
B2
B1
B0
Ci
U2
74LS283N
SUM_4 10
SUM_3 13
SUM_1 4
SUM_2 1
C4 9
B411
A412
B315
A314
B22
A23
B16
A15
C07
U1
74LS283N
SUM_410
SUM_313
SUM_14
SUM_21
C49
B411
A412
B315
A314
B22
A23
B16
A15
C07
BCD adder
sum>9
carry flag
The BCD addition of the input data:
14. BCD SUBTRACTION
DECIMA
L
DIGIT
9’s
COMPLE
MENT
0 9
4 5
The step as flowing :
(a) ADD 9’s COMP. OF B TO A
(b) IF RESULT > 9, CORRECT BY
ADDING 0110
(c) IF MOST SIGNIFICANT CARRY
IS PRODUCED [i.e. =1] THEN
THE RESULT IS POSITIVE AND
THE END ARROUND CARRY MUST
BE ADDED.
(d) IF MOST SIGNIFICANT CARRY
IS 0 [i.e. NO CARRY] THEN THE
RESULT IS NEGATIVE AND WE
GET THE 9’s COMP. OF THE RESULT.
21. 5-inverting of in put data:
Pass the input data on ((NOT)) gate which
Is alogic gate that has one input and one output , the output is
low when the input is high and the output is high when input is
low
22. 6-NANDing of input data:
Pass the input data on ((NAND)) gate which
Is alogic gate which has 2 input and 1 output and the out put is
low when the two input is high and the rest of the possibilities
of input the out put is low
23. 7-NORing of input data:
Pass the input data on ((NOR)) gate which is a logic gate that
Has 2input and 1 out put and the out put is high only when the
two input is low , the rest of the possibilities of input the out
put is low.