Matakuliah
Tahun
Versi
: T0324 / Arsitektur dan Organisasi Komputer
: 2005
:1
Pertemuan 3
Instruksi Mesin dan Program: I
1
Learning Outcomes
Pada akhir pertemuan ini, diharapkan mahasiswa
akan mampu :
• Menjelaskan prinsip kerja instruksi mesin
dan konsep representasi bilangan ( C2 )
( No TIK : 2 )
2
Chapter 2.
Numbers,
Arithmetic Operations,
and
Characters
3
B
Values represented
b3 b2b1b0
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
1
1
1
1
1
1
0
0
1
1
0
0
0
0
1
1
0
0
1
1
1
0
1
0
1
0
1
0
0
1
0
1
0
1
0
1
Sign and
magnitude
1's complement
+7
+6
+5
+4
+3
+2
+1
+0
- 0
- 1
- 2
- 3
- 4
- 5
- 6
- 7
+7
+6
+5
+4
+3
+2
+1
+0
-7
-6
-5
-4
-3
-2
- 1
-0
2's complement
+
+
+
+
+
+
+
+
-
7
6
5
4
3
2
1
0
8
7
6
5
4
3
2
1
Figure 2.1. Binary, signed-integer representations.
4
0
+
0
0
1
+
0
1
0
+
1
1
+
1
1
10
Carry-out
Figure 2.2. Addition of 1-bit numbers.
5
N - 1
0
1
N - 2
2
(a) Circle representation of integers mod N
0000
1111
1110
1101
- 2
- 3
-1
0
0001
+1
- 4
1100
1011
- 5
- 6
1010
0010
+ 2
+ 3
0011
+ 4
- 7 - 8
+ 7
+ 5
+ 6
0100
0101
0110
1001
0111
1000
(b) Mod 16 system for 2's-complement numbers
Figure 2.3. Modular number systems and the 2's-complement system.
6
(a)
(c)
(e)
0010
+ 0011
( + 2)
( + 3)
0101
1011
+ 1110
1001
1101
- 1001
( + 5)
(- 5 )
( - 2)
( - 7)
(f)
(g)
(h)
-
0010
0100
0110
0011
1001
1011
(- 3 )
(- 7 )
( + 2)
( + 4)
( + 6)
( + 3)
( - 7)
( - 5)
(b)
(d)
0100
+ 1010
1110
0111
+ 1101
0100
1101
+ 0111
0100
0010
+ 1100
1110
0110
+ 1101
0011
1001
+ 0101
1110
(i)
(j)
-
1001
0001
0010
1101
(- 7 )
( + 1)
( + 2)
( - 3)
1001
+ 1111
1000
0010
+ 0011
0101
( + 4)
(- 6 )
(- 2 )
( + 7)
( - 3)
( + 4)
( + 4)
( - 2)
( + 3)
( - 2)
( - 8)
( + 5)
Figure 2.4. 2's-complement Add and Subtract operations.
7
B
Values represented
b3 b2b1b0
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
1
1
1
1
1
1
0
0
1
1
0
0
0
0
1
1
0
0
1
1
1
0
1
0
1
0
1
0
0
1
0
1
0
1
0
1
Sign and
magnitude
1's complement
+7
+6
+5
+4
+3
+2
+1
+0
- 0
- 1
- 2
- 3
- 4
- 5
- 6
- 7
+7
+6
+5
+4
+3
+2
+1
+0
-7
-6
-5
-4
-3
-2
- 1
-0
2's complement
+
+
+
+
+
+
+
+
-
7
6
5
4
3
2
1
0
8
7
6
5
4
3
2
1
8
(a)
(c)
(e)
0010
+ 0011
( + 2)
( + 3)
0101
1011
+ 1110
1001
1101
- 1001
( + 5)
(- 5 )
( - 2)
( - 7)
(f)
(g)
(h)
(i)
(j)
-
0010
0100
0110
0011
1001
1011
1001
0001
0010
1101
(- 3 )
(- 7 )
( + 2)
( + 4)
( + 6)
( + 3)
( - 7)
( - 5)
(- 7 )
( + 1)
( + 2)
( - 3)
(b)
(d)
0100
+ 1010
1110
0111
+ 1101
0100
1101
+ 0111
0100
0010
+ 1100
1110
0110
+ 1101
0011
1001
+ 0101
1110
1001
+ 1111
1000
0010
+ 0011
0101
( + 4)
(- 6 )
(- 2 )
( + 7)
( - 3)
( + 4)
( + 4)
( - 2)
( + 3)
( - 2)
( - 8)
( + 5)
Figure 2.4. 2's-complement Add and Subtract operations.
9
n bits
first word
second word
•
•
•
i th word
•
•
•
last word
Figure 2.5. Memory words.
10
Address
Begin execution here
i
i +4
i +8
Contents
Move
Add
Move
A,R0
B,R0
R0,C
3-instruction
program
segment
A
B
Data for
the program
C
Figure 2.8. A program for C  [A] + [B].
A simple program doing the basic arithmetic expression C
= A + B;
Note the simple instructions: Move and Add and that data
is stored with the instructions.
11
Move
Clear
LOOP
Program
loop
N,R1
R0
Determine address of
"Next" number and add
"Next" number to R0
Decrement
Branch>0
Move
SUM
N
NUM1
NUM2
NUM n
R1
LOOP
R0,SUM
•
•
•
n
•
•
•
A branch or looping program. Two new instructions
Branch and Decrement.
12