Chapter 1
Assembly Language for x86 Processors 6th Edition
Chapter 1: Basic Concepts
(c) Pearson Education, 2010. All rights reserved. You may modify and copy this slide show for your personal use, or for use in the classroom, as long as this copyright statement, the author’s name, and the title are not changed.
Kip Irvine
Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
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Chapter Overview
Welcome to Assembly Language
Virtual Machine Concept
Data Representation
Boolean Operations
Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
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Questions to Ask
Why am I learning Assembly Language?
What background should I have?
What is an assembler?
What hardware/software do I need?
What types of programs will I create?
What will I learn?
Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
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Welcome to Assembly Language (cont)
How does assembly language (AL) relate to machine language?
How do C++ and Java relate to AL?
Is AL portable?
Why learn AL?
Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
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Comparing ASM to High-Level Languages
Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
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Welcome to Assembly Language (cont)
Assembly programming
Hardware access is simple
Efficient in space and time
Difficult to program and maintain code
Not portable (x86 machine, RISC machine)
Applications–Device drivers, e.g. camera, printer, Keyboard, displays, F16, F35
Bootstrap, kernel
HLL
Portable
Easy to program
Inefficient in space and time
Hardware access is difficult
Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
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Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
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What’s Next
Welcome to Assembly Language
Data Representation
Boolean Operations
Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
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Translating Languages
English: Display the sum of A times B plus C.
C++: cout << (A * B + C);
Assembly Language:
mov eax,A
mul B
add eax,C
call WriteInt
Intel Machine Language:
A1 00000000
F7 25 00000004
03 05 00000008
E8 00500000
Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
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Specific Machine Levels
(descriptions of individual levels follow . . . )
Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
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What's Next
Welcome to Assembly Language
Data Representation
Boolean Operations
Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
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Data Representation
Binary Numbers
Translating between binary and decimal
Binary Addition
Integer Storage Sizes
Hexadecimal Integers
Translating between decimal and hexadecimal
Hexadecimal subtraction
Signed Integers
Binary subtraction
Character Storage
Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
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Binary Numbers
Digits are 1 and 0
1 = true
0 = false
MSB – most significant bit
LSB – least significant bit
Bit numbering:
Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
704.unknown
Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
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Binary Numbers
Each digit (bit) is either 1 or 0
Each bit represents a power of 2:
Every binary number is a sum of powers of 2
Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
705.unknown
Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
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Translating Binary to Decimal
Weighted positional notation shows how to calculate the decimal value of each binary bit:
dec = (Dn-1 2n-1) + (Dn-2 2n-2) + ... + (D1 21) + (D0 20)
D = binary digit
binary 00001001 = decimal 9:
(1 23) + (1 20) = 9
Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
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Translating Unsigned Decimal to Binary
Repeatedly divide the decimal integer by 2. Each remainder is a binary digit in the translated value:
37 = 100101
Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
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Binary Addition
Starting with the LSB, add each pair of digits, include the carry if present.
Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
706.unknown
Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
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Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
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Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
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Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
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Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
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Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
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Integer Storage Sizes
What is the largest unsigned integer that may be stored in 20 bits?
Standard sizes:
Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
707.unknown
Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
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Hexadecimal Integers
Binary values are represented in hexadecimal.
Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
2s complement
Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
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Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
2s complement
Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
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Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
2s complement
Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
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Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
2s complement
Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
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Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
2s complement
Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
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Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
2s complement
Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
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Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
2s complement
Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
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Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
2s complement
Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
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Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
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Translating Binary to Hexadecimal
Each hexadecimal digit corresponds to 4 binary bits.
Example: Translate the binary integer 000101101010011110010100 to hexadecimal:
Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
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Converting Hexadecimal to Decimal
Multiply each digit by its corresponding power of 16:
dec = (D3 163) + (D2 162) + (D1 161) + (D0 160)
Hex 1234 equals (1 163) + (2 162) + (3 161) + (4 160), or decimal 4,660.
Hex 3BA4 equals (3 163) + (11 * 162) + (10 161) + (4 160), or decimal 15,268.
Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
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Powers of 16
Used when calculating hexadecimal values up to 8 digits long:
Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
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Converting Decimal to Hexadecimal
decimal 422 = 1A6 hexadecimal
Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
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Hexadecimal Addition
Divide the sum of two digits by the number base (16). The quotient becomes the carry value, and the remainder is the sum digit.
36 28 28 6A
42 45 58 4B
78 6D 80 B5
1
1
21 / 16 = 1, rem 5
Important skill: Programmers frequently add and subtract the addresses of variables and instructions.
Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
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Hexadecimal Subtraction
When a borrow is required from the digit to the left, add 16 (decimal) to the current digit's value:
C6 75
A2 47
24 2E
-1
16 + 5 = 21
Practice: The address of var1 is 00400020. The address of the next variable after var1 is 0040006A. How many bytes are used by var1?
Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
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Signed Integers
The highest bit indicates the sign. 1 = negative,
0 = positive
If the highest digit of a hexadecimal integer is > 7, the value is negative. Examples: 8A, C5, A2, 9D
Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
708.unknown
Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
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Forming the Two’s Complement
Negative numbers are stored in two’s complement notation
Represents the additive Inverse
Note that 00000001 + 11111111 = 00000000
Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
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Binary Subtraction
When subtracting A – B, convert B to its two’s complement
Add A to (–B)
0 0 0 0 1 1 0 0 0 0 0 0 1 1 0 0
– 0 0 0 0 0 0 1 1 1 1 1 1 1 1 0 1
0 0 0 0 1 0 0 1
Practice: Subtract 0101 from 1001.
Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
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Learn How To Do the Following:
Form the two’s complement of a hexadecimal integer
Convert signed binary to decimal
Convert signed decimal to binary
Convert signed decimal to hexadecimal
Convert signed hexadecimal to decimal
Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
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Ranges of Signed Integers
The highest bit is reserved for the sign. This limits the range:
Practice: What is the largest positive value that may be stored in 20 bits?
Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
2s complement ranges
Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
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Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
2s complement
Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
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Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
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Character Storage
Character sets
Standard ASCII (0 – 127)
Extended ASCII (0 – 255)
ANSI (0 – 255)
Unicode (0 – 65,535)
Null-terminated String
Array of characters followed by a null byte
Using the ASCII table
back inside cover of book
Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
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Numeric Data Representation
pure binary
can be calculated directly
ASCII binary
string of digits: “01010101”
ASCII decimal
string of digits: “65”
ASCII hexadecimal
string of digits: “9C”
next: Boolean Operations
Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
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Boolean Operations
NOT
AND
OR
Truth Tables
Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
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NOT
Inverts (reverses) a boolean value
Truth table for Boolean NOT operator:
Digital gate diagram for NOT:
Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
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AND
Truth table for Boolean AND operator:
Digital gate diagram for AND:
Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
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OR
Truth table for Boolean OR operator:
Digital gate diagram for OR:
Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
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Summary
Assembly language helps you learn how software is constructed at the lowest levels
Assembly language has a one-to-one relationship with machine language
Each layer in a computer’s architecture is an abstraction of a machine
layers can be hardware or software
Boolean expressions are essential to the design of computer hardware and software
Irvine, Kip R. Assembly Language for Intel-Based Computers 6/e, 2010.
0
15
1 0 1 1 0 0 1 0 1 0 0 1 1 1 0 0
MSB
LSB
1
1
1
1
1
1
1
1
2
7
2
6
2
5
2
4
2
3
2
2
2
1
2
0
0
0
0
0
0
1
1
1
0
0
0
0
0
1
0
0
+
0
0
0
0
1
0
1
1
1
(4)
(7)
(11)
carry:
0
1
2
3
4
bit position:
5
6
7
byte
16
8
32
word
doubleword
64
quadword
1
1
1
1
0
1
1
0
0
0
0
0
1
0
1
0
sign bit
Negative
Positive
NOT
AND
OR