Write Great Code, Volume 1: Understanding the Machine

461 Pages·2004·5.665 MB·English

by  Randall Hyde

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WRITE GREAT
CODE
Volume I:
Understanding the Machine
by Randall Hyde
San Francisco
www.it-ebooks.info
WRITE GREAT CODE. Copyright © 2004 by Randall Hyde.
All rights reserved. No part of this work may be reproduced or transmitted in any form or by any means, electronic or
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1 2 3 4 5 6 7 8 9 10 – 07 06 05 04
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Publisher: William Pollock
Managing Editor: Karol Jurado
Cover and Interior Design: Octopod Studios
Developmental Editor: Hillel Heinstein
Technical Reviewer: Mark de Wever
Copyeditor: Andy Carroll
Compositor: Riley Hoffman
Proofreader: Stephanie Provines
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Library of Congress Cataloguing-in-Publication Data
Hyde, Randall.
Write great code : understanding the machine / Randall Hyde.
p. cm.
ISBN 1-59327-003-8
1. Computer programming. 2. Computer architecture. I. Title.
QA76.6.H94 2004
005.1--dc22
2003017502
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B R I E F C O N T E N T S
Chapter 1 Chapter 6
What You Need to Know to Memory Organization
Write Great Code and Access
1 133
Chapter 2 Chapter 7
Numeric Representation Composite Data Types
9 and Memory Objects
161
Chapter 3
Binary Arithmetic Chapter 8
and Bit Operations Boolean Logic
39 and Digital Design
191
Chapter 4
Floating-Point Chapter 9
Representation CPU Architecture
65 225
Chapter 5 Chapter 10
Character Representation Instruction Set Architecture
103 259
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Chapter 11 Thinking Low-Level,
Memory Architecture Writing High-Level
and Organization 405
295
Appendix A
Chapter 12 ASCII Character Set
Input and Output (I/O) 407
329
Index
411
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C O N T E N T S I N D E T A I L
1
WHAT YOU NEED TO KNOW TO WRITE GREAT CODE
1.1 The Write Great Code Series..............................................................................1
1.2 What This Volume Covers...................................................................................3
1.3 Assumptions This Volume Makes..........................................................................5
1.4 Characteristics of Great Code.............................................................................6
1.5 The Environment for This Volume.........................................................................7
1.6 For More Information.........................................................................................7
2
NUMERIC REPRESENTATION
2.1 What Is a Number?.........................................................................................10
2.2 Numbering Systems.........................................................................................11
2.2.1 The Decimal Positional Numbering System..........................................11
2.2.2 Radix (Base)...................................................................................12
2.2.3 The Binary Numbering System..........................................................13
2.2.4 The Hexadecimal Numbering System.................................................15
2.2.5 The Octal (Base-8) Numbering System...............................................18
2.3 Numeric/String Conversions.............................................................................19
2.4 Internal Numeric Representation........................................................................21
2.4.1 Bits................................................................................................21
2.4.2 Bit Strings.......................................................................................22
2.5 Signed and Unsigned Numbers.........................................................................24
2.6 Some Useful Properties of Binary Numbers.........................................................25
2.7 Sign Extension, Zero Extension, and Contraction.................................................27
2.8 Saturation.......................................................................................................30
2.9 Binary-Coded Decimal (BCD) Representation.......................................................31
2.10 Fixed-Point Representation..............................................................................33
2.11 Scaled Numeric Formats.................................................................................35
2.12 Rational Representation..................................................................................38
2.13 For More Information.....................................................................................38
3
BINARY ARITHMETIC AND BIT OPERATIONS
3.1 Arithmetic Operations on Binary and Hexadecimal Numbers................................39
3.1.1 Adding Binary Values......................................................................40
3.1.2 Subtracting Binary Values.................................................................41
3.1.3 Multiplying Binary Values.................................................................42
3.1.4 Dividing Binary Values.....................................................................43
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3.2 Logical Operations on Bits................................................................................46
3.3 Logical Operations on Binary Numbers and Bit Strings........................................47
3.4 Useful Bit Operations.......................................................................................48
3.4.1 Testing Bits in a Bit String Using AND................................................48
3.4.2 Testing a Set of Bits for Zero/Not Zero Using AND.............................49
3.4.3 Comparing a Set of Bits Within a Binary String...................................49
3.4.4 Creating Modulo-n Counters Using AND............................................51
3.5 Shifts and Rotates............................................................................................52
3.6 Bit Fields and Packed Data...............................................................................55
3.7 Packing and Unpacking Data...........................................................................60
3.8 For More Information.......................................................................................64
4
FLOATING-POINT REPRESENTATION
4.1 Introduction to Floating-Point Arithmetic..............................................................66
4.2 IEEE Floating-Point Formats...............................................................................71
4.2.1 Single-Precision Floating-Point Format................................................72
4.2.2 Double-Precision Floating-Point Format...............................................74
4.2.3 Extended-Precision Floating-Point Format............................................74
4.3 Normalization and Denormalized Values...........................................................75
4.4 Rounding.......................................................................................................77
4.5 Special Floating-Point Values............................................................................78
4.6 Floating-Point Exceptions..................................................................................79
4.7 Floating-Point Operations.................................................................................80
4.7.1 Floating-Point Representation............................................................80
4.7.2 Floating-Point Addition and Subtraction..............................................81
4.7.3 Floating-Point Multiplication and Division...........................................92
4.8 For More Information.....................................................................................100
5
CHARACTER REPRESENTATION
5.1 Character Data.............................................................................................104
5.1.1 The ASCII Character Set................................................................104
5.1.2 The EBCDIC Character Set.............................................................107
5.1.3 Double-Byte Character Sets............................................................108
5.1.4 The Unicode Character Set.............................................................109
5.2 Character Strings..........................................................................................110
5.2.1 Character String Formats................................................................111
5.2.2 Types of Strings: Static, Pseudo-Dynamic, and Dynamic.....................116
5.2.3 Reference Counting for Strings........................................................117
5.2.4 Delphi/Kylix Strings......................................................................118
5.2.5 Creating Your Own String Formats..................................................119
5.3 Character Sets..............................................................................................119
5.3.1 Powerset Representation of Character Sets.......................................120
5.3.2 List Representation of Character Sets................................................120
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5.4 Designing Your Own Character Set.................................................................121
5.4.1 Designing an Efficient Character Set................................................122
5.4.2 Grouping the Character Codes for Numeric Digits.............................124
5.4.3 Grouping Alphabetic Characters.....................................................124
5.4.4 Comparing Alphabetic Characters...................................................126
5.4.5 Other Character Groupings............................................................128
5.5 For More Information.....................................................................................131
6
MEMORY ORGANIZATION AND ACCESS
6.1 The Basic System Components........................................................................134
6.1.1 The System Bus..............................................................................134
6.1.2 The Address Bus............................................................................135
6.1.3 The Control Bus.............................................................................136
6.2 Physical Organization of Memory...................................................................137
6.2.1 8-Bit Data Buses............................................................................139
6.2.2 16-Bit Data Buses..........................................................................140
6.2.3 32-Bit Data Buses..........................................................................142
6.2.4 64-Bit Buses..................................................................................143
6.2.5 Small Accesses on Non-80x86 Processors........................................143
6.3 Big Endian Versus Little Endian Organization....................................................144
6.4 The System Clock..........................................................................................149
6.4.1 Memory Access and the System Clock.............................................151
6.4.2 Wait States...................................................................................152
6.4.3 Cache Memory.............................................................................153
6.5 CPU Memory Access......................................................................................157
6.5.1 The Direct Memory Addressing Mode..............................................158
6.5.2 The Indirect Addressing Mode.........................................................158
6.5.3 The Indexed Addressing Mode........................................................159
6.5.4 The Scaled Indexed Addressing Modes............................................160
6.6 For More Information.....................................................................................160
7
COMPOSITE DATA TYPES AND MEMORY OBJECTS
7.1 Pointer Types................................................................................................162
7.1.1 Pointer Implementation...................................................................163
7.1.2 Pointers and Dynamic Memory Allocation.........................................164
7.1.3 Pointer Operations and Pointer Arithmetic.........................................164
7.2 Arrays..........................................................................................................169
7.2.1 Array Declarations.........................................................................169
7.2.2 Array Representation in Memory.....................................................172
7.2.3 Accessing Elements of an Array.......................................................173
7.2.4 Multidimensional Arrays.................................................................174
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7.3 Records/Structures........................................................................................181
7.3.1 Records in Pascal/Delphi...............................................................181
7.3.2 Records in C/C++........................................................................182
7.3.3 Records in HLA.............................................................................182
7.3.4 Memory Storage of Records...........................................................183
7.4 Discriminant Unions.......................................................................................185
7.4.1 Unions in C/C++..........................................................................186
7.4.2 Unions in Pascal/Delphi/Kylix........................................................186
7.4.3 Unions in HLA...............................................................................187
7.4.4 Memory Storage of Unions.............................................................187
7.4.5 Other Uses of Unions.....................................................................188
7.5 For More Information.....................................................................................189
8
BOOLEAN LOGIC AND DIGITAL DESIGN
8.1 Boolean Algebra...........................................................................................192
8.1.1 The Boolean Operators..................................................................192
8.1.2 Boolean Postulates.........................................................................192
8.1.3 Boolean Operator Precedence........................................................194
8.2 Boolean Functions and Truth Tables.................................................................194
8.3 Function Numbers.........................................................................................197
8.4 Algebraic Manipulation of Boolean Expressions................................................198
8.5 Canonical Forms...........................................................................................199
8.5.1 Sum of Minterms Canonical Form and Truth Tables...........................200
8.5.2 Deriving the Sum of Minterms Canonical Form Algebraically..............202
8.5.3 Product of Maxterms Canonical Form..............................................203
8.6 Simplification of Boolean Functions..................................................................204
8.7 What Does This Have to Do with Computers, Anyway?.....................................212
8.7.1 Correspondence Between Electronic Circuits and Boolean Functions....213
8.7.2 Combinatorial Circuits...................................................................214
8.7.3 Sequential and Clocked Logic.........................................................220
8.8 For More Information.....................................................................................224
9
CPU ARCHITECTURE
9.1 Basic CPU Design.........................................................................................225
9.2 Decoding and Executing Instructions: Random Logic Versus Microcode................228
9.3 Executing Instructions, Step by Step.................................................................229
9.3.1 The mov Instruction........................................................................230
9.3.2 The add Instruction........................................................................232
9.3.3 The jnz Instruction.........................................................................234
9.3.4 The loop Instruction.......................................................................234
9.4 Parallelism — The Key to Faster Processing......................................................235
9.4.1 The Prefetch Queue.......................................................................238
9.4.2 Conditions That Hinder the Performance of the Prefetch Queue...........242
9.4.3 Pipelining — Overlapping the Execution of Multiple Instructions..........243
9.4.4 Instruction Caches — Providing Multiple Paths to Memory..................247
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