Invitation to FORTH

INVITATION TO FORTH The latest entry in the ever changing universe of programming languages is FORTH. A crisp, straightforward language that not only lends itself to the programming of microcomputers, it is equally useful for "larger computers." In fact, the size or type of computer is not at all significant to the prospective user of FORTH. FORTH is a language for doing functional programming, with a specific orientation towards productivity, reliability and efficiency. Included in its capabilities are structured programming, top-down development and virtual memory. How-ever, FORTH is not merely a focal point for popular concepts. It represents a modern way of approaching programming. The structure of a FORTH program and the FORTH language itself is based on reverse Polish notation or post-fix notation, as some computer scientists call it. This basic philosophy combined with an effective definitional structure permits a high degree of language flexibility and the ability to customize the language to the requirements of a particular application environment. This book provides an introduction to the FORTH language and is intended for persons who will program in the language and for persons who will design systems and applications around the language. ABOUT THE AUTHOR: Harry Katzan, Jr. is a consultant. Formerly he was Chairman of the Department of Computer Science at Pratt Institutes. He is the author of numerous books in the fields of computer science and data processing, among which the following were published by Petrocelli Books, Inc.: INVITATION TO PASCAL AN INTRODUCTION TO DISTRIBUTED DATA PROCESSING DISTRIBUTED INFORMATION SYSTEMS THE STANDARD DATA ENCRYPTION ALGORITHM Chapter 0 The FORTH Concept 1 Calculators and FORTH 3 Mathematical Notation 3 Operational Environment 5 The Stack 5 FORTH Operations 6 Execution Mode 7 Definition Mode 8 Additional FORTH Capability 9 Vocabulary 10 Exercises 10 Chapter 1 Computer Fundamentals 13 Computer Philosophy 15 Computer Memory 17 Hardware Software and Firmware 19 Microcomputer Systems Organization 20 Microprocessor Organization and Operation 21 Stack Operation 27 Disk Storage Technology 30 Vocabulary 32 Exercises 33 Chapter 2# Software Technology 35 Reasons for Usin Software 37 Categories of Software 37 The Concept of an Algorithm 38 The Concept of a Program 40 Assembler Lanuae 40 Programming Lan^uasfes 41 Proafram Structure 45 Lansfuatfe Processors 46 Assembler Programs 48 Compiler Programs 48 Interpreter Programs 50 Monitors and Operating Systems 51 Utility Systems 53 Development Systems 54 Vocabuary 56 Exercises 56 Chapter 3 Reverse Polish Notation 57 Mathematical Forms 59 Structure of Expressions 61 Conversion Between Infix Notation and Postfix Notation 67 Interpretive Execution of Infix Notation 71 Vocabulary 73 Exercises 73 Chapter 4» Elementary Calculations and Stack Manipulation 75 FORTH Words 77 Punctuation 78 Looking at the Stack 78 Elementary Arithmetic Operations 79 Number Bases 84 Stack Manipulation Operations 86 Mathematical Functions 91 Complement Arithmetic 95 Vocabulary 100 Exercises 100 Chapter 5# Constants Variables and Memory Operations 103 Constants 105 Variables 106 Fetch Operation 107 Store Operation 109 Add to Memory 110 The Dictionary 111 Vocabulary 115 Exercises 115 Chapter 6« Definitions and Terminal Operations 117 Colon Definitions 119 Comment Lines 120 Dot Operation 122 Dot-R Operation 123 Carriage Return 123 Character Literals 124 Screen Operations 124 Space Characters 126 Unsigned Output 127 Display Contents of Address 128 Vocabulary 129 Exercises 129 Chapter 7 Control Structures 131 Logical Values 133 Comparison Operations 133 Logical Operations 138 DO Loop 142 IF Statement 149 EXIT and LEAVE Operations 151 Indefinite Loops 151 Vocabulary 162 Exercises 163 Chapter fl Double Precision 165 Representation 167 Arithmetic Operations 169 Stack Manipulation 171 Mathematical Functions 175 Comparison Operations 177 Mixed-Manitude Operations 180 Terminal Operations 183 Constants and Variables 184 Memory Operations 185 Vocabulary 188 Exercises 189 Chapter 9» Information Management 191 Memory Organization 193 Allocation 193 Disk Input and Output 194 Prosfram Management 195 Keyboard Operations 197 Character Movement 199 Output Formatting and Conversion 203 Vocabulary 206 Exercises 207 References 209 Answers 213 Index 223 Provides an introduction to the FORTH language and is primarily intended for persons who will program in the language, for persons who will design systems and applications around the language, and for persons that want to stay abreast of recent advances in computer technology