Since its commercialization in 1971, the microprocessor, a modern and integrated form of the central processing unit, has continuously broken records in terms of its integrated functions, computing power, low costs and energy saving status. Today, it is present in almost all electronic devices. Sound knowledge of its internal mechanisms and programming is essential for electronics and computer engineers to understand and master computer operations and advanced programming concepts. This book in five volumes focuses more particularly on the first two generations of microprocessors, those that handle 4- and 8- bit integers. Microprocessor 4 – the fourth of five volumes – addresses the software aspects of this component. Coding of an instruction, addressing modes and the main features of the Instruction Set Architecture (ISA) of a generic component are presented. Futhermore, two approaches are discussed for altering the flow of execution using mechanisms of subprogram and interrupt. A comprehensive approach is used, with examples drawn from current and past technologies that illustrate theoretical concepts, making them accessible.

Table of Contents:
Quotation ix Preface xi Introduction xv Chapter 1. Coding and Addressing Modes 1 1.1. Encoding and formatting an instruction 1 1.1.1. Code compression 8 1.2. Addressing modes 8 1.2.1. Immediate addressing10 1.2.2. Register addressing 11 1.2.3. Memory addressing modes 12 1.2.4. Other addressing modes 24 1.2.5. Summary on addressing 31 1.3. Conclusion 32 Chapter 2. Instruction Set and Class 33 2.1. Definitions 33 2.2. Transfer instructions 35 2.2.1. Data transfer 35 2.2.2. Address manipulation instructions 37 2.3. Data processing instructions 37 2.3.1. Arithmetic instructions for integers 37 2.3.2. Bit manipulation instructions 38 2.4. Control transfer instructions 49 2.4.1. Branchings 50 2.4.2. Conditional execution 56 2.4.3. Iteration control 59 2.4.4. Subroutine call and return instructions 62 2.5. Environmental instructions 63 2.5.1. Interrupt request and interrupt return instructions 63 2.5.2. Stopping instructions 63 2.5.3. Processor management 64 2.5.4. Memory management64 2.5.5. Hardware detection 65 2.5.6. Debugging 66 2.5.7. Updating 66 2.5.8. Verification 66 2.5.9. Various 66 2.6. Parallelism instructions 66 2.6.1. Atomic instructions 66 2.6.2. Synchronization instructions 68 2.7. Extensions to instruction sets 68 2.7.1. Multimedia extension 68 2.7.2. Extension for signal processing 71 2.7.3. Cryptography 72 2.7.4. Randomization management 72 2.7.5. Implications 72 2.8. Various instructions 72 2.8.1. Instructions for handling (strings of) characters 72 2.8.2. Input/output instructions 73 2.8.3. High-level instructions 73 2.8.4. Arithmetic instructions specific to a representation of particular numbers. 73 2.8.5. An unusual instruction 75 2.9. Conclusion 75 Chapter 3. Additional Concepts 77 3.1. Concepts associated with the instruction set and programming 77 3.1.1. llegal, non-implemented, invalid, reserved and trusted instructions 77 3.1.2. Alignment or framing of instructions 78 3.1.3. Orthogonality and symmetry 80 3.1.4. Pure, re-entrant and relocatable codes and code for read-only memory 81 3.1.5. Levels of programming languages 82 3.2. Concepts linked to execution 83 3.2.1. Consequences for execution time and memory requirements 83 3.2.2. Execution modes 84 3.2.3. Portability 88 3.2.4. Virtualization 88 3.3. Hardware and software compatibilities 90 3.3.1. Hardware compatibility 90 3.3.2. Software compatibility 90 3.3.3. Upward and downward compatibilities 91 3.4. Measuring processor performances 93 3.4.1. Clock rate 94 3.4.2. Number of instructions per cycle 95 3.4.3. Execution time 97 3.4.4. Benchmark suites 97 3.4.5. Development of performances over time 101 3.5. Criteria for choosing 102 3.6. Conclusion 103 Chapter 4. Subroutine 105 4.1. Stack memory 105 4.2. Subroutine 113 4.2.1. Nested calls 115 4.2.2. Execution context 116 4.2.3. Passing parameters and call conventions 116 4.3. Conclusion 118 Chapter 5. Interrupt Mechanism 119 5.1. Origin, definition and classification 119 5.2. External causes 121 5.2.1. Execution context 125 5.2.2. Sources 125 5.2.3. Masking 127 5.2.4. Consideration and priority 129 5.2.5. Interrupt controller 132 5.3. Nested interrupts 133 5.4. Internal causes 135 5.5. Debugging 138 5.6. Priority between internal and external interrupts 139 5.7. Identification of the source and vectorization 146 5.8. Nested and queued interrupts 152 5.9. Uses 153 5.10. Interrupts and execution modes 154 5.11. Interrupts and advanced architectures 155 5.12. Conclusion 162 Conclusion of Volume 4 163 Exercises 165 Appendix 171 Acronyms 177 References 197 Index 211