Modern Computer Architecture and Organization Second Edition, by Jim Ledin. Published by Packt Publishing.
This chapter begins our development of a comprehensive understanding of modern processor architectures. Building upon the basic digital circuits introduced in Chapter 2, Digital Logic, we discuss the functional units of a simple, generic computer processor. Concepts related to the instruction set and register set are introduced, followed by a discussion of the steps involved in instruction loading, decoding, execution, and sequencing. Addressing modes and instruction categories are discussed in the context of the 6502 architecture. The need for processor interrupt handling is introduced, using the example of 6502 interrupt processing. The standard approaches modern processors employ for input/output (I/O) operations are introduced, including direct memory access.
After completing this chapter, you will understand the basic parts of a processor and the structure of processor instruction sets. You will have learned the types of processor instructions, why interrupt processing is necessary, and will understand I/O operations.
The following topics will be covered in this chapter:
- A simple processor
- The instruction set
- Addressing modes
- Instruction categories
- Interrupt processing
- Input/output operations
ALU.vhdl is the VHDL implementation of the 6502-like ALU discussed in the Arithmetic logic unit section of Chapter 3.
The following files are 6502 assembly language examples from this chapter:
| File | Description |
|---|---|
| immediate_addressing_mode.asm | Immediate addressing mode. |
| absolute_addressing_mode.asm | Absolute addressing mode. |
| absolute_indexed_addressing_mode.asm | Absolute indexed addressing mode. |
| looping_absolute_indexed_addressing.asm | Looping absolute indexed addressing mode. |
| indirect_indexed_addressing_mode.asm | Indirect indexed addressing mode. |
| interrupt_handler.asm | Interrupt handler. |
| brk_handler.asm | Break handler. |