X65 Book: Preface

The X65 Microcomputer is a modern interpretation of classic 8-bit computing, blending the simplicity and hands-on nature of vintage systems with modern enhancements. This book serves as a comprehensive guide to both the hardware architecture and software development of the X65, ensuring that readers gain a deep understanding of its capabilities and how to program it efficiently.

About This Book

This book is divided into two main parts, each focusing on a crucial aspect of the X65:

Part 1: The X65 Microcomputer

This section covers the hardware and design philosophy behind the X65, detailing what makes it unique and how it builds upon the legacy of classic computing. Topics include:

  • The vision and goals behind the X65 project

  • The 65C816 CPU, its advantages, and how it operates in native mode from boot-up

  • The memory model, including flat 16MB addressing and efficient direct page handling

  • The graphics system, which uses a beam-chased display list instead of a framebuffer

  • The sound system, leveraging a Yamaha SD-1 FM synthesizer for rich audio

  • Peripheral support, expansion options, and system input/output design

By the end of Part 1, readers will have a complete understanding of the X65’s architecture and what makes it a powerful yet accessible computing platform.

Part 2: Programming the X65 in 65816 Assembly

The second half of the book is dedicated to writing software for the X65 using 65816 assembly language. This section provides a structured learning path, covering everything from the basics of the instruction set to advanced optimization techniques. Topics include:

  • An introduction to 65816 assembly syntax and structure

  • Working with registers, addressing modes, and stack operations

  • Handling memory efficiently in a flat 16MB address space

  • Programming the graphics system using the display list

  • Generating sound with the Yamaha SD-1 FM synthesizer

  • Interfacing with peripherals and expansion hardware

  • Optimizing code for performance and efficiency

By the end of Part 2, readers will have the knowledge required to develop software, games, and applications for the X65, as well as extend its capabilities through custom hardware and expansion modules.

Who Should Read This Book?

This book is for retro computing enthusiasts, assembly programmers, and hardware developers who want to explore the fundamentals of low-level programming and hardware interaction. Whether you’re a seasoned developer looking for a modern take on 8-bit computing or a beginner eager to learn about computer architecture, the X65 provides an approachable yet powerful platform to experiment with.

A Journey into Understandable Computing

In an era of ever-increasing complexity, the X65 is a reminder of a time when computers were simple, understandable, and empowering. This book is not just about using the X65 - it’s about rediscovering the joy of low-level programming, hardware hacking, and direct control over a computer’s operation.

With that, let’s dive in and explore the world of the X65!