Building a CPU from Scratch

This book is a hands-on guide to building your own computer with FPGAs, written by three members of the RESPON group at Keio University. Originally published in Japanese as *CPU Jisaku Nyumon: HDL ni yoru Ronri Sekkei, Kiban Seisaku, Puroguramingu* (Introduction to Building Your Own CPU: Logic Design with HDL, Board Fabrication, and Programming), it is designed so that even readers with no chip design experience can truly build a working computer. The authors break a computer into three parts and implement each in turn: first logic design with Verilog HDL, then designing and fabricating a circuit board, and finally writing programs for the self-made computer and debugging them on the machine. Chapter 1 begins with the fundamentals—what a computer, CPU, memory, I/O, and bus are—and fills in the basics of digital circuits and Verilog HDL syntax before moving on to implement the bus, memory, the authors' own AZ Processor, and I/O modules such as timers and a serial port, assembling them into a complete small computer system. Chapter 2 covers the design and fabrication of the circuit board, including component selection, schematics, and layout and routing. Chapter 3 has you write and run assembly programs on this computer, completing full hardware-software co-debugging. Throughout, the book leads with concrete examples and explains principles through practice, helping software engineers understand the hardware layer and write more efficient code, while helping hardware engineers customize their own hardware systems on this foundation.