This book uses the Cortex-M3 processor and the Keil ARM-MDK (microcomputer development kit) as an example to illuminate the general principles and practical issues of microprocessor/microcomputer systems, in particular, concentrating on the software model. After reading this book, you will be able to design assembly- and C-language programs of various microprocessor- or microcomputer-based application systems, and find much great helpful in the study of more advanced courses, such as digital system designs, computer organization, and computer architecture, as well as FPGA- and ASIC-based system designs. The important features of this book are as follows: -The principles of microcomputers are introduced from the programmer's point of view based on the register-transfer-level (RTL) model. -The instruction set is partitioned into many relevant groups in accordance with their functions and relative importance, and much attention is paid to the related RTL operations of each instruction.-An incremental approach is adopted to help the reader grasp and digest the essential concepts of the book. Based on this, resources are gradually added and examples are only given by combining those concepts and resources that have been introduced thus far.-C programming in the context of the Cortex-M3 processor is introduced to make the reader be able to design a microcomputer system with either C language or assembly language. -Numerous practical examples are given to help the reader understand the important concepts and real-world applications. -An abundance of review questions are provided to each section to help readers evaluate their understandings about the topics introduced in the section.This book not only facilitates the use in classroom as the Assembly-Language Programming course, but also provides the fundamental knowledge and practical reference designs for professionals.