ARM Assembly Language Tutorial

Introduction

Welcome to the ARM assembly tutorial! This introductory tutorial is for anyone who wants to learn the ARM (Acorn Risc Machine) assembly language, with particular focus on the instruction set architecture (ISA) . An increasingly popular addition to university courses, the ARM assembly language is now the most popular 32-bit assembly language used in industry. The ARM processor has seen great success in the portable devices market and now dominates with a 90% share of the 32-bit embedded processors market. A good example of their popularity is the use of the ARMv6KZ from the ARM11 family in the Apple iPod Touch and iPhone. The table shows some interesting applications of the ARM cores.

Family	Device
ARM7	Game Boy Advance, Nintendo DS
ARM11	Apple iPhone, iPod Touch, Nokia N82

It is strongly recommended that before you attempt to learn any assembly language you make sure:

you are fully cognisant with the various number systems, especially those used for ARM addressing and bit manipulation, i.e hexadecimal and binary. The latter is an essential tool to analyse assembly code which deals with bit manipulation or arithmetic.
you have a basic understanding of the underlying principles of computer operation, i.e how a CPU interacts with memory etc.
and if possible: you have appreciation of the ARM hardware. Although it has not been covered extensively in this tutorial an understanding of the ARM processor and its caching system is advantageous.

This tutorial does not have to be read from start to finish, as all the chapters are standalone. A number of exercises have been written to test basic understanding of most areas covered by this tutorial. While every effort has been made to ensure that all mistakes have been found and corrected, it is likely that some still remain if this is the case please don't hesitate to email me at matthew.christianson08@imperial.ac.uk .

Why learn an assembly language?

If you want to learn how to write efficient high-level language code, learn how to program in assembly language. Programmers who know how to write assembly code must always think of the underlying hardware implementation of the code they are writing, so it is essential for them not only to write efficient algorithms but to write efficient code. All too often, high-level language programmers use certain high-level language functions/data types without any knowledge of the hardware execution costs of those statements. Learning assembly language forces the programmer to learn the hardware costs associated with various high-level constructs.

Some Notes

ARM assembly code snippets can be seen in blue boxes as shown below.

MOV R0, #&ABC123
LDM R1!, {R0, R3}

Although both Rn and rn are acceptable nototion, the uppercase Rn will be used for clarity.

Some History

Steve Furber and Sophie Wilson led the development of the ARM architecture in 1983. The ARM1 was completed by 1985 at Acorn Computers Ltd.

What you will need

An ARM assembly compiler will be required, the most accessible is the ARMulator. For detailed installation instructions go to the ARMulator section of this website.

Click Here for a large range of ARM assembly books at low prices!

ARM Assembly Language - an Introduction by J. R. Gibson

ARM Assembly by William Hohl