Computer Science and Engineering Hohl Hinds “Assembly language programming is still the best way to learn about the A internals of processors and this is one of a very few books that teaches that R skill for ARM® processors. It covers the necessary material in a well-organized manner. Updated for newer versions of ARM processors, it adds good material M on floating-point arithmetic that was missing from the first edition.” —Ronald W. Mehler, California State University, Northridge, USA A “This text retains the ease of using the ARM7TDMI while moving the F student [or reader] into the more capable Cortex-M4. …The addition of the uS Cortex-M4 makes this a much stronger text.” n S —Ralph Tanner, Western Michigan University, Kalamazoo, USA d a E m Delivering a solid introduction to assembly language and embedded eM systems, ARM Assembly Language: Fundamentals and Techniques, Second n Edition continues to support the popular ARM7TDMI, but also addresses the t latest architectures from ARM, including Cortex™-A, Cortex-R, and Cortex-M aB l s processors—all of which have slightly different instruction sets, programmer’s aL models, and exception handling. nY d Featuring three brand-new chapters, a new appendix, and expanded T L coverage of the ARM7™, this edition: e cA h • Discusses IEEE 754 floating-point arithmetic and explains how to n program with the IEEE standard notation iN q u • Contains step-by-step directions for the use of Keil™ MDK-ARM and eG Texas Instruments (TI) Code Composer Studio™ s U • Provides a resource to be used alongside a variety of hardware evaluation modules, such as TI’s Tiva Launchpad, STMicroelectronics’ A iNemo and Discovery, and NXP Semiconductors’ Xplorer boards G Written by experienced ARM processor designers, ARM Assembly E Language: Fundamentals and Techniques, Second Edition covers the topics essential to writing meaningful assembly programs, making it an ideal textbook and professional reference. SECOND EDITION K22631 ISBN: 978-1-4822-2985-1 90000 9 781482229851 K22631_COVER_final.indd 1 9/12/14 3:07 PM S E C O N D E D I T I O N ARM ASSEMBLY LANGUAGE Fundamentals and Techniques S E C O N D E D I T I O N ARM ASSEMBLY LANGUAGE Fundamentals and Techniques William Hohl Christopher Hinds ARM, Inc., Austin, Texas Boca Raton London New York CRC Press is an imprint of the Taylor & Francis Group, an informa business CRC Press Taylor & Francis Group 6000 Broken Sound Parkway NW, Suite 300 Boca Raton, FL 33487-2742 © 2015 by William Hohl and Christopher Hinds CRC Press is an imprint of Taylor & Francis Group, an Informa business No claim to original U.S. Government works Version Date: 20140915 International Standard Book Number-13: 978-1-4822-2986-8 (eBook - PDF) This book contains information obtained from authentic and highly regarded sources. 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Visit the Taylor & Francis Web site at http://www.taylorandfrancis.com and the CRC Press Web site at http://www.crcpress.com To our families Contents Preface......................................................................................................................xv Acknowledgments ...................................................................................................xxi Authors .................................................................................................................xxiii Chapter 1 An Overview of Computing Systems ...................................................1 1.1 Introduction ...............................................................................1 1.2 History of RISC .........................................................................3 1.2.1 ARM Begins ................................................................5 1.2.2 The Creation of ARM Ltd. ...........................................7 1.2.3 ARM Today ..................................................................9 1.2.4 The Cortex Family .....................................................10 1.2.4.1 The Cortex-A and Cortex-R Families .........10 1.2.4.2 The Cortex-M Family .................................11 1.3 The Computing Device ............................................................12 1.4 Number Systems ......................................................................15 1.5 Representations of Numbers and Characters ..........................18 1.5.1 Integer Representations ..............................................18 1.5.2 Floating-Point Representations ..................................21 1.5.3 Character Representations ..........................................23 1.6 Translating Bits to Commands ................................................24 1.7 The Tools .................................................................................25 1.7.1 Open Source Tools .....................................................27 1.7.2 Keil (ARM) ................................................................27 1.7.3 Code Composer Studio ...............................................28 1.7.4 Useful Documentation ................................................30 1.8 Exercises ..................................................................................30 Chapter 2 The Programmer’s Model ..................................................................33 2.1 Introduction .............................................................................33 2.2 Data Types ...............................................................................33 2.3 ARM7TDMI ...........................................................................34 2.3.1 Processor Modes ........................................................34 2.3.2 Registers .....................................................................35 2.3.3 The Vector Table ........................................................38 2.4 Cortex-M4 ................................................................................39 2.4.1 Processor Modes ........................................................40 2.4.2 Registers .....................................................................40 2.4.3 The Vector Table ........................................................42 2.5 Exercises ..................................................................................43 vii viii Contents Chapter 3 Introduction to Instruction Sets: v4T and v7-M .................................45 3.1 Introduction .............................................................................45 3.2 ARM, Thumb, and Thumb-2 Instructions ..............................46 3.3 Program 1: Shifting Data.........................................................46 3.3.1 Running the Code .......................................................47 3.3.2 Examining Register and Memory Contents ...............49 3.4 Program 2: Factorial Calculation ............................................51 3.5 Program 3: Swapping Register Contents .................................53 3.6 Program 4: Playing with Floating-Point Numbers ..................54 3.7 Program 5: Moving Values between Integer and Floating- Point Registers .........................................................................55 3.8 Programming Guidelines ........................................................56 3.9 Exercises ..................................................................................57 Chapter 4 Assembler Rules and Directives .........................................................59 4.1 Introduction .............................................................................59 4.2 Structure of Assembly Language Modules .............................59 4.3 Predefined Register Names .....................................................63 4.4 Frequently Used Directives .....................................................63 4.4.1 Defining a Block of Data or Code ..............................63 4.4.1.1 Keil Tools ....................................................64 4.4.1.2 Code Composer Studio Tools .....................65 4.4.2 Register Name Definition ...........................................66 4.4.2.1 Keil Tools ....................................................66 4.4.2.2 Code Composer Studio ...............................66 4.4.3 Equating a Symbol to a Numeric Constant ................66 4.4.3.1 Keil Tools ....................................................67 4.4.3.2 Code Composer Studio ...............................67 4.4.4 Declaring an Entry Point ............................................67 4.4.5 Allocating Memory and Specifying Contents ...........68 4.4.5.1 Keil Tools ....................................................68 4.4.5.2 Code Composer Studio ...............................69 4.4.6 Aligning Data or Code to Appropriate Boundaries ......70 4.4.6.1 Keil Tools ....................................................70 4.4.6.2 Code Composer Studio ...............................71 4.4.7 Reserving a Block of Memory ...................................71 4.4.7.1 Keil Tools ....................................................71 4.4.7.2 Code Composer Studio ...............................71 4.4.8 Assigning Literal Pool Origins ..................................72 4.4.9 Ending a Source File ..................................................72 4.5 Macros .....................................................................................73 4.6 Miscellaneous Assembler Features .........................................74 4.6.1 Assembler Operators ..................................................74 4.6.2 Math Functions in CCS ..............................................76 4.7 Exercises ..................................................................................77