ARM Assembly Language Tools v18.1.0.LTS User's Guide Literature Number: SPNU118U January 2018 Contents Preface....................................................................................................................................... 12 1 Introduction to the Software Development Tools.................................................................... 15 1.1 Software Development Tools Overview ................................................................................. 16 1.2 Tools Descriptions.......................................................................................................... 17 2 Introduction to Object Modules ............................................................................................ 18 2.1 Object File Format Specifications ........................................................................................ 19 2.2 Executable Object Files ................................................................................................... 19 2.3 Introduction to Sections ................................................................................................... 19 2.3.1 Special Section Names........................................................................................... 20 2.4 How the Assembler Handles Sections .................................................................................. 20 2.4.1 Uninitialized Sections ............................................................................................. 21 2.4.2 Initialized Sections ................................................................................................ 22 2.4.3 User-Named Sections ............................................................................................ 22 2.4.4 Current Section .................................................................................................... 22 2.4.5 Section Program Counters ....................................................................................... 23 2.4.6 Subsections ........................................................................................................ 23 2.4.7 Using Sections Directives ........................................................................................ 24 2.5 How the Linker Handles Sections........................................................................................ 26 2.5.1 Combining Input Sections ........................................................................................ 27 2.5.2 Placing Sections................................................................................................... 28 2.6 Symbols ..................................................................................................................... 28 2.6.1 External Symbols.................................................................................................. 28 2.6.2 Weak Symbols..................................................................................................... 29 2.6.3 The Symbol Table................................................................................................. 30 2.7 Symbolic Relocations ...................................................................................................... 30 2.8 Loading a Program......................................................................................................... 31 3 Program Loading and Running ............................................................................................ 32 3.1 Loading ...................................................................................................................... 33 3.1.1 Load and Run Addresses ........................................................................................ 33 3.1.2 Bootstrap Loading................................................................................................. 34 3.2 Entry Point................................................................................................................... 38 3.3 Run-Time Initialization ..................................................................................................... 38 3.3.1 _c_int00............................................................................................................. 38 3.3.2 RAM Model vs. ROM Model ..................................................................................... 39 3.3.3 Copy Tables........................................................................................................ 40 3.4 Arguments to main ......................................................................................................... 41 3.5 Run-Time Relocation ...................................................................................................... 41 3.6 Additional Information...................................................................................................... 41 4 Assembler Description........................................................................................................ 42 4.1 Assembler Overview ....................................................................................................... 43 4.2 The Assembler's Role in the Software Development Flow ........................................................... 44 4.3 Invoking the Assembler.................................................................................................... 45 4.4 Controlling Application Binary Interface ................................................................................. 46 4.5 Naming Alternate Directories for Assembler Input..................................................................... 46 2 Contents SPNU118U–January 2018 Submit Documentation Feedback Copyright © 2018, Texas Instruments Incorporated www.ti.com 4.5.1 Using the --include_path Assembler Option ................................................................... 46 4.5.2 Using the TI_ARM_A_DIR Environment Variable............................................................. 47 4.6 Source Statement Format................................................................................................. 49 4.6.1 Label Field.......................................................................................................... 49 4.6.2 Mnemonic Field.................................................................................................... 50 4.6.3 Operand Field ..................................................................................................... 50 4.6.4 Comment Field .................................................................................................... 52 4.7 Literal Constants ........................................................................................................... 53 4.7.1 Integer Literals ..................................................................................................... 53 4.7.2 Character String Literals.......................................................................................... 54 4.7.3 Floating-Point Literals............................................................................................. 55 4.8 Assembler Symbols ........................................................................................................ 55 4.8.1 Identifiers ........................................................................................................... 55 4.8.2 Labels............................................................................................................... 56 4.8.3 Local Labels........................................................................................................ 56 4.8.4 Symbolic Constants ............................................................................................... 58 4.8.5 Defining Symbolic Constants (--asm_define Option) ......................................................... 58 4.8.6 Predefined Symbolic Constants ................................................................................. 60 4.8.7 Registers ........................................................................................................... 61 4.8.8 Substitution Symbols.............................................................................................. 62 4.9 Expressions ................................................................................................................. 63 4.9.1 Mathematical and Logical Operators ........................................................................... 64 4.9.2 Relational Operators and Conditional Expressions........................................................... 65 4.9.3 Well-Defined Expressions........................................................................................ 65 4.9.4 Relocatable Symbols and Legal Expressions ................................................................. 65 4.9.5 Expression Examples............................................................................................. 66 4.10 Built-in Functions and Operators ......................................................................................... 67 4.10.1 Built-In Math and Trigonometric Functions ................................................................... 67 4.11 Unified Assembly Language Syntax Support........................................................................... 68 4.12 Source Listings ............................................................................................................. 69 4.13 Debugging Assembly Source