7. Introduction to Object Modules

The assembler creates object modules from assembly code, and the linker creates executable object files from object modules. These executable object files can be executed by an Arm device.

Object modules make modular programming easier because they encourage you to think in terms of blocks of code and data when you write an assembly language program. These blocks are known as sections. Both the assembler and the linker provide directives that allow you to create and manipulate sections.

This chapter focuses on the concept and use of sections in assembly language programs.

Table of Contents

• 7.1. Object File Format Specifications
• 7.2. Executable Object Files
• 7.3. Introduction to Sections
  • 7.3.1. Special Section Names
• 7.4. How the Assembler Handles Sections
  • 7.4.1. Uninitialized Sections
  • 7.4.2. Initialized Sections
  • 7.4.3. User-Named Sections
  • 7.4.4. Current Section
  • 7.4.5. Section Program Counters
  • 7.4.6. Subsections
  • 7.4.7. Using Sections Directives
• 7.5. How the Linker Handles Sections
  • 7.5.1. Combining Input Sections
  • 7.5.2. Placing Sections
• 7.6. Symbols
  • 7.6.1. Global (External) Symbols
  • 7.6.2. Local Symbols
  • 7.6.3. Weak Symbols
  • 7.6.4. The Symbol Table
• 7.7. Symbolic Relocations
• 7.8. Loading a Program