Introduction

The OS X assembler serves a dual purpose. It assembles the output of gcc, Xcode’s default compiler, for use by the OS X linker. It also provides the means to assemble custom assembly language code written for its supported platforms.

This document provides a reference for the use of the assembler, including basic syntax and statement layout. It also contains a list of the specific directives recognized by the assembler and complete instruction sets for the PowerPC and i386 processor architectures.

Organization of This Document

This document contains the following chapters:

• Using the Assembler describes how to run the assembler and its relevant input/output files. It also discusses specific options that can be passed to the assembler on the command line.

• Assembly Language Syntax describes the basic syntax of assembly language elements and expressions.

• Assembly Language Statements describes in greater detail the assembly language statements that make up an assembly language program.

• Assembler Directives describes assembler directives specific to the OS X assembler and how to use them in your assembly code.

• PowerPC Addressing Modes and Assembler Instructions contains information specific to the PowerPC processor architecture and provides a complete list of addressing modes and instructions relevant to it.

• i386 Addressing Modes and Assembler Instructions contains information specific to the i386 processor architecture and provides a complete list of addressing modes and instructions relevant to it.

• Mode-Independent Macros introduces the macros included in the OS X v10.4 SDK to facilitate the development of assembly code that runs in 32-bit PowerPC and 64-bit PowerPC environments.

This document also contains a revision history, and an index.