Introduction

In whatever manner it is produced, the source input file must have a certain structure and content. The specification of this structure and content constitutes the syntax of the assembly language. A source file may be produced by one of the following:

• A programmer using a text editor

• A compiler as an intermediate step in the process of translating from a high-level language to executable code

• An automatic program generator

• Some other mechanism.

The assembler may also allow ancillary input incidental to the translation process. For example, there are several invocation options available. Each such option exercised constitutes information input to the assembler. However, this ancillary input has little direct connection to the translation process, so it is not properly a subject for this manual. Information about invoking the assembler and the available options appears in the as(1) man pages.

This chapter describes the overall structure required by the assembler for input source files. This structure is relatively simple: the input source file must be a sequence of assembly language statements. This chapter also begins the specification of the contents of the input source file by describing assembly language statements as textual objects of a certain form.

This document completes the specification by presenting detailed assembly language statements that correspond to the IA--32 instruction set. For more information on assembly language instruction sets, please refer to the product documentation from Intel Corporation.