# Introduction

This document describes the application binary interface (ABI) for
Qualcomm® Hexagon™ processor versions V4, V5x, and V6x.

The Hexagon ABI is based on the System V ABI. This document describes
only the Hexagon- specific aspects of the ABI. For information on the
complete ABI specification, see the following documents:

- *System V Application Binary Interface, Edition 4.1*
([http://www.sco.com/developers/devspecs/gabi41.pdf](http://www.sco.com/developers/devspecs/gabi41.pdf))
- *Solaris Linker and Libraries Guide, chapter 8 (Thread-Local Storage)*
([http://docs.oracle.com/cd/E19253-01/817-1984/](http://docs.oracle.com/cd/E19253-01/817-1984/))

## Conventions

Courier font is used for computer text and code samples, for example,

hexagon\_sim\_read\_pcycles().

The following notation is used to define command syntax:

- Square brackets enclose optional items, for example, [**label**].
- **Bold** indicates literal symbols, for example, **[comment]**.
- The vertical bar character, |, indicates a choice of items.
- Parentheses enclose a choice of items, for example,
**add** | **del**).
- An ellipsis, … , follows items that can appear more than once.

## Technical assistance

For assistance or clarification on information in this document,
submit a case to Qualcomm Technologies, Inc. (QTI) at
[https://createpoint.qti.qualcomm.com/](https://createpoint.qti.qualcomm.com/).

If you do not have access to the CDMATech Support website, register
for access or send email to
[support.cdmatech@qti.qualcomm.com.](mailto:support.cdmatech%40qti.qualcomm.com)

Last Published: Oct 06, 2026

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