---
title: Determining Instruction Set Characteristics
framework: kernel
role: article
role_heading: Article
path: kernel/1387446-sysctlbyname/determining_instruction_set_characteristics
---

# Determining Instruction Set Characteristics

Interrogate the system for details about the instruction set.

## Overview

Overview Use parameters with the sysctlbyname interface to check for the existence of Instruction Set Architecture (ISA) features available in Apple silicon and documented at Arm Architecture Reference Manual for A-profile architecture. Implemented features have a parameter value of 1. Features that aren’t implemented have a parameter value of 0. Non-existent features return an error. To verify that your CPU uses the ARM Instruction Set Architecture, use hw.optional.arm64. A value of 1 indicates that the platform uses the ARM ISA. The following parameters provide information about the availability of advanced single instruction multiple data (SIMD) and floating point capabilties. These features are standard in Apple processors beginning with M1 and A7, and don’t need to be checked.

Determine Advanced SIMD and Floating Point Capabilities The following parameters provide information about SIMD and floating point support in the processor.

Determine Integer Capabilities The following parameters provide information about integer support in the processor.

Determine Atomic and Memory Ordering Instruction Capabilities The following parameters provide information about atomicity and memory capabilities.

Determine Encryption Capabilities The following parameters provide information about support for instructions that accelerate encryption and decryption in the processor.

Determine General Capabilities The following parameters provide information about other capabiltiies in the processor.

## See Also

### Parameters

- [Determining system capabilities](kernel/1387446-sysctlbyname/determining_system_capabilities.md)