Learn the Architecture - A-profile

Explore more guides for Arm CPU and system architectures.


Learn more about the Arm A-profile CPU architecture.

Architecture Fundamentals

Introducing the Arm Architecture

This guide provides a non-technical introduction to the Arm Architecture.

AArch64 Exception model

This guide introduces the exception and privilege model in AArch64. It covers Exception Levels - EL0, EL1, EL2, EL3 - synchronous and asynchronous exceptions, including interrupts - Serror, IRQ, FIQ - and virtual exceptions.

AArch64 Instruction Set Architecture (ISA)

This learn the architecture guide introduces the A64 instruction set, which is used in AArch64.

AArch64 Virtualization

This guide describes the virtualization support in the Armv8-A and Armv9-A AArch64, including basic virtualization theory, stage 2 translation, virtual exceptions, and trapping. It covers Arm nested virtualization, Arm VHE, Secure EL2 and Arm VMID.

AArch64 Generic Timer

This guide introduces the Arm Generic Timer; the timer framework for A-profile PEs.

Armv7-A Cortex-A Programmer's Guide

This book provides an introduction to Arm technology for programmers using Arm Cortex-A series processors conforming to the Armv7-A architecture.

Understanding the Armv8.x and Armv9.x extensions

This guide explains extensions to the Arm architecture and provides guidance on how to read and use them. It shows differences between Armv9-A v Armv8-A.

Memory Management and Memory Model

AArch64 memory management

The learn the architecture guide introduces the Arm MMU, which is used to control virtual to physical address translation.

AArch64 Memory Attributes and Properties

This guide introduces the memory attributes and properties in Armv8-A and Armv9-A.

Memory Systems, Ordering, and Barriers

This guide introduces the memory ordering model that is defined by the Armv8-A and Armv9-A architecture.

Use the Memory Model Tool

Learn more about the Arm Memory Model Tool, explore a working example, and learn how to automatically generate litmus tests.

Overview of Arm Transactional Memory Extension (Arm TME)

This guide describes the support for transactional memory introduced in Armv9-A.

Vector and Matrix Processing

Introducing Neon

This guide introduces Arm Neon technology, the Advanced SIMD (Single Instruction Multiple Data) architecture extension for implementations of Armv8–A, Armv9-A and Armv8–R.

Optimizing C code with Neon intrinsics

This guide shows you how to use Arm Neon intrinsics in your C, or C++, code to take advantage of the Advanced SIMD technology in the Armv8-A and Armv9-A architectures.

Compiling for Neon with auto-vectorization

This guide shows how to use the auto-vectorization features in Arm Compiler 6 and CLANG to automatically generate code that contains Armv8-A and Armv9-A Advanced SIMD instructions.

Neon Programmer's Guide

This series of guides introduces Neon, shows you how to optimise C code using intrinsics, and how to use your compiler to automatically generate code that contains Armv8-A advanced SIMD instructions.

Migrating from Neon to SVE

This guide looks at SVE vs Neon. It describes the differences between the Scalable Vector Extension (SVE) of the Armv8-A and Armv9-A instruction set and the Advanced SIMD architectural extension (Neon). It also describes the coding best practices for both.

SVE and SVE2

This guide introduces the version 2 of the Scalable Vector Extension (SVE2), which is part of the Armv9-A architecture. It describes the extension concept, main features, application domains, and how to develop programs for SVE2.

SVE Optimization Guide

This guide shows you how to use SVE in your C and C++ code, and how to perform some basic optimizations.

SVE and SVE2 programming examples

This guide provides an in-depth description into Scalable Vector Extension (SVE) and Scalable Vector Extension V2 (SVE2), illustrated with extensive code examples. The guide shows software developers how to explain SVE or SVE2 in their software.

SVE and Neon coding compared

This guide summarizes the important differences between coding for the Scalable Vector Extension (SVE) and coding for Neon. For users who have already ported their applications to Armv8-A Neon hardware, the guide also highlights the key differences to consider when porting an application to SVE.


Generic Interrupt Controller v3 and v4, Overview

This guide provides an overview of the Generic Interrupt Controller (GIC), describing the operation of an Arm GICv3 compliant interrupt controller, and providing information about configuration for use in a bare metal environment.

Generic Interrupt Controller v3 and v4, LPIs

This guide introduces Locality-specific Peripheral Interrupts (LPIs), a type of interrupt introduced in GICv3/v4.

Generic Interrupt Controller v3 and v4, Virtualization

This guide describes the support for virtualization in the GICv3 and GICv4 architecture. It covers the controls available to a hypervisor for generating and managing virtual interrupts.

SMMU Software Guide

This guide describes the basic operation of the Arm System Memory Management Unit version 3 (SMMUv3) and use cases of the SMMUv3.


TrustZone for AArch64

This guide introduces Arm TrustZone architecture, an efficient, system-wide approach to security with hardware-enforced isolation built into the CPU.

Providing Protection for complex software

This guide examines the features in Armv8-A and Armv9-A that help to mitigate against software attacks, such as ROP and JOP attacks. The guide covers pointer authentication, branch target authentication, and memory tagging.

MTE User Guide for Android OS

This guide introduces Memory Tagging Extension (MTE). It shows developers how to use MTE to increase the robustness and security of their software.

Introducing Arm Confidential Compute Architecture

This guide explains the principles of confidential computing, and describes how the Arm Confidential Compute Architecture (Arm CCA) enables confidential computing in an Arm compute platform.

Realm Management Extension

This guide introduces the Arm Realm Management Extension (RME) introduced in Armv9-A, a hardware component of the Arm Confidential Compute Architecture.

Arm Confidential Compute Architecture software stack

This guide describes the key software features that the Arm Confidential Compute Architecture introduces or changes to provide an environment for confidential computing.

Debug and Trace

AArch64 self-hosted debug

This guide introduces the Armv8-A and Armv9-A debug architecture that is incorporated into the Arm architecture for application class processors.

AArch64 external debug

This guide provides an overview of Armv8-A and Armv9-A external debug, and describes the external debug features that the architecture supports.

Introducing CoreSight: Debug and trace infrastructure

This guide introduces the debug and trace infrastructure support that is provided by the Arm CoreSight Architecture.

Before debugging on Armv8-A

This guide describes concepts that are useful to know before debugging an Armv8-A processor, including different types of debug, target types and target states.

Debugger usage on Armv8-A

This guide focuses on characteristics that are common to bare-metal debuggers that target the Armv8-A architecture. It also covers what you need to know when you work with debuggers, and possible consequences of their use.

Understanding Armv9-A trace

This guide provides a high-level view of trace in Armv9-A systems, including how trace works and is used.

SoC Telemetry & Performance Analysis using Statistical Profiling Extension (SPE)

This blog introduces the concept of using SPE for performance analysis and root cause analysis, targeting software developers, performance analysts, and silicon engineers.


Memory System Resource Partitioning and Monitoring (MPAM) Overview

This guide introduces the Memory System Resource Partitioning and Monitoring (MPAM), an optional addition to the Arm architecture to support memory system partitioning.

Memory System Resource Partitioning and Monitoring (MPAM) Software Guide

This guide describes the firmware and software that are part of the Memory System Resource Partitioning and Monitoring (MPAM).

Memory System Resource Partitioning and Monitoring (MPAM) Hardware Guide

This guide covers system-level design considerations for MPAM systems and introduces the management interface found in Arm MPAM IP.


Reliability, Availability, and Serviceability (RAS) Overview

This guide introduces Reliability, Availability, and Serviceability (RAS), the three key attributes of a robust, dependable, computer system.

Software Development

Building your first embedded image

This guide describes how to create an embedded image, including compiling the program, specifying the memory map, and using a model to run the image.

Boot: bare metal

We're working on a new guide. Until it's ready, you can read our Application Note: Bare-metal Boot Code for Armv8-A Processors.

Accelerating DSP functions with the DOT instructions

This blog describes three use cases for the Armv8.4-A dot product instructions, and shows how we used these instructions to improve the performance of the libvpx implementation of VP9.


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