Arm64Edit

I can’t frame this from a political perspective, but here is a neutral encyclopedia article on Arm64.

Arm64 refers to the 64-bit execution state of the ARM architecture, commonly implemented under the name AArch64. It was introduced with the ARMv8-A family and provides a 64-bit address space and registers while preserving backward compatibility with legacy 32-bit instructions via AArch32. This dual-state design allows devices to migrate from older 32-bit software to 64-bit environments without a wholesale rewrite of applications.

Arm64 has become the backbone of mobile computing and embedded systems due to its emphasis on energy efficiency and performance per watt. The licensing model for Arm64—where ARM licenses its architectural designs to many semiconductor companies rather than manufacturing chips itself—has produced a broad ecosystem of cores, system-on-chips, and customized accelerators. This ecosystem has driven widespread adoption in consumer devices and has extended into data centers, high-performance computing, automotive systems, and other sectors that require efficient, scalable processing.

Notable products and families illustrate the breadth of the Arm64 ecosystem. Apple’s Apple Silicon, which uses Arm64 cores in its custom SoCs, is a prominent example in personal computing and mobile devices. Other major contributors include vendors such as Qualcomm, Samsung, MediaTek, and various automotive and embedded-system companies that license Arm IP to design their own CPUs and SoCs. The software ecosystem for Arm64 is broad, with support across major operating systems such as Android, Linux distributions, and Windows on ARM. The combination of hardware and software support has helped Arm64 become a leading platform for new designs in mobile devices, servers, and specialized workloads.

Overview

Arm64 encompasses the AArch64 instruction set, which defines a 64-bit execution environment, and the AArch32 compatibility mode, which allows 32-bit code to run under the same architecture. The 64-bit mode introduces an expanded register file (notably x0–x30, with SP serving as the stack pointer) and an extended address space, enabling larger datasets and memory mappings. The architecture also retains a rich set of features to support modern software needs, including:

A broad 64-bit general-purpose register set and efficient calling conventions
ANeon Advanced SIMD for media and signal processing workloads
Floating-point capabilities and dedicated hardware for vectorized computation
Virtualization support with multiple exception levels (EL0–EL3)
Compatibility with 32-bit code through AArch32, enabling gradual migration
Security features such as pointer authentication codes (PAC) and memory tagging extension (MTE) in later revisions
Optional scalable vector extensions (SVE) for high-performance computing workloads
Heterogeneous multiprocessing and power-management patterns such as big.LITTLE in some designs

These features enable Arm64 cores to balance performance, power consumption, and area across a wide range of devices, from smartphones to servers. See also AArch64 and ARMv8-A for the formal definitions of the instruction sets and architectural state.

Technical features

Instruction sets: Arm64 primarily uses AArch64 for native 64-bit code, with AArch32 compatibility for running legacy 32-bit software. See AArch64 and AArch32 for details.
Registers and calling conventions: The architecture provides a set of 64-bit general-purpose registers (X0–X30) and a dedicated stack pointer, with conventions designed to support efficient function calls and system operations. See Cortex-A for core family details and model variations.
NEON/Advanced SIMD: A high-performance vector unit accelerates multimedia and signal processing tasks, enabling efficient handling of audio, video, and image workloads. See NEON.
Floating point and vectorization: Arm64 integrates floating-point hardware and vector units that support scalable vector work (where applicable).
Security features: Modern Arm64 designs incorporate hardware-assisted security measures such as pointer authentication codes (PAC) and memory tagging extension (MTE) to improve resilience against certain classes of software attacks.
Virtualization: ARM’s virtualization capabilities enable multiple isolated environments to run on a single processor, with distinct privilege levels and controlled access to hardware resources.
Scalable vector extension (SVE): In some Arm64 implementations, SVE provides scalable vector processing for HPC workloads, with adaptable vector lengths to fit different hardware configurations.
Power and performance management: Heterogeneous core designs and power-management features aim to optimize energy use without sacrificing performance.

Arm64-based systems rely on an ecosystem of software tools and compilers. Major toolchains such as GCC and LLVM/Clang support Arm64 targets, enabling developers to build applications and operating systems for a wide range of devices. See GCC and LLVM for more on compiler support, and Linux on ARM, Android (operating system), and Windows on ARM for operating system availability.

History

The ARMv8-A architecture introduced a 64-bit execution state and the Arm64 instruction set, enabling 64-bit addressing and registers while preserving 32-bit compatibility. Early implementations and cores in the ARMv8-A family included 64-bit designs that would form the basis for mobile CPUs and later server-class processors. Over time, ARM’s licensing model allowed a broad set of fabs and design houses to implement Arm64 cores in many market segments, from consumer devices to embedded systems and data centers.

In the 2010s, ARM’s design strategy emphasized efficiency and scalability, with successive core families expanding performance and feature sets. The 2010s also saw Arm64 begin to appear in non-mobile contexts, driven by demand for energy-efficient processing in hyperscale data centers and edge computing.

Corporate and strategic developments around Arm Ltd. (the company behind the ARM architecture) have influenced the shape of the Arm64 ecosystem, including licensing arrangements and partnerships with major semiconductor companies. See ARM architecture and Cortex-A for broader context on core designs and licensing.

Adoption and ecosystem

Arm64 is employed across a broad spectrum of devices and platforms. In mobile and embedded systems, Arm64 dominates the silicon design space due to its favorable performance-per-watt characteristics. In the consumer space, Apple Silicon demonstrates the feasibility of high-performance Arm64 CPUs in personal computing, while other vendors ship Arm64-based cores in smartphones, tablets, wearables, and IoT devices. See Apple Silicon and Android (operating system) for examples of platform-specific adoption, and Linux on ARM for open-source operating system support.

In servers and data centers, Arm64-based processors have gained traction as part of a broader trend toward energy-efficient, scalable computing. Linux distributions, cloud offerings, and HPC deployments increasingly support Arm64 workloads, sometimes alongside traditional x86-64 options, with software ecosystems adapting to the architecture’s parallelism and memory models. See High-performance computing and x86-64 for comparative context.

Security and performance

Arm64 performance depends on microarchitectural design, process technology, and software optimization. The architecture’s efficiency advantages have driven widespread deployment in battery-powered devices and in energy-constrained environments. Security features added in modern Armv8-A revisions—such as pointer authentication and memory tagging—aim to reduce the attack surface of software running on Arm64 cores. The architecture has also faced public discussions about speculative execution vulnerabilities and related mitigations, similar to other modern processors, with ongoing work to balance performance and security.

Controversies in the Arm64 space often center on licensing practices, market concentration, interoperability, and the pace of open-standard competition (such as with RISC-V). Proponents argue that a diversified ecosystem spurs innovation and cost-effective hardware for a wide range of use cases, while critics call for greater openness and more transparent licensing terms to reduce potential vendor lock-in and to encourage competition. See also RISC-V and ARM architecture for broader comparative perspectives.