ARM architecture

The ARM architecture, originally known as Acorn RISC Machine, is a family of RISC architectures for computer processors, configured for various environments. ARM Holdings develops the architecture and licenses it to other companies, who design their own products that implement one of the ARM architectures—these include system-on-chips (SoC) and microcontrollers. ARM Holdings neither manufactures nor sells CPU devices based on its own designs, but rather licenses the processor architecture to interested parties.

History

The ARM architecture was developed in the early 1980s by Acorn Computers Ltd. of Cambridge, England. The first ARM-based products were co-developed by Acorn and Apple, for use in the Apple Newton, a handheld computing device. This partnership was part of the ARM's rise in the mobile and embedded electronics market, becoming the most widely used 32-bit instruction set architecture by 1995.

Design

The ARM architecture is known for its power efficiency and minimalistic instruction set. An ARM processor is typically composed of:

• A set of 32-bit or 64-bit registers
• A simple set of instructions
• A built-in support for interrupts
• Various control mechanisms

The architecture provides multiple instruction sets, such as ARM (32-bit), Thumb (compressed, 16-bit instructions), and Thumb-2 (a mix of 16-bit and 32-bit instructions for improved performance).

Applications

Originally used in personal digital assistants (PDAs) and other portable devices, ARM processors have expanded their presence into other markets, including:

• Smartphones and tablets
• Embedded systems, such as those in automotive computing systems
• Servers and supercomputers
• Wearable technology
• Internet of Things (IoT) devices

Versions

Over the years, ARM Holdings has released several versions of the ARM architecture. These include:

• ARMv1 to ARMv7, which support 32-bit processing.
• ARMv8, which introduces the 64-bit instruction set.
• ARMv9, the latest version, focuses on enhanced security features, machine learning, and digital signal processing.

Licensing

ARM Holdings licenses its architectures through different licensing models, including perpetual, term, and royalty-bearing licenses. Companies such as Qualcomm, Apple, and Samsung have developed their own processors based on ARM's architecture.

Impact and Reception

Due to its power efficiency, ARM is the dominant architecture in the mobile market, powering most smartphones and tablets. Its adoption in the server and desktop market is growing, challenging traditional x86 architectures by Intel and AMD.

See Also

• Microprocessor
• System on a chip
• RISC-V, an open-source alternative to ARM