ARM Architecture

ARM architecture is a family of Reduced Instruction Set Computer (RISC) instruction set architectures for computer processors. It was developed by Arm Holdings, a company that designs the core architecture and licenses it to other companies. These companies then build the physical devices that employ the ARM instruction set.

Historical Development

Initially, ARM stood for Acorn RISC Machine, which was developed by Acorn Computers in the 1980s. As the architecture evolved, the name later became Advanced RISC Machines. The architecture has gone through numerous iterations, including ARMv3, ARMv7, and the significant ARMv8-A, which introduced 64-bit processing.

Core Features

ARM Cortex Processors

The ARM architecture is implemented through various core designs, the most notable being the ARM Cortex family. These include:

ARM Cortex-A: Designed for application-level computing, they are suitable for smartphones, tablets, and laptops.
ARM Cortex-M: Optimized for low-cost and energy-efficient microcontroller applications.
ARM Cortex-R: Intended for real-time applications, often used in automotive and industrial sectors.

32-bit and 64-bit Processing

The ARM architecture originally featured a 32-bit instruction set and address space. However, with the release of ARMv8-A in 2011, a transition to a 64-bit architecture occurred, allowing for a 64-bit address space and arithmetic, significantly enhancing processing power and efficiency.

Applications and Influence

ARM processors are known for their low costs, low power consumption, and minimal heat generation, making them ideal for portable and battery-powered devices. They are prevalent in a variety of devices such as:

ARM's influence extends beyond consumer electronics. The architecture is utilized in automotive systems, industrial control systems, and even in powerful data center applications.

Licensing Model

Unlike most semiconductor companies, Arm Holdings does not manufacture its own chips. Instead, it licenses its architecture to other companies like Apple Inc., Samsung Electronics, and Qualcomm, which then build and sell ARM-based products. This licensing model has contributed to a broad and diverse ecosystem of ARM-based devices.