arm64

ARM64, or AArch64, is the 64-bit execution state of ARM's ARMv8-A architecture. It represents the successor to 32-bit ARMv7-A and introduces a 64-bit general-purpose register file, a 64-bit address space, and a redesigned instruction set for improved performance and efficiency. AArch64 programs run in the A64 instruction set, while ARMv8 maintains backward compatibility with legacy 32-bit code through the AArch32 state, allowing coexistence of 32-bit and 64-bit software.

The architecture includes a large register set and a unified memory model, supports advanced SIMD (NEON) and floating-point capabilities, and provides features such as virtualization support and hardware security extensions (for example, TrustZone) depending on the revision. The instruction encoding and pipeline are designed to enable high performance while reducing energy consumption, which is important for mobile devices. AArch64 also allows running 32-bit code in its AArch32 compatibility mode, promoting a gradual transition for software.

ARM64 was introduced with the ARMv8-A architecture in 2011 and gained rapid adoption across mobile processors in the early 2010s. Apple’s A7, released in 2013, popularized 64-bit iOS devices, and since then ARM64 has become dominant in smartphones, tablets, embedded systems, and many servers. The ecosystem includes major operating systems such as Android, iOS, Linux distributions, and Windows on ARM, supported by mature toolchains (GCC, Clang/LLVM) and compilers.