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AArch64
AArch64, also known as ARM64, is a 64-bit version of the ARM architecture family, a widely used set of computer processor designs. It was introduced in 2011 with the ARMv8 architecture and later became part of the ARMv9 series. AArch64 allows processors to handle more memory and perform faster calculations than earlier 32-bit versions. It is designed to work alongside the older 32-bit mode, known as AArch32, allowing compatibility with a wide range of software. Devices that use AArch64 include smartphones, tablets, personal computers, and servers. The AArch64 architecture has continued to evolve through updates that improve performance, security, and support for advanced computing tasks.
In ARMv8-A, ARMv8-R, and ARMv9-A, an "Execution state" defines key characteristics of the processor’s environment. This includes the number of bits used in the primary processor registers, the supported instruction sets, and other aspects of the processor's execution environment. These versions of the ARM architecture support two Execution states: the 64-bit AArch64 state and the 32-bit AArch32 state.
Extension: Data gathering hint (ARMv8.0-DGH).
AArch64 was introduced in ARMv8-A and is included in subsequent versions of ARMv8-A, and in all versions of ARMv9-A. It was also introduced in ARMv8-R as an option, after its introduction in ARMv8-A; it is not included in ARMv8-M.
The main opcode for selecting which group an A64 instruction belongs to is at bits 25–28.
Announced in October 2011, ARMv8-A represents a fundamental change to the ARM architecture. It adds an optional 64-bit Execution state, named "AArch64", and the associated new "A64" instruction set, in addition to a 32-bit Execution state, "AArch32", supporting the 32-bit "A32" (original 32-bit ARM) and "T32" (Thumb/Thumb-2) instruction sets. The latter instruction sets provide user-space compatibility with the existing 32-bit ARMv7-A architecture. ARMv8-A allows 32-bit applications to be executed in a 64-bit OS, and a 32-bit OS to be under the control of a 64-bit hypervisor. ARM announced their Cortex-A53 and Cortex-A57 cores on 30 October 2012. Apple was the first to release an ARMv8-A compatible core (Cyclone) in a consumer product (iPhone 5S). AppliedMicro, using an FPGA, was the first to demo ARMv8-A. The first ARMv8-A SoC from Samsung is the Exynos 5433 used in the Galaxy Note 4, which features two clusters of four Cortex-A57 and Cortex-A53 cores in a big.LITTLE configuration; but it only runs in AArch32 mode. ARMv8-A includes VFPv3/v4 and advanced SIMD (Neon) as standard features in both AArch32 and AArch64. It also adds cryptography instructions supporting AES, SHA-1/SHA-256 and finite field arithmetic.
An ARMv8-A processor can support one or both of AArch32 and AArch64; it may support AArch32 and AArch64 at lower Exception levels and only AArch64 at higher Exception levels. For example, the ARM Cortex-A32 supports only AArch32, the ARM Cortex-A34 supports only AArch64, and the ARM Cortex-A72 supports both AArch64 and AArch32. An ARMv9-A processor must support AArch64 at all Exception levels, and may support AArch32 at EL0.
In December 2014, ARMv8.1-A, an update with "incremental benefits over v8.0", was announced. The enhancements fell into two categories: changes to the instruction set, and changes to the exception model and memory translation.
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AArch64 AI simulator
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AArch64
AArch64, also known as ARM64, is a 64-bit version of the ARM architecture family, a widely used set of computer processor designs. It was introduced in 2011 with the ARMv8 architecture and later became part of the ARMv9 series. AArch64 allows processors to handle more memory and perform faster calculations than earlier 32-bit versions. It is designed to work alongside the older 32-bit mode, known as AArch32, allowing compatibility with a wide range of software. Devices that use AArch64 include smartphones, tablets, personal computers, and servers. The AArch64 architecture has continued to evolve through updates that improve performance, security, and support for advanced computing tasks.
In ARMv8-A, ARMv8-R, and ARMv9-A, an "Execution state" defines key characteristics of the processor’s environment. This includes the number of bits used in the primary processor registers, the supported instruction sets, and other aspects of the processor's execution environment. These versions of the ARM architecture support two Execution states: the 64-bit AArch64 state and the 32-bit AArch32 state.
Extension: Data gathering hint (ARMv8.0-DGH).
AArch64 was introduced in ARMv8-A and is included in subsequent versions of ARMv8-A, and in all versions of ARMv9-A. It was also introduced in ARMv8-R as an option, after its introduction in ARMv8-A; it is not included in ARMv8-M.
The main opcode for selecting which group an A64 instruction belongs to is at bits 25–28.
Announced in October 2011, ARMv8-A represents a fundamental change to the ARM architecture. It adds an optional 64-bit Execution state, named "AArch64", and the associated new "A64" instruction set, in addition to a 32-bit Execution state, "AArch32", supporting the 32-bit "A32" (original 32-bit ARM) and "T32" (Thumb/Thumb-2) instruction sets. The latter instruction sets provide user-space compatibility with the existing 32-bit ARMv7-A architecture. ARMv8-A allows 32-bit applications to be executed in a 64-bit OS, and a 32-bit OS to be under the control of a 64-bit hypervisor. ARM announced their Cortex-A53 and Cortex-A57 cores on 30 October 2012. Apple was the first to release an ARMv8-A compatible core (Cyclone) in a consumer product (iPhone 5S). AppliedMicro, using an FPGA, was the first to demo ARMv8-A. The first ARMv8-A SoC from Samsung is the Exynos 5433 used in the Galaxy Note 4, which features two clusters of four Cortex-A57 and Cortex-A53 cores in a big.LITTLE configuration; but it only runs in AArch32 mode. ARMv8-A includes VFPv3/v4 and advanced SIMD (Neon) as standard features in both AArch32 and AArch64. It also adds cryptography instructions supporting AES, SHA-1/SHA-256 and finite field arithmetic.
An ARMv8-A processor can support one or both of AArch32 and AArch64; it may support AArch32 and AArch64 at lower Exception levels and only AArch64 at higher Exception levels. For example, the ARM Cortex-A32 supports only AArch32, the ARM Cortex-A34 supports only AArch64, and the ARM Cortex-A72 supports both AArch64 and AArch32. An ARMv9-A processor must support AArch64 at all Exception levels, and may support AArch32 at EL0.
In December 2014, ARMv8.1-A, an update with "incremental benefits over v8.0", was announced. The enhancements fell into two categories: changes to the instruction set, and changes to the exception model and memory translation.