ARM Architecture Reference Manual for ARMv8-A

This manual describes the ARM® architecture v8, ARMv8. The architecture describes the operation of an ARMv8-A Processing element (PE), and this manual includes descriptions of: • The two Execution states, AArch64 and AArch32. • The instruction sets: — In AArch32 state, the A32 and T32 instruction sets, that are compatible with earlier versions of the ARM architecture. — In AArch64 state, the A64 instruction set. • The states that determine how a PE operates, including the current Exception level and Security state, and in AArch32 state the PE mode. • The Exception model. • The interprocessing model, that supports transitioning between AArch64 state and AArch32 state. • The memory model, that defines memory ordering and memory management. This manual covers a single architecture profile, ARMv8-A, that defines a Virtual Memory System Architecture (VMSA). • The programmers’ model, and its interfaces to System registers that control most PE and memory system features, and provide status information. • The Advanced SIMD and floating-point instructions, that provide high-performance: — Single-precision and double-precision floating-point operations. — Conversions between double-precision, single-precision, and half-precision floating-point values. — Integer, single-precision floating-point, and in A64, double-precision vector operations in all instruction sets. — Double-precision floating-point vector operations in the A64 instruction set. • The security model, that provides two security states to support secure applications. • The virtualization model, that support the virtualization of Non-secure operation. • The Debug architecture, that provides software access to debug features.