| Feature | ARMv8-A (2011) | ARMv8.1 (2016) | ARMv8.2 (2016) | ARMv8.4 (2018) |
|---|---|---|---|---|
| Instruction Set Baseline | First 64-bit support | Enhanced atomic operations | FP16/SVE support | Nested virtualization |
| Typical Processors | Cortex-A53/A72 | Cortex-A75 | Cortex-A55/A76 | Cortex-A76/A77 |
ARMv8.1:
Added AT atomic instructions (LDAPR/STLR)
Support for unaligned atomic access (solving ABA issue in ARMv8-A)
ARMv8.4:
Introduced nested virtualization (NV2 extension)
Improved hypervisor performance by ~40%
ARMv8.2 upgrades:
FP16 half-precision floating point (2× faster AI inference)
Scalable Vector Extension (SVE) with flexible 128–2048-bit vectors
ARMv8.4 additions:
Matrix instructions (accelerated GEMM)
Dot Product (INT8 dot product operations)
| Version | Security Features |
|---|---|
| ARMv8.1 | PAN (Privileged Access Never) |
| ARMv8.2 | Memory Tagging Extension (MTE) |
| ARMv8.4 | Enhanced Pointer Authentication (PAC+BTI) |
| Test Item | A72 (v8.0) | A75 (v8.1) | A76 (v8.2) | A77 (v8.4) |
|---|---|---|---|---|
| SPECint2017 | 25 | 35 (+40%) | 42 (+68%) | 48 (+92%) |
| ResNet-50 INT8 | 12 FPS | 18 FPS | 32 FPS | 45 FPS |
| Memory Latency | 85ns | 78ns | 72ns | 68ns |
ARMv8.1:
✓ Data centers (AWS Graviton Gen1)
✓ Multi-core systems requiring strong consistency
ARMv8.2:
✓ Mobile AI (Kirin 980 / Snapdragon 855)
✓ HPC vector computing (Fujitsu A64FX)
ARMv8.4:
✓ Cloud servers (Ampere Altra)
✓ Autonomous driving (NVIDIA Orin)
Binary Compatibility:
v8.0 code runs on v8.4 hardware
New features require recompilation (e.g., SVE instructions)
Toolchain Requirements:
| Architecture | Minimum GCC | Minimum LLVM |
|---|---|---|
| ARMv8.1 | 6.0 | 5.0 |
| ARMv8.2 | 7.0 | 6.0 |
| ARMv8.4 | 9.0 | 8.0 |
Embedded devices: ARMv8.2 (balanced performance and efficiency)
AI edge computing: ARMv8.4 (matrix instruction acceleration)
Traditional servers: ARMv8.1 (cost-optimized choice)
Note: ARMv8.4 is currently the most widely adopted commercial version. Android 13+ mandates support for the MTE (Memory Tagging Extension) security feature.
