5.2. Architecture support for NEON and VFP

The NEON extension is optionally available only for the ARMv7-A and ARMv7-R architectures. All NEON instructions, with the exception of half-precision instructions, are available on systems that support NEON. Some of these instructions are also available on systems that implement VFP extension without NEON. These are called shared instructions.

The half-precision instructions are only available on NEON or VFPv3 systems that implement the half-precision extension (see Half-precision extension).

Most VFP and the shared instructions are available in all versions of the VFP architecture. Where this is not true, the descriptions of the instructions specify the applicable VFP architecture versions.

ARMv7-M does not support VFP. All other ARMv7 architecture profiles support the VFPv3 architecture.

VFPv3 has variants that do not support all VFPv3 registers and floating-point data types. For details of the implemented VFP architecture and variant, you must always refer to the appropriate product documentation.

NEON and VFP instructions, including the half-precision instructions, are treated as Undefined Instructions on systems that do not support the necessary architecture extension. Even on systems that support NEON and VFP, the instructions are undefined if the necessary coprocessors are not enabled in the Coprocessor Access Control Register (CP15 CPACR). For more information, see the Technical Reference Manual for your processor.

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