Introduction to NEON intrinsics
The ARM compilation tools provide intrinsics to generate NEON code for all Cortex-A series processors in both ARM and Thumb state. The NEON intrinsics are defined in the header file arm_neon.h.
The header file defines both the intrinsics and a set of vector types.
There is no support for NEON intrinsics for architectures before ARMv7. When
compiling for a target without NEON, if you include the header file
arm_neon.h a compiler error occurs.