The ARM architecture defines the Advanced SIMD extension as a part of coprocessors 10 and 11, that are also used for the Vector Floating Point (VFP) extension. There is no architectural requirement for a processor to implement both VFP and NEON, but the common features in the programmers models for these extensions mean an operating system that supports VFP requires little or no modifications to also support NEON.
When optimizing NEON code for a particular processor, you might have to consider implementation defined aspects of how that processor integrates the NEON technology. This means that a sequence of instructions optimized for a specific processor might have different timing characteristics on a different processor even if the NEON instruction cycle timings are identical.
See the ARM Architecture Reference Manual ARMv7-A
and ARMv7-R edition for more information about the Advanced
SIMD extension, including instruction listings and encodings. This
is available on request from