In NEON, you can view the extension register bank as:
Sixteen 128-bit registers,
Thirty-two 64-bit registers,
A combination of registers from the above views.
NEON views each register as containing a vector of 1, 2, 4, 8, or 16 elements, all of the same size and type. Individual elements can also be accessed as scalars.
In NEON, the 64-bit registers are called doubleword registers and the 128-bit registers are called quadword registers.