The 32-bit subset of ARMv8 is (supposedly) better specified at the system level than ARMv7
(ie, by the v8 architecture itself).

There are some cores that do just the 32-bit subset of v8, but apparently Cortex-A53 will do 64 as well,
which I hadn't realised from the Rpi3 announcement I saw.

On 3 March 2016 at 15:37, Richard Miller <9fans@hamnavoe.com> wrote:
>> cpu0: 1200MHz ARM Cortex-A53 r0p4
>
> it's ARMv8-A!

When booted in 32-bit mode, it behaves like armv7a.