Android and compatibility with deprecated armv7 instructions

Arnd Bergmann [off-list ref] writes:

On Friday 04 July 2014 20:24:05 Mark Brown wrote:

quoted

Another question I think it's worth asking is what the use case for 32
bit mode is other than preexisting binaries - I guess there's a case for
smaller binaries giving better cache utilisation?

If you wanted that, you'd probably run x32-mode (or whatever it gets called
on ARM64), which I'd expect to also be more efficient ;-)

Seriously, backwards-compatibility is the only reason I can think of
really, but that doesn't /have/ to mean existing binaries; there is a large
amount of source code that can readily be compiled to any CPU as long as
it's little-endian 32-bit.

There's also a lot of code that has been heavily optimised for 32-bit
ARM but doesn't (yet) have the same level of optimisation for ARM64, so
even if it builds and works for ARM64, it won't be nearly as fast.

-- 
M?ns Rullg?rd
mans at mansr.com