Android ARMv6/v7 and VFP/NEON

Question

I would like to understand more the CPU used on Android phones. The reason is that we are building the C library which has the certain CPU/math processor architecture flags we c

Answer 1

I'd concentrate on v7.

There are hardly any new products shipping with v6, and by the time your library is production ready, v6 will be non-issue.

here are some info: - Neon ALWAYS includes VFP - Coretex A8 can feature either Neon or none - The VFP on A8's Neon is actually VFP-lite which is quite a lot slower. Much slower than V6's VFP. - Coretex A9 and above can feature Neon, VFP, or none. - V7 has many enhanced instructions well suited for mathematical operations beside the dual-issue capability. - The chip vendors can omit Neon and even VFP, but they pay the same license fee to ARM regardlessly. They'd only save very little in manufacturing costs. - Neon is extremely powerful in capable hands, but cannot do double precision. - Except for the ones with the neonless Tegra, no v7 based Android phone is known to me which doesn't feature Neon. (The reason is above) - Tegra3 does have Neon