Lennart Sorensen wrote:
I believe the answer when armhf was originally defined is: Yes.
Main reason as far as I understand it is that ARMv7 has thumb2, which
is what armhf uses by default, which means the code size is smaller
while having the same execution speed as normal arm instructions,
but the smaller code size means less cache usage, so effectively your
instruction cache is made larger and more effective, which certainly
will help performance.
There are also a couple of new constant load instructions "movw" and
"movt" which make loading 16 and 32 bit constants more efficient.
The question I haven't seen really answered is just how much difference
this makes in practice. Anyone fancy loading debian armhf and raspbian
on the same hardware and doing some benchmarking?
I am not sure if ARMv6 has the same VFP3-D16 as ARMv7, but I think
it does.
The version of armv6 used on the raspberry pi (which seems to be the
only armv6 device anyone cares about) has vfpv2. Afaict vfpv3_d16 adds a
constant load instruction, a couple of fixed point conversion
instructions and makes exception support non-mandatory. Altogether not
much difference.
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