nfp: bpf: optimize mov64 a little

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Loading 64bit constants require up to 4 load immediates, since
we can only load 16 bits at a time.  If the 32bit halves of
the 64bit constant are the same, however, we can save a cycle
by doing a register move instead of two loads of 16 bits.

Note that we don't optimize the normal ALU64 load because even
though it's a 64 bit load the upper half of the register is
a coming from sign extension so we can load it in one cycle
anyway.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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Jakub Kicinski 2017-10-23 11:58:14 -07:00 • committed by David S. Miller

parent b14157eeed

commit 9f16c8abcd

1 changed files with 15 additions and 6 deletions

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drivers/net/ethernet/netronome/nfp/bpf/jit.c

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