[PATCH] T3/T4 sparc shifts, plus more timings
davem at davemloft.net
Sun Mar 31 23:22:22 CEST 2013
From: Torbjorn Granlund <tg at gmplib.org>
Date: Sun, 31 Mar 2013 22:57:36 +0200
> David Miller <davem at davemloft.net> writes:
> I'm going to play around with some things to try and fix this.
> Interestingly, UltraSPARC-1 and UltraSPARC-2 would not group the
> final cycle of the loop this way, because of it's requirement that
> integer operations must occur in the first three instructions of
> a group.
> But the code might not run well on US1/2 because shift needs to come
> before any other inter artithmetic op.
Unless the other is a condition code setting arithmetic op :-)
Yes, understood. We have to transpose a few of the shifts with
their neighbouring arithmetic ops in this loop to make it optimal
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