From: Segher Boessenkool <segher@kernel.crashing.org>
To: Matt Brown <matthew.brown.dev@gmail.com>
Cc: linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH v2 2/5] powerpc/lib/sstep: Add popcnt instruction emulation
Date: Mon, 24 Jul 2017 02:36:55 -0500 [thread overview]
Message-ID: <20170724073654.GR13471@gate.crashing.org> (raw)
In-Reply-To: <20170724010109.21263-2-matthew.brown.dev@gmail.com>
Hi Matt,
On Mon, Jul 24, 2017 at 11:01:06AM +1000, Matt Brown wrote:
> + for (i = 0; i < (64 / size); i++) {
If you do
for (i = 0; i < 64; i += size)
things are slightly nicer.
> + if ((i * size) < 32)
> + low |= n << (i * size);
> + else
> + high |= n << ((i * size) - 32);
> + }
> + regs->gpr[ra] = (high << 32) | low;
Why have separate high and low vars?
And there are much better ways to calculate popcount, of course.
Segher
next prev parent reply other threads:[~2017-07-24 7:37 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-07-24 1:01 [PATCH v2 1/5] powerpc/lib/sstep: Add cmpb instruction emulation Matt Brown
2017-07-24 1:01 ` [PATCH v2 2/5] powerpc/lib/sstep: Add popcnt " Matt Brown
2017-07-24 7:36 ` Segher Boessenkool [this message]
2017-07-24 10:28 ` Balbir Singh
2017-07-25 0:53 ` Matt Brown
2017-07-24 1:01 ` [PATCH v2 3/5] powerpc/lib/sstep: Add bpermd " Matt Brown
2017-07-24 1:01 ` [PATCH 4/5] powerpc/lib/sstep: Add prty " Matt Brown
2017-07-24 1:01 ` [PATCH v2 5/5] powerpc/lib/sstep: Add isel " Matt Brown
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