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Date: Mon, 24 Jul 2017 02:36:55 -0500
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
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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