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From: Richard Henderson <rth@twiddle.net>
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Subject: Re: [Qemu-devel] [PATCH] input: sdl: fix guest_cursor logic.
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To: Gerd Hoffmann <kraxel@redhat.com>, qemu-devel@nongnu.org
Cc: Anthony Liguori <aliguori@amazon.com>

On 03/10/2014 01:23 AM, Gerd Hoffmann wrote:
> +        if (guest_cursor) {
> +            x -= guest_x;
> +            y -= guest_y;
> +            guest_x += x;
> +            guest_y += y;
> +            dx = x;
> +            dy = y;
> +        }

Why write it in this funny way?  Surely better as

  dx = x - guest_x;
  dy = y - guest_y;
  guest_x = x;
  guest_y = y;


r~