Looks good to me.
--Justin
On Apr 8, 2011, at 4:45 PM, Ben Pfaff wrote:
> Obviously correct code is easier on everyone. As the C FAQ says:
>
> 20.15c: How can I swap two values without using a temporary?
>
> A: The standard hoary old assembly language programmer's trick is:
>
> a ^= b;
> b ^= a;
> a ^= b;
>
> But this sort of code has little place in modern, HLL
> programming. Temporary variables are essentially free,
> and the idiomatic code using three assignments, namely
>
> int t = a;
> a = b;
> b = t;
>
> is not only clearer to the human reader, it is more likely to be
> recognized by the compiler and turned into the most-efficient
> code (e.g. using a swap instruction, if available). The latter
> code is obviously also amenable to use with pointers and
> floating-point values, unlike the XOR trick. See also questions
> 3.3b and 10.3.
> ---
> lib/netdev-linux.c | 6 +++---
> 1 files changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/lib/netdev-linux.c b/lib/netdev-linux.c
> index eecaaa5..1aa9093 100644
> --- a/lib/netdev-linux.c
> +++ b/lib/netdev-linux.c
> @@ -1144,9 +1144,9 @@ netdev_linux_update_is_pseudo(struct netdev_dev_linux
> *netdev_dev)
> static void
> swap_uint64(uint64_t *a, uint64_t *b)
> {
> - *a ^= *b;
> - *b ^= *a;
> - *a ^= *b;
> + uint64_t tmp = *a;
> + *a = *b;
> + *b = tmp;
> }
>
> /* Retrieves current device stats for 'netdev'. */
> --
> 1.7.1
>
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