Re: Improved Swapping Method In sort.c

H. Peter Anvin
2008-05-02T05:08:30Z

Soumyadip Das Mahapatra wrote:
> Hello everybody,
> The swapping method (in function void u32_swap() line no.. 14 to 16) in lib/sort.c can be improved by using the following code
> *(u32 *)b ^= *(u32 *)a ^= *(u32 *)b ^= *(u32 *)a instead of the code given. This code
> is not using third variable thus not consuming another memory. And I dont see any significance in
> using *int size* argument. so the function should be
> static void u32_swap(void *a, void *b)
> {
> *(u32 *)b ^= *(u32 *)a ^= *(u32 *)b ^= *(u32 *)a;
> }
>

Not only is this invalid C, but it produces massively worse code.

-hpa