Idempotent partition around median of 5?

[Era Scarecrow via Digitalmars-d]

On Friday, 5 February 2016 at 15:41:11 UTC, Fool wrote:
> One swap usually decomposes into three moves.

  Recently from reading some interesting hacks and super code, a 
good swap can also be done via 3 xor operations (and avoiding an 
intermediate storage unit).

http://aggregate.ee.engr.uky.edu/MAGIC/#Swap%20Values%20Without%20a%20Temporary

x ^= y;
y ^= x;
x ^= y;

  Since these can be used directly as registers it might be faster 
(assuming all 5 are mapped to registers until the final write 
out, which might not work).