Raw date related to http://stackoverflow.com/a/27051759/1149736
Time required to calculate popcount on number in comment.
Always in order:
                 1st solution (simple looping),
                 2nd solution (using ecx and loop)
                 David Wohlferd's solution

Data is measured on 100000000 iterations.

-- 0x00000000
real	0m0.568s
user	0m0.543s
sys	0m0.003s

real	0m11.567s
user	0m11.530s
sys	0m0.000s

real	0m0.752s
user	0m0.750s
sys	0m0.000s

-- 0x80000001
real	0m5.047s
user	0m5.040s
sys	0m0.003s

real	0m11.551s
user	0m11.523s
sys	0m0.000s

real	0m5.051s
user	0m4.893s
sys	0m0.000s

-- 0xffffffff
real	0m3.960s
user	0m3.833s
sys	0m0.000s

real	0m11.547s
user	0m11.523s
sys	0m0.007s

real	0m4.900s
user	0m4.890s
sys	0m0.000s