19. Population Count Doubleword X-form (popcntd/POPCNTD)

popcntd RA, RS

31 RS RA /// 506 Rc
0  6  11 16  21  31

n <- 0
do i = 0 to 63
if (RS)i = 1 then
n <- n+1
RA <- n

A count of the number of one bits in register RS is
placed into register RA. This number ranges from 0 to
64, inclusive.

Special Registers Altered:
None