ia64/linux-2.6.18-xen.hg

view lib/hweight.c @ 647:a5bb490065f6

Fix the build after public header sync.
Signed-off-by: Keir Fraser <keir.fraser@citrix.com>
author Keir Fraser <keir.fraser@citrix.com>
date Wed Aug 13 14:01:49 2008 +0100 (2008-08-13)
parents 831230e53067
children
line source
1 #include <linux/module.h>
2 #include <asm/types.h>
4 /**
5 * hweightN - returns the hamming weight of a N-bit word
6 * @x: the word to weigh
7 *
8 * The Hamming Weight of a number is the total number of bits set in it.
9 */
11 unsigned int hweight32(unsigned int w)
12 {
13 unsigned int res = w - ((w >> 1) & 0x55555555);
14 res = (res & 0x33333333) + ((res >> 2) & 0x33333333);
15 res = (res + (res >> 4)) & 0x0F0F0F0F;
16 res = res + (res >> 8);
17 return (res + (res >> 16)) & 0x000000FF;
18 }
19 EXPORT_SYMBOL(hweight32);
21 unsigned int hweight16(unsigned int w)
22 {
23 unsigned int res = w - ((w >> 1) & 0x5555);
24 res = (res & 0x3333) + ((res >> 2) & 0x3333);
25 res = (res + (res >> 4)) & 0x0F0F;
26 return (res + (res >> 8)) & 0x00FF;
27 }
28 EXPORT_SYMBOL(hweight16);
30 unsigned int hweight8(unsigned int w)
31 {
32 unsigned int res = w - ((w >> 1) & 0x55);
33 res = (res & 0x33) + ((res >> 2) & 0x33);
34 return (res + (res >> 4)) & 0x0F;
35 }
36 EXPORT_SYMBOL(hweight8);
38 unsigned long hweight64(__u64 w)
39 {
40 #if BITS_PER_LONG == 32
41 return hweight32((unsigned int)(w >> 32)) + hweight32((unsigned int)w);
42 #elif BITS_PER_LONG == 64
43 __u64 res = w - ((w >> 1) & 0x5555555555555555ul);
44 res = (res & 0x3333333333333333ul) + ((res >> 2) & 0x3333333333333333ul);
45 res = (res + (res >> 4)) & 0x0F0F0F0F0F0F0F0Ful;
46 res = res + (res >> 8);
47 res = res + (res >> 16);
48 return (res + (res >> 32)) & 0x00000000000000FFul;
49 #else
50 #error BITS_PER_LONG not defined
51 #endif
52 }
53 EXPORT_SYMBOL(hweight64);