summaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
-rw-r--r--lib/hweight.c29
1 files changed, 14 insertions, 15 deletions
diff --git a/lib/hweight.c b/lib/hweight.c
index 721a4b8..4382576 100644
--- a/lib/hweight.c
+++ b/lib/hweight.c
@@ -10,28 +10,28 @@
unsigned int hweight32(unsigned int w)
{
- unsigned int res = (w & 0x55555555) + ((w >> 1) & 0x55555555);
+ unsigned int res = w - ((w >> 1) & 0x55555555);
res = (res & 0x33333333) + ((res >> 2) & 0x33333333);
- res = (res & 0x0F0F0F0F) + ((res >> 4) & 0x0F0F0F0F);
- res = (res & 0x00FF00FF) + ((res >> 8) & 0x00FF00FF);
- return (res & 0x0000FFFF) + ((res >> 16) & 0x0000FFFF);
+ res = (res + (res >> 4)) & 0x0F0F0F0F;
+ res = res + (res >> 8);
+ return (res + (res >> 16)) & 0x000000FF;
}
EXPORT_SYMBOL(hweight32);
unsigned int hweight16(unsigned int w)
{
- unsigned int res = (w & 0x5555) + ((w >> 1) & 0x5555);
+ unsigned int res = w - ((w >> 1) & 0x5555);
res = (res & 0x3333) + ((res >> 2) & 0x3333);
- res = (res & 0x0F0F) + ((res >> 4) & 0x0F0F);
- return (res & 0x00FF) + ((res >> 8) & 0x00FF);
+ res = (res + (res >> 4)) & 0x0F0F;
+ return (res + (res >> 8)) & 0x00FF;
}
EXPORT_SYMBOL(hweight16);
unsigned int hweight8(unsigned int w)
{
- unsigned int res = (w & 0x55) + ((w >> 1) & 0x55);
+ unsigned int res = w - ((w >> 1) & 0x55);
res = (res & 0x33) + ((res >> 2) & 0x33);
- return (res & 0x0F) + ((res >> 4) & 0x0F);
+ return (res + (res >> 4)) & 0x0F;
}
EXPORT_SYMBOL(hweight8);
@@ -40,13 +40,12 @@ unsigned long hweight64(__u64 w)
#if BITS_PER_LONG == 32
return hweight32((unsigned int)(w >> 32)) + hweight32((unsigned int)w);
#elif BITS_PER_LONG == 64
- u64 res;
- res = (w & 0x5555555555555555ul) + ((w >> 1) & 0x5555555555555555ul);
+ __u64 res = w - ((w >> 1) & 0x5555555555555555ul);
res = (res & 0x3333333333333333ul) + ((res >> 2) & 0x3333333333333333ul);
- res = (res & 0x0F0F0F0F0F0F0F0Ful) + ((res >> 4) & 0x0F0F0F0F0F0F0F0Ful);
- res = (res & 0x00FF00FF00FF00FFul) + ((res >> 8) & 0x00FF00FF00FF00FFul);
- res = (res & 0x0000FFFF0000FFFFul) + ((res >> 16) & 0x0000FFFF0000FFFFul);
- return (res & 0x00000000FFFFFFFFul) + ((res >> 32) & 0x00000000FFFFFFFFul);
+ res = (res + (res >> 4)) & 0x0F0F0F0F0F0F0F0Ful;
+ res = res + (res >> 8);
+ res = res + (res >> 16);
+ return (res + (res >> 32)) & 0x00000000000000FFul;
#else
#error BITS_PER_LONG not defined
#endif
OpenPOWER on IntegriCloud