X-Git-Url: http://pilppa.org/gitweb/gitweb.cgi?a=blobdiff_plain;f=lib%2Fhweight.c;h=389424ecb129f13760de1677bd297b392264c953;hb=refs%2Fheads%2Fb2.6.28-omap-h63xx;hp=4382576717086eeaaa48d928db67dfb6757cbbb7;hpb=f9b4192923fa6e38331e88214b1fe5fc21583fcc;p=linux-2.6-omap-h63xx.git diff --git a/lib/hweight.c b/lib/hweight.c index 43825767170..389424ecb12 100644 --- a/lib/hweight.c +++ b/lib/hweight.c @@ -1,4 +1,5 @@ #include +#include #include /** @@ -40,14 +41,19 @@ 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 +#ifdef ARCH_HAS_FAST_MULTIPLIER + w -= (w >> 1) & 0x5555555555555555ul; + w = (w & 0x3333333333333333ul) + ((w >> 2) & 0x3333333333333333ul); + w = (w + (w >> 4)) & 0x0f0f0f0f0f0f0f0ful; + return (w * 0x0101010101010101ul) >> 56; +#else __u64 res = w - ((w >> 1) & 0x5555555555555555ul); res = (res & 0x3333333333333333ul) + ((res >> 2) & 0x3333333333333333ul); 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 #endif } EXPORT_SYMBOL(hweight64);