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mkp224o/ifilter_bitsum.h

33 lines
601 B

#ifdef EXPANDMASK
#ifdef __GNUC__
static IFT ifilter_bitsum(IFT x)
{
if (sizeof(IFT) == 16)
return (((IFT) 1) <<
(__builtin_popcountll((unsigned long long) (x >> (sizeof(IFT) * 8 / 2))) +
__builtin_popcountll((unsigned long long) x))) - 1;
if (sizeof(IFT) == 8)
return (((IFT) 1) << __builtin_popcountll((unsigned long long) x)) - 1;
return (((IFT) 1) << __builtin_popcount((unsigned int) x)) - 1;
}
#else // __GNUC__
static IFT ifilter_bitsum(IFT x)
{
int v = 0;
while (x != 0) {
x &= x - 1;
v++;
}
return (((IFT) 1) << v) - 1;
}
#endif // __GNUC__
#endif // EXPANDMASK