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(__sched_cpucount): Allow using special instruction for counting bits.

This commit is contained in:
Ulrich Drepper 2007-06-08 18:29:24 +00:00
parent 47779a7d3c
commit 7d0e41cebe
1 changed files with 7 additions and 3 deletions
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10
posix/sched_cpucount.c
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@ -30,22 +30,26 @@ __sched_cpucount (size_t setsize, cpu_set_t *setp)
if (l == 0)
continue;
#if LONG_BIT > 32
#ifdef POPCNT
s += POPCNT (l);
#else
# if LONG_BIT > 32
l = (l & 0x5555555555555555ul) + ((l >> 1) & 0x5555555555555555ul);
l = (l & 0x3333333333333333ul) + ((l >> 2) & 0x3333333333333333ul);
l = (l & 0x0f0f0f0f0f0f0f0ful) + ((l >> 4) & 0x0f0f0f0f0f0f0f0ful);
l = (l & 0x00ff00ff00ff00fful) + ((l >> 8) & 0x00ff00ff00ff00fful);
l = (l & 0x0000ffff0000fffful) + ((l >> 16) & 0x0000ffff0000fffful);
l = (l & 0x00000000fffffffful) + ((l >> 32) & 0x00000000fffffffful);
#else
# else
l = (l & 0x55555555ul) + ((l >> 1) & 0x55555555ul);
l = (l & 0x33333333ul) + ((l >> 2) & 0x33333333ul);
l = (l & 0x0f0f0f0ful) + ((l >> 4) & 0x0f0f0f0ful);
l = (l & 0x00ff00fful) + ((l >> 8) & 0x00ff00fful);
l = (l & 0x0000fffful) + ((l >> 16) & 0x0000fffful);
#endif
# endif
s += l;
#endif
}
return s;