mirror of
https://sourceware.org/git/glibc.git
synced 2024-12-22 10:50:07 +00:00
36dffb2256
instruction for counting bits. * sysdeps/x86_64/sched_cpucount.c: New file.
61 lines
2.0 KiB
C
61 lines
2.0 KiB
C
/* Copyright (C) 2007 Free Software Foundation, Inc.
|
|
This file is part of the GNU C Library.
|
|
|
|
The GNU C Library is free software; you can redistribute it and/or
|
|
modify it under the terms of the GNU Lesser General Public
|
|
License as published by the Free Software Foundation; either
|
|
version 2.1 of the License, or (at your option) any later version.
|
|
|
|
The GNU C Library is distributed in the hope that it will be useful,
|
|
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
|
Lesser General Public License for more details.
|
|
|
|
You should have received a copy of the GNU Lesser General Public
|
|
License along with the GNU C Library; if not, write to the Free
|
|
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
|
|
02111-1307 USA. */
|
|
|
|
#include <limits.h>
|
|
#include <sched.h>
|
|
|
|
|
|
int
|
|
__sched_cpucount (size_t setsize, const cpu_set_t *setp)
|
|
{
|
|
int s = 0;
|
|
const __cpu_mask *p = setp->__bits;
|
|
const __cpu_mask *end = &setp->__bits[setsize / sizeof (__cpu_mask)];
|
|
|
|
while (p < end)
|
|
{
|
|
__cpu_mask l = *p++;
|
|
|
|
#ifdef POPCNT
|
|
s += POPCNT (l);
|
|
#else
|
|
if (l == 0)
|
|
continue;
|
|
|
|
# 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
|
|
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
|
|
|
|
s += l;
|
|
#endif
|
|
}
|
|
|
|
return s;
|
|
}
|