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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.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, write to the Free
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Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
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02111-1307 USA. */
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#include <limits.h>
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#include <sched.h>
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int
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__sched_cpucount (size_t setsize, const cpu_set_t *setp)
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{
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int s = 0;
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const __cpu_mask *p = setp->__bits;
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const __cpu_mask *end = &setp->__bits[setsize / sizeof (__cpu_mask)];
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while (p < end)
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{
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__cpu_mask l = *p++;
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#ifdef POPCNT
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s += POPCNT (l);
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#else
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if (l == 0)
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continue;
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# if LONG_BIT > 32
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l = (l & 0x5555555555555555ul) + ((l >> 1) & 0x5555555555555555ul);
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l = (l & 0x3333333333333333ul) + ((l >> 2) & 0x3333333333333333ul);
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l = (l & 0x0f0f0f0f0f0f0f0ful) + ((l >> 4) & 0x0f0f0f0f0f0f0f0ful);
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l = (l & 0x00ff00ff00ff00fful) + ((l >> 8) & 0x00ff00ff00ff00fful);
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l = (l & 0x0000ffff0000fffful) + ((l >> 16) & 0x0000ffff0000fffful);
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l = (l & 0x00000000fffffffful) + ((l >> 32) & 0x00000000fffffffful);
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# else
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l = (l & 0x55555555ul) + ((l >> 1) & 0x55555555ul);
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l = (l & 0x33333333ul) + ((l >> 2) & 0x33333333ul);
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l = (l & 0x0f0f0f0ful) + ((l >> 4) & 0x0f0f0f0ful);
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l = (l & 0x00ff00fful) + ((l >> 8) & 0x00ff00fful);
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l = (l & 0x0000fffful) + ((l >> 16) & 0x0000fffful);
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# endif
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s += l;
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#endif
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}
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return s;
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}
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