glibc/posix/sched_cpucount.c
Ulrich Drepper b4afdd0651 * bits/sched.h: Define __CPU_COUNT. Declare __sched_cpucount.
* sysdeps/unix/sysv/linux/bits/sched.h: Likewise.
	* posix/sched.h: Define CPU_COUNT.
2007-04-04 18:51:36 +00:00

53 lines
1.9 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, cpu_set_t *setp)
{
int s = 0;
for (unsigned int j = 0; j < setsize / sizeof (__cpu_mask); ++j)
{
__cpu_mask l = setp->__bits[j];
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;
}
return s;
}