summaryrefslogtreecommitdiff
path: root/libc/sysdeps/linux/common/sched_cpucount.c
diff options
context:
space:
mode:
Diffstat (limited to 'libc/sysdeps/linux/common/sched_cpucount.c')
-rw-r--r--libc/sysdeps/linux/common/sched_cpucount.c60
1 files changed, 60 insertions, 0 deletions
diff --git a/libc/sysdeps/linux/common/sched_cpucount.c b/libc/sysdeps/linux/common/sched_cpucount.c
new file mode 100644
index 000000000..331c0b8df
--- /dev/null
+++ b/libc/sysdeps/linux/common/sched_cpucount.c
@@ -0,0 +1,60 @@
+/* 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;
+}