sched_cpucount.c 1.9 KB

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  1. /* Copyright (C) 2007 Free Software Foundation, Inc.
  2. This file is part of the GNU C Library.
  3. The GNU C Library is free software; you can redistribute it and/or
  4. modify it under the terms of the GNU Lesser General Public
  5. License as published by the Free Software Foundation; either
  6. version 2.1 of the License, or (at your option) any later version.
  7. The GNU C Library is distributed in the hope that it will be useful,
  8. but WITHOUT ANY WARRANTY; without even the implied warranty of
  9. MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  10. Lesser General Public License for more details.
  11. You should have received a copy of the GNU Lesser General Public
  12. License along with the GNU C Library; if not, see
  13. <http://www.gnu.org/licenses/>. */
  14. #include <limits.h>
  15. #include <sched.h>
  16. int
  17. __sched_cpucount (size_t setsize, const cpu_set_t *setp)
  18. {
  19. int s = 0;
  20. const __cpu_mask *p = setp->__bits;
  21. const __cpu_mask *end = &setp->__bits[setsize / sizeof (__cpu_mask)];
  22. while (p < end)
  23. {
  24. __cpu_mask l = *p++;
  25. #ifdef POPCNT
  26. s += POPCNT (l);
  27. #else
  28. if (l == 0)
  29. continue;
  30. # if LONG_BIT > 32
  31. l = (l & 0x5555555555555555ul) + ((l >> 1) & 0x5555555555555555ul);
  32. l = (l & 0x3333333333333333ul) + ((l >> 2) & 0x3333333333333333ul);
  33. l = (l & 0x0f0f0f0f0f0f0f0ful) + ((l >> 4) & 0x0f0f0f0f0f0f0f0ful);
  34. l = (l & 0x00ff00ff00ff00fful) + ((l >> 8) & 0x00ff00ff00ff00fful);
  35. l = (l & 0x0000ffff0000fffful) + ((l >> 16) & 0x0000ffff0000fffful);
  36. l = (l & 0x00000000fffffffful) + ((l >> 32) & 0x00000000fffffffful);
  37. # else
  38. l = (l & 0x55555555ul) + ((l >> 1) & 0x55555555ul);
  39. l = (l & 0x33333333ul) + ((l >> 2) & 0x33333333ul);
  40. l = (l & 0x0f0f0f0ful) + ((l >> 4) & 0x0f0f0f0ful);
  41. l = (l & 0x00ff00fful) + ((l >> 8) & 0x00ff00fful);
  42. l = (l & 0x0000fffful) + ((l >> 16) & 0x0000fffful);
  43. # endif
  44. s += l;
  45. #endif
  46. }
  47. return s;
  48. }