bitops.h 2.6 KB

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  1. /*
  2. * include/asm-xtensa/bitops.h
  3. *
  4. * Atomic operations that C can't guarantee us.Useful for resource counting etc.
  5. *
  6. * This file is subject to the terms and conditions of the GNU General Public
  7. * License. See the file "COPYING" in the main directory of this archive
  8. * for more details.
  9. *
  10. * Copyright (C) 2001 - 2007 Tensilica Inc.
  11. */
  12. #ifndef _XTENSA_BITOPS_H
  13. #define _XTENSA_BITOPS_H
  14. #ifdef __KERNEL__
  15. #ifndef _LINUX_BITOPS_H
  16. #error only <linux/bitops.h> can be included directly
  17. #endif
  18. #include <asm/processor.h>
  19. #include <asm/byteorder.h>
  20. #ifdef CONFIG_SMP
  21. # error SMP not supported on this architecture
  22. #endif
  23. #define smp_mb__before_clear_bit() barrier()
  24. #define smp_mb__after_clear_bit() barrier()
  25. #include <asm-generic/bitops/atomic.h>
  26. #include <asm-generic/bitops/non-atomic.h>
  27. #if XCHAL_HAVE_NSA
  28. static inline unsigned long __cntlz (unsigned long x)
  29. {
  30. int lz;
  31. asm ("nsau %0, %1" : "=r" (lz) : "r" (x));
  32. return lz;
  33. }
  34. /*
  35. * ffz: Find first zero in word. Undefined if no zero exists.
  36. * bit 0 is the LSB of addr; bit 32 is the LSB of (addr+1).
  37. */
  38. static inline int ffz(unsigned long x)
  39. {
  40. return 31 - __cntlz(~x & -~x);
  41. }
  42. /*
  43. * __ffs: Find first bit set in word. Return 0 for bit 0
  44. */
  45. static inline int __ffs(unsigned long x)
  46. {
  47. return 31 - __cntlz(x & -x);
  48. }
  49. /*
  50. * ffs: Find first bit set in word. This is defined the same way as
  51. * the libc and compiler builtin ffs routines, therefore
  52. * differs in spirit from the above ffz (man ffs).
  53. */
  54. static inline int ffs(unsigned long x)
  55. {
  56. return 32 - __cntlz(x & -x);
  57. }
  58. /*
  59. * fls: Find last (most-significant) bit set in word.
  60. * Note fls(0) = 0, fls(1) = 1, fls(0x80000000) = 32.
  61. */
  62. static inline int fls (unsigned int x)
  63. {
  64. return 32 - __cntlz(x);
  65. }
  66. /**
  67. * __fls - find last (most-significant) set bit in a long word
  68. * @word: the word to search
  69. *
  70. * Undefined if no set bit exists, so code should check against 0 first.
  71. */
  72. static inline unsigned long __fls(unsigned long word)
  73. {
  74. return 31 - __cntlz(word);
  75. }
  76. #else
  77. /* Use the generic implementation if we don't have the nsa/nsau instructions. */
  78. # include <asm-generic/bitops/ffs.h>
  79. # include <asm-generic/bitops/__ffs.h>
  80. # include <asm-generic/bitops/ffz.h>
  81. # include <asm-generic/bitops/fls.h>
  82. # include <asm-generic/bitops/__fls.h>
  83. #endif
  84. #include <asm-generic/bitops/fls64.h>
  85. #include <asm-generic/bitops/find.h>
  86. #include <asm-generic/bitops/le.h>
  87. #include <asm-generic/bitops/ext2-atomic-setbit.h>
  88. #include <asm-generic/bitops/hweight.h>
  89. #include <asm-generic/bitops/lock.h>
  90. #include <asm-generic/bitops/sched.h>
  91. #endif /* __KERNEL__ */
  92. #endif /* _XTENSA_BITOPS_H */