bitops.h 4.6 KB

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  1. /*
  2. * Copyright 1995, Russell King.
  3. * Various bits and pieces copyrights include:
  4. * Linus Torvalds (test_bit).
  5. *
  6. * bit 0 is the LSB of addr; bit 32 is the LSB of (addr+1).
  7. *
  8. * Please note that the code in this file should never be included
  9. * from user space. Many of these are not implemented in assembler
  10. * since they would be too costly. Also, they require priviledged
  11. * instructions (which are not available from user mode) to ensure
  12. * that they are atomic.
  13. */
  14. #ifndef __ASM_ARM_BITOPS_H
  15. #define __ASM_ARM_BITOPS_H
  16. #ifdef __KERNEL__
  17. #include <asm/proc-armv/system.h>
  18. #define smp_mb__before_clear_bit() do { } while (0)
  19. #define smp_mb__after_clear_bit() do { } while (0)
  20. /*
  21. * Function prototypes to keep gcc -Wall happy.
  22. */
  23. extern void set_bit(int nr, volatile void * addr);
  24. extern void clear_bit(int nr, volatile void * addr);
  25. extern void change_bit(int nr, volatile void * addr);
  26. static inline void __change_bit(int nr, volatile void *addr)
  27. {
  28. unsigned long mask = BIT_MASK(nr);
  29. unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
  30. *p ^= mask;
  31. }
  32. static inline int __test_and_set_bit(int nr, volatile void *addr)
  33. {
  34. unsigned long mask = BIT_MASK(nr);
  35. unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
  36. unsigned long old = *p;
  37. *p = old | mask;
  38. return (old & mask) != 0;
  39. }
  40. static inline int test_and_set_bit(int nr, volatile void * addr)
  41. {
  42. unsigned long flags = 0;
  43. int out;
  44. local_irq_save(flags);
  45. out = __test_and_set_bit(nr, addr);
  46. local_irq_restore(flags);
  47. return out;
  48. }
  49. static inline int __test_and_clear_bit(int nr, volatile void *addr)
  50. {
  51. unsigned long mask = BIT_MASK(nr);
  52. unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
  53. unsigned long old = *p;
  54. *p = old & ~mask;
  55. return (old & mask) != 0;
  56. }
  57. static inline int test_and_clear_bit(int nr, volatile void * addr)
  58. {
  59. unsigned long flags = 0;
  60. int out;
  61. local_irq_save(flags);
  62. out = __test_and_clear_bit(nr, addr);
  63. local_irq_restore(flags);
  64. return out;
  65. }
  66. extern int test_and_change_bit(int nr, volatile void * addr);
  67. static inline int __test_and_change_bit(int nr, volatile void *addr)
  68. {
  69. unsigned long mask = BIT_MASK(nr);
  70. unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
  71. unsigned long old = *p;
  72. *p = old ^ mask;
  73. return (old & mask) != 0;
  74. }
  75. /*
  76. * This routine doesn't need to be atomic.
  77. */
  78. static inline int test_bit(int nr, const void * addr)
  79. {
  80. return ((unsigned char *) addr)[nr >> 3] & (1U << (nr & 7));
  81. }
  82. static inline int __ilog2(unsigned int x)
  83. {
  84. return generic_fls(x) - 1;
  85. }
  86. /*
  87. * ffz = Find First Zero in word. Undefined if no zero exists,
  88. * so code should check against ~0UL first..
  89. */
  90. static inline unsigned long ffz(unsigned long word)
  91. {
  92. int k;
  93. word = ~word;
  94. k = 31;
  95. if (word & 0x0000ffff) { k -= 16; word <<= 16; }
  96. if (word & 0x00ff0000) { k -= 8; word <<= 8; }
  97. if (word & 0x0f000000) { k -= 4; word <<= 4; }
  98. if (word & 0x30000000) { k -= 2; word <<= 2; }
  99. if (word & 0x40000000) { k -= 1; }
  100. return k;
  101. }
  102. static inline int find_next_zero_bit(void *addr, int size, int offset)
  103. {
  104. unsigned long *p = ((unsigned long *)addr) + (offset >> 5);
  105. unsigned long result = offset & ~31UL;
  106. unsigned long tmp;
  107. if (offset >= size)
  108. return size;
  109. size -= result;
  110. offset &= 31UL;
  111. if (offset) {
  112. tmp = *(p++);
  113. tmp |= ~0UL >> (32-offset);
  114. if (size < 32)
  115. goto found_first;
  116. if (~tmp)
  117. goto found_middle;
  118. size -= 32;
  119. result += 32;
  120. }
  121. while (size & ~31UL) {
  122. tmp = *(p++);
  123. if (~tmp)
  124. goto found_middle;
  125. result += 32;
  126. size -= 32;
  127. }
  128. if (!size)
  129. return result;
  130. tmp = *p;
  131. found_first:
  132. tmp |= ~0UL >> size;
  133. found_middle:
  134. return result + ffz(tmp);
  135. }
  136. /*
  137. * hweightN: returns the hamming weight (i.e. the number
  138. * of bits set) of a N-bit word
  139. */
  140. #define hweight32(x) generic_hweight32(x)
  141. #define hweight16(x) generic_hweight16(x)
  142. #define hweight8(x) generic_hweight8(x)
  143. #define find_first_zero_bit(addr, size) \
  144. find_next_zero_bit((addr), (size), 0)
  145. #define ext2_set_bit test_and_set_bit
  146. #define ext2_clear_bit test_and_clear_bit
  147. #define ext2_test_bit test_bit
  148. #define ext2_find_first_zero_bit find_first_zero_bit
  149. #define ext2_find_next_zero_bit find_next_zero_bit
  150. /* Bitmap functions for the minix filesystem. */
  151. #define minix_test_and_set_bit(nr,addr) test_and_set_bit(nr,addr)
  152. #define minix_set_bit(nr,addr) set_bit(nr,addr)
  153. #define minix_test_and_clear_bit(nr,addr) test_and_clear_bit(nr,addr)
  154. #define minix_test_bit(nr,addr) test_bit(nr,addr)
  155. #define minix_find_first_zero_bit(addr,size) find_first_zero_bit(addr,size)
  156. #endif /* __KERNEL__ */
  157. #include <asm-generic/bitops/__fls.h>
  158. #include <asm-generic/bitops/__ffs.h>
  159. #include <asm-generic/bitops/fls.h>
  160. #include <asm-generic/bitops/fls64.h>
  161. #endif /* _ARM_BITOPS_H */