include/asm-arm/bitops.h

   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
  15 #ifndef __ASM_ARM_BITOPS_H
  16 #define __ASM_ARM_BITOPS_H
  17
  18 #ifdef __KERNEL__
  19
  20 #define smp_mb__before_clear_bit()      do { } while (0)
  21 #define smp_mb__after_clear_bit()       do { } while (0)
  22
  23 /*
  24  * Function prototypes to keep gcc -Wall happy.
  25  */
  26 extern void set_bit(int nr, volatile void * addr);
  27
  28 static inline void __set_bit(int nr, volatile void *addr)
  29 {
  30         ((unsigned char *) addr)[nr >> 3] |= (1U << (nr & 7));
  31 }
  32
  33 extern void clear_bit(int nr, volatile void * addr);
  34
  35 static inline void __clear_bit(int nr, volatile void *addr)
  36 {
  37         ((unsigned char *) addr)[nr >> 3] &= ~(1U << (nr & 7));
  38 }
  39
  40 extern void change_bit(int nr, volatile void * addr);
  41
  42 static inline void __change_bit(int nr, volatile void *addr)
  43 {
  44         ((unsigned char *) addr)[nr >> 3] ^= (1U << (nr & 7));
  45 }
  46
  47 extern int test_and_set_bit(int nr, volatile void * addr);
  48
  49 static inline int __test_and_set_bit(int nr, volatile void *addr)
  50 {
  51         unsigned int mask = 1 << (nr & 7);
  52         unsigned int oldval;
  53
  54         oldval = ((unsigned char *) addr)[nr >> 3];
  55         ((unsigned char *) addr)[nr >> 3] = oldval | mask;
  56         return oldval & mask;
  57 }
  58
  59 extern int test_and_clear_bit(int nr, volatile void * addr);
  60
  61 static inline int __test_and_clear_bit(int nr, volatile void *addr)
  62 {
  63         unsigned int mask = 1 << (nr & 7);
  64         unsigned int oldval;
  65
  66         oldval = ((unsigned char *) addr)[nr >> 3];
  67         ((unsigned char *) addr)[nr >> 3] = oldval & ~mask;
  68         return oldval & mask;
  69 }
  70
  71 extern int test_and_change_bit(int nr, volatile void * addr);
  72
  73 static inline int __test_and_change_bit(int nr, volatile void *addr)
  74 {
  75         unsigned int mask = 1 << (nr & 7);
  76         unsigned int oldval;
  77
  78         oldval = ((unsigned char *) addr)[nr >> 3];
  79         ((unsigned char *) addr)[nr >> 3] = oldval ^ mask;
  80         return oldval & mask;
  81 }
  82
  83 extern int find_first_zero_bit(void * addr, unsigned size);
  84 extern int find_next_zero_bit(void * addr, int size, int offset);
  85
  86 /*
  87  * This routine doesn't need to be atomic.
  88  */
  89 static inline int test_bit(int nr, const void * addr)
  90 {
  91     return ((unsigned char *) addr)[nr >> 3] & (1U << (nr & 7));
  92 }
  93
  94 /*
  95  * ffz = Find First Zero in word. Undefined if no zero exists,
  96  * so code should check against ~0UL first..
  97  */
  98 static inline unsigned long ffz(unsigned long word)
  99 {
 100         int k;
 101
 102         word = ~word;
 103         k = 31;
 104         if (word & 0x0000ffff) { k -= 16; word <<= 16; }
 105         if (word & 0x00ff0000) { k -= 8;  word <<= 8;  }
 106         if (word & 0x0f000000) { k -= 4;  word <<= 4;  }
 107         if (word & 0x30000000) { k -= 2;  word <<= 2;  }
 108         if (word & 0x40000000) { k -= 1; }
 109         return k;
 110 }
 111
 112 /*
 113  * ffs: find first bit set. This is defined the same way as
 114  * the libc and compiler builtin ffs routines, therefore
 115  * differs in spirit from the above ffz (man ffs).
 116  */
 117
 118 #define ffs(x) generic_ffs(x)
 119
 120 /*
 121  * hweightN: returns the hamming weight (i.e. the number
 122  * of bits set) of a N-bit word
 123  */
 124
 125 #define hweight32(x) generic_hweight32(x)
 126 #define hweight16(x) generic_hweight16(x)
 127 #define hweight8(x) generic_hweight8(x)
 128
 129 #define ext2_set_bit                    test_and_set_bit
 130 #define ext2_clear_bit                  test_and_clear_bit
 131 #define ext2_test_bit                   test_bit
 132 #define ext2_find_first_zero_bit        find_first_zero_bit
 133 #define ext2_find_next_zero_bit         find_next_zero_bit
 134
 135 /* Bitmap functions for the minix filesystem. */
 136 #define minix_test_and_set_bit(nr,addr) test_and_set_bit(nr,addr)
 137 #define minix_set_bit(nr,addr)          set_bit(nr,addr)
 138 #define minix_test_and_clear_bit(nr,addr)       test_and_clear_bit(nr,addr)
 139 #define minix_test_bit(nr,addr)         test_bit(nr,addr)
 140 #define minix_find_first_zero_bit(addr,size)    find_first_zero_bit(addr,size)
 141
 142 #endif /* __KERNEL__ */
 143
 144 #endif /* _ARM_BITOPS_H */