arch/arm/include/asm/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 #include <asm/proc/system.h>
  21
  22 #define smp_mb__before_clear_bit()      do { } while (0)
  23 #define smp_mb__after_clear_bit()       do { } while (0)
  24
  25 /*
  26  * Function prototypes to keep gcc -Wall happy.
  27  */
  28 extern void set_bit(int nr, volatile void * addr);
  29
  30 extern void clear_bit(int nr, volatile void * addr);
  31
  32 extern void change_bit(int nr, volatile void * addr);
  33
  34 static inline void __change_bit(int nr, volatile void *addr)
  35 {
  36         unsigned long mask = BIT_MASK(nr);
  37         unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
  38
  39         *p ^= mask;
  40 }
  41
  42 static inline int __test_and_set_bit(int nr, volatile void *addr)
  43 {
  44         unsigned long mask = BIT_MASK(nr);
  45         unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
  46         unsigned long old = *p;
  47
  48         *p = old | mask;
  49         return (old & mask) != 0;
  50 }
  51
  52 static inline int test_and_set_bit(int nr, volatile void * addr)
  53 {
  54         unsigned long flags;
  55         int out;
  56
  57         local_irq_save(flags);
  58         out = __test_and_set_bit(nr, addr);
  59         local_irq_restore(flags);
  60
  61         return out;
  62 }
  63
  64 static inline int __test_and_clear_bit(int nr, volatile void *addr)
  65 {
  66         unsigned long mask = BIT_MASK(nr);
  67         unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
  68         unsigned long old = *p;
  69
  70         *p = old & ~mask;
  71         return (old & mask) != 0;
  72 }
  73
  74 static inline int test_and_clear_bit(int nr, volatile void * addr)
  75 {
  76         unsigned long flags;
  77         int out;
  78
  79         local_irq_save(flags);
  80         out = __test_and_clear_bit(nr, addr);
  81         local_irq_restore(flags);
  82
  83         return out;
  84 }
  85
  86 extern int test_and_change_bit(int nr, volatile void * addr);
  87
  88 static inline int __test_and_change_bit(int nr, volatile void *addr)
  89 {
  90         unsigned long mask = BIT_MASK(nr);
  91         unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
  92         unsigned long old = *p;
  93
  94         *p = old ^ mask;
  95         return (old & mask) != 0;
  96 }
  97
  98 extern int find_first_zero_bit(void * addr, unsigned size);
  99 extern int find_next_zero_bit(void * addr, int size, int offset);
 100
 101 /*
 102  * This routine doesn't need to be atomic.
 103  */
 104 static inline int test_bit(int nr, const void * addr)
 105 {
 106     return ((unsigned char *) addr)[nr >> 3] & (1U << (nr & 7));
 107 }
 108
 109 static inline int __ilog2(unsigned int x)
 110 {
 111         return generic_fls(x) - 1;
 112 }
 113
 114 /*
 115  * ffz = Find First Zero in word. Undefined if no zero exists,
 116  * so code should check against ~0UL first..
 117  */
 118 static inline unsigned long ffz(unsigned long word)
 119 {
 120         int k;
 121
 122         word = ~word;
 123         k = 31;
 124         if (word & 0x0000ffff) { k -= 16; word <<= 16; }
 125         if (word & 0x00ff0000) { k -= 8;  word <<= 8;  }
 126         if (word & 0x0f000000) { k -= 4;  word <<= 4;  }
 127         if (word & 0x30000000) { k -= 2;  word <<= 2;  }
 128         if (word & 0x40000000) { k -= 1; }
 129         return k;
 130 }
 131
 132 /*
 133  * hweightN: returns the hamming weight (i.e. the number
 134  * of bits set) of a N-bit word
 135  */
 136
 137 #define hweight32(x) generic_hweight32(x)
 138 #define hweight16(x) generic_hweight16(x)
 139 #define hweight8(x) generic_hweight8(x)
 140
 141 #define ext2_set_bit                    test_and_set_bit
 142 #define ext2_clear_bit                  test_and_clear_bit
 143 #define ext2_test_bit                   test_bit
 144 #define ext2_find_first_zero_bit        find_first_zero_bit
 145 #define ext2_find_next_zero_bit         find_next_zero_bit
 146
 147 /* Bitmap functions for the minix filesystem. */
 148 #define minix_test_and_set_bit(nr,addr) test_and_set_bit(nr,addr)
 149 #define minix_set_bit(nr,addr)          set_bit(nr,addr)
 150 #define minix_test_and_clear_bit(nr,addr)       test_and_clear_bit(nr,addr)
 151 #define minix_test_bit(nr,addr)         test_bit(nr,addr)
 152 #define minix_find_first_zero_bit(addr,size)    find_first_zero_bit(addr,size)
 153
 154 #endif /* __KERNEL__ */
 155
 156 #endif /* _ARM_BITOPS_H */