include/linux/bitops.h

   1 #ifndef _LINUX_BITOPS_H
   2 #define _LINUX_BITOPS_H
   3 #include <asm/types.h>
   4
   5 #ifdef  __KERNEL__
   6 #define BIT(nr)                 (1UL << (nr))
   7 #define BIT_MASK(nr)            (1UL << ((nr) % BITS_PER_LONG))
   8 #define BIT_WORD(nr)            ((nr) / BITS_PER_LONG)
   9 #define BITS_PER_BYTE           8
  10 #define BITS_TO_LONGS(nr)       DIV_ROUND_UP(nr, BITS_PER_BYTE * sizeof(long))
  11 #endif
  12
  13 /*
  14  * Create a contiguous bitmask starting at bit position @l and ending at
  15  * position @h. For example
  16  * GENMASK_ULL(39, 21) gives us the 64bit vector 0x000000ffffe00000.
  17  */
  18 #define GENMASK(h, l)           (((U32_C(1) << ((h) - (l) + 1)) - 1) << (l))
  19 #define GENMASK_ULL(h, l)       (((U64_C(1) << ((h) - (l) + 1)) - 1) << (l))
  20
  21 extern unsigned int __sw_hweight8(unsigned int w);
  22 extern unsigned int __sw_hweight16(unsigned int w);
  23 extern unsigned int __sw_hweight32(unsigned int w);
  24 extern unsigned long __sw_hweight64(__u64 w);
  25
  26 /*
  27  * Include this here because some architectures need generic_ffs/fls in
  28  * scope
  29  */
  30 #include <asm/bitops.h>
  31
  32 #define for_each_set_bit(bit, addr, size) \
  33         for ((bit) = find_first_bit((addr), (size));            \
  34              (bit) < (size);                                    \
  35              (bit) = find_next_bit((addr), (size), (bit) + 1))
  36
  37 /* same as for_each_set_bit() but use bit as value to start with */
  38 #define for_each_set_bit_from(bit, addr, size) \
  39         for ((bit) = find_next_bit((addr), (size), (bit));      \
  40              (bit) < (size);                                    \
  41              (bit) = find_next_bit((addr), (size), (bit) + 1))
  42
  43 #define for_each_clear_bit(bit, addr, size) \
  44         for ((bit) = find_first_zero_bit((addr), (size));       \
  45              (bit) < (size);                                    \
  46              (bit) = find_next_zero_bit((addr), (size), (bit) + 1))
  47
  48 /* same as for_each_clear_bit() but use bit as value to start with */
  49 #define for_each_clear_bit_from(bit, addr, size) \
  50         for ((bit) = find_next_zero_bit((addr), (size), (bit)); \
  51              (bit) < (size);                                    \
  52              (bit) = find_next_zero_bit((addr), (size), (bit) + 1))
  53
  54 static __inline__ int get_bitmask_order(unsigned int count)
  55 {
  56         int order;
  57
  58         order = fls(count);
  59         return order;   /* We could be slightly more clever with -1 here... */
  60 }
  61
  62 static __inline__ int get_count_order(unsigned int count)
  63 {
  64         int order;
  65
  66         order = fls(count) - 1;
  67         if (count & (count - 1))
  68                 order++;
  69         return order;
  70 }
  71
  72 static inline unsigned long hweight_long(unsigned long w)
  73 {
  74         return sizeof(w) == 4 ? hweight32(w) : hweight64(w);
  75 }
  76
  77 /**
  78  * rol64 - rotate a 64-bit value left
  79  * @word: value to rotate
  80  * @shift: bits to roll
  81  */
  82 static inline __u64 rol64(__u64 word, unsigned int shift)
  83 {
  84         return (word << shift) | (word >> (64 - shift));
  85 }
  86
  87 /**
  88  * ror64 - rotate a 64-bit value right
  89  * @word: value to rotate
  90  * @shift: bits to roll
  91  */
  92 static inline __u64 ror64(__u64 word, unsigned int shift)
  93 {
  94         return (word >> shift) | (word << (64 - shift));
  95 }
  96
  97 /**
  98  * rol32 - rotate a 32-bit value left
  99  * @word: value to rotate
 100  * @shift: bits to roll
 101  */
 102 static inline __u32 rol32(__u32 word, unsigned int shift)
 103 {
 104         return (word << shift) | (word >> (32 - shift));
 105 }
 106
 107 /**
 108  * ror32 - rotate a 32-bit value right
 109  * @word: value to rotate
 110  * @shift: bits to roll
 111  */
 112 static inline __u32 ror32(__u32 word, unsigned int shift)
 113 {
 114         return (word >> shift) | (word << (32 - shift));
 115 }
 116
 117 /**
 118  * rol16 - rotate a 16-bit value left
 119  * @word: value to rotate
 120  * @shift: bits to roll
 121  */
 122 static inline __u16 rol16(__u16 word, unsigned int shift)
 123 {
 124         return (word << shift) | (word >> (16 - shift));
 125 }
 126
 127 /**
 128  * ror16 - rotate a 16-bit value right
 129  * @word: value to rotate
 130  * @shift: bits to roll
 131  */
 132 static inline __u16 ror16(__u16 word, unsigned int shift)
 133 {
 134         return (word >> shift) | (word << (16 - shift));
 135 }
 136
 137 /**
 138  * rol8 - rotate an 8-bit value left
 139  * @word: value to rotate
 140  * @shift: bits to roll
 141  */
 142 static inline __u8 rol8(__u8 word, unsigned int shift)
 143 {
 144         return (word << shift) | (word >> (8 - shift));
 145 }
 146
 147 /**
 148  * ror8 - rotate an 8-bit value right
 149  * @word: value to rotate
 150  * @shift: bits to roll
 151  */
 152 static inline __u8 ror8(__u8 word, unsigned int shift)
 153 {
 154         return (word >> shift) | (word << (8 - shift));
 155 }
 156
 157 /**
 158  * sign_extend32 - sign extend a 32-bit value using specified bit as sign-bit
 159  * @value: value to sign extend
 160  * @index: 0 based bit index (0<=index<32) to sign bit
 161  */
 162 static inline __s32 sign_extend32(__u32 value, int index)
 163 {
 164         __u8 shift = 31 - index;
 165         return (__s32)(value << shift) >> shift;
 166 }
 167
 168 static inline unsigned fls_long(unsigned long l)
 169 {
 170         if (sizeof(l) == 4)
 171                 return fls(l);
 172         return fls64(l);
 173 }
 174
 175 /**
 176  * __ffs64 - find first set bit in a 64 bit word
 177  * @word: The 64 bit word
 178  *
 179  * On 64 bit arches this is a synomyn for __ffs
 180  * The result is not defined if no bits are set, so check that @word
 181  * is non-zero before calling this.
 182  */
 183 static inline unsigned long __ffs64(u64 word)
 184 {
 185 #if BITS_PER_LONG == 32
 186         if (((u32)word) == 0UL)
 187                 return __ffs((u32)(word >> 32)) + 32;
 188 #elif BITS_PER_LONG != 64
 189 #error BITS_PER_LONG not 32 or 64
 190 #endif
 191         return __ffs((unsigned long)word);
 192 }
 193
 194 #ifdef __KERNEL__
 195
 196 #ifndef find_last_bit
 197 /**
 198  * find_last_bit - find the last set bit in a memory region
 199  * @addr: The address to start the search at
 200  * @size: The maximum size to search
 201  *
 202  * Returns the bit number of the first set bit, or size.
 203  */
 204 extern unsigned long find_last_bit(const unsigned long *addr,
 205                                    unsigned long size);
 206 #endif
 207
 208 #endif /* __KERNEL__ */
 209 #endif