include/linux/bitops.h

   1 #ifndef _LINUX_BITOPS_H
   2 #define _LINUX_BITOPS_H
   3
   4 #include <asm/types.h>
   5 #include <asm-generic/bitsperlong.h>
   6 #include <linux/compiler.h>
   7
   8 #ifdef  __KERNEL__
   9 #define BIT(nr)                 (1UL << (nr))
  10 #define BIT_ULL(nr)             (1ULL << (nr))
  11 #define BIT_MASK(nr)            (1UL << ((nr) % BITS_PER_LONG))
  12 #define BIT_WORD(nr)            ((nr) / BITS_PER_LONG)
  13 #define BIT_ULL_MASK(nr)        (1ULL << ((nr) % BITS_PER_LONG_LONG))
  14 #define BIT_ULL_WORD(nr)        ((nr) / BITS_PER_LONG_LONG)
  15 #define BITS_PER_BYTE           8
  16 #define BITS_TO_LONGS(nr)       DIV_ROUND_UP(nr, BITS_PER_BYTE * sizeof(long))
  17 #endif
  18
  19 /*
  20  * Create a contiguous bitmask starting at bit position @l and ending at
  21  * position @h. For example
  22  * GENMASK_ULL(39, 21) gives us the 64bit vector 0x000000ffffe00000.
  23  */
  24 #define GENMASK(h, l) \
  25         (((~0UL) << (l)) & (~0UL >> (BITS_PER_LONG - 1 - (h))))
  26
  27 #define GENMASK_ULL(h, l) \
  28         (((~0ULL) << (l)) & (~0ULL >> (BITS_PER_LONG_LONG - 1 - (h))))
  29
  30 /*
  31  * ffs: find first bit set. This is defined the same way as
  32  * the libc and compiler builtin ffs routines, therefore
  33  * differs in spirit from the above ffz (man ffs).
  34  */
  35
  36 static inline int generic_ffs(int x)
  37 {
  38         int r = 1;
  39
  40         if (!x)
  41                 return 0;
  42         if (!(x & 0xffff)) {
  43                 x >>= 16;
  44                 r += 16;
  45         }
  46         if (!(x & 0xff)) {
  47                 x >>= 8;
  48                 r += 8;
  49         }
  50         if (!(x & 0xf)) {
  51                 x >>= 4;
  52                 r += 4;
  53         }
  54         if (!(x & 3)) {
  55                 x >>= 2;
  56                 r += 2;
  57         }
  58         if (!(x & 1)) {
  59                 x >>= 1;
  60                 r += 1;
  61         }
  62         return r;
  63 }
  64
  65 /**
  66  * fls - find last (most-significant) bit set
  67  * @x: the word to search
  68  *
  69  * This is defined the same way as ffs.
  70  * Note fls(0) = 0, fls(1) = 1, fls(0x80000000) = 32.
  71  */
  72 static inline int generic_fls(int x)
  73 {
  74         int r = 32;
  75
  76         if (!x)
  77                 return 0;
  78         if (!(x & 0xffff0000u)) {
  79                 x <<= 16;
  80                 r -= 16;
  81         }
  82         if (!(x & 0xff000000u)) {
  83                 x <<= 8;
  84                 r -= 8;
  85         }
  86         if (!(x & 0xf0000000u)) {
  87                 x <<= 4;
  88                 r -= 4;
  89         }
  90         if (!(x & 0xc0000000u)) {
  91                 x <<= 2;
  92                 r -= 2;
  93         }
  94         if (!(x & 0x80000000u)) {
  95                 x <<= 1;
  96                 r -= 1;
  97         }
  98         return r;
  99 }
 100
 101
 102 /*
 103  * hweightN: returns the hamming weight (i.e. the number
 104  * of bits set) of a N-bit word
 105  */
 106
 107 static inline unsigned int generic_hweight32(unsigned int w)
 108 {
 109         unsigned int res = (w & 0x55555555) + ((w >> 1) & 0x55555555);
 110         res = (res & 0x33333333) + ((res >> 2) & 0x33333333);
 111         res = (res & 0x0F0F0F0F) + ((res >> 4) & 0x0F0F0F0F);
 112         res = (res & 0x00FF00FF) + ((res >> 8) & 0x00FF00FF);
 113         return (res & 0x0000FFFF) + ((res >> 16) & 0x0000FFFF);
 114 }
 115
 116 static inline unsigned int generic_hweight16(unsigned int w)
 117 {
 118         unsigned int res = (w & 0x5555) + ((w >> 1) & 0x5555);
 119         res = (res & 0x3333) + ((res >> 2) & 0x3333);
 120         res = (res & 0x0F0F) + ((res >> 4) & 0x0F0F);
 121         return (res & 0x00FF) + ((res >> 8) & 0x00FF);
 122 }
 123
 124 static inline unsigned int generic_hweight8(unsigned int w)
 125 {
 126         unsigned int res = (w & 0x55) + ((w >> 1) & 0x55);
 127         res = (res & 0x33) + ((res >> 2) & 0x33);
 128         return (res & 0x0F) + ((res >> 4) & 0x0F);
 129 }
 130
 131 #include <asm/bitops.h>
 132
 133 /* linux/include/asm-generic/bitops/non-atomic.h */
 134
 135 #ifndef PLATFORM__SET_BIT
 136 # define __set_bit generic_set_bit
 137 #endif
 138
 139 #ifndef PLATFORM__CLEAR_BIT
 140 # define __clear_bit generic_clear_bit
 141 #endif
 142
 143 #ifndef PLATFORM_FFS
 144 # define ffs generic_ffs
 145 #endif
 146
 147 #ifndef PLATFORM_FLS
 148 # define fls generic_fls
 149 #endif
 150
 151 static inline unsigned fls_long(unsigned long l)
 152 {
 153         if (sizeof(l) == 4)
 154                 return fls(l);
 155         return fls64(l);
 156 }
 157
 158 /**
 159  * __ffs64 - find first set bit in a 64 bit word
 160  * @word: The 64 bit word
 161  *
 162  * On 64 bit arches this is a synomyn for __ffs
 163  * The result is not defined if no bits are set, so check that @word
 164  * is non-zero before calling this.
 165  */
 166 static inline unsigned long __ffs64(u64 word)
 167 {
 168 #if BITS_PER_LONG == 32
 169         if (((u32)word) == 0UL)
 170                 return __ffs((u32)(word >> 32)) + 32;
 171 #elif BITS_PER_LONG != 64
 172 #error BITS_PER_LONG not 32 or 64
 173 #endif
 174         return __ffs((unsigned long)word);
 175 }
 176
 177 /**
 178  * __set_bit - Set a bit in memory
 179  * @nr: the bit to set
 180  * @addr: the address to start counting from
 181  *
 182  * Unlike set_bit(), this function is non-atomic and may be reordered.
 183  * If it's called on the same region of memory simultaneously, the effect
 184  * may be that only one operation succeeds.
 185  */
 186 static inline void generic_set_bit(int nr, volatile unsigned long *addr)
 187 {
 188         unsigned long mask = BIT_MASK(nr);
 189         unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
 190
 191         *p  |= mask;
 192 }
 193
 194 static inline void generic_clear_bit(int nr, volatile unsigned long *addr)
 195 {
 196         unsigned long mask = BIT_MASK(nr);
 197         unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
 198
 199         *p &= ~mask;
 200 }
 201
 202 #endif