tools/perf/util/include/linux/bitops.h

   1 #ifndef _PERF_LINUX_BITOPS_H_
   2 #define _PERF_LINUX_BITOPS_H_
   3
   4 #include <linux/kernel.h>
   5 #include <linux/compiler.h>
   6 #include <asm/hweight.h>
   7
   8 #define BITS_PER_LONG __WORDSIZE
   9 #define BITS_PER_BYTE           8
  10 #define BITS_TO_LONGS(nr)       DIV_ROUND_UP(nr, BITS_PER_BYTE * sizeof(long))
  11
  12 #define for_each_set_bit(bit, addr, size) \
  13         for ((bit) = find_first_bit((addr), (size));            \
  14              (bit) < (size);                                    \
  15              (bit) = find_next_bit((addr), (size), (bit) + 1))
  16
  17 /* same as for_each_set_bit() but use bit as value to start with */
  18 #define for_each_set_bit_from(bit, addr, size) \
  19         for ((bit) = find_next_bit((addr), (size), (bit));      \
  20              (bit) < (size);                                    \
  21              (bit) = find_next_bit((addr), (size), (bit) + 1))
  22
  23 static inline void set_bit(int nr, unsigned long *addr)
  24 {
  25         addr[nr / BITS_PER_LONG] |= 1UL << (nr % BITS_PER_LONG);
  26 }
  27
  28 static inline void clear_bit(int nr, unsigned long *addr)
  29 {
  30         addr[nr / BITS_PER_LONG] &= ~(1UL << (nr % BITS_PER_LONG));
  31 }
  32
  33 static __always_inline int test_bit(unsigned int nr, const unsigned long *addr)
  34 {
  35         return ((1UL << (nr % BITS_PER_LONG)) &
  36                 (((unsigned long *)addr)[nr / BITS_PER_LONG])) != 0;
  37 }
  38
  39 static inline unsigned long hweight_long(unsigned long w)
  40 {
  41         return sizeof(w) == 4 ? hweight32(w) : hweight64(w);
  42 }
  43
  44 #define BITOP_WORD(nr)          ((nr) / BITS_PER_LONG)
  45
  46 /**
  47  * __ffs - find first bit in word.
  48  * @word: The word to search
  49  *
  50  * Undefined if no bit exists, so code should check against 0 first.
  51  */
  52 static __always_inline unsigned long __ffs(unsigned long word)
  53 {
  54         int num = 0;
  55
  56 #if BITS_PER_LONG == 64
  57         if ((word & 0xffffffff) == 0) {
  58                 num += 32;
  59                 word >>= 32;
  60         }
  61 #endif
  62         if ((word & 0xffff) == 0) {
  63                 num += 16;
  64                 word >>= 16;
  65         }
  66         if ((word & 0xff) == 0) {
  67                 num += 8;
  68                 word >>= 8;
  69         }
  70         if ((word & 0xf) == 0) {
  71                 num += 4;
  72                 word >>= 4;
  73         }
  74         if ((word & 0x3) == 0) {
  75                 num += 2;
  76                 word >>= 2;
  77         }
  78         if ((word & 0x1) == 0)
  79                 num += 1;
  80         return num;
  81 }
  82
  83 /*
  84  * Find the first set bit in a memory region.
  85  */
  86 static inline unsigned long
  87 find_first_bit(const unsigned long *addr, unsigned long size)
  88 {
  89         const unsigned long *p = addr;
  90         unsigned long result = 0;
  91         unsigned long tmp;
  92
  93         while (size & ~(BITS_PER_LONG-1)) {
  94                 if ((tmp = *(p++)))
  95                         goto found;
  96                 result += BITS_PER_LONG;
  97                 size -= BITS_PER_LONG;
  98         }
  99         if (!size)
 100                 return result;
 101
 102         tmp = (*p) & (~0UL >> (BITS_PER_LONG - size));
 103         if (tmp == 0UL)         /* Are any bits set? */
 104                 return result + size;   /* Nope. */
 105 found:
 106         return result + __ffs(tmp);
 107 }
 108
 109 /*
 110  * Find the next set bit in a memory region.
 111  */
 112 static inline unsigned long
 113 find_next_bit(const unsigned long *addr, unsigned long size, unsigned long offset)
 114 {
 115         const unsigned long *p = addr + BITOP_WORD(offset);
 116         unsigned long result = offset & ~(BITS_PER_LONG-1);
 117         unsigned long tmp;
 118
 119         if (offset >= size)
 120                 return size;
 121         size -= result;
 122         offset %= BITS_PER_LONG;
 123         if (offset) {
 124                 tmp = *(p++);
 125                 tmp &= (~0UL << offset);
 126                 if (size < BITS_PER_LONG)
 127                         goto found_first;
 128                 if (tmp)
 129                         goto found_middle;
 130                 size -= BITS_PER_LONG;
 131                 result += BITS_PER_LONG;
 132         }
 133         while (size & ~(BITS_PER_LONG-1)) {
 134                 if ((tmp = *(p++)))
 135                         goto found_middle;
 136                 result += BITS_PER_LONG;
 137                 size -= BITS_PER_LONG;
 138         }
 139         if (!size)
 140                 return result;
 141         tmp = *p;
 142
 143 found_first:
 144         tmp &= (~0UL >> (BITS_PER_LONG - size));
 145         if (tmp == 0UL)         /* Are any bits set? */
 146                 return result + size;   /* Nope. */
 147 found_middle:
 148         return result + __ffs(tmp);
 149 }
 150
 151 #endif