include/asm-x86/bitops_32.h

   1 #ifndef _I386_BITOPS_H
   2 #define _I386_BITOPS_H
   3
   4 /*
   5  * Copyright 1992, Linus Torvalds.
   6  */
   7
   8 /**
   9  * find_first_zero_bit - find the first zero bit in a memory region
  10  * @addr: The address to start the search at
  11  * @size: The maximum size to search
  12  *
  13  * Returns the bit number of the first zero bit, not the number of the byte
  14  * containing a bit.
  15  */
  16 static inline int find_first_zero_bit(const unsigned long *addr, unsigned size)
  17 {
  18         int d0, d1, d2;
  19         int res;
  20
  21         if (!size)
  22                 return 0;
  23         /* This looks at memory.
  24          * Mark it volatile to tell gcc not to move it around
  25          */
  26         asm volatile("movl $-1,%%eax\n\t"
  27                      "xorl %%edx,%%edx\n\t"
  28                      "repe; scasl\n\t"
  29                      "je 1f\n\t"
  30                      "xorl -4(%%edi),%%eax\n\t"
  31                      "subl $4,%%edi\n\t"
  32                      "bsfl %%eax,%%edx\n"
  33                      "1:\tsubl %%ebx,%%edi\n\t"
  34                      "shll $3,%%edi\n\t"
  35                      "addl %%edi,%%edx"
  36                      : "=d" (res), "=&c" (d0), "=&D" (d1), "=&a" (d2)
  37                      : "1" ((size + 31) >> 5), "2" (addr),
  38                        "b" (addr) : "memory");
  39         return res;
  40 }
  41
  42 /**
  43  * find_next_zero_bit - find the first zero bit in a memory region
  44  * @addr: The address to base the search on
  45  * @offset: The bit number to start searching at
  46  * @size: The maximum size to search
  47  */
  48 int find_next_zero_bit(const unsigned long *addr, int size, int offset);
  49
  50 /**
  51  * __ffs - find first bit in word.
  52  * @word: The word to search
  53  *
  54  * Undefined if no bit exists, so code should check against 0 first.
  55  */
  56 static inline unsigned long __ffs(unsigned long word)
  57 {
  58         __asm__("bsfl %1,%0"
  59                 :"=r" (word)
  60                 :"rm" (word));
  61         return word;
  62 }
  63
  64 /**
  65  * find_first_bit - find the first set bit in a memory region
  66  * @addr: The address to start the search at
  67  * @size: The maximum size to search
  68  *
  69  * Returns the bit number of the first set bit, not the number of the byte
  70  * containing a bit.
  71  */
  72 static inline unsigned find_first_bit(const unsigned long *addr, unsigned size)
  73 {
  74         unsigned x = 0;
  75
  76         while (x < size) {
  77                 unsigned long val = *addr++;
  78                 if (val)
  79                         return __ffs(val) + x;
  80                 x += sizeof(*addr) << 3;
  81         }
  82         return x;
  83 }
  84
  85 /**
  86  * find_next_bit - find the first set bit in a memory region
  87  * @addr: The address to base the search on
  88  * @offset: The bit number to start searching at
  89  * @size: The maximum size to search
  90  */
  91 int find_next_bit(const unsigned long *addr, int size, int offset);
  92
  93 /**
  94  * ffz - find first zero in word.
  95  * @word: The word to search
  96  *
  97  * Undefined if no zero exists, so code should check against ~0UL first.
  98  */
  99 static inline unsigned long ffz(unsigned long word)
 100 {
 101         __asm__("bsfl %1,%0"
 102                 :"=r" (word)
 103                 :"r" (~word));
 104         return word;
 105 }
 106
 107 #ifdef __KERNEL__
 108
 109 #include <asm-generic/bitops/sched.h>
 110
 111 /**
 112  * ffs - find first bit set
 113  * @x: the word to search
 114  *
 115  * This is defined the same way as
 116  * the libc and compiler builtin ffs routines, therefore
 117  * differs in spirit from the above ffz() (man ffs).
 118  */
 119 static inline int ffs(int x)
 120 {
 121         int r;
 122
 123         __asm__("bsfl %1,%0\n\t"
 124                 "jnz 1f\n\t"
 125                 "movl $-1,%0\n"
 126                 "1:" : "=r" (r) : "rm" (x));
 127         return r+1;
 128 }
 129
 130 /**
 131  * fls - find last bit set
 132  * @x: the word to search
 133  *
 134  * This is defined the same way as ffs().
 135  */
 136 static inline int fls(int x)
 137 {
 138         int r;
 139
 140         __asm__("bsrl %1,%0\n\t"
 141                 "jnz 1f\n\t"
 142                 "movl $-1,%0\n"
 143                 "1:" : "=r" (r) : "rm" (x));
 144         return r+1;
 145 }
 146
 147 #include <asm-generic/bitops/hweight.h>
 148
 149 #endif /* __KERNEL__ */
 150
 151 #include <asm-generic/bitops/fls64.h>
 152
 153 #ifdef __KERNEL__
 154
 155 #include <asm-generic/bitops/ext2-non-atomic.h>
 156
 157 #define ext2_set_bit_atomic(lock, nr, addr)                     \
 158         test_and_set_bit((nr), (unsigned long *)(addr))
 159 #define ext2_clear_bit_atomic(lock, nr, addr)                   \
 160         test_and_clear_bit((nr), (unsigned long *)(addr))
 161
 162 #include <asm-generic/bitops/minix.h>
 163
 164 #endif /* __KERNEL__ */
 165
 166 #endif /* _I386_BITOPS_H */