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  * __ffs - find first bit in word.
  44  * @word: The word to search
  45  *
  46  * Undefined if no bit exists, so code should check against 0 first.
  47  */
  48 static inline unsigned long __ffs(unsigned long word)
  49 {
  50         __asm__("bsfl %1,%0"
  51                 :"=r" (word)
  52                 :"rm" (word));
  53         return word;
  54 }
  55
  56 /**
  57  * find_first_bit - find the first set bit in a memory region
  58  * @addr: The address to start the search at
  59  * @size: The maximum size to search
  60  *
  61  * Returns the bit number of the first set bit, not the number of the byte
  62  * containing a bit.
  63  */
  64 static inline unsigned find_first_bit(const unsigned long *addr, unsigned size)
  65 {
  66         unsigned x = 0;
  67
  68         while (x < size) {
  69                 unsigned long val = *addr++;
  70                 if (val)
  71                         return __ffs(val) + x;
  72                 x += sizeof(*addr) << 3;
  73         }
  74         return x;
  75 }
  76
  77 /**
  78  * ffz - find first zero in word.
  79  * @word: The word to search
  80  *
  81  * Undefined if no zero exists, so code should check against ~0UL first.
  82  */
  83 static inline unsigned long ffz(unsigned long word)
  84 {
  85         __asm__("bsfl %1,%0"
  86                 :"=r" (word)
  87                 :"r" (~word));
  88         return word;
  89 }
  90
  91 #ifdef __KERNEL__
  92
  93 #include <asm-generic/bitops/sched.h>
  94
  95 /**
  96  * ffs - find first bit set
  97  * @x: the word to search
  98  *
  99  * This is defined the same way as
 100  * the libc and compiler builtin ffs routines, therefore
 101  * differs in spirit from the above ffz() (man ffs).
 102  */
 103 static inline int ffs(int x)
 104 {
 105         int r;
 106
 107         __asm__("bsfl %1,%0\n\t"
 108                 "jnz 1f\n\t"
 109                 "movl $-1,%0\n"
 110                 "1:" : "=r" (r) : "rm" (x));
 111         return r+1;
 112 }
 113
 114 /**
 115  * fls - find last bit set
 116  * @x: the word to search
 117  *
 118  * This is defined the same way as ffs().
 119  */
 120 static inline int fls(int x)
 121 {
 122         int r;
 123
 124         __asm__("bsrl %1,%0\n\t"
 125                 "jnz 1f\n\t"
 126                 "movl $-1,%0\n"
 127                 "1:" : "=r" (r) : "rm" (x));
 128         return r+1;
 129 }
 130
 131 #include <asm-generic/bitops/hweight.h>
 132
 133 #endif /* __KERNEL__ */
 134
 135 #include <asm-generic/bitops/fls64.h>
 136
 137 #ifdef __KERNEL__
 138
 139 #include <asm-generic/bitops/ext2-non-atomic.h>
 140
 141 #define ext2_set_bit_atomic(lock, nr, addr)                     \
 142         test_and_set_bit((nr), (unsigned long *)(addr))
 143 #define ext2_clear_bit_atomic(lock, nr, addr)                   \
 144         test_and_clear_bit((nr), (unsigned long *)(addr))
 145
 146 #include <asm-generic/bitops/minix.h>
 147
 148 #endif /* __KERNEL__ */
 149
 150 #endif /* _I386_BITOPS_H */