include/asm-m68k/bitops.h

   1 /*
   2  * bitops.h: Bit string operations on the m68k
   3  */
   4
   5 #ifndef _M68K_BITOPS_H
   6 #define _M68K_BITOPS_H
   7
   8 #include <linux/config.h>
   9 #include <asm/byteorder.h>
  10
  11 extern void set_bit(int nr, volatile void *addr);
  12 extern void clear_bit(int nr, volatile void *addr);
  13 extern void change_bit(int nr, volatile void *addr);
  14 extern int test_and_set_bit(int nr, volatile void *addr);
  15 extern int test_and_clear_bit(int nr, volatile void *addr);
  16 extern int test_and_change_bit(int nr, volatile void *addr);
  17
  18 #ifdef __KERNEL__
  19
  20 /*
  21  * ffs: find first bit set. This is defined the same way as
  22  * the libc and compiler builtin ffs routines, therefore
  23  * differs in spirit from the above ffz (man ffs).
  24  */
  25 extern __inline__ int ffs(int x)
  26 {
  27         int r = 1;
  28
  29         if (!x)
  30                 return 0;
  31         if (!(x & 0xffff)) {
  32                 x >>= 16;
  33                 r += 16;
  34         }
  35         if (!(x & 0xff)) {
  36                 x >>= 8;
  37                 r += 8;
  38         }
  39         if (!(x & 0xf)) {
  40                 x >>= 4;
  41                 r += 4;
  42         }
  43         if (!(x & 3)) {
  44                 x >>= 2;
  45                 r += 2;
  46         }
  47         if (!(x & 1)) {
  48                 x >>= 1;
  49                 r += 1;
  50         }
  51         return r;
  52 }
  53 #define __ffs(x) (ffs(x) - 1)
  54
  55 #endif /* __KERNEL__ */
  56
  57 #endif /* _M68K_BITOPS_H */