diff options
Diffstat (limited to 'include/asm-m68k/bitops.h')
| -rw-r--r-- | include/asm-m68k/bitops.h | 39 |
1 files changed, 39 insertions, 0 deletions
diff --git a/include/asm-m68k/bitops.h b/include/asm-m68k/bitops.h index 3283714..0f9e8ab 100644 --- a/include/asm-m68k/bitops.h +++ b/include/asm-m68k/bitops.h @@ -15,4 +15,43 @@ extern int test_and_set_bit(int nr, volatile void *addr); extern int test_and_clear_bit(int nr, volatile void *addr); extern int test_and_change_bit(int nr, volatile void *addr); +#ifdef __KERNEL__ + +/* + * ffs: find first bit set. This is defined the same way as + * the libc and compiler builtin ffs routines, therefore + * differs in spirit from the above ffz (man ffs). + */ +extern __inline__ int ffs(int x) +{ + int r = 1; + + if (!x) + return 0; + if (!(x & 0xffff)) { + x >>= 16; + r += 16; + } + if (!(x & 0xff)) { + x >>= 8; + r += 8; + } + if (!(x & 0xf)) { + x >>= 4; + r += 4; + } + if (!(x & 3)) { + x >>= 2; + r += 2; + } + if (!(x & 1)) { + x >>= 1; + r += 1; + } + return r; +} +#define __ffs(x) (ffs(x) - 1) + +#endif /* __KERNEL__ */ + #endif /* _M68K_BITOPS_H */ |