diff options
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/Makefile | 1 | ||||
| -rw-r--r-- | lib/find_next_bit.c | 58 |
2 files changed, 59 insertions, 0 deletions
diff --git a/lib/Makefile b/lib/Makefile index bf8000fc7d48..2d7001b7f5a4 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -29,6 +29,7 @@ obj-$(CONFIG_DEBUG_LOCKING_API_SELFTESTS) += locking-selftest.o obj-$(CONFIG_DEBUG_SPINLOCK) += spinlock_debug.o lib-$(CONFIG_RWSEM_GENERIC_SPINLOCK) += rwsem-spinlock.o lib-$(CONFIG_RWSEM_XCHGADD_ALGORITHM) += rwsem.o +lib-$(CONFIG_GENERIC_FIND_FIRST_BIT) += find_next_bit.o lib-$(CONFIG_GENERIC_FIND_NEXT_BIT) += find_next_bit.o obj-$(CONFIG_GENERIC_HWEIGHT) += hweight.o obj-$(CONFIG_LOCK_KERNEL) += kernel_lock.o diff --git a/lib/find_next_bit.c b/lib/find_next_bit.c index ce94c4c92d10..d3f5784807b4 100644 --- a/lib/find_next_bit.c +++ b/lib/find_next_bit.c @@ -16,6 +16,7 @@ #define BITOP_WORD(nr) ((nr) / BITS_PER_LONG) +#ifdef CONFIG_GENERIC_FIND_NEXT_BIT /* * Find the next set bit in a memory region. */ @@ -102,6 +103,63 @@ found_middle: return result + ffz(tmp); } EXPORT_SYMBOL(__find_next_zero_bit); +#endif /* CONFIG_GENERIC_FIND_NEXT_BIT */ + +#ifdef CONFIG_GENERIC_FIND_FIRST_BIT +/* + * Find the first set bit in a memory region. + */ +unsigned long __find_first_bit(const unsigned long *addr, + unsigned long size) +{ + const unsigned long *p = addr; + unsigned long result = 0; + unsigned long tmp; + + while (size & ~(BITS_PER_LONG-1)) { + if ((tmp = *(p++))) + goto found; + result += BITS_PER_LONG; + size -= BITS_PER_LONG; + } + if (!size) + return result; + + tmp = (*p) & (~0UL >> (BITS_PER_LONG - size)); + if (tmp == 0UL) /* Are any bits set? */ + return result + size; /* Nope. */ +found: + return result + __ffs(tmp); +} +EXPORT_SYMBOL(__find_first_bit); + +/* + * Find the first cleared bit in a memory region. + */ +unsigned long __find_first_zero_bit(const unsigned long *addr, + unsigned long size) +{ + const unsigned long *p = addr; + unsigned long result = 0; + unsigned long tmp; + + while (size & ~(BITS_PER_LONG-1)) { + if (~(tmp = *(p++))) + goto found; + result += BITS_PER_LONG; + size -= BITS_PER_LONG; + } + if (!size) + return result; + + tmp = (*p) | (~0UL << size); + if (tmp == ~0UL) /* Are any bits zero? */ + return result + size; /* Nope. */ +found: + return result + ffz(tmp); +} +EXPORT_SYMBOL(__find_first_zero_bit); +#endif /* CONFIG_GENERIC_FIND_FIRST_BIT */ #ifdef __BIG_ENDIAN |