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author | Linus Torvalds <torvalds@linux-foundation.org> | 2008-04-27 00:46:11 +0400 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2008-04-27 00:46:11 +0400 |
commit | 9b79ed952bd7344d40152f8a560ad8a0d93f3886 (patch) | |
tree | 0cdf72321a9eeb2a766b7b98d5a87ad3d46ad620 /lib | |
parent | a52b0d25a722e84da999005b75f972aa4824253c (diff) | |
parent | 19870def587554c4055df3e74a21508e3647fb7e (diff) | |
download | linux-9b79ed952bd7344d40152f8a560ad8a0d93f3886.tar.xz |
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/x86/linux-2.6-generic-bitops-v3
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/x86/linux-2.6-generic-bitops-v3:
x86, bitops: select the generic bitmap search functions
x86: include/asm-x86/pgalloc.h/bitops.h: checkpatch cleanups - formatting only
x86: finalize bitops unification
x86, UML: remove x86-specific implementations of find_first_bit
x86: optimize find_first_bit for small bitmaps
x86: switch 64-bit to generic find_first_bit
x86: generic versions of find_first_(zero_)bit, convert i386
bitops: use __fls for fls64 on 64-bit archs
generic: implement __fls on all 64-bit archs
generic: introduce a generic __fls implementation
x86: merge the simple bitops and move them to bitops.h
x86, generic: optimize find_next_(zero_)bit for small constant-size bitmaps
x86, uml: fix uml with generic find_next_bit for x86
x86: change x86 to use generic find_next_bit
uml: Kconfig cleanup
uml: fix build error
Diffstat (limited to 'lib')
-rw-r--r-- | lib/Kconfig | 6 | ||||
-rw-r--r-- | lib/Makefile | 1 | ||||
-rw-r--r-- | lib/find_next_bit.c | 77 |
3 files changed, 72 insertions, 12 deletions
diff --git a/lib/Kconfig b/lib/Kconfig index 2d53dc092e8b..8cc8e8722a3f 100644 --- a/lib/Kconfig +++ b/lib/Kconfig @@ -7,6 +7,12 @@ menu "Library routines" config BITREVERSE tristate +config GENERIC_FIND_FIRST_BIT + def_bool n + +config GENERIC_FIND_NEXT_BIT + def_bool n + config CRC_CCITT tristate "CRC-CCITT functions" help 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 78ccd73a8841..d3f5784807b4 100644 --- a/lib/find_next_bit.c +++ b/lib/find_next_bit.c @@ -16,14 +16,12 @@ #define BITOP_WORD(nr) ((nr) / BITS_PER_LONG) -/** - * find_next_bit - find the next set bit in a memory region - * @addr: The address to base the search on - * @offset: The bitnumber to start searching at - * @size: The maximum size to search +#ifdef CONFIG_GENERIC_FIND_NEXT_BIT +/* + * Find the next set bit in a memory region. */ -unsigned long find_next_bit(const unsigned long *addr, unsigned long size, - unsigned long offset) +unsigned long __find_next_bit(const unsigned long *addr, + unsigned long size, unsigned long offset) { const unsigned long *p = addr + BITOP_WORD(offset); unsigned long result = offset & ~(BITS_PER_LONG-1); @@ -60,15 +58,14 @@ found_first: found_middle: return result + __ffs(tmp); } - -EXPORT_SYMBOL(find_next_bit); +EXPORT_SYMBOL(__find_next_bit); /* * This implementation of find_{first,next}_zero_bit was stolen from * Linus' asm-alpha/bitops.h. */ -unsigned long find_next_zero_bit(const unsigned long *addr, unsigned long size, - unsigned long offset) +unsigned long __find_next_zero_bit(const unsigned long *addr, + unsigned long size, unsigned long offset) { const unsigned long *p = addr + BITOP_WORD(offset); unsigned long result = offset & ~(BITS_PER_LONG-1); @@ -105,8 +102,64 @@ found_first: 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; -EXPORT_SYMBOL(find_next_zero_bit); + 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 |