diff options
Diffstat (limited to 'arch/powerpc/lib/bitops.c')
-rw-r--r-- | arch/powerpc/lib/bitops.c | 150 |
1 files changed, 150 insertions, 0 deletions
diff --git a/arch/powerpc/lib/bitops.c b/arch/powerpc/lib/bitops.c new file mode 100644 index 00000000000..f68ad71a018 --- /dev/null +++ b/arch/powerpc/lib/bitops.c @@ -0,0 +1,150 @@ +#include <linux/types.h> +#include <linux/module.h> +#include <asm/byteorder.h> +#include <asm/bitops.h> + +/** + * 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 + */ +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); + unsigned long tmp; + + if (offset >= size) + return size; + size -= result; + offset %= BITS_PER_LONG; + if (offset) { + tmp = *(p++); + tmp &= (~0UL << offset); + if (size < BITS_PER_LONG) + goto found_first; + if (tmp) + goto found_middle; + size -= BITS_PER_LONG; + result += BITS_PER_LONG; + } + while (size & ~(BITS_PER_LONG-1)) { + if ((tmp = *(p++))) + goto found_middle; + result += BITS_PER_LONG; + size -= BITS_PER_LONG; + } + if (!size) + return result; + tmp = *p; + +found_first: + tmp &= (~0UL >> (BITS_PER_LONG - size)); + if (tmp == 0UL) /* Are any bits set? */ + return result + size; /* Nope. */ +found_middle: + return result + __ffs(tmp); +} +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) +{ + const unsigned long *p = addr + BITOP_WORD(offset); + unsigned long result = offset & ~(BITS_PER_LONG-1); + unsigned long tmp; + + if (offset >= size) + return size; + size -= result; + offset %= BITS_PER_LONG; + if (offset) { + tmp = *(p++); + tmp |= ~0UL >> (BITS_PER_LONG - offset); + if (size < BITS_PER_LONG) + goto found_first; + if (~tmp) + goto found_middle; + size -= BITS_PER_LONG; + result += BITS_PER_LONG; + } + while (size & ~(BITS_PER_LONG-1)) { + if (~(tmp = *(p++))) + goto found_middle; + result += BITS_PER_LONG; + size -= BITS_PER_LONG; + } + if (!size) + return result; + tmp = *p; + +found_first: + tmp |= ~0UL << size; + if (tmp == ~0UL) /* Are any bits zero? */ + return result + size; /* Nope. */ +found_middle: + return result + ffz(tmp); +} +EXPORT_SYMBOL(find_next_zero_bit); + +static inline unsigned int ext2_ilog2(unsigned int x) +{ + int lz; + + asm("cntlzw %0,%1": "=r"(lz):"r"(x)); + return 31 - lz; +} + +static inline unsigned int ext2_ffz(unsigned int x) +{ + u32 rc; + if ((x = ~x) == 0) + return 32; + rc = ext2_ilog2(x & -x); + return rc; +} + +unsigned long find_next_zero_le_bit(const unsigned long *addr, + unsigned long size, unsigned long offset) +{ + const unsigned int *p = ((const unsigned int *)addr) + (offset >> 5); + unsigned int result = offset & ~31; + unsigned int tmp; + + if (offset >= size) + return size; + size -= result; + offset &= 31; + if (offset) { + tmp = cpu_to_le32p(p++); + tmp |= ~0U >> (32 - offset); /* bug or feature ? */ + if (size < 32) + goto found_first; + if (tmp != ~0) + goto found_middle; + size -= 32; + result += 32; + } + while (size >= 32) { + if ((tmp = cpu_to_le32p(p++)) != ~0) + goto found_middle; + result += 32; + size -= 32; + } + if (!size) + return result; + tmp = cpu_to_le32p(p); +found_first: + tmp |= ~0 << size; + if (tmp == ~0) /* Are any bits zero? */ + return result + size; /* Nope. */ +found_middle: + return result + ext2_ffz(tmp); +} +EXPORT_SYMBOL(find_next_zero_le_bit); |