diff options
Diffstat (limited to 'arch/i386/lib/bitops_32.c')
-rw-r--r-- | arch/i386/lib/bitops_32.c | 70 |
1 files changed, 70 insertions, 0 deletions
diff --git a/arch/i386/lib/bitops_32.c b/arch/i386/lib/bitops_32.c new file mode 100644 index 00000000000..afd0045595d --- /dev/null +++ b/arch/i386/lib/bitops_32.c @@ -0,0 +1,70 @@ +#include <linux/bitops.h> +#include <linux/module.h> + +/** + * find_next_bit - find the first 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 + */ +int find_next_bit(const unsigned long *addr, int size, int offset) +{ + const unsigned long *p = addr + (offset >> 5); + int set = 0, bit = offset & 31, res; + + if (bit) { + /* + * Look for nonzero in the first 32 bits: + */ + __asm__("bsfl %1,%0\n\t" + "jne 1f\n\t" + "movl $32, %0\n" + "1:" + : "=r" (set) + : "r" (*p >> bit)); + if (set < (32 - bit)) + return set + offset; + set = 32 - bit; + p++; + } + /* + * No set bit yet, search remaining full words for a bit + */ + res = find_first_bit (p, size - 32 * (p - addr)); + return (offset + set + res); +} +EXPORT_SYMBOL(find_next_bit); + +/** + * find_next_zero_bit - find the first zero 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 + */ +int find_next_zero_bit(const unsigned long *addr, int size, int offset) +{ + const unsigned long *p = addr + (offset >> 5); + int set = 0, bit = offset & 31, res; + + if (bit) { + /* + * Look for zero in the first 32 bits. + */ + __asm__("bsfl %1,%0\n\t" + "jne 1f\n\t" + "movl $32, %0\n" + "1:" + : "=r" (set) + : "r" (~(*p >> bit))); + if (set < (32 - bit)) + return set + offset; + set = 32 - bit; + p++; + } + /* + * No zero yet, search remaining full bytes for a zero + */ + res = find_first_zero_bit(p, size - 32 * (p - addr)); + return (offset + set + res); +} +EXPORT_SYMBOL(find_next_zero_bit); |