mirror of https://gitee.com/openkylin/linux.git
128 lines
2.7 KiB
C
128 lines
2.7 KiB
C
#include <linux/bitops.h>
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/**
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* find_next_bit - find the next set bit in a memory region
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* @addr: The address to base the search on
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* @offset: The bitnumber to start searching at
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* @size: The maximum size to search
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*/
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unsigned long find_next_bit(const unsigned long *addr, unsigned long size,
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unsigned long offset)
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{
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const unsigned long *p = addr + (offset >> 6);
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unsigned long result = offset & ~63UL;
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unsigned long tmp;
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if (offset >= size)
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return size;
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size -= result;
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offset &= 63UL;
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if (offset) {
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tmp = *(p++);
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tmp &= (~0UL << offset);
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if (size < 64)
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goto found_first;
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if (tmp)
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goto found_middle;
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size -= 64;
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result += 64;
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}
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while (size & ~63UL) {
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if ((tmp = *(p++)))
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goto found_middle;
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result += 64;
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size -= 64;
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}
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if (!size)
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return result;
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tmp = *p;
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found_first:
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tmp &= (~0UL >> (64 - size));
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if (tmp == 0UL) /* Are any bits set? */
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return result + size; /* Nope. */
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found_middle:
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return result + __ffs(tmp);
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}
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/* find_next_zero_bit() finds the first zero bit in a bit string of length
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* 'size' bits, starting the search at bit 'offset'. This is largely based
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* on Linus's ALPHA routines, which are pretty portable BTW.
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*/
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unsigned long find_next_zero_bit(const unsigned long *addr,
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unsigned long size, unsigned long offset)
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{
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const unsigned long *p = addr + (offset >> 6);
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unsigned long result = offset & ~63UL;
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unsigned long tmp;
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if (offset >= size)
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return size;
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size -= result;
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offset &= 63UL;
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if (offset) {
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tmp = *(p++);
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tmp |= ~0UL >> (64-offset);
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if (size < 64)
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goto found_first;
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if (~tmp)
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goto found_middle;
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size -= 64;
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result += 64;
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}
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while (size & ~63UL) {
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if (~(tmp = *(p++)))
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goto found_middle;
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result += 64;
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size -= 64;
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}
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if (!size)
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return result;
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tmp = *p;
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found_first:
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tmp |= ~0UL << size;
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if (tmp == ~0UL) /* Are any bits zero? */
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return result + size; /* Nope. */
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found_middle:
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return result + ffz(tmp);
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}
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unsigned long find_next_zero_le_bit(unsigned long *addr, unsigned long size, unsigned long offset)
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{
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unsigned long *p = addr + (offset >> 6);
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unsigned long result = offset & ~63UL;
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unsigned long tmp;
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if (offset >= size)
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return size;
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size -= result;
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offset &= 63UL;
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if(offset) {
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tmp = __swab64p(p++);
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tmp |= (~0UL >> (64-offset));
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if(size < 64)
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goto found_first;
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if(~tmp)
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goto found_middle;
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size -= 64;
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result += 64;
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}
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while(size & ~63) {
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if(~(tmp = __swab64p(p++)))
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goto found_middle;
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result += 64;
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size -= 64;
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}
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if(!size)
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return result;
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tmp = __swab64p(p);
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found_first:
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tmp |= (~0UL << size);
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if (tmp == ~0UL) /* Are any bits zero? */
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return result + size; /* Nope. */
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found_middle:
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return result + ffz(tmp);
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}
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