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arm: implement find_next_zero_bit function

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This commit copies implementation of the find_next_zero_bit() from
git://git.denx.de/u-boot.git/arch/mips/include/asm/bitops.h. v2014.07

The function is required to enable MCAST_TFTP support for ARM platforms.

Signed-off-by: Vitaly Andrianov <vitalya@ti.com>
This commit is contained in:
Vitaly Andrianov 2015-02-05 11:24:46 -05:00 committed by Albert ARIBAUD
parent a32d279129
commit 81e9fe5a29
1 changed files with 40 additions and 3 deletions
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43
arch/arm/include/asm/bitops.h
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@ -95,9 +95,6 @@ static inline int __test_and_change_bit(int nr, volatile void *addr)
return (old & mask) != 0;
}
extern int find_first_zero_bit(void * addr, unsigned size);
extern int find_next_zero_bit(void * addr, int size, int offset);
/*
* This routine doesn't need to be atomic.
*/
@ -129,6 +126,43 @@ static inline unsigned long ffz(unsigned long word)
return k;
}
static inline int find_next_zero_bit(void *addr, int size, int offset)
{
unsigned long *p = ((unsigned long *)addr) + (offset >> 5);
unsigned long result = offset & ~31UL;
unsigned long tmp;
if (offset >= size)
return size;
size -= result;
offset &= 31UL;
if (offset) {
tmp = *(p++);
tmp |= ~0UL >> (32-offset);
if (size < 32)
goto found_first;
if (~tmp)
goto found_middle;
size -= 32;
result += 32;
}
while (size & ~31UL) {
tmp = *(p++);
if (~tmp)
goto found_middle;
result += 32;
size -= 32;
}
if (!size)
return result;
tmp = *p;
found_first:
tmp |= ~0UL >> size;
found_middle:
return result + ffz(tmp);
}
/*
* hweightN: returns the hamming weight (i.e. the number
* of bits set) of a N-bit word
@ -138,6 +172,9 @@ static inline unsigned long ffz(unsigned long word)
#define hweight16(x) generic_hweight16(x)
#define hweight8(x) generic_hweight8(x)
#define find_first_zero_bit(addr, size) \
find_next_zero_bit((addr), (size), 0)
#define ext2_set_bit test_and_set_bit
#define ext2_clear_bit test_and_clear_bit
#define ext2_test_bit test_bit