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#ifndef __BITOPS_H__
#define __BITOPS_H__
#include <stdint.h>
#include "util.h"
#define DIV_ROUND_UP(n, d) (((n) + (d) - 1) / (d))
#define BITS_PER_BYTE 8
#define BITS_TO_LONGS(nr) DIV_ROUND_UP(nr, BITS_PER_BYTE * sizeof(long))
#define DECLARE_BITMAP(name, bits) \
unsigned long name[BITS_TO_LONGS(bits)]
#define BITS_PER_LONG (BITS_PER_BYTE * sizeof(long))
#define BITS_PER_UINT64 (BITS_PER_BYTE * sizeof(uint64_t))
#define __ffs(x) (x ? __builtin_ffsl(x) - 1 : 0)
#define ffz(x) __ffs(~(x))
#define BITOP_WORD(nr) ((nr) / BITS_PER_LONG)
/*
* Iterate over a bitmap
*
* @nr: the bit number to use as a loop cursor
* @addr: the bitmap you iterate over
* @bits: the number of bits this bitmap contains
*/
#define FOR_EACH_BIT(nr, addr, bits) \
for (nr = find_next_bit((addr), (bits), 0); \
nr < (bits); \
nr = find_next_bit((addr), (bits), nr + 1))
/*
* Change the size of allocated bitmap
*
* This doesn't change the contents of the old bitmap pointed to by `ptr`, and
* initializes the newly allocated area with zeros.
*/
static inline unsigned long *alloc_bitmap(unsigned long *old_bmap,
size_t old_bits, size_t new_bits)
{
size_t old_size = BITS_TO_LONGS(old_bits) * sizeof(long);
size_t new_size = BITS_TO_LONGS(new_bits) * sizeof(long);
unsigned long *new_bmap = xrealloc(old_bmap, new_size);
if (old_bits < new_bits)
memset((char *)new_bmap + old_size, 0, new_size - old_size);
return new_bmap;
}
static inline 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)) {
tmp = *(p++);
if (~tmp)
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);
}
static inline 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)) {
tmp = *(p++);
if (tmp)
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);
}
static inline void set_bit(int nr, unsigned long *addr)
{
addr[nr / BITS_PER_LONG] |= 1UL << (nr % BITS_PER_LONG);
}
static inline void set_bit_64(int nr, uint64_t *addr)
{
addr[nr / BITS_PER_UINT64] |= 1ULL << (nr % BITS_PER_UINT64);
}
static inline void atomic_set_bit(int nr, unsigned long *addr)
{
uatomic_or(addr + nr / BITS_PER_LONG, 1UL << (nr % BITS_PER_LONG));
}
static inline int test_bit(unsigned int nr, const unsigned long *addr)
{
return ((1UL << (nr % BITS_PER_LONG)) &
(((unsigned long *)addr)[nr / BITS_PER_LONG])) != 0;
}
static inline void clear_bit(unsigned int nr, unsigned long *addr)
{
addr[nr / BITS_PER_LONG] &= ~(1UL << (nr % BITS_PER_LONG));
}
/*
* fls64 - find last set bit in a 64-bit word
* @x: the word to search
*
* This is defined in a similar way as the libc and compiler builtin
* ffsll, but returns the position of the most significant set bit.
*
* fls64(value) returns 0 if value is 0 or the position of the last
* set bit if value is nonzero. The last (most significant) bit is
* at position 64.
*/
#if SIZEOF_LONG == 4
static __always_inline int fls64(uint64_t x)
{
uint32_t h = x >> 32;
if (x == 0)
return 0;
if (h)
return 64 - __builtin_clzl(h);
return 32 - __builtin_clzl(x);
}
#elif SIZEOF_LONG == 8
static __always_inline int fls64(uint64_t x)
{
if (x == 0)
return 0;
return 64 - __builtin_clzl(x);
}
#else
#error SIZEOF_LONG not 4 or 8
#endif
#endif /* __BITOPS_H__ */
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