bitops.h
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#ifndef _PERF_LINUX_BITOPS_H_
#define _PERF_LINUX_BITOPS_H_
#include <linux/kernel.h>
#include <linux/compiler.h>
#include <asm/hweight.h>
#ifndef __WORDSIZE
#define __WORDSIZE (__SIZEOF_LONG__ * 8)
#endif
#define BITS_PER_LONG __WORDSIZE
#define BITS_PER_BYTE 8
#define BITS_TO_LONGS(nr) DIV_ROUND_UP(nr, BITS_PER_BYTE * sizeof(long))
#define BITS_TO_U64(nr) DIV_ROUND_UP(nr, BITS_PER_BYTE * sizeof(u64))
#define BITS_TO_U32(nr) DIV_ROUND_UP(nr, BITS_PER_BYTE * sizeof(u32))
#define BITS_TO_BYTES(nr) DIV_ROUND_UP(nr, BITS_PER_BYTE)
#define BIT_WORD(nr) ((nr) / BITS_PER_LONG)
#define BIT_MASK(nr) (1UL << ((nr) % BITS_PER_LONG))
#define for_each_set_bit(bit, addr, size) \
for ((bit) = find_first_bit((addr), (size)); \
(bit) < (size); \
(bit) = find_next_bit((addr), (size), (bit) + 1))
/* same as for_each_set_bit() but use bit as value to start with */
#define for_each_set_bit_from(bit, addr, size) \
for ((bit) = find_next_bit((addr), (size), (bit)); \
(bit) < (size); \
(bit) = find_next_bit((addr), (size), (bit) + 1))
static inline void set_bit(int nr, unsigned long *addr)
{
addr[nr / BITS_PER_LONG] |= 1UL << (nr % BITS_PER_LONG);
}
static inline void clear_bit(int nr, unsigned long *addr)
{
addr[nr / BITS_PER_LONG] &= ~(1UL << (nr % BITS_PER_LONG));
}
static __always_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 unsigned long hweight_long(unsigned long w)
{
return sizeof(w) == 4 ? hweight32(w) : hweight64(w);
}
#define BITOP_WORD(nr) ((nr) / BITS_PER_LONG)
/**
* __ffs - find first bit in word.
* @word: The word to search
*
* Undefined if no bit exists, so code should check against 0 first.
*/
static __always_inline unsigned long __ffs(unsigned long word)
{
int num = 0;
#if BITS_PER_LONG == 64
if ((word & 0xffffffff) == 0) {
num += 32;
word >>= 32;
}
#endif
if ((word & 0xffff) == 0) {
num += 16;
word >>= 16;
}
if ((word & 0xff) == 0) {
num += 8;
word >>= 8;
}
if ((word & 0xf) == 0) {
num += 4;
word >>= 4;
}
if ((word & 0x3) == 0) {
num += 2;
word >>= 2;
}
if ((word & 0x1) == 0)
num += 1;
return num;
}
typedef const unsigned long __attribute__((__may_alias__)) long_alias_t;
/*
* Find the first set bit in a memory region.
*/
static inline unsigned long
find_first_bit(const unsigned long *addr, unsigned long size)
{
long_alias_t *p = (long_alias_t *) addr;
unsigned long result = 0;
unsigned long tmp;
while (size & ~(BITS_PER_LONG-1)) {
if ((tmp = *(p++)))
goto found;
result += BITS_PER_LONG;
size -= BITS_PER_LONG;
}
if (!size)
return result;
tmp = (*p) & (~0UL >> (BITS_PER_LONG - size));
if (tmp == 0UL) /* Are any bits set? */
return result + size; /* Nope. */
found:
return result + __ffs(tmp);
}
/*
* Find the next set bit in a memory region.
*/
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)) {
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);
}
#endif