mirror of https://gitee.com/openkylin/linux.git
89 lines
1.8 KiB
C
89 lines
1.8 KiB
C
#include <linux/compiler.h>
|
|
#include <linux/types.h>
|
|
#include <asm/intrinsics.h>
|
|
#include <linux/module.h>
|
|
#include <linux/bitops.h>
|
|
|
|
/*
|
|
* Find next zero bit in a bitmap reasonably efficiently..
|
|
*/
|
|
|
|
int __find_next_zero_bit (const void *addr, unsigned long size, unsigned long offset)
|
|
{
|
|
unsigned long *p = ((unsigned long *) addr) + (offset >> 6);
|
|
unsigned long result = offset & ~63UL;
|
|
unsigned long tmp;
|
|
|
|
if (offset >= size)
|
|
return size;
|
|
size -= result;
|
|
offset &= 63UL;
|
|
if (offset) {
|
|
tmp = *(p++);
|
|
tmp |= ~0UL >> (64-offset);
|
|
if (size < 64)
|
|
goto found_first;
|
|
if (~tmp)
|
|
goto found_middle;
|
|
size -= 64;
|
|
result += 64;
|
|
}
|
|
while (size & ~63UL) {
|
|
if (~(tmp = *(p++)))
|
|
goto found_middle;
|
|
result += 64;
|
|
size -= 64;
|
|
}
|
|
if (!size)
|
|
return result;
|
|
tmp = *p;
|
|
found_first:
|
|
tmp |= ~0UL << size;
|
|
if (tmp == ~0UL) /* any bits zero? */
|
|
return result + size; /* nope */
|
|
found_middle:
|
|
return result + ffz(tmp);
|
|
}
|
|
EXPORT_SYMBOL(__find_next_zero_bit);
|
|
|
|
/*
|
|
* Find next bit in a bitmap reasonably efficiently..
|
|
*/
|
|
int __find_next_bit(const void *addr, unsigned long size, unsigned long offset)
|
|
{
|
|
unsigned long *p = ((unsigned long *) addr) + (offset >> 6);
|
|
unsigned long result = offset & ~63UL;
|
|
unsigned long tmp;
|
|
|
|
if (offset >= size)
|
|
return size;
|
|
size -= result;
|
|
offset &= 63UL;
|
|
if (offset) {
|
|
tmp = *(p++);
|
|
tmp &= ~0UL << offset;
|
|
if (size < 64)
|
|
goto found_first;
|
|
if (tmp)
|
|
goto found_middle;
|
|
size -= 64;
|
|
result += 64;
|
|
}
|
|
while (size & ~63UL) {
|
|
if ((tmp = *(p++)))
|
|
goto found_middle;
|
|
result += 64;
|
|
size -= 64;
|
|
}
|
|
if (!size)
|
|
return result;
|
|
tmp = *p;
|
|
found_first:
|
|
tmp &= ~0UL >> (64-size);
|
|
if (tmp == 0UL) /* Are any bits set? */
|
|
return result + size; /* Nope. */
|
|
found_middle:
|
|
return result + __ffs(tmp);
|
|
}
|
|
EXPORT_SYMBOL(__find_next_bit);
|