44 lines
895 B
C
44 lines
895 B
C
#ifndef _ASM_GENERIC_BITOPS___FLS_H_
|
|
#define _ASM_GENERIC_BITOPS___FLS_H_
|
|
|
|
#include <linux/types.h>
|
|
|
|
/**
|
|
* __fls - find last (most-significant) set bit in a long word
|
|
* @word: the word to search
|
|
*
|
|
* Undefined if no set bit exists, so code should cheggck against 0 first.
|
|
*/
|
|
static __always_inline unsigned long __fls(unsigned long word)
|
|
{
|
|
int num = BITS_PER_LONG - 1;
|
|
|
|
#if BITS_PER_LONG == 64
|
|
if (!(word & (~0ul << 32))) {
|
|
num -= 32;
|
|
word <<= 32;
|
|
}
|
|
#endif
|
|
if (!(word & (~0ul << (BITS_PER_LONG - 16)))) {
|
|
num -= 16;
|
|
word <<= 16;
|
|
}
|
|
if (!(word & (~0ul << (BITS_PER_LONG - 8)))) {
|
|
num -= 8;
|
|
word <<= 8;
|
|
}
|
|
if (!(word & (~0ul << (BITS_PER_LONG - 4)))) {
|
|
num -= 4;
|
|
word <<= 4;
|
|
}
|
|
if (!(word & (~0ul << (BITS_PER_LONG - 2)))) {
|
|
num -= 2;
|
|
word <<= 2;
|
|
}
|
|
if (!(word & (~0ul << (BITS_PER_LONG - 1))))
|
|
num -= 1;
|
|
return num;
|
|
}
|
|
|
|
#endif /* _ASM_GENERIC_BITOPS___FLS_H_ */
|