44 lines
729 B
C
44 lines
729 B
C
#ifndef _ASM_GENERIC_BITOPS___FFS_H_
|
|
#define _ASM_GENERIC_BITOPS___FFS_H_
|
|
|
|
#include <asm/types.h>
|
|
|
|
/**
|
|
* __ffs - find first bit in word.
|
|
* @word: The word to search
|
|
*
|
|
* Undefined if no bit exists, so code should check against 0 first.
|
|
*/
|
|
static 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;
|
|
}
|
|
|
|
#endif /* _ASM_GENERIC_BITOPS___FFS_H_ */
|