43 lines
644 B
C
43 lines
644 B
C
/* SPDX-License-Identifier: GPL-2.0 */
|
|
#ifndef _ASM_GENERIC_BITOPS_FFS_H_
|
|
#define _ASM_GENERIC_BITOPS_FFS_H_
|
|
|
|
/**
|
|
* ffs - find first bit set
|
|
* @x: the word to search
|
|
*
|
|
* This is defined the same way as
|
|
* the libc and compiler builtin ffs routines, therefore
|
|
* differs in spirit from ffz (man ffs).
|
|
*/
|
|
static inline int ffs(int x)
|
|
{
|
|
int r = 1;
|
|
|
|
if (!x)
|
|
return 0;
|
|
if (!(x & 0xffff)) {
|
|
x >>= 16;
|
|
r += 16;
|
|
}
|
|
if (!(x & 0xff)) {
|
|
x >>= 8;
|
|
r += 8;
|
|
}
|
|
if (!(x & 0xf)) {
|
|
x >>= 4;
|
|
r += 4;
|
|
}
|
|
if (!(x & 3)) {
|
|
x >>= 2;
|
|
r += 2;
|
|
}
|
|
if (!(x & 1)) {
|
|
x >>= 1;
|
|
r += 1;
|
|
}
|
|
return r;
|
|
}
|
|
|
|
#endif /* _ASM_GENERIC_BITOPS_FFS_H_ */
|