136abb32d6
This patch introduces the C-language equivalent of the function: int fls(int x); In include/asm-generic/bitops/fls.h This code largely copied from: include/linux/bitops.h Signed-off-by: Akinobu Mita <mita@miraclelinux.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
41 lines
626 B
C
41 lines
626 B
C
#ifndef _ASM_GENERIC_BITOPS_FLS_H_
|
|
#define _ASM_GENERIC_BITOPS_FLS_H_
|
|
|
|
/**
|
|
* fls - find last (most-significant) bit set
|
|
* @x: the word to search
|
|
*
|
|
* This is defined the same way as ffs.
|
|
* Note fls(0) = 0, fls(1) = 1, fls(0x80000000) = 32.
|
|
*/
|
|
|
|
static inline int fls(int x)
|
|
{
|
|
int r = 32;
|
|
|
|
if (!x)
|
|
return 0;
|
|
if (!(x & 0xffff0000u)) {
|
|
x <<= 16;
|
|
r -= 16;
|
|
}
|
|
if (!(x & 0xff000000u)) {
|
|
x <<= 8;
|
|
r -= 8;
|
|
}
|
|
if (!(x & 0xf0000000u)) {
|
|
x <<= 4;
|
|
r -= 4;
|
|
}
|
|
if (!(x & 0xc0000000u)) {
|
|
x <<= 2;
|
|
r -= 2;
|
|
}
|
|
if (!(x & 0x80000000u)) {
|
|
x <<= 1;
|
|
r -= 1;
|
|
}
|
|
return r;
|
|
}
|
|
|
|
#endif /* _ASM_GENERIC_BITOPS_FLS_H_ */
|