^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1) /* SPDX-License-Identifier: GPL-2.0 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2) #ifndef _ASM_GENERIC_BITOPS_FLS_H_
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3) #define _ASM_GENERIC_BITOPS_FLS_H_
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 4)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 5) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 6) * fls - find last (most-significant) bit set
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 7) * @x: the word to search
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 8) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 9) * This is defined the same way as ffs.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 10) * Note fls(0) = 0, fls(1) = 1, fls(0x80000000) = 32.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 11) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 12)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 13) static __always_inline int fls(unsigned int x)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 14) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 15) int r = 32;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 16)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 17) if (!x)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 18) return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 19) if (!(x & 0xffff0000u)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 20) x <<= 16;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 21) r -= 16;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 22) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 23) if (!(x & 0xff000000u)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 24) x <<= 8;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 25) r -= 8;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 26) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 27) if (!(x & 0xf0000000u)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 28) x <<= 4;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 29) r -= 4;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 30) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 31) if (!(x & 0xc0000000u)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 32) x <<= 2;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 33) r -= 2;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 34) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 35) if (!(x & 0x80000000u)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 36) x <<= 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 37) r -= 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 38) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 39) return r;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 40) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 41)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 42) #endif /* _ASM_GENERIC_BITOPS_FLS_H_ */