| /* SPDX-License-Identifier: GPL-2.0 */ |
| #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 __always_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_ */ |
