| /* |
| * SPDX-License-Identifier: GPL-2.0-only |
| * Copyright Linux |
| */ |
| |
| #pragma once |
| |
| #include "../unimplemented.h" |
| |
| /* |
| * ffs: find first bit set. This is defined the same way as |
| * the libc and compiler builtin ffs routines, therefore |
| * differs in spirit from the above ffz (man ffs). |
| */ |
| |
| static inline int generic_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; |
| } |
| |
| #ifndef PLATFORM_FFS |
| # define ffs generic_ffs |
| #endif |
