1 | /* ===-- ffsti2.c - Implement __ffsti2 -------------------------------------=== |
2 | * |
3 | * The LLVM Compiler Infrastructure |
4 | * |
5 | * This file is dual licensed under the MIT and the University of Illinois Open |
6 | * Source Licenses. See LICENSE.TXT for details. |
7 | * |
8 | * ===----------------------------------------------------------------------=== |
9 | * |
10 | * This file implements __ffsti2 for the compiler_rt library. |
11 | * |
12 | * ===----------------------------------------------------------------------=== |
13 | */ |
14 | |
15 | #include "int_lib.h" |
16 | |
17 | #ifdef CRT_HAS_128BIT |
18 | |
19 | /* Returns: the index of the least significant 1-bit in a, or |
20 | * the value zero if a is zero. The least significant bit is index one. |
21 | */ |
22 | |
23 | COMPILER_RT_ABI si_int |
24 | __ffsti2(ti_int a) |
25 | { |
26 | twords x; |
27 | x.all = a; |
28 | if (x.s.low == 0) |
29 | { |
30 | if (x.s.high == 0) |
31 | return 0; |
32 | return __builtin_ctzll(x.s.high) + (1 + sizeof(di_int) * CHAR_BIT); |
33 | } |
34 | return __builtin_ctzll(x.s.low) + 1; |
35 | } |
36 | |
37 | #endif /* CRT_HAS_128BIT */ |
38 | |