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#if __x86_64
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
23si_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 /* __x86_64 */
38