1276789Sdim/* ===-- ffsdi2.c - Implement __ffsdi2 -------------------------------------===
2276789Sdim *
3276789Sdim *                     The LLVM Compiler Infrastructure
4276789Sdim *
5276789Sdim * This file is dual licensed under the MIT and the University of Illinois Open
6276789Sdim * Source Licenses. See LICENSE.TXT for details.
7276789Sdim *
8276789Sdim * ===----------------------------------------------------------------------===
9276789Sdim *
10276789Sdim * This file implements __ffsdi2 for the compiler_rt library.
11276789Sdim *
12276789Sdim * ===----------------------------------------------------------------------===
13276789Sdim */
14276789Sdim
15276789Sdim#include "int_lib.h"
16276789Sdim
17276789Sdim/* Returns: the index of the least significant 1-bit in a, or
18276789Sdim * the value zero if a is zero. The least significant bit is index one.
19276789Sdim */
20276789Sdim
21276789SdimCOMPILER_RT_ABI si_int
22276789Sdim__ffsdi2(di_int a)
23276789Sdim{
24276789Sdim    dwords x;
25276789Sdim    x.all = a;
26276789Sdim    if (x.s.low == 0)
27276789Sdim    {
28276789Sdim        if (x.s.high == 0)
29276789Sdim            return 0;
30276789Sdim        return __builtin_ctz(x.s.high) + (1 + sizeof(si_int) * CHAR_BIT);
31276789Sdim    }
32276789Sdim    return __builtin_ctz(x.s.low) + 1;
33276789Sdim}
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