1//===-- ffsti2.c - Implement __ffsti2 -------------------------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This file implements __ffsti2 for the compiler_rt library.
10//
11//===----------------------------------------------------------------------===//
12
13#include "int_lib.h"
14
15#ifdef CRT_HAS_128BIT
16
17// Returns: the index of the least significant 1-bit in a, or
18// the value zero if a is zero. The least significant bit is index one.
19
20COMPILER_RT_ABI si_int __ffsti2(ti_int a) {
21  twords x;
22  x.all = a;
23  if (x.s.low == 0) {
24    if (x.s.high == 0)
25      return 0;
26    return __builtin_ctzll(x.s.high) + (1 + sizeof(di_int) * CHAR_BIT);
27  }
28  return __builtin_ctzll(x.s.low) + 1;
29}
30
31#endif // CRT_HAS_128BIT
32