1353358Sdim//===-- ffsdi2.c - Implement __ffsdi2 -------------------------------------===//
2353358Sdim//
3353358Sdim// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4353358Sdim// See https://llvm.org/LICENSE.txt for license information.
5353358Sdim// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6353358Sdim//
7353358Sdim//===----------------------------------------------------------------------===//
8353358Sdim//
9353358Sdim// This file implements __ffsdi2 for the compiler_rt library.
10353358Sdim//
11353358Sdim//===----------------------------------------------------------------------===//
12276789Sdim
13276789Sdim#include "int_lib.h"
14276789Sdim
15353358Sdim// Returns: the index of the least significant 1-bit in a, or
16353358Sdim// the value zero if a is zero. The least significant bit is index one.
17276789Sdim
18353358SdimCOMPILER_RT_ABI si_int __ffsdi2(di_int a) {
19353358Sdim  dwords x;
20353358Sdim  x.all = a;
21353358Sdim  if (x.s.low == 0) {
22353358Sdim    if (x.s.high == 0)
23353358Sdim      return 0;
24353358Sdim    return __builtin_ctz(x.s.high) + (1 + sizeof(si_int) * CHAR_BIT);
25353358Sdim  }
26353358Sdim  return __builtin_ctz(x.s.low) + 1;
27276789Sdim}
28