xref: /freebsd/contrib/llvm-project/compiler-rt/lib/builtins/ffssi2.c (revision 7fdf597e96a02165cfe22ff357b857d5fa15ed8a)
1 //===-- ffssi2.c - Implement __ffssi2 -------------------------------------===//
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 __ffssi2 for the compiler_rt library.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #include "int_lib.h"
14 
15 // Returns: the index of the least significant 1-bit in a, or
16 // the value zero if a is zero. The least significant bit is index one.
17 
18 COMPILER_RT_ABI int __ffssi2(si_int a) {
19   if (a == 0) {
20     return 0;
21   }
22   return ctzsi(a) + 1;
23 }
24