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 si_int __ffssi2(si_int a) { 19 if (a == 0) { 20 return 0; 21 } 22 return __builtin_ctz(a) + 1; 23 } 24