1*0b57cec5SDimitry Andric //===-- ffssi2.c - Implement __ffssi2 -------------------------------------===// 2*0b57cec5SDimitry Andric // 3*0b57cec5SDimitry Andric // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4*0b57cec5SDimitry Andric // See https://llvm.org/LICENSE.txt for license information. 5*0b57cec5SDimitry Andric // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6*0b57cec5SDimitry Andric // 7*0b57cec5SDimitry Andric //===----------------------------------------------------------------------===// 8*0b57cec5SDimitry Andric // 9*0b57cec5SDimitry Andric // This file implements __ffssi2 for the compiler_rt library. 10*0b57cec5SDimitry Andric // 11*0b57cec5SDimitry Andric //===----------------------------------------------------------------------===// 12*0b57cec5SDimitry Andric 13*0b57cec5SDimitry Andric #include "int_lib.h" 14*0b57cec5SDimitry Andric 15*0b57cec5SDimitry Andric // Returns: the index of the least significant 1-bit in a, or 16*0b57cec5SDimitry Andric // the value zero if a is zero. The least significant bit is index one. 17*0b57cec5SDimitry Andric 18*0b57cec5SDimitry Andric COMPILER_RT_ABI si_int __ffssi2(si_int a) { 19*0b57cec5SDimitry Andric if (a == 0) { 20*0b57cec5SDimitry Andric return 0; 21*0b57cec5SDimitry Andric } 22*0b57cec5SDimitry Andric return __builtin_ctz(a) + 1; 23*0b57cec5SDimitry Andric } 24