1*0b57cec5SDimitry Andric //===-- ffsti2.c - Implement __ffsti2 -------------------------------------===// 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 __ffsti2 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 #ifdef CRT_HAS_128BIT 16*0b57cec5SDimitry Andric 17*0b57cec5SDimitry Andric // Returns: the index of the least significant 1-bit in a, or 18*0b57cec5SDimitry Andric // the value zero if a is zero. The least significant bit is index one. 19*0b57cec5SDimitry Andric 20*0b57cec5SDimitry Andric COMPILER_RT_ABI si_int __ffsti2(ti_int a) { 21*0b57cec5SDimitry Andric twords x; 22*0b57cec5SDimitry Andric x.all = a; 23*0b57cec5SDimitry Andric if (x.s.low == 0) { 24*0b57cec5SDimitry Andric if (x.s.high == 0) 25*0b57cec5SDimitry Andric return 0; 26*0b57cec5SDimitry Andric return __builtin_ctzll(x.s.high) + (1 + sizeof(di_int) * CHAR_BIT); 27*0b57cec5SDimitry Andric } 28*0b57cec5SDimitry Andric return __builtin_ctzll(x.s.low) + 1; 29*0b57cec5SDimitry Andric } 30*0b57cec5SDimitry Andric 31*0b57cec5SDimitry Andric #endif // CRT_HAS_128BIT 32