1 //===-- ffsdi2.c - Implement __ffsdi2 -------------------------------------===//
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
7 //===----------------------------------------------------------------------===//
9 // This file implements __ffsdi2 for the compiler_rt library.
11 //===----------------------------------------------------------------------===//
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.
18 COMPILER_RT_ABI si_int __ffsdi2(di_int a) {
24 return __builtin_ctz(x.s.high) + (1 + sizeof(si_int) * CHAR_BIT);
26 return __builtin_ctz(x.s.low) + 1;