1 //===-- ffsdi2.c - Implement __ffsdi2 -------------------------------------===//
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 __ffsdi2 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
__ffsdi2(di_int a)18 COMPILER_RT_ABI int __ffsdi2(di_int a) {
19 dwords x;
20 x.all = a;
21 if (x.s.low == 0) {
22 if (x.s.high == 0)
23 return 0;
24 return ctzsi(x.s.high) + (1 + sizeof(si_int) * CHAR_BIT);
25 }
26 return ctzsi(x.s.low) + 1;
27 }
28