compiler-rt/lib/builtins/ffssi2.c

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