llvm-project/compiler-rt/lib/builtins/ffssi2.c

29 lines
806 B
C

/* ===-- ffssi2.c - Implement __ffssi2 -------------------------------------===
*
* Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
* See https://llvm.org/LICENSE.txt for license information.
* SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
*
* ===----------------------------------------------------------------------===
*
* This file implements __ffssi2 for the compiler_rt library.
*
* ===----------------------------------------------------------------------===
*/
#include "int_lib.h"
/* Returns: the index of the least significant 1-bit in a, or
* the value zero if a is zero. The least significant bit is index one.
*/
COMPILER_RT_ABI si_int
__ffssi2(si_int a)
{
if (a == 0)
{
return 0;
}
return __builtin_ctz(a) + 1;
}