1276789Sdim/* ===-- ctzdi2.c - Implement __ctzdi2 -------------------------------------===
2276789Sdim *
3276789Sdim *                     The LLVM Compiler Infrastructure
4276789Sdim *
5276789Sdim * This file is dual licensed under the MIT and the University of Illinois Open
6276789Sdim * Source Licenses. See LICENSE.TXT for details.
7276789Sdim *
8276789Sdim * ===----------------------------------------------------------------------===
9276789Sdim *
10276789Sdim * This file implements __ctzdi2 for the compiler_rt library.
11276789Sdim *
12276789Sdim * ===----------------------------------------------------------------------===
13276789Sdim */
14276789Sdim
15276789Sdim#include "int_lib.h"
16276789Sdim
17276789Sdim/* Returns: the number of trailing 0-bits  */
18276789Sdim
19276789Sdim/* Precondition: a != 0 */
20276789Sdim
21276789SdimCOMPILER_RT_ABI si_int
22276789Sdim__ctzdi2(di_int a)
23276789Sdim{
24276789Sdim    dwords x;
25276789Sdim    x.all = a;
26276789Sdim    const si_int f = -(x.s.low == 0);
27276789Sdim    return __builtin_ctz((x.s.high & f) | (x.s.low & ~f)) +
28276789Sdim              (f & ((si_int)(sizeof(si_int) * CHAR_BIT)));
29276789Sdim}
30