blob: 1c9508fd5524d8668a8b3b207e5baca93c3dbe61 [file] [log] [blame]
Edward O'Callaghandabf71f2009-08-05 19:06:50 +00001/* ===-- ctzti2.c - Implement __ctzti2 -------------------------------------===
2 *
3 * The LLVM Compiler Infrastructure
4 *
Howard Hinnant5b791f62010-11-16 22:13:33 +00005 * This file is dual licensed under the MIT and the University of Illinois Open
6 * Source Licenses. See LICENSE.TXT for details.
Edward O'Callaghandabf71f2009-08-05 19:06:50 +00007 *
8 * ===----------------------------------------------------------------------===
9 *
10 * This file implements __ctzti2 for the compiler_rt library.
11 *
12 * ===----------------------------------------------------------------------===
13 */
Daniel Dunbarfd089992009-06-26 16:47:03 +000014
15#if __x86_64
16
17#include "int_lib.h"
18
Edward O'Callaghandabf71f2009-08-05 19:06:50 +000019/* Returns: the number of trailing 0-bits */
Daniel Dunbarfd089992009-06-26 16:47:03 +000020
Edward O'Callaghandabf71f2009-08-05 19:06:50 +000021/* Precondition: a != 0 */
Daniel Dunbarfd089992009-06-26 16:47:03 +000022
23si_int
24__ctzti2(ti_int a)
25{
26 twords x;
27 x.all = a;
Edward O'Callaghan665671e2009-09-03 09:12:20 +000028 const di_int f = -(x.s.low == 0);
29 return __builtin_ctzll((x.s.high & f) | (x.s.low & ~f)) +
Daniel Dunbarfd089992009-06-26 16:47:03 +000030 ((si_int)f & ((si_int)(sizeof(di_int) * CHAR_BIT)));
31}
32
33#endif