llvm-project/compiler-rt/lib/ctzti2.c

34 lines
851 B
C

/* ===-- ctzti2.c - Implement __ctzti2 -------------------------------------===
*
* The LLVM Compiler Infrastructure
*
* This file is dual licensed under the MIT and the University of Illinois Open
* Source Licenses. See LICENSE.TXT for details.
*
* ===----------------------------------------------------------------------===
*
* This file implements __ctzti2 for the compiler_rt library.
*
* ===----------------------------------------------------------------------===
*/
#include "int_lib.h"
#if __x86_64
/* Returns: the number of trailing 0-bits */
/* Precondition: a != 0 */
si_int
__ctzti2(ti_int a)
{
twords x;
x.all = a;
const di_int f = -(x.s.low == 0);
return __builtin_ctzll((x.s.high & f) | (x.s.low & ~f)) +
((si_int)f & ((si_int)(sizeof(di_int) * CHAR_BIT)));
}
#endif