Home | History | Annotate | Download | only in builtins
      1 /* ===-- ffsti2.c - Implement __ffsti2 -------------------------------------===
      2  *
      3  *                     The LLVM Compiler Infrastructure
      4  *
      5  * This file is dual licensed under the MIT and the University of Illinois Open
      6  * Source Licenses. See LICENSE.TXT for details.
      7  *
      8  * ===----------------------------------------------------------------------===
      9  *
     10  * This file implements __ffsti2 for the compiler_rt library.
     11  *
     12  * ===----------------------------------------------------------------------===
     13  */
     14 
     15 #include "int_lib.h"
     16 
     17 #ifdef CRT_HAS_128BIT
     18 
     19 /* Returns: the index of the least significant 1-bit in a, or
     20  * the value zero if a is zero. The least significant bit is index one.
     21  */
     22 
     23 COMPILER_RT_ABI si_int
     24 __ffsti2(ti_int a)
     25 {
     26     twords x;
     27     x.all = a;
     28     if (x.s.low == 0)
     29     {
     30         if (x.s.high == 0)
     31             return 0;
     32         return __builtin_ctzll(x.s.high) + (1 + sizeof(di_int) * CHAR_BIT);
     33     }
     34     return __builtin_ctzll(x.s.low) + 1;
     35 }
     36 
     37 #endif /* CRT_HAS_128BIT */
     38