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1 /* ===-- clzti2.c - Implement __clzti2 -------------------------------------===
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 __clzti2 for the compiler_rt library.
11  *
12  * ===----------------------------------------------------------------------===
13  */
14 
15 #include "int_lib.h"
16 
17 #ifdef CRT_HAS_128BIT
18 
19 /* Returns: the number of leading 0-bits */
20 
21 /* Precondition: a != 0 */
22 
23 COMPILER_RT_ABI si_int
__clzti2(ti_int a)24 __clzti2(ti_int a)
25 {
26     twords x;
27     x.all = a;
28     const di_int f = -(x.s.high == 0);
29     return __builtin_clzll((x.s.high & ~f) | (x.s.low & f)) +
30            ((si_int)f & ((si_int)(sizeof(di_int) * CHAR_BIT)));
31 }
32 
33 #endif /* CRT_HAS_128BIT */
34