1 //===-- clzti2.c - Implement __clzti2 -------------------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This file implements __clzti2 for the compiler_rt library.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #include "int_lib.h"
14 
15 #ifdef CRT_HAS_128BIT
16 
17 // Returns: the number of leading 0-bits
18 
19 // Precondition: a != 0
20 
__clzti2(ti_int a)21 COMPILER_RT_ABI si_int __clzti2(ti_int a) {
22   twords x;
23   x.all = a;
24   const di_int f = -(x.s.high == 0);
25   return __builtin_clzll((x.s.high & ~f) | (x.s.low & f)) +
26          ((si_int)f & ((si_int)(sizeof(di_int) * CHAR_BIT)));
27 }
28 
29 #endif // CRT_HAS_128BIT
30