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 21 COMPILER_RT_ABI 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