1/* ===-- clzti2.c - Implement __clzti2 -------------------------------------=== 2 * 3 * The LLVM Compiler Infrastructure 4 * 5 * This file is distributed under the University of Illinois Open Source 6 * License. See LICENSE.TXT for details. 7 * 8 * ===----------------------------------------------------------------------=== 9 * 10 * This file implements __clzti2 for the compiler_rt library. 11 * 12 * ===----------------------------------------------------------------------=== 13 */ 14 15#if __x86_64 16 17#include "int_lib.h" 18 19/* Returns: the number of leading 0-bits */ 20 21/* Precondition: a != 0 */ 22 23si_int 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 /* __x86_64 */ 34