1*0a6a1f1dSLionel Sambuc /* ===-- ctzdi2.c - Implement __ctzdi2 -------------------------------------=== 2*0a6a1f1dSLionel Sambuc * 3*0a6a1f1dSLionel Sambuc * The LLVM Compiler Infrastructure 4*0a6a1f1dSLionel Sambuc * 5*0a6a1f1dSLionel Sambuc * This file is dual licensed under the MIT and the University of Illinois Open 6*0a6a1f1dSLionel Sambuc * Source Licenses. See LICENSE.TXT for details. 7*0a6a1f1dSLionel Sambuc * 8*0a6a1f1dSLionel Sambuc * ===----------------------------------------------------------------------=== 9*0a6a1f1dSLionel Sambuc * 10*0a6a1f1dSLionel Sambuc * This file implements __ctzdi2 for the compiler_rt library. 11*0a6a1f1dSLionel Sambuc * 12*0a6a1f1dSLionel Sambuc * ===----------------------------------------------------------------------=== 13*0a6a1f1dSLionel Sambuc */ 14*0a6a1f1dSLionel Sambuc 15*0a6a1f1dSLionel Sambuc #include "int_lib.h" 16*0a6a1f1dSLionel Sambuc 17*0a6a1f1dSLionel Sambuc /* Returns: the number of trailing 0-bits */ 18*0a6a1f1dSLionel Sambuc 19*0a6a1f1dSLionel Sambuc /* Precondition: a != 0 */ 20*0a6a1f1dSLionel Sambuc 21*0a6a1f1dSLionel Sambuc COMPILER_RT_ABI si_int __ctzdi2(di_int a)22*0a6a1f1dSLionel Sambuc__ctzdi2(di_int a) 23*0a6a1f1dSLionel Sambuc { 24*0a6a1f1dSLionel Sambuc dwords x; 25*0a6a1f1dSLionel Sambuc x.all = a; 26*0a6a1f1dSLionel Sambuc const si_int f = -(x.s.low == 0); 27*0a6a1f1dSLionel Sambuc return __builtin_ctz((x.s.high & f) | (x.s.low & ~f)) + 28*0a6a1f1dSLionel Sambuc (f & ((si_int)(sizeof(si_int) * CHAR_BIT))); 29*0a6a1f1dSLionel Sambuc } 30