1214152Sed/* ===-- ffsdi2.c - Implement __ffsdi2 -------------------------------------=== 2214152Sed * 3214152Sed * The LLVM Compiler Infrastructure 4214152Sed * 5222656Sed * This file is dual licensed under the MIT and the University of Illinois Open 6222656Sed * Source Licenses. See LICENSE.TXT for details. 7214152Sed * 8214152Sed * ===----------------------------------------------------------------------=== 9214152Sed * 10214152Sed * This file implements __ffsdi2 for the compiler_rt library. 11214152Sed * 12214152Sed * ===----------------------------------------------------------------------=== 13214152Sed */ 14214152Sed 15214152Sed#include "int_lib.h" 16214152Sed 17214152Sed/* Returns: the index of the least significant 1-bit in a, or 18214152Sed * the value zero if a is zero. The least significant bit is index one. 19214152Sed */ 20214152Sed 21222656SedCOMPILER_RT_ABI si_int 22214152Sed__ffsdi2(di_int a) 23214152Sed{ 24214152Sed dwords x; 25214152Sed x.all = a; 26214152Sed if (x.s.low == 0) 27214152Sed { 28214152Sed if (x.s.high == 0) 29214152Sed return 0; 30214152Sed return __builtin_ctz(x.s.high) + (1 + sizeof(si_int) * CHAR_BIT); 31214152Sed } 32214152Sed return __builtin_ctz(x.s.low) + 1; 33214152Sed} 34